JP2018182617A - Information processing apparatus, information processing method, program, and recording medium manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable converting a format of a content from a first format to a second format having a time axis being different from each other.SOLUTION: An information processing apparatus according to the present technology converts a time stamp of a first format that is represented by a counter value of a 32+n bit counter in which accuracy being less than or equal to 1 second is 2Hz (n is an integer being more than or equal to 24) to a time stamp of a second format that is represented by a counter value of a 33 bit counter in which accuracy being less than or equal to 1 second is 90 kHz, and converts reference time of the first format represented by the counter value of the 32+n bit counter to reference time of the second format represented by a counter value of a 42 bit counter in which accuracy being less than or equal to 1 second is 27 MHz. The present technology can be applied to a recording apparatus such as a PC or a hard disk recorder and the like.SELECTED DRAWING: Figure 2

Description

  The present technology relates to an information processing apparatus, an information processing method, a program, and a recording medium manufacturing method, and in particular, it has become possible to convert the format of content from a first format different in time axis to a second format. The present invention relates to an information processing apparatus, an information processing method, a program, and a recording medium manufacturing method.

  Transmission of content in the next-generation broadcast standard is performed by MMT (MPEG Media Transport), not by the conventional MPEG-2 TS. MMT enables transmission of content using not only the transmission path of broadcast waves but also the transmission path of communication such as the Internet.

JP, 2016-103745, A

  When receiving and recording MMT content, it is conceivable to record MMT content as it is, but recording with MPEG-2 TS is also considered. Recording with MPEG-2 TS makes it possible to take advantage of the already widespread MPEG-2 TS assets.

  No technology has been established to convert MMT content into MPEG-2 TS content.

  The present technology has been made in view of such a situation, and enables the format of content to be converted from a first format different in time axis to a second format.

An information processing apparatus according to one aspect of the present technology is configured to set a time stamp of a first format represented by a counter value of a 32 + n-bit counter with an accuracy of 1 second or less as 2 ⁿ Hz (n is an integer of 24 or more). A time stamp conversion unit for converting the time stamp of the second format represented by the counter value of the 33-bit counter having an accuracy of 90 kHz or less to the second, and the first format represented by the counter value of the 32 + n-bit counter A reference time converter for converting the reference time of the second time to the reference time of the second format represented by the counter value of the 42-bit counter with an accuracy of 1 second or less, and the counter of the 33-bit counter in time stamp conversion Initial value of the value, and the initial value of the counter value of the 42-bit counter in the conversion of setting reference time And a controller configured to set

  The time stamp conversion unit may generate a time stamp of a second format corrected in accordance with the leap second adjustment performed on the time stamp of the first format.

  A processing unit may be further provided to multiplex, in the second format, data including a video stream and an audio stream multiplexed in the first format and generate multiplexed data.

  The processing unit may generate the multiplexed data to which a timestamp of the second format and a reference time are added.

  The control unit may set initial values based on processing times of time stamp conversion processing, reference time conversion processing, and multiplexing processing.

  The first format may be MMT, and the second format may be MPEG-2 TS.

In one aspect of the present technology, the time stamp of the first format represented by the counter value of the 32 + n-bit counter with an accuracy of 1 second or less as 2 ⁿ Hz (n is an integer of 24 or more) is 1 second or less The reference time of the first format is converted to a time stamp of the second format represented by the counter value of the 33-bit counter with an accuracy of 90 kHz, and represented by the counter value of the 32 + n-bit counter is less than 1 second. Is converted to the reference time of the second format represented by the counter value of the 42-bit counter with an accuracy of 27 MHz. Further, the initial value of the counter value of the 33-bit counter in time stamp conversion and the initial value of the counter value of the 42-bit counter in conversion of the setting reference time are respectively set.

  According to the present technology, it is possible to convert the format of the content from the first format having a different time axis to the second format.

  In addition, the effect described here is not necessarily limited, and may be any effect described in the present disclosure.

It is a figure showing an example of format conversion by an information processor concerning one embodiment of this art. It is a figure which shows the example of conversion of a counter value. FIG. 2 shows a protocol stack of a broadcast system using MMT. It is a figure which shows the structure of a NTP format. It is a figure which shows arrangement | positioning of the TLV packet which stores the IP packet containing the time information of a NTP format. It is a figure which shows the example which comprises a MMTP payload from a video and an audio | voice signal. It is a figure which shows the structure of a MMTP packet. It is a figure which shows the meaning of the value of payload_type. It is a figure which shows the structure of MMTP_payload (). It is a figure which shows the structure of MMTP_payload (). It is a figure which shows the structure of MMT-SI. It is a figure which shows the kind and function of a message of MMT-SI. It is a figure which shows the structure of PA message. It is a figure which shows the meaning of the value of message_id. It is a figure which shows the structure of MPT. It is a figure which shows the structure of MPU time stamp descriptor. It is a figure which shows the structure of MPU extended time stamp descriptor. It is a figure which shows the calculation method of PTS in D and MTS. It is a figure which shows the structure of TS packet. It is a figure which shows the structure of an adaptation field. It is a figure which shows the structure of a PES packet. It is a block diagram showing an example of composition of an information processor. FIG. 23 is a block diagram showing a configuration example of an MMT signal processing unit and a recording control unit of FIG. 22. It is a figure which shows the example of a process delay. It is a figure which shows the relationship of the counter value and time in MPEG-2 TS. It is a figure which shows the relationship of the counter value and time in MMT. It is a figure shown about conversion of a time stamp. It is another figure shown about conversion of a time stamp. It is a figure shown about conversion of the time stamp at the time of leap second insertion. It is a figure showing conversion of the time stamp at the time of leap second deletion. It is a block diagram showing an example of composition of PLL. It is a flow chart explaining conversion processing of an information processor. It is a figure which shows a series of format conversion. It is a block diagram showing an example of composition of a computer.

Hereinafter, modes for carrying out the present technology will be described. The description will be made in the following order.
1. Example of format conversion About MMT 3. About MPEG-2 TS 4. Configuration example of information processing apparatus 5. About conversion of counter value Operation of Information Processing Device Modified example

<1. Format conversion example>
FIG. 1 is a diagram illustrating an example of format conversion by an information processing apparatus according to an embodiment of the present technology.

  The information processing apparatus 1 is, for example, an apparatus such as a recording device incorporating a recording medium such as a hard disk drive (HDD) or a solid state drive (SSD), a television receiver, a personal computer, a set top box, or the like. The information processing apparatus 1 receives content such as a television program including video and audio, which is broadcast (distributed) via a transmission path of broadcast waves or a transmission path of communication such as the Internet. Transmission channels of broadcast waves include transmission channels of terrestrial broadcasting and satellite broadcasting.

  Transmission of content via a broadcast wave transmission path or communication transmission path is performed by MMT. The information processing apparatus 1 receives multiplexed data obtained by multiplexing a video stream and an audio stream by MMT. Subtitle data is also appropriately included in the multiplexed data.

  The information processing apparatus 1 is an apparatus compatible with reception of MMT content compliant with ARIB STD-B 60 (“Media transport method by MMT in digital broadcasting”). Further, the information processing apparatus 1 is also an apparatus compatible with content transmission conforming to ARIB TR-B 39 (“Advanced broadband satellite digital broadcast operation definition”).

  The information processing apparatus 1 has a function of reproducing the received MMT content and outputting the video and audio of the content from a television receiver (not shown) or the like connected to the information processing apparatus 1.

  In addition, the information processing apparatus 1 has a function of converting the received MMT content into the content of the MPEG-2 TS. MPEG-2 TS is defined by ITU-H.222.0.

  At the time of format conversion from MMT to MPEG-2 TS, the information processing apparatus 1 acquires video data and audio data stored in an MMTP (MMT Protocol) packet, and stores them again in a TS packet. The information processing apparatus 1 generates a TS (transport stream) by multiplexing a video TS packet and an audio TS packet together with a TS packet storing control information such as SI (Service Information).

  At the time of format conversion, the information processing device 1 converts time information included in the content of MMT into time information of MPEG-2 TS. MMT and MPEG-2 TS have different time axis formats. A different time axis means that at least one of the number of bits of the counter value defining the time and the precision (resolution) is different.

  The MMT content and the MPEG-2 TS content include, as time information, a counter value representing a reference time serving as a reference for operation, and a counter value representing a PTS (Presentation Time Stamp) and a DTS (Decode Time Stamp). .

  FIG. 2 is a diagram showing an example of conversion of counter values.

  As shown on the left side of FIG. 2, in the MMT, the reference time is represented as time information in the NTP (Network Time Protocol) format.

Although the details will be described later, in the NTP format, the reference time is represented by a counter value of 32 + ⁿ bits / 2 ⁿ Hz. Here, 32 + nbit / 2 ⁿ Hz indicates that a time of 1 second or more is expressed using 32 bits in seconds, and a time of 1 second or less is expressed using ⁿ bit. The precision for less than one second is 2 ⁿ Hz.

  In ARIB TR-B39, it is specified that n is 24 or more as the operation of the NTP format.

In MMT, PTS and DTS are obtained from the time represented by the counter value of 32 + nbit / 2 ⁿ Hz.

  On the other hand, as shown on the right side of FIG. 2, in MPEG-2 TS, PCR which is a reference time serving as a reference of operation is represented by a counter value of 42 bits / 27 MHz.

  Also, in the MPEG-2 TS, PTS and DTS are each represented by a counter value of 33 bits / 90 kHz.

The information processing apparatus 1 converts the reference time of the MMT represented by the counter value of 32 + nbit / 2 ⁿ Hz into the PCR of the MPEG-2 TS represented by the counter value of 42 bit / 27 MHz.

