WO2014049974A1 - Dispositifs électroniques destinés à la signalisation de multiples paramètres tampons initiaux - Google Patents

Dispositifs électroniques destinés à la signalisation de multiples paramètres tampons initiaux Download PDF

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Publication number
WO2014049974A1
WO2014049974A1 PCT/JP2013/005248 JP2013005248W WO2014049974A1 WO 2014049974 A1 WO2014049974 A1 WO 2014049974A1 JP 2013005248 W JP2013005248 W JP 2013005248W WO 2014049974 A1 WO2014049974 A1 WO 2014049974A1
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Prior art keywords
cpb
picture
electronic device
initial
removal
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PCT/JP2013/005248
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English (en)
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Sachin G. Deshpande
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Sharp Kabushiki Kaisha
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/42—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals characterised by implementation details or hardware specially adapted for video compression or decompression, e.g. dedicated software implementation
    • H04N19/423—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals characterised by implementation details or hardware specially adapted for video compression or decompression, e.g. dedicated software implementation characterised by memory arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/44—Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/70—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals characterised by syntax aspects related to video coding, e.g. related to compression standards

Definitions

  • the present disclosure relates generally to electronic devices. More specifically, the present disclosure relates to electronic devices for signaling multiple initial buffering parameters for random access.
  • Electronic devices have become smaller and more powerful in order to meet consumer needs and to improve portability and convenience. Consumers have become dependent upon electronic devices and have come to expect increased functionality. Some examples of electronic devices include desktop computers, laptop computers, cellular phones, smart phones, media players, integrated circuits, etc.
  • Some electronic devices are used for processing and displaying digital media. For example, portable electronic devices now allow for digital media to be consumed at almost any location where a consumer may be. Furthermore, some electronic devices may provide download or streaming of digital media content for the use and enjoyment of a consumer.
  • An aspect of the invention provides an electronic device for sending a message, including:
  • instructions stored in the memory the instructions being executable to:
  • RAP random access point
  • BLA broken link access
  • DLP decodable leading pictures
  • NAL network access layer
  • Another aspect of the invention provides an electronic device for buffering a bitstream, including:
  • instructions stored in the memory the instructions being executable to:
  • RAP random access point
  • CPB coded picture buffer
  • Figure 1 is a block diagram illustrating an example of one or more electronic devices in which systems and methods for sending a message and buffering a bitstream may be implemented.
  • Figure 2 is a flow diagram illustrating one configuration of a method for sending a message.
  • Figure 3 is a flow diagram illustrating a more specific configuration of a method for sending a message.
  • Figure 4 is a flow diagram illustrating one configuration of a method for buffering a bitstream.
  • Figure 5 is a flow diagram illustrating a more specific configuration of a method for buffering a bitstream.
  • Figure 6 is a block diagram illustrating one configuration of an encoder on an electronic device.
  • Figure 7 is a block diagram illustrating one configuration of a decoder on an electronic device.
  • Figure 8 illustrates various components that may be utilized in a transmitting electronic device.
  • Figure 9 is a block diagram illustrating various components that may be utilized in a receiving electronic device.
  • Figure 10 is a block diagram illustrating one configuration of an electronic device in which systems and methods for sending a message may be implemented.
  • Figure 11 is a block diagram illustrating one configuration of an electronic device in which systems and methods for buffering a bitstream may be implemented.
  • Figure 12 is a flow diagram illustrating another configuration of a method for sending a message.
  • Figure 13 is a flow diagram illustrating another more specific configuration of a method for sending a message.
  • Figure 14 is a flow diagram illustrating another configuration of a method for buffering a bitstream.
  • Figure 15 is a flow diagram illustrating another more specific configuration of a method for buffering a bitstream.
  • Figure 16 is a flow diagram illustrating yet another configuration of a method for buffering a bitstream.
  • the electronic device includes a processor and instructions stored in memory that is in electronic communication with the processor.
  • the electronic device determines whether a picture is a random access point (RAP) picture.
  • the electronic device also determines whether the picture is associated with a broken link access (BLA) with decodable leading pictures (DLP) network access layer (NAL) unit type if the picture is a RAP picture.
  • the electronic device further generates a message including a RAP coded picture buffer (CPB) parameter flag and an initial additional CPB removal delay parameter if the BLA with DLP NAL unit type is present.
  • the electronic device additionally sends the message.
  • RAP random access point
  • BLA broken link access
  • DLP decodable leading pictures
  • NAL network access layer
  • the electronic device may determine whether the RAP picture is a BLA picture.
  • the initial additional CPB removal delay parameter may be an initial_alt1_cpb_removal_delay[ SchedSelIdx ], SchedSelIdx may be an index variable.
  • the RAP CPB parameter flag may be a rap_cpb_params_present_flag.
  • the RAP CPB parameter flag may be a new parameter flag.
  • the electronic device may generate an initial additional CPB removal delay offset parameter if the BLA with DLP NAL unit type is present.
  • the BLA with DLP NAL unit type may indicate that no associated tagged for discard (TFD) pictures are present in the bitstream associated with the BLA picture.
  • the BLA with DLP NAL unit type may be BLA_W_DLP.
  • the message may be a buffering period supplemental enhancement information (SEI) message.
  • SEI buffering period supplemental enhancement information
  • the electronic device includes a processor and instructions stored in memory that is in electronic communication with the processor.
  • the electronic device receives a message.
  • the electronic device also determines whether a RAP CPB parameter flag indicates an initial additional CPB removal delay parameter.
  • the electronic device further performs an operation based on the initial additional CPB removal delay parameter.
  • the initial additional CPB removal delay parameter may be an initial_alt1_cpb_removal_delay[ SchedSelIdx ].
  • SchedSelIdx may be an index variable.
  • the RAP CPB parameter flag may be a rap_cpb_params_present_flag.
  • Receiving the message may include receiving a RAP CPB parameter flag, an initial additional CPB removal delay parameter and an initial additional CPB removal delay offset parameter.
  • the electronic device may obtain a BLA with DLP NAL unit type associated with a RAP picture from the message.
  • the BLA with DLP NAL unit type may indicate that no associated TFD pictures are present in the bitstream associated with the BLA picture.
  • the BLA with DLP NAL unit type may be BLA_W_DLP.
  • the message may be a buffering period SEI message.
  • a method for sending a message by an electronic device is also described.
  • the electronic device determines whether a picture is a RAP picture.
  • the electronic device also determines whether the picture is associated with a BLA with DLP NAL unit type if the picture is a RAP picture.
  • a message is generated including a RAP CPB parameter flag and an initial additional CPB removal delay parameter if the BLA with DLP NAL unit type is present. The message is sent.
  • a method for buffering a bitstream by an electronic device is also described.
  • a message is received.
  • the electronic device determines whether a RAP CPB parameter flag indicates an initial additional CPB removal delay parameter.
  • An operation is performed based on the initial additional CPB removal delay parameter.
  • the systems and methods disclosed herein describe electronic devices for sending a message and buffering a bitstream.
  • the systems and methods disclosed herein describe buffering for bitstreams starting with a clean random access (CRA) picture.
  • the systems and methods disclosed herein may describe hypothetical reference decoder (HRD) buffering for bitstreams starting with a CRA picture.
  • HRD hypothetical reference decoder
  • the systems and methods disclosed herein describe modification to a buffering period supplemental enhancement information (SEI) message and to an HRD for bitstreams starting with CRA pictures when leading pictures are present.
  • SEI Supplemental Enhancement
  • the systems and methods disclosed herein (e.g., the HRD modification) may provide a benefit of reducing initial buffering latency when starting playback at a CRA picture at a random access point.
  • the random access point may be any point in a stream of data (e.g., bitstream) where decoding of the bitstream does not require access to any point in a bitstream preceding the random access point to decode a current picture and all pictures subsequent to said current picture in output order.
  • the systems and methods disclosed herein may provide a benefit that the HRD will not underflow when one or more leading pictures after a CRA picture are discarded.
  • an HRD may be physically implemented.
  • HRD may be used to describe an implementation of an actual decoder.
  • an HRD may be implemented in order to determine whether a bitstream conforms to High Efficiency Video Coding (HEVC) specifications.
  • HEVC High Efficiency Video Coding
  • an HRD may be used to determine whether Type I bitstreams and Type II bitstreams conform to HEVC specifications.
  • a Type I bitstream may contain only Video Coding Layer (VCL) network access layer (NAL) units and filler data NAL units.
  • a Type II bitstream may contain additional other NAL units and syntax elements.
  • JCTVC-H0496 proposes bitstreams starting with CRA pictures. This functionality has been incorporated into the High Efficiency Video Coding (HEVC) Committee Draft (JCTVC-J1003).
  • HEVC High Efficiency Video Coding
  • buffering period SEI message semantics in accordance with the systems and methods disclosed herein are given as follows.
  • additional detail regarding the semantics of the modified syntax elements are given as follows.
  • a 'cra_leadingpict_discard_flag' equal to 1 indicates the presence of 'initial_cra_cpb_removal_delay[ SchedSelIdx ]' and 'initial_cra_cpb_removal_delay_offset[ SchedSelIdx ]' syntax elements.
  • a 'cra_leadingpict_discard_flag' indicates the absence of the 'initial_cra_cpb_removal_delay[ SchedSelIdx ] and initial_cra_cpb_removal_delay_offset[ SchedSelIdx ]' syntax elements. This flag may not be 1 when the associated or corresponding picture is not a CRA picture.
  • SchedSelIdx ]' specifies the delay for the SchedSelIdx-th coded picture buffer (CPB) between the time of arrival in the CPB of the first bit of the coded data associated with the access unit associated with the buffering period SEI message and the time of removal from the CPB of the coded data associated with the same access unit, for the first buffering period after HRD initialization at a starting CRA picture when access units containing leading pictures associated with the starting CRA picture are discarded.
  • the syntax element may have a length in bits given by initial_cpb_removal_delay_length_minus1 + 1. In some configurations, this syntax element is in units of a 90 kilohertz (kHz) clock.
  • 'initial_cra_cpb_removal_delay[ SchedSelIdx ]' may not be equal to 0. Furthermore, it may not exceed 90000 * ( CpbSize[ SchedSelIdx ] / BitRate[ SchedSelIdx ] ), which is the time equivalent of the CPB size in 90 kHz clock units.
  • 'initial_cra_cpb_removal_delay_offset [ SchedSelIdx ]' may be used for the SchedSelIdx-th CPB in combination with the cpb_removal_delay to specify the initial delivery time of coded access units to the CPB for a bitstream starting with a CRA picture when access units containing leading pictures associated with the starting CRA picture are discarded.
  • 'initial_cra_cpb_removal_delay_offset[ SchedSelIdx ]' is in units of a 90 kHz clock.
  • the 'initial_cra_cpb_removal_delay_offset[ SchedSelIdx ]' syntax element may be a fixed length code whose length in bits is given by initial_cpb_removal_delay_length_minus1 + 1. This syntax element may not be used by decoders and may be needed only for the delivery scheduler (e.g., a hypothetical stream scheduler (HSS) specified in Annex C of JCTVC-H1003).
  • HSS hypothetical stream scheduler
  • the sum of 'initial_cra_cpb_removal_delay[ SchedSelIdx ]' and 'initial_cra_cpb_removal_delay_offset[ SchedSelIdx ]' may be constant for each value of SchedSelIdx.
  • SchedSelIdx may be an index variable.
  • payloadSize may refer to bytes of data.
  • seq_parameter_set_id specifies the sequence parameter set that contains the sequence HRD attributes.
  • the value of seq_parameter_set_id may be equal to the value of seq_parameter_set_id in the picture parameter set referenced by the primary coded picture associated with the buffering period SEI message.
