HK1209552B

HK1209552B - Methods, devices and appratuses for processing and encoding multi-layer video data

Info

Publication number: HK1209552B
Application number: HK15110263.2A
Authority: HK
Inventors: 王益魁
Original assignee: 高通股份有限公司
Priority date: 2012-10-02
Filing date: 2013-10-01
Publication date: 2020-03-13

Abstract

A device for processing video data receives an indication of a maximum layer identification (ID) value for a bitstream; receives a flag for a first layer with a layer ID value less than the maximum layer ID value; and, based on a value of the flag, determines if the first layer is included in an operation point.

Description

Method, apparatus and device for processing and encoding multi-layer video data

This application claims the benefit of U.S. Provisional Patent Application No. 61/709,094, filed October 2, 2012, which is incorporated herein by reference in its entirety.

Technical Field

The present invention relates generally to processing video data and, more particularly, to processing operation points for use in video data.

Background Art

Digital video capabilities can be incorporated into a wide range of devices, including digital televisions, digital live broadcast systems, wireless broadcast systems, personal digital assistants (PDAs), laptop or desktop computers, tablet computers, e-book readers, digital cameras, digital recording devices, digital media players, video game devices, video game consoles, cellular or satellite radio telephones, so-called "smartphones", video teleconferencing devices, video streaming devices, and the like. Digital video devices implement video coding techniques, such as those described in the standards defined by MPEG-2, MPEG-4, ITU-T H.263, ITU-T H.264/MPEG-4 Part 10 Advanced Video Coding (AVC), the High Efficiency Video Coding (HEVC) standard currently under development, and extensions of such standards. By implementing such video coding techniques, video devices can more efficiently transmit, receive, encode, decode, and/or store digital video information.

Video coding techniques include spatial (intra-picture) prediction and/or temporal (inter-picture) prediction to reduce or remove redundancy inherent in video sequences. For block-based video coding, a video slice (e.g., a video frame or portion of a video frame) may be partitioned into video blocks, which may also be referred to as treeblocks, coding units (CUs), and/or coding nodes. Video blocks in an intra-coded (I) slice of a picture are encoded using spatial prediction with respect to reference samples in neighboring blocks in the same picture. Video blocks in an inter-coded (P or B) slice of a picture may use spatial prediction with respect to reference samples in neighboring blocks in the same picture or temporal prediction with respect to reference samples in other reference pictures. Pictures may be referred to as frames, and reference pictures may be referred to as reference frames.

Spatial prediction or temporal prediction results in a predictive block for the coded block. The residual data represents the pixel differences between the original block to be coded and the predictive block. Inter-coded blocks are encoded according to a motion vector pointing to a block of reference samples forming the predictive block and residual data indicating the difference between the coded block and the predictive block. Intra-coded blocks are encoded according to an intra-coding mode and the residual data. For further compression, the residual data can be transformed from the pixel domain to the transform domain, thereby generating residual transform coefficients, which can then be quantized. The quantized transform coefficients, initially arranged in a two-dimensional array, can be scanned to generate a one-dimensional vector of transform coefficients, and entropy coding can be applied to achieve even more compression.

Summary of the Invention

In general, this disclosure describes techniques for signaling layer identifiers for operation points in video coding.

In one example, a method of processing video data includes receiving an indication of a maximum layer identification (ID) value for a bitstream; receiving a flag for a first layer having a layer ID value less than the maximum layer ID value; and determining whether the first layer is included in an operation point based on the value of the flag.

In another example, a device for processing video data includes one or more processors configured to: receive an indication of a maximum layer identification (ID) value for a bitstream; receive a flag for a first layer having a layer ID value less than the maximum layer ID value; and determine whether the first layer is included in an operation point based on the value of the flag.

In another example, an apparatus for processing video data includes means for receiving an indication of a maximum layer identification (ID) value for a bitstream; means for receiving a flag for a first layer having a layer ID value less than the maximum layer ID value; and means for determining whether the first layer is included in an operation point based on the value of the flag.

In another example, a non-transitory computer-readable storage medium stores instructions that, when executed by one or more processors, cause the one or more processors to: receive an indication of a maximum layer identification (ID) value for a bitstream; receive a flag for a first layer having a layer ID value less than the maximum layer ID value; and determine whether the first layer is included in an operation point based on the value of the flag.

In another example, a method of encoding video data includes generating an indication of a maximum layer identification (ID) value for a bitstream; and generating a flag for a first layer having a layer ID value less than the maximum layer ID value, wherein the value for the flag signals whether the first layer is included in an operation point.