  Further, the information processing apparatus 1 converts PTS and DTS in MMT into PTS and DTS in MPEG-2 TS represented by a counter value of 33 bits / 90 kHz.

  The information processing apparatus 1 generates a TS including time information of the MPEG-2 TS converted in this manner.

  Returning to the explanation of FIG. 1, the information processing apparatus 1 records the content of the MPEG-2 TS generated by converting the content of the MMT in the recording medium 11 mounted on the information processing apparatus 1. The recording medium 11 is, for example, Blu-ray (registered trademark) Disc (hereinafter referred to as BD as appropriate). BD is a recording medium capable of recording an MPEG-2 TS file.

  The information processing apparatus 1 can record the content transmitted by the MMT on the BD. The playback device compatible with playback of BD can play back the content written to BD by the information processing device 1.

  Further, the information processing apparatus 1 transmits the content of the MPEG-2 TS generated by converting the content of the MMT via the network 12 such as the Internet. A playback device compatible with playback of MPEG-2 TS content can play back the content generated by the information processing device 1.

  As described above, by enabling conversion of MMT content to MPEG-2 TS content, various devices capable of processing MPEG-2 TS can process content provided by MMT. Become. That is, it is possible to make use of the assets of MPEG-2 TS.

<2. About MMT>
<2-1. MMT packet structure>
The MMT will be described. Here, among the rules of ARIB STD-B 60, portions related to the processing of the information processing device 1 will be described. Basically, the rules are based on ARIB STD-B 60.1.7, except for those explicitly stated.

  FIG. 3 is a diagram showing a protocol stack of a broadcast system using MMT.

  The codes of video and audio signals of a program are divided into transmission units of MFU (Media Fragment Unit) / MPU (Media Processing Unit). An MPU, which is a unit including data of one or more access units, is configured to include a plurality of MFUs.

  The MFU is placed in the MMTP payload, and an MMTP packet is configured by adding an MMTP header. MMTP packets are transmitted using IP packets. One MMTP packet is transmitted in one IP packet.

  The MMT-SI, which is control information indicating the configuration of a broadcast program, is also arranged in the MMTP payload as an MMT control message format, is MMTP packetized, and is transmitted as an IP packet.

  The time information in the NTP format described above is also transmitted using an IP packet.

  FIG. 4 is a diagram showing the configuration of the NTP format.

  An IP packet in the NTP format specified in IETF RFC 5905 "Network Time Protocol Version 4: Protocol and Algorithms Specification" is used to provide Coordinated Universal Time (UTC).

  leap_indicator (leap second indicator) indicates that the leap second (leap second) is inserted or deleted in the last 1 minute of the current month.

  When the content of the MMT before format conversion interposes insertion or deletion of the leap second, in the information processing apparatus 1, time stamp conversion is performed by adjusting the insertion or deletion of the leap second.

  Since the MPEG-2 TS does not have the concept of leap seconds, if the content of the MMT before format conversion interposes the insertion or deletion of leap seconds, the MMT timestamp is considered in consideration of the insertion or deletion of leap seconds. It is necessary to convert to MPEG-2 TS time stamp.

  In NTP, the accumulated number of seconds from January 1, 1900 at 00:00:00 is used. The NTP format includes reference_timestamp (reference timestamp).

  reference_timestamp indicates the time when the system time was last corrected in the NTP long format. The NTP long format includes a 32-bit field indicating seconds and a 32-bit field indicating 1 second or less.

  In ARIB TR-B 39, it is defined that the time of 1 second or less is indicated using nbit (n: 24 or more). n is 32 or less.

The time indicated by the NTP is expressed as a counter value of a 32 + nbit counter obtained by adding 32 bits representing the time of 1 second or more in seconds and nbit representing the time of 1 second or less. The accuracy for less than one second is 2 ⁿ Hz.

  The precision n of 1 second or less is indicated by the precision in FIG. n indicates log 2 of system clock precision (seconds).

In ARIB STD-B60, the transmission system and receiver in a broadcast system using MMT need to meet the following requirements.
The delivery system should maintain a clock based on the NTP timestamp.
In the transmission system, the clock and the clock for encoding video and audio should be synchronized.
The receiver must reproduce and hold a clock based on the received NTP time information.
In the receiver, the system clock for holding the clock and the clock for decoding video and audio should be synchronized.

  FIG. 5 is a diagram showing the arrangement of a TLV (Type Length Value) packet for storing an IP packet including time information in NTP format in STD-B44.

  It is defined by STD-B 323_1 that IP packets, including IP packets including time information in NTP format, are transmitted by TLV packets. A TLV packet storing an IP packet including time information in NTP format is placed at the beginning of the first slot among the slots allocated for each TLV stream ID.

  By arranging TLV packets storing IP packets including time information in NTP format in this manner, it is possible to suppress delay variations in IP packets including time information in NTP format.

  The information processing apparatus 1 extracts an IP packet from the TLV packet forming the TLV stream, and acquires NTP time information stored in the IP packet or a video or audio MMTP packet.

  FIG. 6 is a diagram showing an example of forming an MMTP payload from video and audio signals.

  In the processing of the video signal and the audio signal, the MPU is a unit of processing. As shown by broken lines in the middle of FIG. 6 as sample data, the MPU includes one or more access units, and is a unit that can perform video and audio decoding processing by itself. The size of the MPU is arbitrary and can include any number of access units. In a video signal to be encoded using inter-frame prediction, the MPU needs to be in GOP (Group of Picture) units.

  As shown in the middle of FIG. 6, the MPU is composed of MPU metadata including information on the configuration of the entire MPU, movie fragment metadata including information of encoded media data, and sample data which is encoded media data. Ru. Since one MPU can be composed of one or more movie fragments, multiple movie fragment metadata and sample data may exist.

  The same sequence number is added to the MPU for each MPU belonging to the same asset. It becomes possible to distinguish each MPU by using an asset ID for identifying an asset and a sequence number of the MPU.

  MFU is a unit smaller than MPU. The MFU can be taken out of the sample data that constitutes the MPU. As a method of configuring the MFU, there is a method of configuring the MFU in units of NAL units or in units of access units as shown by the downward arrow in FIG. By configuring the MFU in consideration of the medium, it is possible to suppress the propagation of an error when a drop in transmission quality such as packet loss occurs.

  The presentation time (the PTS in the above-described MMT) is indicated in units of MPUs in media in which presentation times such as video components and audio components are specified. The presentation time of MPU is designated using a common time axis based on UTC. Therefore, the device on the receiving side can synchronously present the necessary media components regardless of the difference in the transmission path between broadcast and communication or the difference in the transmission source.

  Thus, there are MPU, MFU, MMTP packet, and MMTP payload as elements that make up the encoded signal in MMT.

  FIG. 6 shows an example in which one MFU is stored in one MMTP payload. Multiple MMUs may be stored in one MMTP payload, and conversely, one MFU may be stored in multiple MMTP payloads.

  FIG. 7 is a diagram showing the configuration of the MMTP packet.

  An MMTP packet is composed of an MMTP header and an MMTP payload. Among the descriptions shown in FIG. 7, the descriptions from the top to the front of MMTP_payload () constitute an MMTP header.

  The payload_type (payload type) included in the MMTP header indicates the data type of the MMTP payload.

  FIG. 8 is a diagram showing the meaning of the value of payload_type.

  As shown in FIG. 8, the value of payload_type being 0x00 indicates that the MMTP payload includes an MPU such as video and audio.

  Also, that the value of payload_type is 0x02 indicates that the MMTP payload includes a control message.

  Returning to the description of FIG. 7, packet_id (packet identifier) included in the MMTP header is information for identifying the data type of the MMTP payload.

  In ARIB TR-B39, when the MMTP payload includes an MPU (when the value of payload_type is 0x00), it is defined that the packet_id of the asset shown in the MMT package table described later is described.

  FIG. 9 and FIG. 10 are diagrams showing the configuration of MMTP_payload ().

  FIG. 9 shows a description when the value of payload_type is 0x00, that is, the relevant MMTP payload includes an MPU. On the other hand, FIG. 10 shows a description in the case where the value of payload_type is 0x02, that is, the MMTP payload includes a control message.

  In the description shown in FIG. 9, fragment_type (fragment type) indicates a fragment type of information stored in the MMTP payload.

  When the value of fragment_type is 2, it indicates that the MMTP payload includes the sample data (NAL unit, access unit) of timed media data making up the MFU, the subsample data, or the item of timeless media data. . For example, MFU_data_byte of FIG. 9 described when the value of fragment_type is 2 and the value of timed_flag is 1 corresponds to the sample data of time-added media data making up the MFU.

  Further, in the description shown in FIG. 9, when the MMTP payload stores MPU metadata, movie fragment metadata, and MFU, MPU_sequence_number (MPU sequence number) indicates the sequence number of the MPU to which they belong.

  In the description shown in FIG. 10, message_length (message data length) described when the value of payload_type is 0x02 indicates the size of one control message arranged immediately after this field in units of bytes.

  message_byte (message data) is a data byte of a control message. Hereinafter, as appropriate, the control message is also simply referred to as a message.

2-2. MMT control message>
Here, control messages stored in the MMTP payload will be described.

  FIG. 11 is a diagram showing the structure of MMT-SI which is control information.

  MMT-SI showing information related to MMT package configuration and broadcast service, as shown in FIG. 11, a message storing a table or descriptor, a table with elements or attributes indicating specific information, and details It is composed of three layers of descriptors that indicate specific information.