  • the value of seq_parameter_set_id may be in the range of 0 to 31, inclusive.
  • initial_cpb_removal_delay[ SchedSelIdx ] may specify the initial CPB removal delays for the SchedSelIdx-th CPB.
  • the syntax element may have a length in bits given by initial_cpb_removal_delay_length_minus1 + 1 and may be in units of a 90 kHz clock.
  • initial_cpb_removal_delay[ SchedSelIdx ] may not be equal to 0 and may not exceed 90000 * ( CpbSize[ SchedSelIdx ] / BitRate[ SchedSelIdx ] ), the time-equivalent of the CPB size in 90 kHz clock units.
  • initial_cpb_removal_delay_offset[ SchedSelIdx ] may be used for the SchedSelIdx-th CPB to specify the initial delivery time of coded data units to the CPB.
  • the syntax elements may have a length in bits given by initial_cpb_removal_delay_length_minus1 + 1 and may be in units of a 90 kHz clock. These syntax elements may not be used by decoders and may be needed only for the delivery scheduler (HSS) specified in Annex C of HEVC specifications.
  • initial_cpb_removal_delay[ SchedSelIdx ] and initial_cpb_removal_delay_offset[ SchedSelIdx ] may be constant for each value of SchedSelIdx.
  • the sum of initial_alt_cpb_removal_delay[ SchedSelIdx ] and initial_alt_cpb_removal_delay_offset[ SchedSelIdx ] may be constant for each value of SchedSelIdx.
  • cpb_cnt_minus1 plus 1 specifies the number of alternative CPB specifications in the bitstream.
  • the value of cpb_cnt_minus1 may be in the range of 0 to 31, inclusive.
  • cpb_cnt_minus1 may be equal to 0.
  • cpb_cnt_minus1 is not present, it may be inferred to be equal to 0.
  • a nal_hrd_parameters_present_flag 1 specifies that NAL HRD parameters (pertaining to Type II bitstream conformance) are present.
  • a nal_hrd_parameters_present_flag 0 specifies that NAL HRD parameters are not present. It should be noted that when the nal_hrd_parameters_present_flag is equal to 0, the conformance of the bitstream cannot be verified without provision of the NAL HRD parameters, including the NAL sequence HRD parameter information and all buffering period and picture timing SEI messages, by some means not specified in HEVC specifications.
  • NalHrdBpPresentFlag may be derived as follows. If any of the following is true, the value of NalHrdBpPresentFlag may be set equal to 1: nal_hrd_parameters_present_flag is present in the bitstream and is equal to 1 or the need for presence of buffering periods for NAL HRD operation to be present in the bitstream in buffering period SEI messages is determined by the application, by some means not specified in HEVC specifications. Otherwise, the value of NalHrdBpPresentFlag may be set equal to 0.
  • a vcl_hrd_parameters_present_flag 1 specifies that VCL HRD parameters (pertaining to all bitstream conformance) are present.
  • a vcl_hrd_parameters_present_flag 0 specifies that VCL HRD parameters are not present. It should be noted that when the vcl_hrd_parameters_present_flag is equal to 0, the conformance of the bitstream cannot be verified without provision of the VCL HRD parameters and all buffering period and picture timing SEI messages, by some means not specified in HEVC specifications. When the vcl_hrd_parameters_present_flag is equal to 1, VCL HRD parameters (from subclauses E.1.2 and E.2.2 of HEVC specifications, for example) immediately follow the flag.
  • variable VclHrdBpPresentFlag may be derived as follows. If any of the following is true, the value of VclHrdBpPresentFlag may be set equal to 1: the vcl_hrd_parameters_present_flag is present in the bitstream and is equal to 1 or the need for presence of buffering periods for VCL HRD operation to be present in the bitstream in buffering period SEI messages is determined by the application, by some means not specified in HEVC specifications. Otherwise, the value of VclHrdBpPresentFlag may be set equal to 0.
  • the timing of bitstream arrival may be determined as follows.
  • the HRD may be initialized at any one of the buffering period SEI messages. Prior to initialization, the CPB may be empty. It should be noted that after initialization, the HRD may not be initialized again by subsequent buffering period SEI messages.
  • the access unit that is associated with the buffering period SEI message that initializes the CPB may be referred to as access unit 0. All other access units may be referred to as access unit n, with n being incremented by 1 for the next access unit in decoding order.
  • use_initial_cpb_removal_delay[ SchedSelIdx ] may be set to the value of initial_cra_cpb_removal_delay[ SchedSelIdx ]. Otherwise, the value of use_initial_cpb_removal_delay[ SchedSelIdx ] may be set to the value of initial_cpb_removal_delay[ SchedSelIdx ].
  • the time at which the first bit of access unit n begins to enter the CPB may be referred to as the initial arrival time t ai ( n ).
  • use_initial_cpb_removal_delay[ SchedSelIdx ] may be specified as described above based on the buffering period SEI message associated with access unit n.
  • b( n ) may be the size in bits of access unit n, counting the bits of the Type I bitstream for Type I conformance or the bits of the Type II bitstream for Type II conformance.
  • the values of SchedSelIdx, BitRate[ SchedSelIdx ], and CpbSize[ SchedSelIdx ] may be constrained as follows. If access unit n and access unit n - 1 are part of different coded video sequences and the content of the active sequence parameter sets of the two coded video sequences differ, the HSS may select a value SchedSelIdx1 of SchedSelIdx from among the values of SchedSelIdx provided for the coded video sequence containing access unit n that results in a BitRate[ SchedSelIdx1 ] or CpbSize[ SchedSelIdx1 ] for the second of the two coded video sequences (which contains access unit n - 1) that differs from the value of BitRate[ SchedSelIdx0 ] or CpbSize[ SchedSelIdx0 ] for the value SchedSelIdx0
  • bitRate[ SchedSelIdx ] or CpbSize[ SchedSelIdx ] may come into effect at time t ai ( n ).
  • the variable CpbSize[ SchedSelIdx ] may come into effect as follows. If the new value of CpbSize[ SchedSelIdx ] exceeds the old CPB size, it may come into effect at time t ai ( n ). Otherwise, the new value of CpbSize[ SchedSelIdx ] may come into effect at the time t r ( n ).
  • the timing of coded picture removal may be implemented as follows. It may be assumed that the nominal CPB removal time and the CPB removal time of a coded picture are determined (e.g., calculated) immediately after the previous coded picture is removed from the CPB, or, for access unit 0, when the HRD is initialized.
  • t r,n ( n b ) is the nominal removal time of the first picture of the previous buffering period and cpb_removal_delay( n ) is specified in the picture timing SEI message associated with access unit n.
  • n b may be set equal to n at the removal time t r,n ( n ) of access unit n.
  • the exact number of bits in the CPB at the removal time of each picture may depend on which buffering period SEI message is selected to initialize the HRD. Encoders may take this into account to ensure that all specified constraints are obeyed regardless of which buffering period SEI message is selected to initialize the HRD, as the HRD may be initialized at any one of the buffering period SEI messages.
  • the systems and methods disclosed herein provide syntax and semantics that modify a buffering period SEI message for bitstreams starting with CRA pictures when leading pictures are present.
  • the systems and methods disclosed herein may be applied to HEVC specifications.
  • the systems and methods disclosed herein may also describe electronic devices for signaling multiple initial buffering parameters for random access.
  • the systems and methods disclosed herein describe starting playback at a random access point (RAP) picture.
  • the systems and methods disclosed herein may describe hypothetical reference decoder (HRD) buffering for signaling multiple initial buffering parameters.
  • HRD hypothetical reference decoder
  • the systems and methods disclosed herein describe modification to a buffering period supplemental enhancement information (SEI) message and to an HRD for signaling multiple initial buffering parameters.
  • SEI buffering period supplemental enhancement information
  • the systems and methods disclosed herein (e.g., the HRD modification) may provide a benefit of reducing initial buffering latency when starting playback at a RAP picture.
  • the systems and methods disclosed herein may provide a benefit that the HRD will not underflow or overflow when starting playback at a RAP picture.
  • buffering period SEI message semantics in accordance with the systems and methods disclosed herein are given as follows.
  • additional detail regarding the semantics of the modified syntax elements are given as follows.
  • An 'initial_alt1_cpb_removal_delay' [ SchedSelIdx ] specifies the initial coded picture buffer (CPB) removal delay for the SchedSelIdx-th CPB.
  • initial_alt1_cpb_removal_delay[ SchedSelIdx ] has a length in bits given by initial_cpb_removal_delay_length_minus1 + 1, and is in units of a 90 kHz clock.
  • initial_alt1_cpb_removal_delay[ SchedSelIdx ] may not be equal to 0 and may be less than or equal to 90000 * ( CpbSize[ SchedSelIdx ] / BitRate[ SchedSelIdx ] ), the time-equivalent of the CPB size in 90 kHz clock units.
  • SchedSelIdx may be an index variable.
  • the initial CPB removal delay parameter information may be used by the CPB in defining constraints on the timing of bitstream arrival.
  • the initial CPB removal delay parameter information may also specify the timing of decoding unit removal and decoding the decoding unit.
  • the initial CPB removal delay may define the amount of initial buffering that occurs in the HRD before playback of media is started.
  • initial_cpb_removal_delay[ SchedSelIdx ] and initial_alt_cpb_removal_delay[ SchedSelIdx ] may have the same syntax element values as initial_alt1_cpb_removal_delay[ SchedSelIdx ].
  • initial_cpb_removal_delay[ SchedSelIdx ] and initial_alt_cpb_removal_delay[ SchedSelIdx ] may all specify the initial CPB removal delay for the SchedSelIdx-th CPB.
  • initial_cpb_removal_delay[ SchedSelIdx ] and initial_alt_cpb_removal_delay[ SchedSelIdx ] may provide similar information. However, the information provided may vary according to the bitstream. For example initial_cpb_removal_delay[ SchedSelIdx ] may provide information that may be used when the entire bitstream is transmitted and/or played back starting at a RAP picture without discarding any subsequent NAL units.
  • initial_alt_cpb_removal_delay[ SchedSelIdx ] may provide information that may be used when the entire bitstream is transmitted and/or played back starting at a RAP picture, but with discarding subsequent NAL units that have leading pictures associated with that RAP picture.
  • initial_alt1_cpb_removal_delay[ SchedSelIdx ] may provide information that may be used when the entire bitstream is transmitted and/or played back starting at a RAP picture, but with discarding subsequent NAL units which are tagged for discard (TFD) (e.g., TFD NAL units) associated with that RAP picture, for example.
  • TFD tagged for discard
  • the bitstream may have decodable leading pictures present in the bitstream.
  • rap_cpb_params_present_flag 1 specifies the presence of the initial_alt_cpb_removal_delay[ SchedSelIdx ] and initial_alt_cpb_removal_delay_offset[ SchedSelIdx ] syntax elements.
  • the value of rap_cpb_params_present_flag may be inferred to be equal to 0.
  • the value of rap_cpb_params_present_flag may be equal to 0.
  • rap_cpb_params_present_flag 1 also indicates the presence of the initial_alt1_cpb_removal_delay[ SchedSelIdx ] and initial_alt1_cpb_removal_delay_offset[ SchedSelIdx ] syntax elements.
  • initial_cpb_removal_delay[ SchedSelIdx ] and initial_cpb_removal_delay_offset[ SchedSelIdx ] may be constant for each value of SchedSelIdx
  • initial_alt_cpb_removal_delay[ SchedSelIdx ] and initial_alt_cpb_removal_delay_offset[ SchedSelIdx ] may be constant for each value of SchedSelIdx.
  • initial_alt1_cpb_removal_delay[ SchedSelIdx ] and initial_alt1_cpb_removal_delay_offset[ SchedSelIdx ] may be constant for each value of SchedSelIdx.