In another example, a video decoding device includes a video encoder configured to: generate an indication of a maximum layer identification (ID) value for a bitstream; and generate a flag for a first layer having a layer ID value less than the maximum layer ID value, wherein the value for the flag signals whether the first layer is included in an operation point.

In another example, an apparatus for video coding includes means for generating an indication of a maximum layer identification (ID) value for a bitstream; and means for generating a flag for a first layer having a layer ID value less than the maximum layer ID value, wherein the value for the flag signals whether the first layer is included in an operation point.

In another example, a non-transitory computer-readable medium stores instructions that, when executed by one or more processors, cause the one or more processors to: generate an indication of a maximum layer identification (ID) value for a bitstream; and generate a flag for a first layer having a layer ID value less than the maximum layer ID value, wherein the value for the flag signals whether the first layer is included in an operation point.

The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

1 is a block diagram illustrating an example video encoding and decoding system that may utilize the techniques described in this disclosure.

2 is a block diagram illustrating an example video encoder that may implement the techniques described in this disclosure.

3 is a block diagram illustrating an example video decoder that may implement the techniques described in this disclosure.

4 is a block diagram illustrating an example set of devices forming part of a network.

5 is a flowchart illustrating an example method for encoding video data, in accordance with the techniques described in this disclosure.

6 is a flowchart illustrating an example method for processing video data, in accordance with the techniques described in this disclosure.

DETAILED DESCRIPTION

This disclosure relates to video coding (i.e., the encoding and/or decoding of video data) and video processing, and more particularly, to operation point syntax used in video processing. Generally, this disclosure describes techniques for signaling layer identifiers for operation points in video coding. An operation point refers to a sub-bitstream that can be extracted from an original bitstream that is temporally scalable and/or has multiple layers or views. The sub-bitstream can be extracted from the bitstream based on the values of a layer identifier (i.e., layer ID) and a temporal sub-layer identifier (i.e., temporal ID) that identify the operation point of the bitstream. Generally, this disclosure uses the terms "layer identifier" and "layer ID" to refer to identifiers of spatial layers and/or views, while the terms "temporal sub-layer identifier" and "temporal ID" refer to identifiers of temporal sub-layers.

For example, operation points can be signaled in parameter sets (e.g., video parameter sets (VPSs)) within a bitstream. For each of the operation points, an operation point syntax structure generated by, for example, a video encoder specifies a set of layer identifiers used to identify network abstraction layer (NAL) units in the bitstream that belong to a sub-bitstream at a given operation point. In this way, network physics (e.g., media-aware network physics (MANE)) can parse the NAL unit header to extract the NAL units that constitute the sub-bitstream of a given operation point from the original bitstream. Each NAL unit in the bitstream can include a layer ID and a temporal ID, and by parsing the layer ID and temporal ID, the MANE can identify the NAL unit for a specific operation point.

Techniques of this disclosure can improve the efficiency of signaling information associated with operation points by improving the signaling of layer IDs for operation points. According to one example technique of this disclosure, explained in more detail below, a layer identification value (i.e., layer ID) for a maximum layer ID can be signaled, and the presence of additional layer IDs can be signaled in the form of a series of flags. For example, assume a bitstream includes six substreams with various temporal and spatial resolutions, each with a layer ID. The maximum layer ID value can be signaled in the bitstream. For the purposes of this example, assume a maximum layer ID value of 9, which means there are potentially ten layers that can be included in an operation point, with layer IDs 0 through 9. Nine flags can be used to signal the remaining layer ID values for the operation point, with the first flag indicating the presence of layer ID value 0, the second flag indicating the presence of layer ID value 1, and so on, up to the final flag indicating the presence of layer ID value 8. Thus, to signal layer ID values of 2, 5, and 9, the value 9 may be signaled first, followed by the signaling flag sequence 001001000, where a 1 for the third bit indicates the presence of layer ID value 2, and a 1 for the sixth bit indicates the presence of layer ID value 5. Other techniques for signaling layer IDs will also be discussed in this disclosure.

This disclosure will generally use the term "video coding" to refer to video encoding or video decoding. This disclosure also uses the term "video processing," which is generally meant to include video coding, but is also meant to include other types of video processing, such as video data parsing, video data routing, video bitstream splicing, and other such processes. A video coder may generally be considered to refer to a device that encodes and/or decodes video data, while a video processor or video processing device may be considered to refer to a device that decodes video data, but may also refer to a device that performs other processes on video data.