  As mentioned above, messages are stored in the MMTP payload and transmitted using MMTP packets. The value of payload_type when the message configures the MMTP payload is 0x02. Storing a plurality of messages in one MMTP payload is not performed, and one message is stored in one MMTP payload.

  FIG. 12 shows the types and functions of MMT-SI messages.

  As shown in FIG. 12, the messages mainly include Package Access (PA) messages, M2 section messages, CA messages, M2 short section messages, and data transmission messages. For example, a PA message is an entry point of MMT-SI, and is used to transmit various tables of MMT-SI.

  The type of such message is identified by message_id (message identifier) described in the MMTP payload as message_byte.

  FIG. 13 is a diagram showing the structure of a PA message.

  The message_id is set as 0x0000 as shown in FIG.

  number_of_tables (number of tables) indicates the number of tables stored in this PA message.

  table_id (table identification) indicates an identifier of a table stored in this PA message.

  table is a table stored by this PA message. One of the tables, MPT (MMT package table), is described in table () of the PA message.

  A description of such a PA message is included in the MMTP payload (FIG. 10) as message_byte.

  FIG. 15 is a diagram showing the configuration of the MPT.

  The MPT provides information that configures the package, such as a list of assets and the asset location on the network. The MPT contains a descriptor.

  The MPT_descriptors_length (MPT descriptor length) in the description shown in FIG. 15 indicates the length of the MPT descriptor area in units of bytes.

  MPT_descriptors_byte (MPT descriptor area) is an area for storing MPT descriptors. The descriptors stored in the MPT_descriptors_byte include, for example, an MPU time stamp descriptor (MPU_Timestamp_Descriptor ()) and an MPU extended time stamp descriptor (MPU_Extended_Timestamp_Descriptor ()).

  The MPU time stamp descriptor is a descriptor that indicates the presentation time of the first access unit in the presentation order in the MPU. Furthermore, the MPU extended time stamp descriptor is a descriptor that provides the decoding time of the access unit in the MPU.

  FIG. 16 is a diagram showing the configuration of the MPU time stamp descriptor.

  The descriptor_tag of the MPU timestamp descriptor is set as 0x001.

  mpu_sequence_number (MPU sequence number) indicates a sequence number of MPU describing a time stamp in the MPU time stamp descriptor. As described above, the same sequence number is added to each MPU that belongs to the same asset.

mpu_presentation_time (MPU presentation time) indicates the presentation time of the MPU in the NTP format (indicated by a counter value of 32 + nbit / 2 ⁿ Hz).

  FIG. 17 is a diagram showing the configuration of the MPU extended time stamp descriptor.

  The descriptor_tag of the MPU extended time stamp descriptor is set as 0x8026.

  mpu_sequence_number (MPU sequence number) indicates a sequence number of an MPU including an access unit for specifying a decoding time or the like in the MPU extended time stamp descriptor.

  mpu_decoding_time_offset (MPU decoding time offset) is an MPU specified by the MPU sequence number, which is an absolute value of the difference between the decoding time of the first access unit in decoding order and the presentation time of the first access unit in presentation order Indicated in units of time indicated by the scale.

  num_of_au (the number of access units) indicates the number of access units for which a decoding time or the like is designated by the MPU extended time stamp descriptor.

  dts_pts_offset (decoding time and presentation time offset) indicates the time from the decoding time of the access unit to the presentation time in time units indicated by the time scale.

  pts_offset (PTS offset) indicates the difference in presentation time between the immediately preceding access unit and the current access unit in the order of presentation in the same MPU in the time unit indicated by the time scale.

  The presentation time of the first access unit in the presentation order of the MPU is specified from the MPU time stamp descriptor. Also, the decoding time of each access unit is specified from the MPU extended time stamp descriptor.

  The MPU extension time stamp descriptor includes mpu_presentation_time_leap_indicator (MPU presentation time / second indicator).

  mpu_presentation_time_leap_indicator indicates whether or not there is adjustment of time information by insertion or deletion of leap seconds. A value of 1 for mpu_presentation_time_leap_indicator indicates that an insertion of 8:59:59 as a leap second will be made after 8:59:59, and a value of 2 will be 8:59:59 Indicates that seconds will be deleted.

  FIG. 18 is a diagram showing a method of calculating PTS and DTS in MMT.

  Each rectangle shown in FIG. 18 indicates a picture (access unit) forming GOPn included in a certain MPU. The upper part of FIG. 18 shows the alignment in the decoding order of each access unit, and the lower part shows the alignment in the presentation order of each access unit. The alphabet of I / P / B shows a picture type, and a number shows the number of each picture in presentation order.

  The mpu_presentation_time of the MPU time stamp descriptor indicates the presentation time of the first access unit in presentation order in the MPU. The presentation time indicated by the MPU time stamp descriptor is a time indicated by the upward triangle at the lower left of FIG.

  On the other hand, the MPU extended time stamp descriptor presents the decoding time of the first access unit in the decoding order and the first access unit in the presentation order in the MPU as indicated by the dashed arrow on the left side of FIG. Indicates the difference value with the time.

  Further, the MPU extended time stamp descriptor indicates the difference value between the decoding time and the presentation time of each access unit by dts_pts_offest as a value having a time scale as a unit time. Furthermore, the MPU extended time stamp descriptor indicates the difference value between the presentation time of the immediately preceding access unit in the presentation order and the presentation time of the current access unit in the same MPU by pts_offset using a time scale as a unit time. .

Using these times and values, the decoding time DTS (n) and the presentation time PTS (n) of the nth access unit in the MPU are calculated by the following equations (1) and (2), respectively.

Thus, the PTS and DTS of each access unit are specified from the MPU time stamp descriptor and the MPU extended time stamp descriptor. Since it is determined using mpu_presentation_time, which is a counter value of 32 + nbit / 2 ⁿ Hz, it can be said that DTS of the MPU is also a time indicated by the counter value of 32 + ⁿ bit / 2 ⁿ Hz.

  In the information processing apparatus 1, the MPU time stamp descriptor and the MPU extended time stamp descriptor are obtained from the control message of the MMTP packet, and the PTS and DTS are obtained based on the MPU time stamp descriptor and the MPU extended time stamp descriptor. Be The calculation of PTS and DTS is performed before the start of decoding of each access unit constituting the MPU transmitted using another MMTP packet.

<3. About MPEG-2 TS>
Next, the MPEG-2 TS will be described.

  FIG. 19 is a diagram showing the configuration of a TS packet that constitutes a TS.

  One TS packet is configured by adding 184 bytes of payload, adaptation field, or both to a 4 bytes header. The header includes, for example, a PID that is identification information of the type of data contained in the payload. The configuration of such a TS packet is defined, for example, by ISO / IEC 138180-1.

  The adaptation field of the TS packet includes a PCR as indicated by hatching in FIG. FIG. 20 shows the configuration of the adaptation field.

  At the time of conversion from MMT to MPEG-2 TS, in the information processing apparatus 1, a PCR obtained by converting the reference time of the MMT represented by time information in the NTP format is set in the adaptation field of the TS packet. .

  FIG. 21 is a diagram showing the configuration of a PES (Packetized Elementary Stream) packet.

  In MPEG-2 TS, video and audio streams are divided into predetermined units and stored in PES packets. One PES packet is divided into a plurality of TS packets. A header is added to the PES packet, and PTS and DTS are described as shown in FIG.

  At the time of conversion from MMT to MPEG-2 TS, in the information processing apparatus 1, PTS and DTS obtained by converting PTS and DTS of MMT calculated by analyzing MMT-SI are set in PES packets Ru.

<4. Configuration Example of Information Processing Device>
FIG. 22 is a block diagram showing a configuration example of the information processing device 1.

  The information processing apparatus 1 includes a receiving unit 31, an MMT signal processing unit 32, a recording control unit 33, a drive 34, an output control unit 35, and a communication unit 36.

  The receiver 31 receives a broadcast wave signal from an antenna (not shown) and performs various processes such as demodulation and error correction. The receiving unit 31 outputs the TVL stream obtained by performing various processes to the MMT signal processing unit 32 as MMT content.

  In addition, when transmission of content is performed via a transmission channel of communication, the reception unit 31 controls the communication unit 36 to receive the content of MMT, and performs MMT on the TVL stream obtained by performing predetermined processing. The signal is output to the signal processing unit 32.

  The MMT signal processing unit 32 reproduces the content of the MMT, outputs the video and audio of the content from the television receiver, and converts the content of the MMT into the content of the MPEG-2 TS.

  For example, when playing back MMT content, the MMT signal processing unit 32 extracts video data and audio data from the TLV stream supplied from the receiving unit 31 and decodes the data. The MMT signal processing unit 32 outputs the video and audio data of the content obtained by decoding to the output control unit 35.

  When converting MMT content into MPEG-2 TS content, the MMT signal processing unit 32 stores data stored in the MMTP packet extracted from the TLV stream supplied from the receiving unit 31 in the TS packet. Correct and generate the TS. The MMT signal processing unit 32 outputs the generated TS to the recording control unit 33 when recording the content of the MPEG-2 TS on the recording medium 11, and transmits the generated TS to the other device via the network 12, the generated TS Are output to the communication unit 36.

  The recording control unit 33 controls the drive 34 to record the TS generated by the MMT signal processing unit 32 in the recording medium 11 mounted on the drive 34.

  The output control unit 35 supplies the video and audio data supplied from the MMT signal processing unit 32 to, for example, a television receiver connected to the information processing apparatus 1, and outputs the data from the display and the speaker.