  • Other parameter elements may be the same as corresponding syntax elements described in connection with Table 1. For example, seq_parameter_set_id, NalHrdBpPresentFlag and VclHrdBpPresentFlag may be the same as defined above.
  • a buffering period SEI message can be associated with any access unit in the bitstream. Also, when NalHrdBpPresentFlag or VclHrdBpPresentFlag is equal to 1, a buffering period SEI message may be associated with each RAP access unit and with each access unit associated with a recovery point SEI message. It should be noted that for some applications, the frequent presence of a buffering period SEI message may be desirable.
  • the SEI NAL unit may precede, in decoding order, the first VCL NAL unit in the access unit.
  • a "buffering period" is specified as the set of access units between two instances of the buffering period SEI message in decoding order.
  • the HRD may be initialized at any one of the buffering period SEI messages. Prior to initialization, the CPB may be empty. In some instances, after initialization, the HRD may not be initialized again by subsequent buffering period SEI messages.
  • Each access unit may be referred to as access unit n, where the number n identifies the particular access unit.
  • the access unit that is associated with the buffering period SEI message that initializes the CPB may be referred to as access unit 0.
  • the value of n may be incremented by 1 for each subsequent access unit in decoding order.
  • Each decoding unit may be referred to as decoding unit m, where the number m identifies the particular decoding unit.
  • the first decoding unit in decoding order in access unit 0 may be referred to as decoding unit 0.
  • the value of m may be incremented by 1 for each subsequent decoding unit in decoding order.
  • InitCpbRemovalDelay[ SchedSelIdx ] and InitCpbRemovalDelayOffset[ SchedSelIdx ] may be set as follows. If InitCpbRemovalDelay[ SchedSelIdx ] is set to the value of the corresponding initial_alt_cpb_removal_delay[ SchedSelIdx ] of the associated buffering period SEI message or if InitCpbRemovalDelayOffset[ SchedSelIdx ] is set to the value of the corresponding initial_alt_cpb_removal_delay_offset[ SchedSelIdx ] of the associated buffering period SEI message, then access unit 0 may be a BLA access unit for which the coded picture has nal_unit_type equal to BLA_N_LP, and the value of rap_cpb_params_present_flag of the associated buffering period SEI message
  • the access unit 0 is a BLA access unit for which the coded picture has nal_unit_type equal to BLA_N_LP
  • the value of rap_cpb_params_present_flag of the associated buffering period SEI message may be equal to 1.
  • SubPicCpbFlag equals to 1
  • InitCpbRemovalDelay[ SchedSelIdx ] may be set to the value of the corresponding initial_alt_cpb_removal_delay[ SchedSelIdx ] of the associated buffering period SEI message.
  • SubPicCpbFlag if SubPicCpbFlag equals to 1, then InitCpbRemovalDelayOffset[ SchedSelIdx ] may be set to the value of the corresponding initial_alt_cpb_removal_delay_offset[ SchedSelIdx ] of the associated buffering period SEI message. In addition, SubPicCpbFlag may be equal to 1.
  • access unit 0 may be a BLA access unit for which the coded picture has nal_unit_type equal to BLA_W_DLP, and the value of rap_cpb_params_present_flag of the associated buffering period SEI message may be equal to 1.
  • the access unit 0 is a BLA access unit for which the coded picture has nal_unit_type equal to BLA_W_DLP
  • the value of rap_cpb_params_present_flag of the associated buffering period SEI message may be equal to 1.
  • SubPicCpbFlag equals to 1
  • InitCpbRemovalDelay[ SchedSelIdx ] may be set to the value of the corresponding initial_alt1_cpb_removal_delay[ SchedSelIdx ] of the associated buffering period SEI message.
  • InitCpbRemovalDelayOffset[ SchedSelIdx ] may be set to the value of the corresponding initial_alt1_cpb_removal_delay_offset[ SchedSelIdx ] of the associated buffering period SEI message.
  • InitCpbRemovalDelay[ SchedSelIdx ] and InitCpbRemovalDelayOffset[ SchedSelIdx ] may be set to the values of the corresponding initial_cpb_removal_delay[ SchedSelIdx ] and initial_cpb_removal_delay_offset[ SchedSelIdx ], respectively, of the associated buffering period SEI message.
  • a random access point may be any point in a stream of data (e.g., bitstream) where decoding of the bitstream does not require access to any point in a bitstream preceding the random access point to decode a current picture and all pictures subsequent to said current picture in output order.
  • a RAP picture may include only I slices and may be a broken link access (BLA) picture, a clean random access (CRA) picture or an instantaneous decoding refresh (IDR) picture.
  • the first picture in the bitstream must be a RAP picture.
  • a broken link access (BLA) picture is one type of RAP picture.
  • a BLA picture may include only I slices, and may be the first picture in the bitstream in decoding order, or may appear later in the bitstream.
  • Each BLA picture begins a new coded video sequence, and has the same effect on the decoding process as an IDR picture.
  • a BLA picture may include syntax elements that, if it had been CRA picture instead, would specify a non-empty reference picture set. When a BLA picture is encountered in a bitstream, these syntax elements are ignored and the reference picture set is instead initialized as an empty set.
  • a clean random access (CRA) picture is one type of RAP picture.
  • a CRA picture may include only I slices, and may be the first picture in the bitstream in decoding order, or may appear later in the bitstream.
  • a CRA picture may have associated decodable leading pictures (DLP) and tagged for discard (TFD) pictures.
  • DLP decodable leading pictures
  • TFD tagged for discard
  • An instantaneous decoding refresh (IDR) picture is a type of RAP picture.
  • An IDR picture may include only I slices, and may be the first picture in the bitstream in decoding order, or may appear later in the bitstream.
  • Each IDR picture is the first picture of a coded video sequence in decoding order.
  • a decodable leading picture is a leading picture.
  • a DLP is not used as a reference picture for the decoding process of trailing pictures of the same associated RAP picture.
  • Tagged for discard (TFD) pictures are leading pictures of an associated BLA or CRA picture.
  • a leading picture is a picture that precedes the associated RAP picture in output order.
  • a trailing picture is a picture that follows the associated RAP picture in output order.
  • a buffering period may be specified as a set of access units between two instances of the buffering period SEI message in decoding order.
  • Supplemental enhancement information (SEI) messages may include information that is not necessary to decode the samples of coded pictures from VCL NAL units. SEI messages may assist in procedures related to decoding, display or other purposes. However, SEI messages may not be required for constructing luma or chroma samples by a decoding process. Conforming decoders may not be required to process this information for output order conformance to HEVC specifications (Annex C of HEVC specifications includes specifications for conformance, for example). Some SEI message information may be required to check bitstream conformance and for output timing decoder conformance.
  • a buffering period SEI message may be an SEI message related to a buffering period. It may define syntax and semantics which define bitstream arrival timing and coded picture removal timing.
  • a picture parameter set is a syntax structure containing syntax elements that apply to zero or more entire coded pictures as determined by the pic_parameter_set_id syntax element found in each slice header.
  • pic_parameter_set_id may identify the picture parameter set that is referred to in the slice header.
  • the value of pic_parameter_set_id may be in the range of 0 to 255, inclusive.
  • a coded picture buffer may be a first-in first-out buffer containing access units in decoding order specified in a hypothetical reference decoder (HRD).
  • An access unit may be a set of network access layer (NAL) units that are consecutive in decoding order and contain exactly one coded picture. In addition to the coded slice NAL units of the coded picture, the access unit may also contain other NAL units not containing slices of the coded picture. The decoding of an access unit always results in a decoded picture.
  • a NAL unit may be a syntax structure containing an indication of the type of data to follow and bytes containing that data in the form of a raw byte sequence payload interspersed as necessary with emulation prevention bytes.
  • Figure 1 is a block diagram illustrating an example of one or more electronic devices 102 in which systems and methods for sending a message and buffering a bitstream may be implemented.
  • electronic device A 102a and electronic device B 102b are illustrated.
  • one or more of the features and functionality described in relation to electronic device A 102a and electronic device B 102b may be combined into a single electronic device in some configurations.
  • Electronic device A 102a includes an encoder 104.
  • the encoder 104 includes a message generation module 108.
  • Each of the elements included within electronic device A 102a e.g., the encoder 104 and the message generation module 108, may be implemented in hardware, software or a combination of both.
  • Electronic device A 102a may obtain one or more input pictures 106.
  • the input picture(s) 106 may be captured on electronic device A 102a using an image sensor, may be retrieved from memory and/or may be received from another electronic device.
  • the encoder 104 may encode the input picture(s) 106 to produce encoded data.
  • the encoder 104 may encode a series of input pictures 106 (e.g., video).
  • the encoder 104 may be an HEVC encoder.
  • the encoded data may be digital data (e.g., part of a bitstream 114).
  • the encoder 104 may generate overhead signaling based on the input signal.
  • the message generation module 108 may generate one or more messages. For example, the message generation module 108 may generate one or more SEI messages or other messages.
  • the electronic device 102 e.g., the encoder 104 may determine whether a first picture (e.g., an encoded picture) is a CRA picture and whether a leading picture is present if the first picture is a CRA picture.
  • the message generation module 108 may generate a message (e.g., buffering period SEI message or other message) that includes one or more of a CRA leading picture discard flag (e.g., cra_leadingpict_discard_flag), an initial CRA CPB removal delay parameter (e.g., initial_cra_cpb_removal_delay[ SchedSelIdx ]) and an initial CRA CPB removal delay offset parameter (e.g., initial_cra_cpb_removal_delay_offset[ SchedSelIdx ]).
  • a message e.g., buffering period SEI message or other message
  • a message e.g., buffering period SEI message or other message
  • a message e.g., buffering period SEI message or other message
  • a message e.g., buffering period SEI message or other message
  • a message e.g., buffering period SEI message or other message
  • a message e
  • the electronic device 102 may determine whether a picture (e.g., an encoded picture) is a random access point (RAP) and whether the picture is associated with a broken link access (BLA) with decodable leading pictures (DLP) network access layer (NAL) unit type if the picture is a RAP picture.
  • BLA broken link access
  • DLP decodable leading pictures
  • NAL network access layer
  • the BLA with DLP NAL unit type may indicate that no associated tagged for discard (TFD) pictures are present in the bitstream.
  • the message generation module 108 may generate a message (e.g., buffering period SEI message or other message) that includes one or more of a RAP CPB flag (e.g., rap_cpb_params_present_flag), an initial additional CPB removal delay parameter (e.g., initial_alt1_cpb_removal_delay[ SchedSelIdx ]) and an initial additional CPB removal delay offset parameter (e.g., initial_alt1_cpb_removal_delay_offset[ SchedSelIdx ]).
  • a message e.g., buffering period SEI message or other message
  • a message e.g., buffering period SEI message or other message
  • a message e.g., buffering period SEI message or other message
  • a message e.g., buffering period SEI message or other message
  • a message e.g., buffering period SEI message or other message
  • a message
  • electronic device A 102a may send the message to electronic device B 102b as part of the bitstream 114.
  • electronic device A 102a may send the message to electronic device B 102b by a separate transmission 110.
  • the separate transmission may not be part of the bitstream 114.
  • a buffering period SEI message or other message may be sent using some out-of-band mechanism.
  • the other message may include one or more of the features of a buffering period SEI message described above.
  • the other message in one or more aspects, may be utilized similarly to the SEI message described above.
  • the encoder 104 may produce a bitstream 114.
  • the bitstream 114 may include encoded picture data based on the input picture(s) 106.
  • the bitstream 114 may also include overhead data, such as a buffering period SEI message or other message, slice header(s), PPS(s), etc.
  • the bitstream 114 may include one or more encoded pictures.