FIG1 is a block diagram illustrating an example video encoding and decoding system 10 that may utilize the techniques for signaling layer IDs described in this disclosure. As shown in FIG1 , system 10 includes a source device 12 that generates encoded video data to be decoded at a later time by a destination device 14. The encoded video data may be delivered from source device 12 to destination device 14 via a network device 13, which may be part of a larger network of network devices. Source device 12 and destination device 14 may comprise any of a wide range of devices, including desktop computers, notebook (i.e., laptop) computers, tablet computers, set-top boxes, telephone handsets such as so-called "smart" phones, so-called "smart" tablet computers, televisions, cameras, display devices, digital media players, video game consoles, video streaming devices, or the like. In some cases, source device 12 and destination device 14 may be equipped for wireless communication.

1 , source device 12 includes a video source 18, a video encoder 20, and an output interface 22. Destination device 14 includes an input interface 28, a video decoder 30, and a display device 32. In other examples, source device 12 and destination device 14 may include other components or arrangements. For example, source device 12 may receive video data from an external video source 18 (e.g., an external camera). Likewise, destination device 14 may interface with an external display device rather than including an integrated display device.

The illustrated system 10 of FIG. 1 is merely one example. The techniques of this disclosure may be performed by any digital video coding and/or processing device. While typically performed by a video encoding device or a video decoding device, the techniques may also be performed by a video encoder/decoder (often referred to as a "codec"). Furthermore, the techniques of this disclosure may also be performed by a video preprocessor. Source device 12 and destination device 14 are merely examples of such coding devices in which source device 12 generates coded video data for transmission to destination device 14. In some examples, devices 12, 14 may operate in a substantially symmetrical manner, such that each of devices 12, 14 includes video encoding and decoding components. Thus, system 10 may support one-way or two-way video transmission between video devices 12, 14, e.g., for video streaming, video playback, video broadcasting, or video telephony.

In one example, video encoder 20 of source device 12 may generate a bitstream of video data. A VPS for the video data may define multiple operation points corresponding to sub-bitstreams of the bitstream. Video encoder 20 may include operation point syntax that identifies the layers and temporal sub-layers to be included in a particular operation point. The operation point syntax in the VPS may include an indication of the maximum layer ID value for the operation point and one or more flags. The flags indicate whether layers with layer IDs less than the maximum layer ID are included in the operation point. Thus, upon receiving the VPS with the maximum layer ID and the flags, network device 13 may identify NAL units for the operation point and deliver those NAL units to destination device 14. Upon receiving the NAL units, video decoder 30 of destination device 14 may decode the encoded video data. Video decoder 30 may potentially parse the operation point syntax contained in the VPS in the same manner as network device 13. For example, video decoder 30 may parse the operation point syntax to check whether all expected layers have been received or to determine the hypothetical reference decoder (HRD) parameter set to be applied.

Video source 18 of source device 12 may include a video capture device such as a video camera, a video archive containing previously captured video, and/or a video feed interface for receiving video from a video content provider. As another alternative, video source 18 may generate computer graphics-based data as the source video, or a combination of live video, archived video, and computer-generated video. In some cases, if video source 18 is a video camera, source device 12 and destination device 14 may form so-called camera phones or video phones. However, as mentioned above, the techniques described in this disclosure may be applicable to video coding in general and may be applied to wireless and/or wired applications.

In each case, the captured, pre-captured, or computer-generated video may be encoded by video encoder 20. The encoded video data may be transmitted directly to destination device 14 via output interface 22 of source device 12. The encoded video data may also (or instead) be stored on a storage device for later access by destination device 14 or other devices, for decoding and/or playback.

Link 16 may include transient media, such as wireless broadcasts or wired network transmissions, or storage media (i.e., non-transitory storage media), such as a hard drive, flash drive, compact disc, digital video disc, Blu-ray disc, or other computer-readable media. In some examples, a network server may receive encoded video data from source device 12 and provide the encoded video data to destination device 14, for example, via network transmission. Similarly, a computing device at a media production facility (e.g., a disc imprinting facility) may receive encoded video data from source device 12 and produce a disc containing the encoded video data. Thus, in various examples, link 16 may be understood to include one or more computer-readable media in various forms. Link 16 may include any type of media or device capable of moving encoded video data from source device 12 to destination device 14. In one example, link 16 may include a communication medium that enables source device 12 to transmit encoded video data directly to destination device 14 in real time. The encoded video data may be modulated according to a communication standard (e.g., a wireless communication protocol) and transmitted to destination device 14. The communication medium may comprise any wireless or wired communication medium, such as a radio frequency (RF) spectrum or one or more physical transmission lines. The communication medium may form part of a packet-based network, such as a local area network, a wide area network, or a global area network such as the Internet. The communication medium may include routers, switches, base stations, or any other equipment that may be used to facilitate communication from source device 12 to destination device 14.