  The communication unit 36 communicates with various devices via the network 12. For example, the communication unit 36 receives the content of the MMT distributed from the server via the network 12 and outputs the content to the receiving unit 31. The communication unit 36 also transmits the TS generated by the MMT signal processing unit 32 to another device via the network 12.

  FIG. 23 is a block diagram showing a configuration example of the MMT signal processing unit 32 and the recording control unit 33 of FIG.

  The demultiplexer 51 extracts an IP packet from the TLV packet forming the TLV stream supplied from the reception unit 31, and performs a DEMUX process on the MMT data transmitted using the IP packet.

  For example, the demultiplexer 51 extracts an IP packet including time information in NTP format transmitted using a TLV packet, and outputs the IP packet to the comparator 52. As described with reference to FIG. 5, the IP packet including the time information in the NTP format is placed at the beginning of the first one of the slots constituting the TLV stream.

  Further, the demultiplexer 51 outputs, to the MMT-SI analysis unit 55, an MMTP packet storing the MMT-SI among the MMTP packets transmitted using the IP packet. The demultiplexer 51 outputs, to the MPU / MMT packet analysis unit 58, an MMTP packet storing video data and audio data constituting the MPU. The type of data stored in the MMTP payload is identified by the payload_type of the MMTP packet (FIG. 8).

  The comparator 52 outputs the time information (counter value of 32 + n bits) of the NTP format stored in the IP packet supplied from the demultiplexer 51 to the NTP clock counter 53, and sets it as the initial value of the counter value.

  Further, the comparator 52 is configured to receive time information from the NTP clock counter 53 and NTP time information supplied from the demultiplexer 51 every time an IP packet including time information in NTP format is supplied from the demultiplexer 51. And the result is output to the NTP clock counter 53.

The NTP clock counter 53 counts a 2 ⁿ Hz clock signal generated by a VCO (not shown), and outputs a 2 ⁿ Hz system clock signal representing a 32 + ⁿ bit counter value. The system clock signal output from the NTP clock counter 53 is supplied to the comparator 52, the clock conversion unit 54, and the video / audio synchronization control unit 56.

The clock conversion unit 54 converts the 32 + n-bit counter value represented by the 2 ⁿ Hz system clock signal supplied from the NTP clock counter 53 into a 42-bit counter value (27 MHz) indicating PCR of the MPEG-2 TS. Details of the conversion by the clock conversion unit 54 will be described later. The clock converter 54 outputs the 42-bit counter value obtained by the conversion to the TS processor 62 as a PCR.

  The MMT-SI analysis unit 55 acquires and analyzes MMT-SI from the MMTP packet stored in the IP packet supplied from the demultiplexer 51. For example, the MMT-SI analysis unit 55 acquires the MPT transmitted by the PA message stored in the MMTP packet, and the MPU time stamp descriptor (FIG. 16) described in the MPT and the MPU extended time stamp descriptor (FIG. 17) to get.

  Further, the MMT-SI analysis unit 55 calculates (specifies) the PTS of each MPU based on the MPU time stamp descriptor. The MMT-SI analysis unit 55 calculates the DTS of the access unit constituting each MPU using the PTS of each MPU and the description of the MPU extended time stamp descriptor as described with reference to FIG. .

  The MMT-SI analysis unit 55 outputs the calculated PTS and DTS to the video / audio synchronization control unit 56 and the time stamp conversion unit 57 together with mpu_sequence_number indicating the sequence number of the MPU. As described above, mpu_sequence_number included in the MPU time stamp descriptor indicates the sequence number of the MPU specifying the presentation time (FIG. 16). Further, mpu_sequence_number included in the MPU extended time stamp descriptor indicates the sequence number of the MPU including the access unit for specifying the decoding time and the like (FIG. 17).

  The MMT-SI analysis unit 55 performs transmission of subtitle data in TTML format (hereinafter referred to as TTML subtitle as appropriate), and the MH-data encoding method is used when the time in the TTML document is represented in NTP format The descriptor is analyzed, and RST (Reference Start Time), which is the time that is the starting point, is specified. The MMT-SI analysis unit 55 outputs the identified RST to the video and audio synchronization control unit 56 and the time stamp conversion unit 57.

  The video and audio synchronization control unit 56 operates according to the system clock signal from the NTP clock counter 53, and controls the timing of decoding and output by the video and audio decoder 60 based on PTS and DTS calculated by the MMT-SI analysis unit 55. Do. Control of the video / audio decoder 60 by the video / audio synchronization control unit 56 is also performed based on metadata such as MPU metadata and movie fragment metadata supplied from the MPU / MMT packet analysis unit 58.

  The time stamp conversion unit 57 converts the 32 + n-bit counter values representing PTS and DTS calculated by the MMT-SI analysis unit 55 into counter values (90 kHz) representing 33-bit PTS and DTS of MPEG-2 TS, respectively. . Details of the conversion by the time stamp conversion unit 57 will be described later. The time stamp conversion unit 57 outputs the PTS and DTS of the MPEG-2 TS obtained by the conversion to the TS conversion processing unit 62.

  The time stamp conversion unit 57 outputs mpu_sequence_number representing the sequence number of the MPU to which the PTS and DTS of the MPEG-2 TS obtained by the conversion are related. In addition, in the time stamp conversion unit 57, an SI that needs to be included in the MPEG-2 TS is generated based on the MMT-SI, as appropriate, and is output to the TS processing unit 62.

  Further, the time stamp conversion unit 57 converts the RST counter value specified by the MMT-SI analysis unit 55 into a 33-bit counter value (90 kHz) of the MPEG-2 TS. The timestamp conversion unit 57 outputs the counter value obtained by the conversion to the TS conversion processing unit 62 as MTS (Module Time Stamp).

  The time stamp conversion unit 57 performs time stamp conversion so as to eliminate the influence of the leap second adjustment when transmission of MMT video and audio to be converted is performed over the leap second.

  The MPU / MMT packet analysis unit 58 analyzes the MMTP packet stored in the IP packet supplied from the demultiplexer 51 to acquire data of each MPU. The MPU metadata, movie fragment metadata, and MFU which are data of each MPU are specified by MPU_sequence_number (FIG. 9) which is information indicating the sequence number of the MPU to which they belong.

  The MPU / MMT packet analysis unit 58 outputs the metadata such as MPU metadata and movie fragment metadata of each MPU acquired from the MMTP payload to the video / audio synchronization control unit 56 at the time of reproduction of the content of the MMT. Further, the MPU / MMT packet analysis unit 58 outputs the video data and audio data of the MFUs constituting the respective MPUs acquired from the MMTP payload to the decoder buffer 59.

  On the other hand, when converting the format from MMT to MPEG-2 TS, the MPU / MMT packet analysis unit 58 acquires the video data (VIDEO ES) and audio data (AUDIO ES) of MFUs constituting each MPU, which are acquired from the MMTP payload. , MPU_sequence_number and the buffer 61.

  When transmission of TTML subtitles is performed, the MPU / MMT packet analysis unit 58 outputs TTML subtitle data (SUBTITLE DATA) acquired from the MMTP payload to the buffer 61 together with MPU_sequence_number.

  The video and audio decoder 60 decodes and outputs the video data and audio data recorded in the decoder buffer 59 under the control of the video and audio synchronization control unit 56. The data output from the video and audio decoder 60 is supplied to the output control unit 35, and the video and audio of the content are output.

  The TS conversion processing unit 62 constructs a PES by putting together data of the video data and audio data recorded in the buffer 61 in which the same value is set as the MPU_sequence_number. Further, the TS conversion processing unit 62 adds the PTS and DTS related to each PES supplied from the time stamp conversion unit 57 to each PES, and generates a PES packet. The PES to which each PTS / DTS is to be added is identified based on the mpu_sequence_number supplied from the time stamp conversion unit 57.

  The TS formation processing unit 62 performs TS packetization of the generated PES packet. The TS conversion processing unit 62 generates a TS based on the TS packet in which the data of the PES packet is stored in the payload and the TS packet in which the PCR generated by the clock conversion unit 54 is included in the adaptation field.

  The TS conversion processing unit 62 also generates a TS by multiplexing data of TTML subtitles in a Multi Part Module format of Digital Storage Media Command and Control (DSM-CC).

  At the time of generation of Partial TS, TS conversion processing unit 62 converts SI of MPEG-2 TS such as PAT, PMT, DAT, SIT, etc. defined by ARIB STD-B 14 into information supplied from time stamp conversion unit 57. Embed in TS based on.

  The PAT (Program Association Table) is information specifying a packet identifier of a TS packet that transmits a PMT related to the Partial TS. PMT (Program Map Table) is information for specifying a packet identifier of a TS packet for transmitting each encoded signal constituting a broadcast program. The PAT and PMT are retransmitted every 100 ms with one or more cycles.

  The DIT (Discontinuity Information Table) is information indicating a change point at which program arrangement information of a program transmitted by Partial TS may be discontinuous. SIT (Selection Information Table) is information indicating information on a program transmitted by Partial TS.

  The TS conversion processing unit 62 outputs the TS obtained by performing the above-described TS conversion processing to the recording control unit 33.

  The control unit 63 sets the initial value of the counter value used in the clock conversion process in the clock conversion unit 54, and sets the initial value of the counter value used in the time stamp conversion process in the time stamp conversion unit 57.

  The clock conversion process, the time stamp conversion process, and the ES remultiplex conversion process performed at the time of format conversion require different processing times. The clock conversion process is a process in the comparator 52, the NTP clock counter 53, and the clock conversion unit 54, which is indicated by an arrow # 11 in FIG. The time stamp conversion process is a process in the MMT-SI analysis unit 55 and the time stamp conversion unit 57 indicated by an arrow # 12. The ES remultiplexing conversion processing is processing in the MPU / MMT packet analysis unit 58 and buffer 61 indicated by an arrow # 13.