  • the bitstream 114 may include one or more encoded pictures with corresponding overhead data (e.g., a buffering period SEI message or other message).
  • the bitstream 114 may be provided to a decoder 112.
  • the bitstream 114 may be transmitted to electronic device B 102b using a wired or wireless link. In some cases, this may be done over a network, such as the Internet or a Local Area Network (LAN).
  • the decoder 112 may be implemented on electronic device B 102b separately from the encoder 104 on electronic device A 102a. However, it should be noted that the encoder 104 and decoder 112 may be implemented on the same electronic device in some configurations. In an implementation where the encoder 104 and decoder 112 are implemented on the same electronic device, for instance, the bitstream 114 may be provided over a bus to the decoder 112 or stored in memory for retrieval by the decoder 112.
  • the decoder 112 may be implemented in hardware, software or a combination of both.
  • the decoder 112 may be an HEVC decoder.
  • the decoder 112 may receive (e.g., obtain) the bitstream 114.
  • the decoder 112 may generate one or more decoded pictures 118 based on the bitstream 114.
  • the decoded picture(s) 118 may be displayed, played back, stored in memory and/or transmitted to another device, etc.
  • the decoder 112 may include a CPB 120.
  • the CPB 120 may temporarily store encoded pictures.
  • the CPB 120 may store encoded pictures until a removal time.
  • one or more of an arrival time (of bitstream data, for example) and a removal time (of a coded picture, for example) may be determined by the decoder 112 based on a message (e.g., buffering period SEI message or other message).
  • the decoder 112 may receive a message (e.g., buffering period SEI message or other message). The decoder 112 may also determine whether a first access unit is a CRA access unit, whether leading pictures are not present and whether a CRA leading picture discard flag indicates discard. In some cases, if a first access unit is a CRA access unit and if leading pictures are not present, the access unit may be marked as BLA_N_LP access unit.
  • a first access unit is a CRA access unit
  • the decoder 112 may set an initial removal delay variable to an initial CRA CPB removal delay parameter and may remove the first access unit (e.g., encoded picture) from the CPB based on the CRA CPB removal delay parameter.
  • the CPB 120 may perform one or more of the procedures described in connection with Figure 4 and Figure 5 below.
  • the decoder 112 may receive a message (e.g., buffering period SEI message or other message). The decoder 112 may also determine whether a RAP CPB parameter flag indicates an initial additional CPB removal delay parameter. If the RAP CPB parameter flag indicates an initial additional CPB removal delay parameter the decoder 112 may perform an operation based on the initial additional CPB removal delay parameter. For instance, the CPB 120 may perform one or more of the procedures described in connection with Figure 14, Figure 15 and Figure 16 below.
  • the HRD described above may be one example of the decoder 112 illustrated in Figure 1.
  • an electronic device 102 may operate in accordance with the HRD and CPB described above, in some configurations.
  • one or more of the elements or parts thereof included in the electronic device(s) 102 may be implemented in hardware.
  • one or more of these elements or parts thereof may be implemented as a chip, circuitry or hardware components, etc.
  • one or more of the functions or methods described herein may be implemented in and/or performed using hardware.
  • one or more of the methods described herein may be implemented in and/or realized using a chipset, an Application-Specific Integrated Circuit (ASIC), a Large-Scale Integrated circuit (LSI) or integrated circuit, etc.
  • ASIC Application-Specific Integrated Circuit
  • LSI Large-Scale Integrated circuit
  • FIG. 2 is a flow diagram illustrating one configuration of a method 200 for sending a message.
  • An electronic device 102 e.g., electronic device A 102a
  • the encoder 104 may encode an input picture 106 as a CRA picture.
  • a CRA picture may be an encoded picture that may be decoded using intra prediction only.
  • a CRA picture may include one or more (e.g., only) I slices, where each slice has a nal_unit_type (e.g., network abstraction layer unit type) equal to 4.
  • nal_unit_type e.g., network abstraction layer unit type
  • All coded pictures that follow the CRA picture both in decoding order and output order may not use inter prediction from any picture that precedes the CRA picture either in decoding order or output order. Furthermore, any picture that precedes the CRA picture in decoding order may also precede the CRA picture in output order. Accordingly, if the encoder 104 encodes an input picture 106 as a CRA picture (e.g., if a coded picture includes only I slices), the electronic device 102 may determine 202 that a first picture is a CRA picture. Otherwise, the electronic device 102 may determine 202 that a first picture is not a CRA picture.
  • a CRA picture may occur at a random access point in the bitstream 114.
  • the random access point may be any point in a stream of data (e.g., bitstream) where decoding of the bitstream does not require access to any point in a bitstream preceding the random access point to decode a current picture and all pictures subsequent to said current picture in output order.
  • the electronic device 102 may determine 204 whether a leading picture is present if the first picture is a CRA picture. Additionally or alternatively, the electronic device 102 may determine if the first access unit is either BLA_W_DLP or BLA_N_LP NAL unit and a CPB parameter flag is equal to 1.
  • a leading picture may be a picture that follows the CRA picture in decoding order and precedes the CRA picture in output order. For example, a leading picture may be present if a picture is specified by the encoder 104 to follow a CRA picture in decoding order and to precede the CRA picture in output order (e.g., order output from the decoder 112).
  • Determining 204 whether a leading picture is present may be accomplished in accordance with one or more approaches.
  • the electronic device 102 determines 204 that a leading picture is present if the first picture is a CRA picture and another picture is present that is specified (by the encoder 104, for example) to follow the CRA picture in decoding order and precede the CRA picture in output order.
  • the electronic device 102 may read data corresponding to the CRA picture and one or more other pictures to determine whether a leading picture is present.
  • the electronic device 102 may read data that specifies decoding order and output order of the CRA picture and one or more other pictures. For example, a picture order count (POC) may be utilized to determine output order.
  • POC picture order count
  • the decoding order may be determined based on the order in which syntax elements appear in the bitstream 114.
  • output order may be defined as the order in which the decoded pictures are output from a decoded picture buffer in a case that the decoded pictures are to be output from the decoded picture buffer.
  • the output order of a picture may be specified by the POC value, regardless of whether the picture is to be output.
  • the decoding order may be defined as the order in which syntax elements are processed in a decoding process. If the conditions are met that a picture is designated to follow the CRA picture in decoding order and is designated to precede the CRA picture in output order, the electronic device 102 may determine 204 that a leading picture is present.
  • the electronic device 102 may generate 206 a message (e.g., buffering period SEI message or other message) including a CRA leading picture discard flag and an initial CRA CPB removal delay parameter if a leading picture is present.
  • a message e.g., buffering period SEI message or other message
  • the electronic device 102 may generate 206 a message that includes a cra_leadingpict_discard_flag and an initial_cra_cpb_removal_delay[ SchedSelIdx ].
  • the message may also include a CRA CPB removal delay offset parameter.
  • the electronic device 102 may generate 206 a buffering period SEI message, as illustrated in Table 1 above.
  • the electronic device 102 may send 208 the message (e.g., buffering period SEI message or other message).
  • the electronic device 102 may transmit the message via one or more of wireless transmission, wired transmission, device bus, network, etc.
  • electronic device A 102a may transmit the message to electronic device B 102b.
  • the message may be part of the bitstream 114, for example.
  • electronic device A 102a may send 208 the message to electronic device B 102b in a separate transmission 110 (that is not part of the bitstream 114).
  • the message may be sent using some out-of-band mechanism.
  • FIG 3 is a flow diagram illustrating a more specific configuration of a method 300 for sending a message.
  • An electronic device 102 e.g., electronic device A 102a
  • the electronic device 102 may determine 304 whether a leading picture is present if the first picture is a CRA picture. Additionally or alternatively, the electronic device 102 may determine if the first access unit is either BLA_W_DLP or BLA_N_LP NAL unit and a CPB parameter flag is equal to 1. This may be accomplished as described in connection with Figure 2 above.
  • the electronic device 102 may generate 306 a buffering period SEI message including a CRA leading picture discard flag, an initial CRA CPB removal delay parameter and an initial CRA CPB removal delay offset parameter if a leading picture is present.
  • the electronic device 102 may generate 306 a buffering period SEI message that includes a cra_leadingpict_discard_flag, an initial_cra_cpb_removal_delay[ SchedSelIdx ] and an initial_cra_cpb_removal_delay_offset[ SchedSelIdx ].
  • the electronic device 102 may generate 306 a buffering period SEI message, as illustrated in Table 1 above.
  • the electronic device 102 may send 308 the buffering period SEI message.
  • the electronic device 102 may transmit the buffering period SEI message via one or more of wireless transmission, wired transmission, device bus, network, etc.
  • electronic device A 102a may transmit the buffering period SEI message to electronic device B 102b.
  • the buffering period SEI message may be part of the bitstream 114, for example.
  • FIG. 4 is a flow diagram illustrating one configuration of a method 400 for buffering a bitstream.
  • An electronic device 102 e.g., electronic device B 102b
  • may receive 402 a message e.g., a buffering period SEI message or other message.
  • the electronic device 102 may receive 402 the message via one or more of wireless transmission, wired transmission, device bus, network, etc.
  • electronic device B 102b may receive 402 the message from electronic device A 102a.
  • the message may be part of the bitstream 114, for example.
  • electronic device B 102b may receive the message from electronic device A 102a in a separate transmission 110 (that is not part of the bitstream 114, for example).
  • the buffering period SEI message may be received using some out-of-band mechanism.
  • the message may include one or more of a CRA discard flag, an initial CRA CPB removal delay parameter and an initial CRA CPB removal delay offset parameter.
  • receiving 402 the message may include receiving one or more of a CRA discard flag, an initial CRA CPB removal delay parameter and an initial CRA CPB removal delay offset parameter.
  • the electronic device 102 may determine 404 whether a first access unit is a CRA access unit, whether one or more leading pictures are not present and whether a CRA leading picture flag indicates discard. Additionally or alternatively, the electronic device 102 may determine if the first access unit is either BLA_W_DLP or BLA_N_LP NAL unit and a CPB parameter flag is equal to 1.
  • An access unit may be a set of one or more NAL units that contain an encoded picture.
  • the bitstream 114 may include one or more access units.
  • the electronic device 102 may determine 404 whether a first access unit is a CRA access unit based on a NAL unit type parameter (e.g., nal_unit_type) corresponding to the first access unit.
  • a NAL unit type parameter e.g., nal_unit_type
  • a nal_unit_type 4 may indicate a coded slice of a CRA picture.
  • the electronic device may determine that an access unit is a CRA access unit if one or more (e.g., all) of the NAL unit types (e.g., nal_unit_types) corresponding to the first access unit indicate a coded slice of a CRA picture (e.g., are equal to 4). Otherwise, the electronic device 102 may determine that the first access unit is not a CRA access unit.
  • the electronic device 102 may determine whether any leading pictures are present. For example, the electronic device 102 may determine whether any leading picture(s) are included in a portion of the bitstream 114.
  • a leading picture may be a picture that follows the CRA picture in decoding order and precedes the CRA picture in output order.
  • a leading picture may be present if a picture is specified by the encoder 104 to follow a CRA picture in decoding order and to precede the CRA picture in output order (e.g., order output from the decoder 112).
  • Determining whether a leading picture is present may be accomplished in accordance with one or more approaches.
  • the electronic device 102 determines that a leading picture is present if a picture (in the first access unit) is a CRA picture and another picture is present that is specified (by the encoder 104, for example) to follow the CRA picture in decoding order and precede the CRA picture in output order.
  • the electronic device 102 may read data corresponding to the CRA picture and one or more other pictures to determine whether a leading picture is present.
  • the electronic device 102 may read data that specifies decoding order and output order of the CRA picture and one or more other pictures.
  • the electronic device 102 may receive an indicator in the bitstream 114.