Input interface 28 of destination device 14 receives information from link 16, which may be a computer-readable medium. The information from link 16 may include syntax information defined by video encoder 20 (which is also used by video decoder 30), including syntax elements that describe characteristics and/or processing of blocks and other coded units (e.g., GOPs). Display device 32 may be integrated with destination device 14 or located external to destination device 14. Display device 32 displays the decoded video data to a user and may include any of a variety of display devices, such as a cathode ray tube (CRT), a liquid crystal display (LCD), a plasma display, an organic light emitting diode (OLED) display, or another type of display device.

Alternatively, the encoded data may be output from output interface 22 to storage device 34. Similarly, the encoded data may be accessed from storage device 34 via input interface. Storage device 34 may include any of a variety of distributed or locally accessible data storage media, such as a hard disk, Blu-ray disc, DVD, CD-ROM, flash memory, volatile or non-volatile memory, or any other suitable digital storage medium for storing encoded video data. In another example, storage device 34 may correspond to a file server or another intermediate storage device that can hold the encoded video generated by source device 12. Destination device 14 may access the stored video data from storage device 34 via streaming or downloading. The file server may be any type of server capable of storing encoded video data and transmitting it to destination device 14. Example file servers include a web server (e.g., for a website), an FTP server, a network attached storage (NAS) device, or a local disk drive. Destination device 14 may access the encoded video data via any standard data connection, including an Internet connection. This data connection may include a wireless channel (e.g., a Wi-Fi connection), a wired connection (e.g., DSL, cable modem, etc.) suitable for accessing encoded video data stored on a file server, or a combination of both. The transmission of the encoded video data from storage device 34 may be a streaming transmission, a download transmission, or a combination of both.

The techniques of this disclosure are not necessarily limited to wireless applications or settings. The techniques may be applied to video coding to support any of a variety of multimedia applications, such as over-the-air television broadcasts, cable television transmissions, satellite television transmissions, streaming video transmissions over the Internet, encoding of digital video for storage on data storage media, decoding of digital video stored on data storage media, or other applications. In some examples, system 10 may be configured to support one-way or two-way video transmission to support applications such as video streaming, video playback, video broadcasting, and/or video telephony.

Video encoder 20 and video decoder 30 may each be implemented as any of a variety of suitable encoder or decoder circuitry, such as one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), discrete logic circuitry, software, hardware, firmware, or any combination thereof. When the techniques are partially implemented in software, the device may store instructions for the software in a suitable non-transitory computer-readable medium and execute the instructions in hardware using one or more processors to perform the techniques of this disclosure. Each of video encoder 20 and video decoder 30 may be included in one or more encoders or decoders, either of which may be integrated as part of a combined encoder/decoder (codec) in the respective device. A device including video encoder 20 and/or video decoder 30 may include an integrated circuit, a microprocessor, and/or a wireless communication device (e.g., a cellular telephone).

Video encoder 20 and video decoder 30 may operate according to a video coding standard, such as the HEVC standard currently under development, and may conform to the HEVC Test Model (HM). A draft of the upcoming HEVC standard, referred to as "HEVC Working Draft 8" or "WD8," is described in document JCTVC-J1003_d7, entitled "High Efficiency Video Coding (HEVC) Text Specification Draft 8," by Bross et al. (Joint Collaboration Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11, 10th Meeting: Stockholm, Sweden, July 2012). The entire text of Working Draft 8 of the HEVC standard is hereby incorporated by reference herein. Another recent draft of the HEVC standard, referred to as "HEVC Working Draft 10" or "WD10," is described in Bross et al., document JCTVC-L1003v34, entitled "High Efficiency Video Coding (HEVC) Text Specification Draft 10 (for FDIS & Last Call)" (Joint Collaboration Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11, 12th Meeting: Geneva, Switzerland, January 14-23, 2013). The entire text of WD10 is hereby incorporated by reference herein.