  The control unit 63 performs offset adjustment by setting an initial value so as to eliminate the influence of the delay of each process.

  The recording control unit 33 includes a T-STD 81, a PLL 82, an arrival time clock counter 83, a source packetizer 84, and a write buffer 85. The configuration of the recording control unit 33 shown in FIG. 23 is a conceptual model for defining a recording process. The recording control unit 33 has a function of adding an ATS (Arrival_time_stamp) to a TS packet forming the TS according to this recorder model, and generating a sequence of source packets.

  The i-th byte of the TS supplied from the MMT signal processing unit 32 is input to a T-STD (Transport stream system target decoder) 81 and a Source packetizer 84 at time t (i).

  T-STD 81 is a virtual decoder in the recorder model. A decoder corresponding to T-STD 81 is not necessarily present in the recording control unit 33.

  PLL 82 generates a 27 MHz clock locked to the value of TS PCR.

  The arrival time clock counter 83 is a binary counter that counts pulses of 27 MHz frequency output from the PLL 82. Arrival_time_clock (i) is a counter value of the arrival time clock counter 83 at time t (i).

  The Source packetizer 84 adds TP_extra_header to all TS packets to generate a source packet. The Source packetizer 84 also adds an ATS to the TS packet.

  Specifically, the source packetizer 84 sets the value of ATS in the TP_extra_header of the source packet based on Arrival_time_clock (i) supplied from the Arrival time clock counter 83. ATS represents the time when the first byte of the TS packet arrives at both T-STD 81 and Source packetizer 84.

  The Write Buffer 85 records source packets generated by the Source packetizer 84. Each source packet output from the write buffer 85 is supplied to the drive 34 and recorded in the recording medium 11.

  As described above, in the case where transmission of a TTML subtitle is performed, the MMT signal processing unit 32 also performs conversion of the time stamp. In the following, the conversion of clocks for video, audio, TTML subtitles, and conversion of video and audio timestamps will be mainly described.

<5. About conversion of counter value>
<5-1. Time stamp conversion>
Here, conversion of the counter value indicating PTS / DTS will be described.

(1) Basic Flow of Timestamp Conversion FIG. 25 is a diagram showing the relationship between counter values and time in MPEG-2 TS.

  The horizontal axis of the graph shown in FIG. 25 indicates time, and the vertical axis indicates the counter value. The same applies to FIG. 26 and thereafter.

  The PTS / DTS of the MPEG-2 TS is represented by a counter value of 33 bits @ 90 kHz. The notation "@ 90 kHz" indicates that the precision (resolution) of the counter is 90 kHz.

The wrap around of the MPEG-2 TS counter value occurs approximately every 26.5 h as shown in the following equation (3).

  The relationship between the MPEG-2 TS counter value and the real time is as shown by the solid line in FIG.

  FIG. 26 is a diagram showing the relationship between counter values and time in the MMT.

The PTS / DTS of the MMT is represented by a counter value of 32 + nbit @ 2 ⁿ Hz in the NTP format.

The wrap around of the MMT counter value occurs every 1193046 h as shown in the following equation (4).

  The relationship between the MMT counter value and the real time is as shown by the solid line in FIG.

  The NTP counter value is a value starting from UTC at January 1, 1900 at 00:00:00. The characteristics of the counter of the MPEG-2 TS with the time at the start point of the STC (System Time Clock) of the MPEG-2 TS as an arbitrary time after 00:00:00 on January 1, 1900 of the origin (FIG. The characteristics of the MMT and MMT counters (FIG. 26) are shown in FIG.

  There is a fixed relationship between the start point of the STC of MPEG-2 TS clocked independently for each system / program and the start point of the PCR (Program Clock Reference) that transmits it at 00:00:00 on January 1, 1900. There is no need to match the NTP origin and the STC origin.

  Here, it is assumed that the STC count start time of the MPEG-2 TS is a time S. The time S is, for example, a recording start time when converting the format of the content and recording (recording) on the BD.

  In addition, the counter value of MMT (UTC time) at time S is S @ MMT, and the counter value of MPEG-2 TS (STC count start value (initial value)) is S '@ MPEG-2 TS.

  When the PTS / DTS of MMT indicates a predetermined time, the PTS / DTS of the corresponding MPEG-2 TS obtains the counter value of the MPEG-2 TS representing the predetermined time based on the MMT counter value. Identified by

  Specifically, the counter value X 'of the MPEG-2 TS can be obtained by the following procedure based on the counter value X of the MMT.

・ Step 1
The counter value A ′ at which wrap around of the MPEG-2 TS counter (33 bit @ 90 kHz) occurs is expressed by the following equation (5).

Assuming that less than one second of the MMT counter (32 + nbit @ 2 ⁿ Hz) is an nbit resolution (2 ⁿ Hz), the ratio of 2 ³³ to 2 90 ^k is used. In this case, the interval A of the MMT counter value for each wraparound of the MPEG-2 TS counter is expressed by the following equation (6).

  The interval A between the counter value A 'of the MPEG-2 TS and the counter value of the MMT is shown in FIG.

・ Step 2
The counter value X of the MMT is X @ MMT, and the counter value X 'of the MPEG-2 TS which is sought based on the X @ MMT is X' @ MPEG-2 TS. An example of X @ MMT and X '@ MPEG-2 TS is shown in FIG.

When the MMT counter value becomes X @ MMT (time X), the MPEG-2 TS counter value X '@ MPEG-2 TS increases the MMT counter value from S @ MMT to X @ MMT The initial value S 'of the counter of the MPEG-2 TS is added to the increment of the counter value of the MPEG-2 TS between them. The X 'alias indicated by a white circle in FIG. 28 is expressed by the following equation (7).

If the effect of wraparound of the MPEG-2 TS counter is eliminated by finding the remainder of A ′ (MPEG-2 TS counter value A ′), the MPEG-2 TS counter value X ′ to be sought is It is represented by (8).

  As described above, after setting an arbitrary initial value S 'as the MPEG-2 TS counter value, it becomes possible to obtain the MPEG-2 TS counter value X' corresponding to the MMT counter value X.

  By setting an arbitrary initial value S ', it is possible to adjust the timing difference due to the delay difference between clock conversion processing and ES remultiplex conversion processing, and the difference between MMT and MPEG-2 TS buffer models. .

  That is, the control unit 63 sets an initial value S ′ for adjusting a delay difference or the like in the time stamp conversion unit 57, and converts PTS / DTS of MMT into PTS / DTS of MPEG-2 TS.

(2) Time stamp conversion in consideration of adjustment of leap seconds (2-1) When insertion of leap seconds is performed FIG. 29 is a diagram showing an example of conversion of timestamps in the case of insertion of leap seconds. . In FIG. 29, the vicinity of the time (8:59:59 am) at which the insertion of the leap second was performed is shown enlarged.

  As shown in the lower part of FIG. 29, when the leap second is inserted, the value of mpu_presentation_time_leap_indicator (FIG. 17) of the MPU extension time stamp descriptor is 1 at the timing immediately after the first time 8:59:59. Switch from 0 to 0. The value of reference_start_time_leap_indicator of the MH-data encoding method descriptor used to adjust the leap second of the time of the TTML subtitle also switches in the same manner as the value of mpu_presentation_time_leap_indicator.

  Also, if there is a leap second insertion, the value of NTP's leap_indicator (FIG. 4) switches from 1 to 0 immediately after the insertion of 8:59:59.

  In this case, as shown in the upper part of FIG. 29, the MMT counter value corresponds to leap seconds (1 second) at the timing immediately before the second 8:59:59 am which is leap seconds. It decreases and then increases as it did before the insertion of the leap second. The counter value of the MMT increases across the discontinuous point as shown by the solid line # 21 and the solid line # 22.

  Here, for example, since the continuous recording time of 1 Clip (1TS) in the case of recording on BD is at most about 26 and a half hours, the number of times of adjustment by leap second should be considered within the practical continuous recording time It can be assumed.

  Based on the MMT counter value X (X @ MMT) at a certain time after the insertion of the leap second, when the counter value X ′ of the MPEG-2 TS is determined as described above, the MPEG indicated by the black circle in FIG. -2 TS counter value X '(X' @ MPEG-2 TS) is obtained. The counter value X 'of the MPEG-2 TS is the counter value before the insertion of' seconds' is corrected.

  The MPEG-2 TS counter value X 'determined based on the MMT counter value X is corrected as follows. Since the UTC correction by the insertion of the leap second is a correction of 1 second, the correction amount of the counter value of the MPEG-2 TS is 90000 for the 90 kHz counter.

(I) The period in which the value of leap_indicator of the descriptor on which the information of the MMT counter value of the conversion source is 1 is between the recording start time (time S) and the time of the MMT counter value When the value of leap_indicator is 0 at the time of the counter value of MMT which becomes.

In this case, the MPEG-2 TS counter value X ′ obtained based on the MMT counter value X is corrected by the following equation (9).

  As a result, the MPEG-2 TS counter value X 'obtained based on the MMT counter value X at a certain time after insertion of the second is corrected as indicated by the point of the upward arrow. Even when there is an insertion of 'seconds', the increase in the counter value X' of the MPEG-2 TS is represented by a straight line # 31 without inserting a discontinuity.

(Ii) otherwise. That is, the period in which the value of leap_indicator of the descriptor on which the information of the MMT counter value of the conversion source is 1 is not between the recording start time and the time of the MMT counter value, or the MMT to be converted When the value of leap_indicator is 1 at the time of the counter value of.