  • the electronic device 102 may determine whether a leading picture is present by determining a POC value for the picture and comparing it to the POC value of a corresponding CRA picture. If the conditions are met that a picture is designated to follow the CRA picture in decoding order and is designated to precede the CRA picture in output order, the electronic device 102 may determine that a leading picture is present. If one or more of the criteria are not met, however, then the electronic device 102 may determine that no leading picture(s) are present.
  • the electronic device 102 may determine whether a CRA leading picture discard flag indicates discard. For example, the electronic device 102 may read the message to determine whether a CRA leading picture discard flag in the SEI message indicates discard. For instance, if the cra_leadingpict_discard_flag has a value of 1, then the electronic device 102 may determine that the CRA leading picture discard flag indicates discard. However, if the cra_leadingpict_discard_flag has a value of 0, then the electronic device 102 may determine that the CRA leading picture discard flag does not indicate discard. Additionally or alternatively, the electronic device 102 may determine if the first access unit is either BLA_W_DLP or BLA_N_LP NAL unit and a CPB parameter flag is equal to 1, for exmaple.
  • the electronic device 102 may set 406 an initial removal delay variable to an initial CRA CPB removal delay parameter. In this case, for example, the electronic device 102 may set use_initial_cpb_removal_delay[ SchedSelIdx ] to the value of initial_cra_cpb_removal_delay[ SchedSelIdx ].
  • the electronic device 102 may determine a bitstream arrival time based one or more of the initial CRA CPB removal delay parameter and the initial CRA CPB removal delay offset parameter. For example, if the first access unit is a CRA access unit, if no leading pictures are present and if the CRA picture discard flag indicates discard, the bitstream arrival time may be determined as follows.
  • the electronic device 102 may determine the bitstream arrival time t ai ( n ), which is based on t ai,earliest ( n ).
  • initial removal delay variable e.g., use_initial_cpb_removal_delay[ SchedSelIdx ]
  • initial removal delay offset variable e.g., use_initial_cpb_removal_delay_offset.
  • the initial removal delay variable may be set 406 to the initial CRA CPB removal delay parameter (e.g., initial_cra_cpb_removal_delay[ SchedSelIdx ]). Therefore, determining the bitstream arrival time may be based on the initial CRA CPB removal delay parameter.
  • the initial removal delay offset variable (e.g., use_initial_cpb_removal_delay_offset[ SchedSelIdx ]) may also be set to the initial CRA CPB removal delay offset parameter (e.g., initial_cra_cpb_removal_delay_offset[ SchedSelIdx ]).
  • determining the bitstream arrival time may be additionally based on the initial CRA CPB removal delay offset parameter.
  • the electronic device 102 may determine the bitstream arrival time t ai ( n ) based on the initial removal delay variable (e.g., use_initial_cpb_removal_delay[ SchedSelIdx ]).
  • the initial removal delay variable may be set 406 to the initial CRA CPB removal delay parameter (e.g., initial_cra_cpb_removal_delay[ SchedSelIdx ]). Therefore, determining the bitstream arrival time may be based on the initial CRA CPB removal delay parameter.
  • initial CRA CPB removal delay parameter e.g., initial_cra_cpb_removal_delay[ SchedSelIdx ]
  • the electronic device 102 may remove 408 the first access unit based on the initial CRA CPB removal delay parameter. For example, the electronic device 102 may determine a removal time for the first access unit based on the initial CRA CPB removal delay parameter (e.g., initial_cra_cpb_removal_delay[ SchedSelIdx ]). When the removal time arrives, the electronic device 102 may remove the first access unit from the CPB, for instance.
  • the initial CRA CPB removal delay parameter e.g., initial_cra_cpb_removal_delay[ SchedSelIdx ]
  • the electronic device 102 may decode 410 the first access unit. For example, the electronic device 102 may decode 410 an encoded picture included in the first access unit. In some configurations, the electronic device 102 may remove 408 the first access unit and decode 410 upon removal. For example, the data associated with each access unit may be removed and decoded instantaneously by an instantaneous decoding process at CPB removal time. It should be noted that the term "instantaneous" and variations thereof may not necessarily indicate the absence of any time period. For example, an "instantaneous" process may occupy some period of time.
  • the electronic device 102 may set 412 an initial removal delay variable to an initial CPB removal delay parameter. In this case, for example, the electronic device 102 may set use_initial_cpb_removal_delay[ SchedSelIdx ] to the value of initial_cpb_removal_delay[ SchedSelIdx ].
  • the electronic device 102 may remove 414 the first access unit based on the initial CPB removal delay parameter. For example, the electronic device 102 may determine a removal time for the first access unit based on the initial CPB removal delay parameter (e.g., initial_cpb_removal_delay[ SchedSelIdx ]). When the removal time arrives, the electronic device 102 may remove the first access unit from the CPB, for instance.
  • the initial CPB removal delay parameter e.g., initial_cpb_removal_delay[ SchedSelIdx ]
  • the electronic device 102 may decode 416 the first access unit. For example, the electronic device 102 may decode 416 an encoded picture included in the first access unit. For example, the data associated with each access unit may be removed and decoded instantaneously by an instantaneous decoding process at CPB removal time.
  • FIG. 5 is a flow diagram illustrating a more specific configuration of a method 500 for buffering a bitstream.
  • An electronic device 102 e.g., electronic device B 102b
  • the electronic device 102 may determine 504 whether a first access unit is a CRA access unit, whether one or more leading pictures are not present and whether a CRA leading picture flag indicates discard. Additionally or alternatively, the electronic device 102 may determine if the first access unit is either BLA_W_DLP or BLA_N_LP NAL unit and a CPB parameter flag is equal to 1. This may be accomplished as described above in connection with Figure 4, for example.
  • the electronic device 102 may set 506 an initial removal delay variable to an initial CRA CPB removal delay parameter. In this case, for example, the electronic device 102 may set use_initial_cpb_removal_delay[ SchedSelIdx ] to the value of initial_cra_cpb_removal_delay[ SchedSelIdx ].
  • the electronic device 102 may determine a bitstream arrival time based on one or more of the initial CRA CPB removal delay parameter and the initial CRA CPB removal delay offset parameter. This may be done as described in connection with Figure 4 above, for example.
  • the electronic device 102 may determine 508 a removal time (e.g., t r,n ) based on the initial CRA CPB removal delay parameter. This may be accomplished as described above in connection with initial_cra_cpb_removal_delay[ SchedSelIdx ] / 90000.
  • the electronic device 102 may remove 510 the first access unit based on the initial CRA CPB removal delay parameter. For example, the electronic device 102 may determine 508 a removal time (e.g., t r,n ) for the first access unit based on the initial CRA CPB removal delay parameter (e.g., initial_cra_cpb_removal_delay[ SchedSelIdx ]) as described above. When the removal time (e.g., t r,n ) arrives, the electronic device 102 may remove 510 the first access unit from the CPB, for instance.
  • a removal time e.g., t r,n
  • the electronic device 102 may decode 512 the first access unit.
  • the electronic device 102 may decode 512 an encoded picture included in the first access unit.
  • the data associated with each access unit may be removed and decoded instantaneously by an instantaneous decoding process at CPB removal time.
  • the electronic device 102 may set 514 an initial removal delay variable to an initial CPB removal delay parameter. In this case, for example, the electronic device 102 may set use_initial_cpb_removal_delay[ SchedSelIdx ] to the value of initial_cpb_removal_delay[ SchedSelIdx ].
  • the electronic device 102 may determine 516 a removal time (e.g., t r,n ) based on the initial CPB removal delay parameter. This may be accomplished as described above in connection with initial_cpb_removal_delay[ SchedSelIdx ] / 90000.
  • the electronic device 102 may remove 518 the first access unit based on the initial CPB removal delay parameter. For example, the electronic device 102 may determine 516 a removal time (e.g., t r,n ) for the first access unit based on the initial CPB removal delay parameter (e.g., initial_cpb_removal_delay[ SchedSelIdx ]) as described above. When the removal time (e.g., t r,n ) arrives, the electronic device 102 may remove 518 the first access unit from the CPB, for instance.
  • the initial CPB removal delay parameter e.g., initial_cpb_removal_delay[ SchedSelIdx ]
  • the electronic device 102 may decode 520 the first access unit.
  • the electronic device 102 may decode 520 an encoded picture included in the first access unit.
  • the data associated with each access unit may be removed and decoded instantaneously by an instantaneous decoding process at CPB removal time.
  • Figure 6 is a block diagram illustrating one configuration of an encoder 604 on an electronic device 602.
  • the electronic device 602 includes an encoder 604, which may be implemented in hardware, software or a combination of both.
  • the encoder 604 may be implemented as a circuit, integrated circuit, application-specific integrated circuit (ASIC), processor in electronic communication with memory with executable instructions, firmware, field-programmable gate array (FPGA), etc., or a combination thereof.
  • the encoder 604 may be an HEVC coder.
  • the electronic device 602 may include a source 622.
  • the source 622 may provide picture or image data (e.g., video) as one or more input pictures 606 to the encoder 604. Examples of the source 622 may include image sensors, memory, communication interfaces, network interfaces, wireless receivers, ports, etc.
  • One or more input pictures 606 may be provided to an intra-frame prediction module and reconstruction buffer 624.
  • An input picture 606 may also be provided to a motion estimation and motion compensation module 646 and to a subtraction module 628.
  • the intra-frame prediction module and reconstruction buffer 624 may generate intra mode information 640 and an intra signal 626 based on one or more input pictures 606 and reconstructed data 660.
  • the motion estimation and motion compensation module 646 may generate inter mode information 648 and an inter signal 644 based on one or more input pictures 606 and a reference picture buffer 676 signal 678.
  • the reference picture buffer 676 may include data from one or more reference pictures in the reference picture buffer 676.
  • the encoder 604 may select between the intra signal 626 and the inter signal 644 in accordance with a mode.
  • the intra signal 626 may be used in order to exploit spatial characteristics within a picture in an intra coding mode.
  • the inter signal 644 may be used in order to exploit temporal characteristics between pictures in an inter coding mode. While in the intra coding mode, the intra signal 626 may be provided to the subtraction module 628 and the intra mode information 640 may be provided to an entropy coding module 642. While in the inter coding mode, the inter signal 644 may be provided to the subtraction module 628 and the inter mode information 648 may be provided to the entropy coding module 642.
  • Either the intra signal 626 or the inter signal 644 (depending on the mode) is subtracted from an input picture 606 at the subtraction module 628 in order to produce a prediction residual 630.
  • the prediction residual 630 is provided to a transformation module 632.
  • the transformation module 632 may compress the prediction residual 630 to produce a transformed signal 634 that is provided to a quantization module 636.
  • the quantization module 636 quantizes the transformed signal 634 to produce transformed and quantized coefficients (TQCs) 638.
  • the TQCs 638 are provided to an entropy coding module 642 and an inverse quantization module 650.
  • the inverse quantization module 650 performs inverse quantization on the TQCs 638 to produce an inverse quantized signal 652 that is provided to an inverse transformation module 654.
  • the inverse transformation module 654 decompresses the inverse quantized signal 652 to produce a decompressed signal 656 that is provided to a reconstruction module 658.
  • the reconstruction module 658 may produce reconstructed data 660 based on the decompressed signal 656.
  • the reconstruction module 658 may reconstruct (modified) pictures.
  • the reconstructed data 660 may be provided to a deblocking filter 662 and to the intra prediction module and reconstruction buffer 624.
  • the deblocking filter 662 may produce a filtered signal 664 based on the reconstructed data 660.
  • the filtered signal 664 may be provided to a sample adaptive offset (SAO) module 666.
  • the SAO module 666 may produce SAO information 668 that is provided to the entropy coding module 642 and an SAO signal 670 that is provided to an adaptive loop filter (ALF) 672.