Alternatively, video encoder 20 and video decoder 30 may operate according to other proprietary or industry standards, such as the ITU-T H.264 standard (alternatively referred to as MPEG-4 Part 10 Advanced Video Coding (AVC)), or extensions of such standards. However, the techniques of this disclosure are not limited to any particular coding standard. Other examples of video coding standards include MPEG-2 and ITU-T H.263. In some aspects, video encoder 20 and video decoder 30 may each be integrated with an audio encoder and decoder, and may include appropriate MUX-DEMUX units or other hardware and software to handle the encoding of both audio and video in a common data stream or in separate data streams. Where applicable, the MUX-DEMUX units may conform to the ITU H.223 multiplexer protocol or other protocols, such as the User Datagram Protocol (UDP).

The ITU-T H.264/MPEG-4 (AVC) standard was developed by the ITU-T Video Coding Experts Group (VCEG) in conjunction with the ISO/IEC Moving Picture Experts Group (MPEG) as a collective effort known as the Joint Video Team (JVT). In some aspects, the techniques described in this disclosure may be applied to devices generally compliant with the H.264 standard. The H.264 standard is described in the ITU-T Study Group's ITU-T Recommendation H.264 (Advanced Video Coding for General Audiovisual Services), dated March 2005, which may be referred to herein as the H.264 standard, the H.264 specification, or the H.264/AVC standard or specification. The Joint Video Team (JVT) continues to work on extensions to H.264/MPEG-4 AVC.

The JCT-VC is working on the development of the HEVC standard. The HEVC standardization effort is based on an evolving model of video coding devices, known as the HEVC Test Model (HM). The HM assumes several additional capabilities of video coding devices relative to existing devices based on, for example, ITU-T H.264/AVC. For example, while H.264 provides nine intra-frame prediction coding modes, the HM can provide up to 33 intra-frame prediction coding modes.

In general, the HM's working model describes that a video frame or picture can be divided into a sequence of treeblocks or largest coding units (LCUs) that include both luma and chroma samples. Syntax data within the bitstream can define the size of an LCU, which is the largest coding unit in terms of the number of pixels. A slice includes several consecutive treeblocks in coding order. A video frame or picture can be partitioned into one or more slices. Each treeblock can be split into coding units (CUs) according to a quadtree. In general, a quadtree data structure includes one node per CU, with the root node corresponding to a treeblock. If a CU is split into four sub-CUs, the node corresponding to the CU includes four leaf nodes, each of which corresponds to one of the sub-CUs.

Each node in the quadtree data structure may provide syntax data for the corresponding CU. For example, a node in the quadtree may include a split flag that indicates whether the CU corresponding to the node is split into sub-CUs. Syntax elements for a CU may be defined recursively and may depend on whether the CU is split into sub-CUs. If a CU is not split further, it is referred to as a leaf-CU. In this disclosure, the four sub-CUs of a leaf-CU will be referred to as leaf-CUs even if there is no explicit splitting of the original leaf-CU. For example, if a 16x16 sized CU is not split further, the four 8x8 sub-CUs will also be referred to as leaf-CUs, but the 16x16 CU has never been split.

CUs have a purpose similar to that of macroblocks in the H.264 standard, except that CUs do not have a size distinction. For example, a treeblock can be split into four child nodes (also referred to as sub-CUs), and each child node can in turn be a parent node and split into another four child nodes. The final unsplit child nodes, referred to as leaf nodes of the quadtree, comprise coding nodes, which are also referred to as leaf-CUs. Syntax data associated with the coded bitstream may define the maximum number of times a treeblock can be split (which is referred to as the maximum CU depth) and may also define the minimum size of a coding node. Thus, the bitstream may also define a smallest coding unit (SCU). This disclosure uses the term "block" to refer to any of a CU, PU, or TU in the context of HEVC, or similar data structures in the context of other standards (e.g., macroblocks and their sub-blocks in H.264/AVC).

A CU includes a coding node and a number of prediction units (PUs) and transform units (TUs) associated with the coding node. The size of the CU corresponds to the size of the coding node and must be square in shape. The size of a CU can range from 8×8 pixels up to the size of a treeblock with a maximum of 64×64 pixels or larger. Each CU may contain one or more PUs and one or more TUs. Syntax data associated with a CU may describe, for example, the partitioning of the CU into one or more PUs. The partitioning mode may differ depending on whether the CU is skipped or directly coded, intra-prediction mode coded, or inter-prediction mode coded. The shape of a PU may be partitioned into non-square shapes. Syntax data associated with a CU may also describe, for example, the partitioning of the CU into one or more TUs according to a quadtree. The shape of a TU may be square or non-square (e.g., rectangular).