  In this case, correction of the MPEG-2 TS counter value X 'is not performed, and the MPEG-2 TS counter value X' obtained based on the MMT counter value X is used as it is.

(2-2) When there is a deletion of leap seconds FIG. 30 is a diagram showing an example of conversion of a time stamp when there is a deletion of leap seconds. In FIG. 30, the vicinity of the time (8:59:59 am) when the leap second was deleted is shown enlarged.

  As shown in the lower part of FIG. 30, when there is a leap second deletion, the value of mpu_presentation_time_leap_indicator (FIG. 17) of the MPU extended time stamp descriptor is changed from 2 to 0 immediately after 8:59:58. Switch. The value of reference_start_time_leap_indicator of the MH-data encoding method descriptor used to adjust the leap second of the time of the TTML subtitle also switches in the same manner as the value of mpu_presentation_time_leap_indicator.

  When the leap second is deleted, the value of NTP's leap_indicator (FIG. 4) switches from 2 to 0 at a timing immediately after 8:59:58.

  In this case, as shown in the upper part of FIG. 30, the MMT counter value is increased by an amount corresponding to leap seconds (one second) immediately before 8:59:59 am, and then leap seconds As before there is a deletion of. The counter value of the MMT increases across the discontinuous point as shown by the solid line # 51 and the solid line # 52.

  Here, for example, since the continuous recording time of 1 Clip (1TS) in the case of recording on BD is at most 26 hours and a half, it is assumed that the number of times of adjustment by leap second should be considered within practical continuous recording time it can.

  When the counter value X 'of the MPEG-2 TS is obtained as described above based on the MMT counter value X (X @ MMT) at a certain time after the leap second deletion, the MPEG shown by the black circle in FIG. -2 TS counter value X '(X' @ MPEG-2 TS) is obtained. The counter value X 'of this MPEG-2 TS is the counter value before correcting the deletion of' seconds'.

  The MPEG-2 TS counter value X 'determined based on the MMT counter value X is corrected as follows. Since the UTC correction by the deletion of the leap second is a correction of 1 second each time, the correction amount of the counter value of the MPEG-2 TS is 90000 for the 90 kHz counter.

(I) A period in which the value of leap_indicator of the descriptor on which the information of the MMT counter value of conversion source is 2 is from the recording start time to the time of the MMT counter value, and the MMT counter to be converted When the value of leap_indicator is 0 at the time of value.

In this case, the MPEG-2 TS counter value X ′ determined based on the MMT counter value X is corrected by the following equation (10).

  As a result, the MPEG-2 TS counter value X 'obtained based on the MMT counter value X at a certain time after deletion of the second is corrected as indicated by the point of the downward arrow. Even when there is a deletion of 'seconds', the increase of the counter value X' of the MPEG-2 TS is represented by a straight line # 61 without inserting a discontinuous point.

(Ii) otherwise. That is, the period in which the value of leap_indicator of the descriptor on which the information of the MMT counter value of conversion source is 2 is not between the recording start time and the time of the MMT counter value, or the MMT to be converted When the value of leap_indicator is 2 at the time of the counter value of.

  In this case, correction of the MPEG-2 TS counter value X 'is not performed, and the MPEG-2 TS counter value X' obtained based on the MMT counter value X is used as it is.

  As described above, when there is an adjustment by 'second' in the time information of the MMT, the time stamp conversion unit 57 corrects the counter value X 'of the MPEG-2 TS so as to eliminate the influence.

  The determination as to whether or not the leap second adjustment is made may be made based on the analysis result of the MPU extended time stamp descriptor, or may be made based on the analysis result of the NTP. . In the latter case, for example, the analysis unit (not shown) analyzes the NTP, and information representing the value of leap_indicator is supplied to the time stamp conversion unit 57 as the analysis result.

5-2. Clock conversion>
Next, clock conversion will be described.

In MMT, the reference time in NTP format is represented as a counter value of 32 + nbit @ 2 ⁿ Hz.

Also, in the MPEG-2 TS, PCR as a reference time is represented as a counter value of 42 bits @ 27 MHz (lower equation).
³³ bits (90 kHz counter 0-(2 ³³ -1)) + 6 bits (Reserve) + 9 bits (27 MHz counter 0-300)

The clock conversion unit 54 converts the counter value of 32 + nbit @ 2 ⁿ Hz into a counter value of 42 bit @ 27 MHz and outputs the result as PCR.

  FIG. 31 is a block diagram showing a configuration for performing clock conversion processing.

Among the configurations shown in FIG. 31, the configurations described with reference to FIG. As shown in FIG. 31, the clock conversion process is performed by two stages of PLLs of 2 ⁿ Hz PLL 101 and 27 MHz PLL 102. The 27 MHz PLL 102 corresponds to the clock converter 54.

2 ⁿ Hz PLL 101 is composed of a comparator 52,2 ⁿ Hz VCO111 and NTP clock counter 53,. The time information in the NTP format is input from the demultiplexer 51 to the 2 ⁿ Hz PLL 101.

The comparator 52 uses the fact that the time information (reference_timestamp) in NTP format is input as a trigger, and compares the input 32 + nbit @ 2 ⁿ Hz counter value with the counter value of the NTP clock counter 53.

For example, the value of reference_timestamp analyzed by an analysis unit (not shown) is input to the comparator 52. As described with reference to FIG. 4, reference_timestamp is a counter value of 32 + nbit @ 2 ⁿ Hz. The comparator 52 controls the oscillation frequency of the 2 ⁿ Hz VCO 111 according to the comparison result. The comparison of the counter values by the comparator 52 is performed each time the time information in the NTP format is input.

The 2 ⁿ Hz VCO 111 outputs a 2 ⁿ Hz clock signal (NTP clock) to the NTP clock counter 53 under the control of the comparator 52.

  The NTP clock counter 53 sets an initial value of the counter value based on time information in NTP format at the start of counting. When the leap second adjustment is performed, the leap second adjusted counter value is set.

The NTP clock counter 53 comprises an nbit counter 53A and a 32 bit counter 53B. The NTP clock counter 53 counts the counter value representing 1 second or less in the nbit counter 53A according to the NTP clock supplied from the 2 ⁿ Hz VCO 111, and counts the counter value representing 1 second or more in the 32 bit counter 53B. Do. The 32 + nbit @ 2 ⁿ Hz counter value by the NTP clock counter 53 is supplied to the comparator 52.

  On the other hand, the 27 MHz PLL 102 is configured of a frequency divider 121, a setting unit 122, a comparator 123, a 27 MHz VCO 124, an STC counter 125, and an arithmetic unit 126. The counter value of the nbit counter 53A is input to the frequency divider 121.

  That is, the counter value representing one second or more of the NTP clock counter 53 is not used in the 27 MHz PLL 102. Since the leap second adjustment is one second adjustment, the influence of the leap second adjustment that may occur in the MMT is absorbed, so to speak, by causing only the counter value of the nbit counter 53A to be input to the 27 MHz PLL 102. It will be

  The frequency divider 121 divides the count value of the n-bit counter 53A by the frequency division ratio x, and periodically outputs a trigger signal to the comparator 123.

  The setting unit 122 sets the expected value d in the comparator 123. The expected value d is an expected value of STC increment ΔSTC while the counter value of the nbit counter 53A is counted up by x.

Here, the division ratio x and the expected value d are set so as to satisfy the relationship of the following expression (11).

If the division ratio x and the expected value d satisfy the relationship of the above equation (11), it is determined by the comparator 123 at a frequency at which no error (residue) occurs in the time granularity (2 ⁿ Hz and 27 MHz) of NTP and STC. Indicates that a comparison is to be made.

For example, when n = 24 bits and the comparison frequency is 32 Hz, the frequency division ratio x and the expected value d are expressed as the following equations (12) and (13), respectively.

  In this example, the comparison by the comparator 123 is performed in a cycle of 31.25 msec (1/32 Hz). This comparison period is close to 33.04647 msec, which is the transmission interval of the NTP, so that the phase comparison (comparison of counter values) in the 27 MHz PLL 102 is performed in a period close to the transmission interval of the NTP.

  The comparator 123 compares the expected value d set by the setting unit 122 with the STC increment ΔSTC obtained by the computing unit 126 each time the trigger signal is supplied from the frequency divider 121. The comparator 123 controls the oscillation frequency of the 27 MHz VCO 124 according to the comparison result.

  When the increase ΔSTC is behind the expected value d, the oscillation frequency is controlled to advance STC. When the increase ΔSTC is ahead of the expected value d, the oscillation is delayed so as to delay the STC. The frequency is controlled.

  The 27 MHz VCO 124 outputs a 27 MHz clock signal (STC clock) to the STC counter 125 under the control of the comparator 123.

  The STC counter 125 is composed of a 9-bit counter 125A and a 33-bit counter 125B. The STC counter 125 counts the counter value in the 9-bit counter 125A in response to the STC clock supplied from the 27 MHz VCO 124. Further, the STC counter 125 counts the counter value in the 33-bit counter 125B according to the 90 kHz clock signal obtained by dividing the 27 MHz STC clock by 300.

  The 42-bit (33-bit + 9-bit) counter values of the 9-bit counter 125A and the 33-bit counter 125B are STC, and are supplied to the computing unit 126. The 42-bit (33-bit + 9-bit) counter value is output as a 42-bit counter value indicating the PCR of the MPEG-2 TS.