  • the ALF 672 produces an ALF signal 674 that is provided to the reference picture buffer 676.
  • the ALF signal 674 may include data from one or more pictures that may be used as reference pictures.
  • the entropy coding module 642 may code the TQCs 638 to produce bitstream A 614a (e.g., encoded picture data).
  • the entropy coding module 642 may code the TQCs 638 using Context-Adaptive Variable Length Coding (CAVLC) or Context-Adaptive Binary Arithmetic Coding (CABAC).
  • CAVLC Context-Adaptive Variable Length Coding
  • CABAC Context-Adaptive Binary Arithmetic Coding
  • the entropy coding module 642 may code the TQCs 638 based on one or more of intra mode information 640, inter mode information 648 and SAO information 668.
  • Bitstream A 614a (e.g., encoded picture data) may be provided to a message generation module 608.
  • the message generation module 608 may be configured similarly to the message generation module 108 described in connection with Figure 1. Additionally or alternatively, the message generation module 608 may perform one or more of the procedures described in connection with Figure 2 and Figure 3.
  • the message generation module 608 may generate a message (e.g., buffering period SEI message or other message) including one or more of a CRA leading picture discard flag, an initial CRA CPB removal delay parameter and an initial CRA CPB removal delay offset parameter if a first picture (in the bitstream 614a, for example) is a CRA picture and if a leading picture is present.
  • a message e.g., buffering period SEI message or other message
  • the message generation module 608 may generate a message (e.g., buffering period SEI message or other message) including one or more of a random access point (RAP) CPB parameter flag, an initial additional CPB removal delay parameter and an initial additional CPB removal delay offset parameter if the picture is a RAP picture if a picture (in the bitstream 614a, for example) is a RAP picture and if a broken link access (BLA) with decodable leading pictures (DLP) network access layer (NAL) unit type is present.
  • a message e.g., buffering period SEI message or other message
  • a message e.g., buffering period SEI message or other message
  • a message e.g., buffering period SEI message or other message
  • a message e.g., buffering period SEI message or other message
  • a message e.g., buffering period SEI message or other message
  • a message e.g., buffering period SEI message or other message
  • the message may be inserted into bitstream A 614a to produce bitstream B 614b.
  • the message may be generated after the entire bitstream A 614a is generated (e.g., after most of bitstream B 614b is generated), for example.
  • the message may not be inserted into bitstream A 614a (in which case bitstream B 614b may be the same as bitstream A 614a), but may be provided in a separate transmission 610.
  • the electronic device 602 sends the bitstream 614 to another electronic device.
  • the bitstream 614 may be provided to a communication interface, network interface, wireless transmitter, port, etc.
  • the bitstream 614 may be transmitted to another electronic device via LAN, the Internet, a cellular phone base station, etc.
  • the bitstream 614 may additionally or alternatively be stored in memory or other component on the electronic device 602.
  • Figure 7 is a block diagram illustrating one configuration of a decoder 712 on an electronic device 702.
  • the decoder 712 may be included in an electronic device 702.
  • the decoder 712 may be an HEVC decoder.
  • the decoder 712 and one or more of the elements illustrated as included in the decoder 712 may be implemented in hardware, software or a combination of both.
  • the decoder 712 may receive a bitstream 714 (e.g., one or more encoded pictures and overhead data included in the bitstream 714) for decoding.
  • the received bitstream 714 may include received overhead data, such as a message (e.g., buffer period SEI message or other message), slice header, PPS, etc.
  • the decoder 712 may additionally receive a separate transmission 710.
  • the separate transmission 710 may include a message (e.g., a buffer period SEI message or other message).
  • a buffer period SEI message or other message may be received in a separate transmission 710 instead of in the bitstream 714.
  • the separate transmission 710 may be optional and may not be utilized in some configurations.
  • the decoder 712 includes a CPB 720.
  • the CPB 720 may be configured similarly to the CPB 120 described in connection with Figure 1 above. Additionally or alternatively, the decoder 712 may perform one or more of the procedures described in connection with Figure 4 and Figure 5. For example, the decoder 712 may receive a message (e.g., buffering period SEI message or other message). Additionally, the decoder 712 may perform one or more of setting an initial removal delay variable to an initial CRA CPB removal delay parameter and removing a first access unit based on the initial CRA CPB removal delay parameter if the first access unit is a CRA access unit, if a leading picture is not present and if a CRA leading picture discard flag indicates discard. It should be noted that one or more access units may be included in the bitstream and may include one or more of encoded picture data and overhead data.
  • the decoder 712 may perform one or more of the procedures described in connection with Figure 14, Figure 15 and Figure 16, described below.
  • the decoder 712 may receive a message (e.g., buffering period SEI message or other message). Additionally, the decoder 712 may perform one or more of processing an initial additional CPB removal delay parameter, processing a broken link access (BLA) with decodable leading pictures (DLP) network access layer (NAL) unit type and performing an operation based on the initial additional CPB removal delay parameter.
  • a message e.g., buffering period SEI message or other message.
  • BLA broken link access
  • DLP decodable leading pictures
  • NAL network access layer
  • the coded picture buffer (CPB) 720 may provide encoded picture data to an entropy decoding module 701.
  • the encoded picture data may be entropy decoded by an entropy decoding module 701, thereby producing a motion information signal 703 and quantized, scaled and/or transformed coefficients 705.
  • the motion information signal 703 may be combined with a portion of a reference frame signal 798 from a frame memory 709 at a motion compensation module 780, which may produce an inter-frame prediction signal 782.
  • the quantized, descaled and/or transformed coefficients 705 may be inverse quantized, scaled and inverse transformed by an inverse module 707, thereby producing a decoded residual signal 784.
  • the decoded residual signal 784 may be added to a prediction signal 792 to produce a combined signal 786.
  • the prediction signal 792 may be a signal selected from either the inter-frame prediction signal 782 produced by the motion compensation module 780 or an intra-frame prediction signal 790 produced by an intra-frame prediction module 788. In some configurations, this signal selection may be based on (e.g., controlled by) the bitstream 714.
  • the intra-frame prediction signal 790 may be predicted from previously decoded information from the combined signal 786 (in the current frame, for example).
  • the combined signal 786 may also be filtered by a de-blocking filter 794.
  • the resulting filtered signal 796 may be written to frame memory 709.
  • the resulting filtered signal 796 may include a decoded picture.
  • the frame memory 709 may provide a decoded picture 718.
  • Figure 8 illustrates various components that may be utilized in a transmitting electronic device 802.
  • One or more of the electronic devices 102, 602, 702 described herein may be implemented in accordance with the transmitting electronic device 802 illustrated in Figure 8.
  • the transmitting electronic device 802 includes a processor 817 that controls operation of the electronic device 802.
  • the processor 817 may also be referred to as a CPU.
  • Memory 811 which may include both read-only memory (ROM), random access memory (RAM) or any type of device that may store information, provides instructions 813a (e.g., executable instructions) and data 815a to the processor 817.
  • a portion of the memory 811 may also include non-volatile random access memory (NVRAM).
  • NVRAM non-volatile random access memory
  • the memory 811 may be in electronic communication with the processor 817.
  • Instructions 813b and data 815b may also reside in the processor 817. Instructions 813b and/or data 815b loaded into the processor 817 may also include instructions 813a and/or data 815a from memory 811 that were loaded for execution or processing by the processor 817. The instructions 813b may be executed by the processor 817 to implement the systems and methods disclosed herein. For example, the instructions 813b may be executable to perform one or more of the methods 200, 300, 400, 500 described above.
  • the transmitting electronic device 802 may include one or more communication interfaces 819 for communicating with other electronic devices (e.g., receiving electronic device).
  • the communication interfaces 819 may be based on wired communication technology, wireless communication technology, or both. Examples of a communication interface 819 include a serial port, a parallel port, a Universal Serial Bus (USB), an Ethernet adapter, an IEEE 1394 bus interface, a small computer system interface (SCSI) bus interface, an infrared (IR) communication port, a Bluetooth wireless communication adapter, a wireless transceiver in accordance with 3 rd Generation Partnership Project (3GPP) specifications and so forth.
  • USB Universal Serial Bus
  • Ethernet adapter an IEEE 1394 bus interface
  • SCSI small computer system interface
  • IR infrared
  • Bluetooth wireless communication adapter a wireless transceiver in accordance with 3 rd Generation Partnership Project (3GPP) specifications and so forth.
  • 3GPP 3 rd Generation Partnership Project
  • the transmitting electronic device 802 may include one or more output devices 823 and one or more input devices 821.
  • Examples of output devices 823 include a speaker, printer, etc.
  • One type of output device that may be included in an electronic device 802 is a display device 825.
  • Display devices 825 used with configurations disclosed herein may utilize any suitable image projection technology, such as a cathode ray tube (CRT), liquid crystal display (LCD), light-emitting diode (LED), gas plasma, electroluminescence or the like.
  • a display controller 827 may be provided for converting data stored in the memory 811 into text, graphics, and/or moving images (as appropriate) shown on the display 825.
  • Examples of input devices 821 include a keyboard, mouse, microphone, remote control device, button, joystick, trackball, touchpad, touchscreen, lightpen, etc.
  • the various components of the transmitting electronic device 802 are coupled together by a bus system 829, which may include a power bus, a control signal bus and a status signal bus, in addition to a data bus. However, for the sake of clarity, the various buses are illustrated in Figure 8 as the bus system 829.
  • the transmitting electronic device 802 illustrated in Figure 8 is a functional block diagram rather than a listing of specific components.
  • Figure 9 is a block diagram illustrating various components that may be utilized in a receiving electronic device 902.
  • One or more of the electronic devices 102, 602, 702 described herein may be implemented in accordance with the receiving electronic device 902 illustrated in Figure 9.
  • the receiving electronic device 902 includes a processor 917 that controls operation of the electronic device 902.
  • the processor 917 may also be referred to as a CPU.
  • Memory 911 which may include both read-only memory (ROM), random access memory (RAM) or any type of device that may store information, provides instructions 913a (e.g., executable instructions) and data 915a to the processor 917.
  • a portion of the memory 911 may also include non-volatile random access memory (NVRAM).
  • the memory 911 may be in electronic communication with the processor 917.
  • Instructions 913b and data 915b may also reside in the processor 917. Instructions 913b and/or data 915b loaded into the processor 917 may also include instructions 913a and/or data 915a from memory 911 that were loaded for execution or processing by the processor 917. The instructions 913b may be executed by the processor 917 to implement the systems and methods disclosed herein. For example, the instructions 913b may be executable to perform one or more of the methods 200, 300, 400, 500 described above.
  • the receiving electronic device 902 may include one or more communication interfaces 919 for communicating with other electronic devices (e.g., a transmitting electronic device).
  • the communication interface 919 may be based on wired communication technology, wireless communication technology, or both. Examples of a communication interface 919 include a serial port, a parallel port, a Universal Serial Bus (USB), an Ethernet adapter, an IEEE 1394 bus interface, a small computer system interface (SCSI) bus interface, an infrared (IR) communication port, a Bluetooth wireless communication adapter, a wireless transceiver in accordance with 3 rd Generation Partnership Project (3GPP) specifications and so forth.
  • USB Universal Serial Bus
  • Ethernet adapter an IEEE 1394 bus interface
  • SCSI small computer system interface
  • IR infrared
  • Bluetooth wireless communication adapter a wireless transceiver in accordance with 3 rd Generation Partnership Project (3GPP) specifications and so forth.
  • 3GPP 3 rd Generation Partnership Project
  • the receiving electronic device 902 may include one or more output devices 923 and one or more input devices 921.
  • Examples of output devices 923 include a speaker, printer, etc.