  The STC counter 125 sets an initial value of the counter value at the time of reset. The initial value is set so as to eliminate the influence of the delay of the time stamp conversion process and the delay of the ES remultiplexing process.

  Arithmetic unit 126 obtains an increment ΔSTC of STC for each comparison cycle, and outputs it to comparator 123. The influence of the wrap around of the STC counter 125 is eliminated when calculating the increase ΔSTC.

Thus, clock conversion is performed using a two-stage PLL of 2 ⁿ Hz PLL 101 and 27 MHz PLL 102. By providing the 27 MHz PLL 102 after the 2 ⁿ Hz PLL 101 that demodulates the NTP clock, the STC clock can be synchronized with the NTP clock.

  The adjustment of the leap second of NTP is ± 1 second, so that the comparison operation in the 27 MHz PLL 102 is performed at a predetermined integer comparison frequency such as 32 Hz based on the counter value of the nbit counter 53A. The adjustment of the leap second of the NTP will not affect the clock conversion in the 27 MHz PLL 102. That is, it is possible to perform clock conversion that is not affected by the adjustment of the leap second.

  Further, by setting an arbitrary value as an initial value of the STC counter 125, the 27 MHz PLL 102 has an offset adjustment function. This makes it possible to eliminate the influence of the delay difference between the time stamp conversion process and the ES remultiplexing conversion process.

  Further, since the comparison by the comparator 123 is a comparison using an incremental expected value, it is possible to freely select the relationship between the NTP / UTC value and the STC initial value.

<6. Operation of Information Processing Device>
Next, a series of processes of the information processing apparatus 1 for converting MMT content into MPEG-2 TS content and recording the content on the recording medium 11 will be described with reference to the flowchart in FIG.

  In step S1, the reception unit 31 receives and acquires the content of the MMT supplied via the transmission path of the broadcast wave or the transmission path of the communication. The receiving unit 31 outputs a TVL stream, which is data of MMT content, to the MMT signal processing unit 32.

  In step S2, the demultiplexer 51 of the MMT signal processing unit 32 extracts an IP packet from the TLV packet forming the TLV stream, and performs DEMUX processing. That is, an IP packet including time information in NTP format is supplied to the comparator 52, and an MMTP packet storing MMT-SI is supplied to the MMT-SI analysis unit 55. The MMTP packet storing video data and audio data constituting the MPU is supplied to the MPU / MMT packet analysis unit 58.

  In step S3, the MPU / MMT packet analysis unit 58 extracts the MFU video data and audio data that constitute each MPU from the MMTP packet. The extracted data is output to the buffer 61 together with MPU_sequence_number and stored.

  In step S4, the MMT-SI analysis unit 55 acquires the MPU time stamp descriptor and the MPU extended time stamp descriptor by analyzing the MMT-SI stored in the MMTP packet.

  In step S5, the MMT-SI analysis unit 55 calculates the PTS of each MPU and the DTS of the access unit constituting each MPU based on the MPU time stamp descriptor and the MPU extended time stamp descriptor.

  In addition, the MMT-SI analysis unit 55 determines, for example, whether or not the leap second adjustment is performed by analyzing the MPU extended time stamp descriptor. Information indicating whether or not the leap second adjustment is performed is supplied to the time stamp conversion unit 57 together with the information on PTS / DTS.

  In step S6, the control unit 63 sets a predetermined counter value as an initial value in the clock conversion unit 54 and the time stamp conversion unit 57, and performs offset adjustment. The initial value set here is, for example, a value determined in advance based on the delay of three processes of clock conversion process, time stamp conversion process, and ES re-multiplex conversion process.

  Specifically, of the above three processes for obtaining data of the same timing to be multiplexed into the MPEG-2 TS, it is assumed that the clock conversion process is the process with the shortest processing time. Further, it is assumed that there is a delay of +0.5 seconds in the time stamp conversion processing and a delay of +1.0 seconds in the ES remultiplex conversion processing based on the processing time of the clock conversion processing. The PCR, time stamp, and video / audio data to be multiplexed as data of the same time need to be supplied to the TS conversion processing unit 62 at substantially the same timing.

  In this case, the control unit 63 sets a value such that the counter value of the STC counter 125 is delayed by 1.0 second as an initial value of the clock conversion process, and delays the time S by 0.5 second as an initial value of the time stamp conversion process. Set a similar value.

Referring back to FIG. 32, in step S7, the time stamp conversion unit 57 converts the MMT time stamp into an MPEG-2 TS time stamp. That is, the time stamp conversion unit 57 calculates the 32 + nbit @ 2 ⁿ Hz counter value representing PTS / DTS of MMT calculated by the MMT-SI analysis unit 55, 33 bit @ representing PTS / DTS of MPEG-2 TS. Convert to a 90 kHz counter value.

In step S8, the clock conversion unit 54 converts the time information in the NTP format represented as a 32 + nbit @ 2 ⁿ Hz counter value into a 42-bit counter value indicating the PCR of the MPEG-2 TS. Here, the processing described with reference to FIG. 31 is performed by the 2 ⁿ Hz PLL 101 and the 27 MHz PLL 102, and a 42 bit @ 27 MHz counter value is generated. The generated counter value is supplied to the TS conversion processing unit 62 as a PCR.

  In step S9, the TS formation processing unit 62 constructs a PES using video data and audio data in which the same value is set as MPU_sequence_number, and generates a PES packet by adding PTS and DTS associated with each PES. .

  In step S10, the TS formation processing unit 62 performs TS packetization of PES packets.

  In step S11, the TS conversion processing unit 62 inserts a TS packet including the PCR generated by the clock conversion unit 54 in the adaptation field into the TS packet in which the data of the PES packet is stored in the payload to generate a TS. . As appropriate, a TS packet storing SI generated based on MMT-SI is also inserted into TS.

  In step S12, the recording control unit 33 controls the drive 34 to record the TS generated by the MMT signal processing unit 32 on the recording medium 11. The information processing apparatus 1 also functions as a manufacturing apparatus for manufacturing a recording medium in which the file of the MPEG-2 TS obtained by the conversion is recorded.

  FIG. 33 is a diagram showing a series of conversion processing in the information processing device 1.

As indicated by the end of the leftmost dashed arrow # 101, as a clock conversion process, a process of converting a 32 + nbit @ 2 ⁿ Hz counter value, which is time information in NTP format, into a 42bit @ 27 MHz counter value is performed. Offset adjustment is performed in the clock conversion process.

  As indicated by the end of the dashed arrow # 102, the 42 bit @ 27 MHz counter value obtained by the clock conversion process is described as PCR in the adaptation field of the TS packet.

  As indicated by the dotted arrow # 103, A / V coded information (SI) such as PMT generated by analyzing MPT of MMT is multiplexed into TS.

  The MPU time stamp descriptor and the MPU extended time stamp descriptor included in the MPT are analyzed, and the PTS / DTS of each AU is calculated for each MPU as indicated by the end of the broken arrow # 104.

The PTS / DTS of each AU indicated at the end of the broken line arrow # 105, represented as a counter value of 32 + nbit @ 2 ⁿ Hz, is subjected to time stamp conversion processing as indicated at the end of the broken line arrow # 106. It is converted to PTS / DTS of MPEG-2 TS. Offset adjustment is performed in the time stamp conversion process.

  The PTS / DTS of the MPEG-2 TS obtained by the time stamp conversion process, which is expressed as a counter value of 33 bits @ 90 kHz, is described in the PES header of each PES packet, as indicated by the dotted arrow # 107. .

  By the above processing, the content of MMT with different time axis can be converted to the content of MPEG-2 TS and recorded on a recording medium such as BD.

<7. Modified example>
<7-1. About inverse transformation>
Although the case of converting MMT content to MPEG-2 TS content has been described, it is also possible to convert MPEG-2 TS content to MMT content.

  In this case, the information processing apparatus 1 acquires video data and audio data from TS packets constituting the TS of the content of the MPEG-2 TS to be converted, and stores the data in the MMTP packet again.

Further, the information processing apparatus 1 extracts the PCR represented as a 42-bit @ 27 MHz counter value from the TS packet, and converts it into NTP-format time information represented as a 32 + nbit @ 2 ⁿ Hz counter value.

Further, the information processing apparatus 1 extracts PTS / DTS of the MPEG-2 TS represented as a counter value of 33 bits @ 90 kHz from the PES packet, and MTS PTS / DTS represented as a counter value of 32 + nbit @ 2 ⁿ Hz Convert to This process is a process of obtaining the MMT counter value X based on the MPEG-2 TS counter value X '.

  The information processing apparatus 1 generates an MMTP packet storing video data and audio data, and an MMTP packet storing a control message transmitting a descriptor used for calculating PTS / DTS of MMT. Further, the information processing device 1 generates a TLV stream by multiplexing the generated IP packet storing the MMTP packet and the IP packet including time information in NTP format.

7-2. Other examples>
Although the conversion from MMT to MPEG-2 TS and the reverse conversion from MPEG-2 TS to MMT have been described, the format of contents to be converted / reverse converted is not limited to MMT and MPEG-2 TS. The process described above can be used for conversion / inverse conversion of various formats having different time axes.

  Although the content subject to conversion / inverse conversion includes both video data and audio data, the above-described processing may be applied to conversion / inverse conversion of the format of any one content. . In addition, the present invention may be applied to conversion / inverse conversion of formats of data other than video data and audio data.

Computer Configuration Example The above-described series of processes may be performed by hardware or software. When the series of processes are executed by software, a program constituting the software is installed from a program recording medium in a computer incorporated in dedicated hardware, a general-purpose personal computer, or the like.