  • One type of output device that may be included in an electronic device 902 is a display device 925.
  • Display devices 925 used with configurations disclosed herein may utilize any suitable image projection technology, such as a cathode ray tube (CRT), liquid crystal display (LCD), light-emitting diode (LED), gas plasma, electroluminescence or the like.
  • a display controller 927 may be provided for converting data stored in the memory 911 into text, graphics, and/or moving images (as appropriate) shown on the display 925.
  • Examples of input devices 921 include a keyboard, mouse, microphone, remote control device, button, joystick, trackball, touchpad, touchscreen, lightpen, etc.
  • the various components of the receiving electronic device 902 are coupled together by a bus system 929, which may include a power bus, a control signal bus and a status signal bus, in addition to a data bus. However, for the sake of clarity, the various buses are illustrated in Figure 9 as the bus system 929.
  • the receiving electronic device 902 illustrated in Figure 9 is a functional block diagram rather than a listing of specific components.
  • Figure 10 is a block diagram illustrating one configuration of an electronic device 1002 in which systems and methods for sending a message may be implemented.
  • the electronic device 1002 includes encoding means 1031 and transmitting means 1033.
  • the encoding means 1031 and transmitting means 1033 may be configured to perform one or more of the functions described in connection with one or more of Figure 1, Figure 2, Figure 3, Figure 6 and Figure 8 above, as well as Figure 12 and Figure 13 below.
  • the encoding means 1031 and transmitting means 1033 may generate a bitstream 1014.
  • Figure 8 above illustrates one example of a concrete apparatus structure of Figure 10.
  • Other various structures may be implemented to realize one or more of the functions of Figure 1, Figure 2, Figure 3, Figure 6 and Figure 8 above, as well as Figure 12 and Figure 13 below.
  • a DSP may be realized by software.
  • Figure 11 is a block diagram illustrating one configuration of an electronic device 1102 in which systems and methods for buffering a bitstream 1114 may be implemented.
  • the electronic device 1102 may include receiving means 1135 and decoding means 1137.
  • the receiving means 1135 and decoding means 1137 may be configured to perform one or more of the functions described in connection with one or more of Figure 1, Figure 4, Figure 5, Figure 7 and Figure 9 above, as well as Figure 14, Figure 15 and Figure 16 below.
  • the receiving means 1135 and decoding means 1137 may receive a bitstream 1114.
  • Figure 9 above illustrates one example of a concrete apparatus structure of Figure 11.
  • Other various structures may be implemented to realize one or more functions of Figure 1, Figure 4, Figure 5, Figure 7 and Figure 9 above, as well as Figure 14, Figure 15 and Figure 16 below.
  • a DSP may be realized by software.
  • FIG. 12 is a flow diagram illustrating another configuration of a method 1200 for sending a message.
  • An electronic device 102 e.g., electronic device A 102a
  • the encoder 104 may encode an input picture 106 as a RAP picture.
  • a RAP picture may be an encoded picture that may be decoded using intra prediction only.
  • a RAP picture may include one or more (e.g., only) I slices, where each slice has a nal_unit_type (e.g., network abstraction layer (NAL) unit type) equal to a value between 7 to 12.
  • NAL network abstraction layer
  • All coded pictures that follow the RAP picture both in decoding order and output order may not use inter prediction from any picture that precedes the RAP picture either in decoding order or output order. Furthermore, any picture that precedes the RAP picture in decoding order may also precede the RAP picture in output order. Accordingly, if the encoder 104 encodes an input picture 106 as a RAP picture (e.g., if a coded picture includes only I slices), the electronic device 102 may determine 1202 that the picture is a RAP picture. Otherwise, the electronic device 102 may determine 1202 that picture is not a RAP picture. The electronic device 102 may also determine whether the RAP picture is a BLA picture.
  • a RAP picture may be a broken link access (BLA) picture, a CRA picture or an instantaneous decoding refresh (IDR) picture.
  • BLA broken link access
  • IDR instantaneous decoding refresh
  • the RAP picture and all subsequent non-tagged for discard (non-TFD) pictures in decoding order may be correctly decoded without performing the decoding process of any pictures that precede the RAP picture in decoding order.
  • a RAP picture may occur at a random access point in the bitstream 114.
  • the random access point may be any point in a stream of data (e.g., bitstream) where decoding of the bitstream does not require access to any point in a bitstream preceding the random access point to decode a current picture and all pictures subsequent to said current picture in output order.
  • the electronic device 102 may determine 1204 whether the picture is associated with a broken link access (BLA) with decodable leading pictures (DLP) network access layer (NAL) unit type if the picture is a RAP picture. For example, electronic device 102 may generate a BLA with DLP NAL unit to be associated with the RAP picture.
  • BLA broken link access
  • DLP decodable leading pictures
  • NAL network access layer
  • the electronic device 102 may determine 1204 whether the picture is associated with a BLA based on the definition of BLA pictures. Additionally or alternatively, the electronic device 102 may determine 1204 whether the picture is associated with a BLA based on if there are any DLP pictures present subsequent to the BLA picture in decoding order and if all subsequent TFD pictures in decoding order after the BLA picture are discarded. For example, the electronic device 102 may determine that the picture as associated with a BLA_W_DLP picture.
  • a BLA_W_DLP picture may indicate to the electronic device 102 to drop all the TFD pictures subsequent to it. If there is a DLP picture present, it may be label the picture as a BLA picture (e.g., BLA_W_DLP). If the electronic device 102 obtains such a stream, it can decode the BLA and DLP pictures and all other sunsequent pictures in decoding order.
  • BLA_W_DLP picture may indicate to the electronic device 102 to drop all the TFD pictures subsequent to it. If there is a DLP picture present, it may be label the picture as a BLA picture (e.g., BLA_W_DLP). If the electronic device 102 obtains such a stream, it can decode the BLA and DLP pictures and all other sunsequent pictures in decoding order.
  • the electronic device 102 may generate 1206 a message including a RAP coded picture buffer (CPB) parameter flag and initial additional CPB removal delay parameter if the BLA with DLP NAL unit type is present.
  • the electronic device 102 may generate 1206 a message that includes a rap_cpb_params_present_flag and an initial_alt1_cpb_removal_delay[ SchedSelIdx ].
  • a flag other than rap_cpb_params_present_flag may be included in the message when the additional initial CPB removal delay parameter is included in the message. It should be noted that since rap_cpb_params_present_flag already existed, it may be reused in this example.
  • the RAP CPB parameter flag may be a new parameter flag.
  • the RAP CPB parameter flag may be another flag other than rap_cpb_params_present_flag.
  • the RAP CPB parameter flag may be a Boolean flag.
  • the RAP CPB parameter flag may be set to 1 when the picture (e.g., coded picture) has a nal_unit_type equal to BLA_W_DLP.
  • the RAP CPB parameter flag may indicate a BLA with DLP NAL unit type is present when the picture is associated with a BLA with DLP NAL unit type.
  • the message may also include an initial additional CPB removal delay offset parameter.
  • the electronic device 102 may generate 206 a buffering period SEI message, as illustrated in Table 2 above.
  • the electronic device 102 may send 1208 the message (e.g., buffering period SEI message or other message).
  • the electronic device 102 may transmit the message via one or more of wireless transmission, wired transmission, device bus, network, etc.
  • electronic device A 102a may transmit the message to electronic device B 102b.
  • the message may be part of the bitstream 114, for example.
  • electronic device A 102a may send 1208 the message to electronic device B 102b in a separate transmission 110 (that is not part of the bitstream 114).
  • the message may be sent using some out-of-band mechanism.
  • FIG 13 is a flow diagram illustrating another more specific configuration of a method 1300 for sending a message.
  • An electronic device 102 e.g., electronic device A 102a
  • RAP random access point
  • the electronic device 102 may determine 1304 whether the picture is associated with a broken link access (BLA) with decodable leading pictures (DLP) network access layer (NAL) unit type if the picture is a RAP picture. This may be accomplished as described in connection with Figure 12 above.
  • BLA broken link access
  • DLP decodable leading pictures
  • NAL network access layer
  • the electronic device 102 may generate 1306 a buffering period SEI message including whether the picture is associated with a broken link access (BLA) with decodable leading pictures (DLP) network access layer (NAL) unit type if the picture is a RAP picture.
  • the electronic device 102 may generate 1306 a buffering period SEI message that includes a rap_cpb_params_present_flag, an initial_alt1_cpb_removal_delay[ SchedSelIdx ] and initial_alt1_cpb_removal_delay_offset[ SchedSelIdx ].
  • a flag other than rap_cpb_params_present_flag may be included in the message when the additional initial CPB removal delay offset parameter is included in the message. It should be noted that since rap_cpb_params_present_flag already existed, it may be reused in this example. In addition, another flag signaling this additional parameter may be sent.
  • the RAP CPB parameter flag may be a new parameter flag. In other words, the RAP CPB parameter flag may be another flag other than rap_cpb_params_present_flag.
  • the electronic device 102 may generate 1306 a buffering period SEI message.
  • a buffering period SEI message One example of this is illustrated in Table 2 above.
  • the electronic device 102 may send 1308 the buffering period SEI message.
  • the electronic device 102 may transmit the buffering period SEI message via one or more of wireless transmission, wired transmission, device bus, network, etc.
  • electronic device A 102a may transmit the buffering period SEI message to electronic device B 102b.
  • the buffering period SEI message may be part of the bitstream 114, for example.
  • the buffering period SEI message may indicate multiple initial buffering parameters for random access.
  • the buffering period SEI message may include additional information regarding the initial buffering parameters that assist the HRD and the decoder 112 in decoding pictures. In this way, initial buffering latency when starting playback at a RAP picture may be reduced.
  • buffering period SEI message may prevent buffing overflow and underflow when starting playback at a RAP picture.
  • buffing overflow and underflow may be prevented by using correct values for initial buffering as signaled in initial_alt1_cpb_removal_delay[SchedSelIdx] and initial_alt1_cpb_removal_delay_offset[SchedSelIdx]. This may occur when Access Unit 0 is a BLA access unit for which the coded picture has nal_unit_type equal to BLA_W_DLP. However, if an incorrect value of buffering is used for initialization, then a buffer underflow and/or overflow can occur.
  • FIG 14 is a flow diagram illustrating another configuration of a method 1400 for buffering a bitstream.
  • An electronic device 102 e.g., electronic device B 102b
  • may receive 1402 a message e.g., a buffering period SEI message or other message.
  • the electronic device 102 may receive 1402 the message via one or more of wireless transmission, wired transmission, device bus, network, etc.
  • electronic device B 102b may receive 1402 the message from electronic device A 102a.
  • the message may be part of the bitstream 114, for example.
  • electronic device B 102b may receive the message from electronic device A 102a in a separate transmission 110 (that is not part of the bitstream 114, for example).
  • the message may be received using some out-of-band mechanism.
  • the message may include one or more of a RAP CPB parameter flag, an initial additional CPB removal delay parameter and an initial additional CPB removal delay offset parameter.
  • receiving 1402 the message may include receiving one or more of a RAP CPB parameter flag, an initial additional CPB removal delay parameter and an initial additional CPB removal delay offset parameter.
  • initial buffering parameter sets may be employed.
  • Table 2 illustrates initial_cpb_removal_delay, initial_alt_cpb_removal_delay and initial_alt1_cpb_removal_delay along with initial_cpb_removal_delay_offset, initial_alt_cpb_removal_delay_offset and initial_alt1_cpb_removal_delay_offset, respectively.