  FIG. 34 is a block diagram showing a configuration example of hardware of a computer that executes the series of processes described above according to a program.

  A central processing unit (CPU) 1001, a read only memory (ROM) 1002, and a random access memory (RAM) 1003 are mutually connected by a bus 1004.

  Further, an input / output interface 1005 is connected to the bus 1004. The input / output interface 1005 is connected to an input unit 1006 including a keyboard, a mouse and the like, and an output unit 1007 including a display, a speaker and the like. Further, connected to the input / output interface 1005 are a storage unit 1008 such as a hard disk and a non-volatile memory, a communication unit 1009 such as a network interface, and a drive 1010 for driving the removable medium 1011.

  In the computer configured as described above, the CPU 1001 loads, for example, the program stored in the storage unit 1008 into the RAM 1003 via the input / output interface 1005 and the bus 1004, and executes the above-described series of processes. Is done.

  The program executed by the CPU 1001 is provided, for example, via a wired or wireless transmission medium such as a local area network, the Internet, or digital broadcasting, recorded in the removable medium 1011 or installed in the storage unit 1008.

  Note that the program executed by the computer may be a program that performs processing in chronological order according to the order described in this specification, in parallel, or when necessary, such as when a call is made. It may be a program to be processed.

  The embodiments of the present technology are not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present technology.

  For example, the present technology can have a cloud computing configuration in which one function is shared and processed by a plurality of devices via a network.

  Further, each step described in the above-described flowchart can be executed by one device or in a shared manner by a plurality of devices.

  Furthermore, in the case where a plurality of processes are included in one step, the plurality of processes included in one step can be executed by being shared by a plurality of devices in addition to being executed by one device.

  The embodiments of the present technology are not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present technology.

-Example of combination of configuration The present technology can also have the following configuration.
(1)
A 33-bit counter with a first format timestamp represented by the counter value of a 32 + n-bit counter with an accuracy of 1 second or less as 2 ⁿ Hz (n is an integer of 24 or more) and an accuracy of 1 second or less with 90 kHz A time stamp conversion unit for converting into a time stamp of the second format represented by the counter value of
Converting the reference time of the first format represented by the counter value of the 32 + n-bit counter into the reference time of the second format represented by the counter value of a 42-bit counter having an accuracy of 1 second or less as 27 MHz A reference time conversion unit,
An information processing apparatus comprising: an initial value of a counter value of the 33-bit counter in time stamp conversion; and an initial value of a counter value of the 42-bit counter in conversion of a setting reference time.
(2)
The information processing apparatus according to (1), wherein the time stamp conversion unit generates a time stamp of a second format corrected according to the adjustment of the leap second to the time stamp of the first format. .
(3)
A processing unit that multiplexes data including a video stream and an audio stream multiplexed in the first format in the second format and generates multiplexed data according to the above (1) or (2). Information processing equipment.
(4)
The information processing apparatus according to (3), wherein the processing unit generates the multiplexed data to which a time stamp of the second format and a reference time are added.
(5)
The information processing apparatus according to (4), wherein the control unit sets initial values based on processing times of time stamp conversion processing, reference time conversion processing, and multiplexing processing.
(6)
The first format is MMT,
The information processing apparatus according to any one of (1) to (5), wherein the second format is an MPEG-2 TS.
(7)
A 33-bit counter with a first format timestamp represented by the counter value of a 32 + n-bit counter with an accuracy of 1 second or less as 2 ⁿ Hz (n is an integer of 24 or more) and an accuracy of 1 second or less with 90 kHz Convert to a second format timestamp represented by a counter value of
Converting the reference time of the first format represented by the counter value of the 32 + n-bit counter into the reference time of the second format represented by the counter value of a 42-bit counter having an accuracy of 1 second or less as 27 MHz; ,
An information processing method comprising: setting an initial value of a counter value of the 33-bit counter in time stamp conversion and an initial value of a counter value of the 42-bit counter in conversion of a reference time.
(8)
A 33-bit counter with a first format timestamp represented by the counter value of a 32 + n-bit counter with an accuracy of 1 second or less as 2 ⁿ Hz (n is an integer of 24 or more) and an accuracy of 1 second or less with 90 kHz Convert to a second format timestamp represented by a counter value of
Converting the reference time of the first format represented by the counter value of the 32 + n-bit counter into the reference time of the second format represented by the counter value of a 42-bit counter having an accuracy of 1 second or less as 27 MHz; ,
A program that causes a computer to execute a process including the steps of setting an initial value of the counter value of the 33-bit counter in time stamp conversion and an initial value of the counter value of the 42-bit counter in conversion of reference time.
(9)
A 33-bit counter with a first format timestamp represented by the counter value of a 32 + n-bit counter with an accuracy of 1 second or less as 2 ⁿ Hz (n is an integer of 24 or more) and an accuracy of 1 second or less with 90 kHz Convert to a second format timestamp represented by a counter value of
Converting the reference time of the first format represented by the counter value of the 32 + n-bit counter into the reference time of the second format represented by the counter value of a 42-bit counter having an accuracy of 1 second or less as 27 MHz; ,
The initial value of the counter value of the 33-bit counter in time stamp conversion and the initial value of the counter value of the 42-bit counter in conversion of a reference time are set,
Generating multiplexed data by multiplexing, in the second format, data including a video stream and an audio stream multiplexed in the first format;
A recording medium manufacturing method, wherein the multiplexed data is recorded on a recording medium.

Reference Signs List 1 information processing apparatus, 11 recording medium, 32 MMT signal processing unit, 33 recording control unit, 51 demultiplexer, 52 comparison unit, 53 NTP clock counter, 54 clock conversion unit, 55 MMT-SI analysis unit, 56 video audio synchronous control Parts, 57 time stamp conversion part, 58 MPU / MMT packet analysis part, 59 decoder buffer, 60 video and audio decoder, 61 buffer, 62 TS processing part, 63 control part, 101 2 ⁿ Hz PLL, 102 27 MHz PLL, 111 2 ⁿ Hz VCO, 121 divider, 122 setting units, 123 comparators, 124 27 MHz VCO, 125 STC counters, 126 arithmetic units

Claims (9)

A 33-bit counter with a first format timestamp represented by the counter value of a 32 + n-bit counter with an accuracy of 1 second or less as 2 ⁿ Hz (n is an integer of 24 or more) and an accuracy of 1 second or less with 90 kHz A time stamp conversion unit for converting into a time stamp of the second format represented by the counter value of
Converting the reference time of the first format represented by the counter value of the 32 + n-bit counter into the reference time of the second format represented by the counter value of a 42-bit counter having an accuracy of 1 second or less as 27 MHz A reference time conversion unit,
An information processing apparatus comprising: a control unit configured to set an initial value of a counter value of the 33-bit counter in time stamp conversion and an initial value of a counter value of the 42-bit counter in conversion of reference time. The information processing apparatus according to claim 1, wherein the time stamp conversion unit generates a time stamp of a second format corrected according to the adjustment of the leap second to the time stamp of the first format. The information processing apparatus according to claim 1, further comprising: a processing unit that multiplexes data including a video stream and an audio stream multiplexed in the first format in the second format and generates multiplexed data. The information processing apparatus according to claim 3, wherein the processing unit generates the multiplexed data to which a timestamp of the second format and a reference time are added. The information processing apparatus according to claim 4, wherein the control unit sets initial values based on processing times of time stamp conversion processing, reference time conversion processing, and multiplexing processing. The first format is MMT,
The information processing apparatus according to claim 1, wherein the second format is an MPEG-2 TS. A 33-bit counter with a first format timestamp represented by the counter value of a 32 + n-bit counter with an accuracy of 1 second or less as 2 ⁿ Hz (n is an integer of 24 or more) and an accuracy of 1 second or less with 90 kHz Convert to a second format timestamp represented by a counter value of
Converting the reference time of the first format represented by the counter value of the 32 + n-bit counter into the reference time of the second format represented by the counter value of a 42-bit counter having an accuracy of 1 second or less as 27 MHz; ,
An information processing method comprising: setting an initial value of a counter value of the 33-bit counter in time stamp conversion and an initial value of a counter value of the 42-bit counter in conversion of a reference time. A 33-bit counter with a first format timestamp represented by the counter value of a 32 + n-bit counter with an accuracy of 1 second or less as 2 ⁿ Hz (n is an integer of 24 or more) and an accuracy of 1 second or less with 90 kHz Convert to a second format timestamp represented by a counter value of
Converting the reference time of the first format represented by the counter value of the 32 + n-bit counter into the reference time of the second format represented by the counter value of a 42-bit counter having an accuracy of 1 second or less as 27 MHz; ,
A program that causes a computer to execute a process including the steps of setting an initial value of the counter value of the 33-bit counter in time stamp conversion and an initial value of the counter value of the 42-bit counter in conversion of reference time. A 33-bit counter with a first format timestamp represented by the counter value of a 32 + n-bit counter with an accuracy of 1 second or less as 2 ⁿ Hz (n is an integer of 24 or more) and an accuracy of 1 second or less with 90 kHz Convert to a second format timestamp represented by a counter value of
Converting the reference time of the first format represented by the counter value of the 32 + n-bit counter into the reference time of the second format represented by the counter value of a 42-bit counter having an accuracy of 1 second or less as 27 MHz; ,
The initial value of the counter value of the 33-bit counter in time stamp conversion and the initial value of the counter value of the 42-bit counter in conversion of a reference time are set,
Generating multiplexed data by multiplexing, in the second format, data including a video stream and an audio stream multiplexed in the first format;
A recording medium manufacturing method, wherein the multiplexed data is recorded on a recording medium.

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