  • initial_cpb_removal_delay initial_alt_cpb_removal_delay_offset
  • initial_alt1_cpb_removal_delay_offset initial_alt1_cpb_removal_delay_offset
  • initial_alt2_cpb_removal_delay initial_alt3_cpb_removal_delay
  • initial_alt4_cpb_removal_delay_offset along with initial_alt2_cpb_removal_delay_offset
  • initial_alt3_cpb_removal_delay initial_alt4_cpb_removal_delay_offset
  • the electronic device 102 may determine 1404 whether a random access point (RAP) coded picture buffer (CPB) parameter flag indicates an initial additional CPB removal delay parameter.
  • RAP random access point
  • CPB coded picture buffer
  • the RAP CPB parameter flag may be a Boolean value that equals 1 when an initial additional CPB removal delay parameter is present and equals 0 when an initial additional CPB removal delay parameter is not present.
  • the RAP CPB parameter flag may also indicate the presence of an initial alternative CPB removal delay parameter.
  • the electronic device 102 may determine 1404 that the RAP CPB parameter flag indicates that an initial additional CPB removal delay parameter is present. Alternatively, the electronic device 102 may determine 1404 that the RAP CPB parameter flag indicates that an initial additional CPB removal delay parameter is not present. In some configurations, the electronic device 102 may determine 1404, based on the RAP CPB parameter flag missing that an initial additional CPB removal delay parameter is not present.
  • the electronic device 102 may perform 1406 an operation based on the initial CPB removal delay parameter.
  • the HRD or decoder 112 may employ the initial additional CPB removal delay parameter to determine the timing of the decoding unit removal and for decoding of the decoding units.
  • the initial additional CPB removal delay parameter also assists in determining constraints on the bitstream arrival and assists a bitstream conformance checking entity to check if the generated bitstream will cause an overflow and/or underflow of HRD buffer or decoder 112.
  • FIG. 15 is a flow diagram illustrating another more specific configuration of a method 1500 for buffering a bitstream.
  • An electronic device 102 e.g., electronic device B 102b
  • the electronic device 102 may receive 1502 the buffering period SEI message via one or more of wireless transmission, wired transmission, device bus, network, etc.
  • electronic device B 102b may receive 1402 the buffering period SEI message from electronic device A 102a.
  • the buffering period SEI message may be part of the bitstream 114, for example.
  • the buffering period SEI message from electronic device A 102a in a separate transmission 110 that is not part of the bitstream 114, for example).
  • the buffering period SEI message may be received using some out-of-band mechanism.
  • the buffering period SEI message may include a RAP CPB parameter flag, an initial additional CPB removal delay parameter and an initial additional CPB removal delay offset parameter.
  • the electronic device 102 may receive 1502 a buffering period SEI message may including a RAP CPB parameter flag, an initial additional CPB removal delay parameter and an initial additional CPB removal delay offset parameter.
  • the electronic device 102 may obtain 1504 a broken link access (BLA) with decodable leading pictures (DLP) network access layer (NAL) unit type associated with a picture from the message.
  • BLA decodable leading pictures
  • NAL network access layer
  • the picture may have associated TFD pictures present in the bitstream, but may have associated DLP pictures in the bitstream.
  • BLA with DLP NAL unit type may be BLA_W_DLP.
  • the picture may not have associated TFD pictures present in the bitstream, but may have associated DLP pictures in the bitstream.
  • the picture may be a BLA picture.
  • the electronic device 102 may determine 1506 whether a RAP CPB parameter flag indicates an initial additional CPB removal delay parameter.
  • the electronic device 102 may determine 1404 that the RAP CPB parameter flag indicates that an initial additional CPB removal delay parameter and an initial additional CPB removal delay offset parameter is present.
  • the electronic device 102 may determine 1404 that the RAP CPB parameter flag indicates that an initial additional CPB removal delay parameter and an initial additional CPB removal delay offset parameter is not present.
  • the RAP CPB parameter flag may also indicate the presence of an initial alternative CPB removal delay parameter.
  • the electronic device 102 may perform 1508 an operation based on the initial CPB removal delay parameter and/or the initial additional CPB removal delay offset parameter. This may be accomplished as described above in connection with Figure 14, for example.
  • FIG 16 is a flow diagram illustrating yet another configuration of a method 1600 for buffering a bitstream.
  • An electronic device 102 e.g., electronic device B 102b
  • the buffering period SEI message may include a RAP CPB parameter flag, a sub-picture CPB flag, a BLA with no leading pictures unit and/or a BLA with decodable leading pictures and with no TFD pictures unit.
  • the electronic device 102 may receive 1502 a buffering period SEI message including a RAP CPB parameter flag, a sub-picture CPB flag, a BLA with no leading pictures NAL unit and/or a BLA with decodable leading pictures and with no TFD pictures NAL unit.
  • a BLA with no leading pictures NAL unit may be a BLA_N_LP NAL unit.
  • a BLA with decodable leading pictures and with no TFD pictures NAL unit may be a BLA_W_DLP NAL unit.
  • the electronic device 102 may determine 1604 whether the sub-picture CPB flag is equal to one, or whether a BLA with no leading pictures NAL unit is present and the CPB parameter flag is equal to one.
  • the electronic device 102 may set 1606 an initial removal delay variable to an initial alternative CPB removal delay parameter. In this case, for example, the electronic device 102 may set use_initial_cpb_removal_delay[ SchedSelIdx ] to the value of initial_alt_cpb_removal_delay[ SchedSelIdx ].
  • the electronic device 102 may determine a bitstream arrival time based on one or more of the initial alternative CPB removal delay parameter and the initial alternative CPB removal delay offset parameter.
  • the electronic device 102 may determine 1608 a removal time (e.g., t r,n ) based on the initial alternative CPB removal delay parameter. This may be accomplished as described above in connection with initial_alt_cpb_removal_delay[ SchedSelIdx ] / 90000.
  • the electronic device 102 may remove 1610 the first access unit based on the initial alternative CPB removal delay parameter. For example, the electronic device 102 may determine 1608 a removal time (e.g., t r,n ) for the first access unit based on the initial alternative CPB removal delay parameter (e.g., initial_alt_cpb_removal_delay[ SchedSelIdx ]) as described above. When the removal time (e.g., t r,n ) arrives, the electronic device 102 may remove 1610 the first access unit from the CPB, for instance.
  • a removal time e.g., t r,n
  • the electronic device 102 may decode 1612 the first access unit.
  • the electronic device 102 may decode 1612 an encoded picture included in the first access unit.
  • the data associated with each access unit may be removed and decoded instantaneously by an instantaneous decoding process at CPB removal time.
  • the electronic device 102 determine 1624 whether a BLA with decodable leading pictures and with no TFD pictures unit is present, and whether the CPB parameter flag is equal to one.
  • the electronic device 102 may set 1614 an initial removal delay variable to an initial CPB removal delay parameter. In this case, for example, the electronic device 102 may set use_initial_cpb_removal_delay[ SchedSelIdx ] to the value of initial_cpb_removal_delay[ SchedSelIdx ].
  • the electronic device 102 may determine 1616 a removal time (e.g., t r,n ) based on the initial CPB removal delay parameter. This may be accomplished as described above in connection with initial_cpb_removal_delay[ SchedSelIdx ] / 90000.
  • the electronic device 102 may remove 1618 the first access unit based on the initial CPB removal delay parameter. For example, the electronic device 102 may determine 1616 a removal time (e.g., t r,n ) for the first access unit based on the initial CPB removal delay parameter (e.g., initial_cpb_removal_delay[ SchedSelIdx ]) as described above. When the removal time (e.g., t r,n ) arrives, the electronic device 102 may remove 1618 the first access unit from the CPB, for instance.
  • the initial CPB removal delay parameter e.g., initial_cpb_removal_delay[ SchedSelIdx ]
  • the electronic device 102 may decode 1620 the first access unit.
  • the electronic device 102 may decode 1620 an encoded picture included in the first access unit.
  • the data associated with each access unit may be removed and decoded instantaneously by an instantaneous decoding process at CPB removal time.
  • the electronic device 102 may set 1626 an initial removal delay variable to an initial additional CPB removal delay parameter.
  • the electronic device 102 may set use_initial_cpb_removal_delay[ SchedSelIdx ] to the value of initial_alt1_cpb_removal_delay[ SchedSelIdx ].
  • the electronic device 102 may determine a bitstream arrival time based on one or more of the initial additional CPB removal delay parameter and the initial additional CPB removal delay offset parameter.
  • the electronic device 102 may determine 1628 a removal time (e.g., t r,n ) based on the initial additional CPB removal delay parameter. This may be accomplished as described above in connection with initial_alt1_cpb_removal_delay[ SchedSelIdx ] / 90000.
  • the electronic device 102 may remove 1630 the first access unit based on the initial additional CPB removal delay parameter. For example, the electronic device 102 may determine 1628 a removal time (e.g., t r,n ) for the first access unit based on the initial additional CPB removal delay parameter (e.g., initial_alt1_cpb_removal_delay[ SchedSelIdx ]) as described above. When the removal time (e.g., t r,n ) arrives, the electronic device 102 may remove 1630 the first access unit from the CPB, for instance.
  • a removal time e.g., t r,n
  • the electronic device 102 may decode 1632 the first access unit. For example, the electronic device 102 may decode 1632 an encoded picture included in the first access unit. For example, the data associated with each access unit may be removed and decoded instantaneously by an instantaneous decoding process at CPB removal time.
  • computer-readable medium refers to any available medium that can be accessed by a computer or a processor.
  • computer-readable medium may denote a computer- and/or processor-readable medium that is non-transitory and tangible.
  • a computer-readable or processor-readable medium may comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer or processor.
  • Disk and disc include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray (registered trademark) disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers.
  • CD compact disc
  • DVD digital versatile disc
  • floppy disk floppy disk
  • Blu-ray registered trademark
  • one or more of the methods described herein may be implemented in and/or performed using hardware.
  • one or more of the methods or approaches described herein may be implemented in and/or realized using a chipset, an ASIC, a large-scale integrated circuit (LSI) or integrated circuit, etc.
  • LSI large-scale integrated circuit
  • Each of the methods disclosed herein comprises one or more steps or actions for achieving the described method.
  • the method steps and/or actions may be interchanged with one another and/or combined into a single step without departing from the scope of the claims.
  • the order and/or use of specific steps and/or actions may be modified without departing from the scope of the claims.

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Compression Or Coding Systems Of Tv Signals (AREA)

Abstract

La présente invention concerne un dispositif électronique permettant d'envoyer un message. Le dispositif électronique comprend un processeur et des instructions stockées dans une mémoire qui est en communication électronique avec le processeur. Le dispositif électronique détermine si une image est une image de point d'accès aléatoire (RAP). Le dispositif électronique détermine également si l'image est associée à un accès de lien mort (BLA) avec un type d'unité de couche d'accès réseau (NAL) d'images principales décodables (DLP) si l'image est une image RAP. Le dispositif électronique génère en outre un message comprenant un indicateur de paramètre de tampon d'images codées RAP (CPB) et un paramètre de retard de retrait CPB supplémentaire initial si le BLA avec le type d'unité NAL DLP est présent. Le dispositif électronique envoie en outre le message.
PCT/JP2013/005248 2012-09-28 2013-09-04 Dispositifs électroniques destinés à la signalisation de multiples paramètres tampons initiaux WO2014049974A1 (fr)

Applications Claiming Priority (2)

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US201261707699P 2012-09-28 2012-09-28
US61/707,699 2012-09-28

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WO2014049974A1 true WO2014049974A1 (fr) 2014-04-03

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Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
BENJAMIN BROSS ET AL.: "High efficiency video coding (HEVC) text specification draft 8", JOINT COLLABORATIVE TEAM ON VIDEO CODING (JCT-VC) OF ITU-T SG16 WP3 AND ISO/IEC JTCL/SC29/WG11 10TH MEETING, 28 July 2012 (2012-07-28), STOCKHOLM, SE *

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