The HEVC standard allows for transforms based on TUs, which can be different for different CUs. The TU size is typically set based on the size of the PU within a given CU defined for the partitioned LCU, but this is not always the case. A TU is typically the same size as a PU or smaller than a PU. In some examples, a quadtree structure called a "residual quadtree" (RQT) can be used to subdivide the residual samples corresponding to a CU into smaller units. The leaf nodes of the RQT can be referred to as transform units (TUs). Pixel difference values associated with a TU can be transformed to produce transform coefficients that can be quantized.

A leaf-CU may include one or more prediction units (PUs). Generally, a PU represents a spatial region corresponding to all or a portion of the corresponding CU and may include data for retrieving reference samples for the PU. In addition, a PU includes data related to prediction. For example, when the PU is intra-mode encoded, the data for the PU may be included in a residual quadtree (RQT), which may include data describing the intra-prediction mode for the TU corresponding to the PU. As another example, when the PU is inter-mode encoded, the PU may include data defining one or more motion vectors for the PU. The data defining the motion vector of the PU may describe, for example, the horizontal component of the motion vector, the vertical component of the motion vector, the resolution used for the motion vector (e.g., quarter-pixel precision or eighth-pixel precision), the reference picture to which the motion vector points, and/or the reference picture list used for the motion vector (e.g., List 0, List 1, or List C).

A leaf-CU with one or more PUs may also include one or more transform units (TUs). The transform units may be specified using an RQT (also known as a TU quadtree structure), as discussed above. For example, a split flag may indicate whether a leaf-CU is split into four transform units. Each transform unit may then be further split into additional sub-TUs. When a TU is not further split, it may be referred to as a leaf-TU. Generally speaking, for intra coding, all leaf-TUs belonging to a leaf-CU share the same intra prediction mode. That is, the same intra prediction mode is generally applied to calculate prediction values for all TUs of a leaf-CU. For intra coding, the video encoder may use the intra prediction mode to calculate the residual value of each leaf-TU as the difference between the portion of the CU corresponding to the TU and the original block. A TU is not necessarily limited to the size of a PU. Thus, a TU may be larger or smaller than a PU. For intra coding, a PU may be collocated with a corresponding leaf-TU of the same CU. In some examples, the maximum size of a leaf-TU may correspond to the size of the corresponding leaf-CU.

Furthermore, the TUs of a leaf-CU may also be associated with corresponding quadtree data structures called residual quadtrees (RQTs). That is, a leaf-CU may include a quadtree that indicates how the leaf-CU is partitioned into TUs. The root node of a TU quadtree generally corresponds to a leaf-CU, while the root node of a CU quadtree generally corresponds to a treeblock (or LCU). TUs of an RQT that are not split are referred to as leaf-TUs. In general, unless otherwise noted, this disclosure uses the terms "CU" and "TU" to refer to a leaf-CU and a leaf-TU, respectively.

A video sequence typically includes a series of video frames or pictures. A group of pictures (GOP) generally includes one or more of a series of video pictures. A GOP may include syntax data describing the number of pictures included in the GOP in a header of the GOP, a header of one or more of the pictures, or elsewhere. Each slice of a picture may include slice syntax data describing the encoding mode of the respective slice. Video encoder 20 typically operates on video blocks within individual video slices to encode the video data. A video block may correspond to a coding node within a CU. Video blocks may have a fixed or varying size and may differ in size according to a specified coding standard.

As an example, the HM supports prediction with various PU sizes. Assuming a particular CU is 2N×2N in size, the HM supports intra prediction with PU sizes of 2N×2N or N×N, and inter prediction with symmetric PU sizes of 2N×2N, 2N×N, N×2N, or N×N. The HM also supports asymmetric partitioning for inter prediction with PU sizes of 2N×nU, 2N×nD, nL×2N, and nR×2N. In an asymmetric partitioning, the CU is not partitioned in one direction, while the other direction is partitioned into 25% and 75%. The portion of the CU corresponding to the 25% partition is indicated by an "n" followed by an indication of "above," "below," "left," or "right." Thus, for example, "2N×nU" refers to a 2N×2N CU partitioned horizontally with a 2N×0.5N PU at the top and a 2N×1.5N PU at the bottom.

In this disclosure, "NxN" and "N by N" may be used interchangeably to refer to the pixel dimensions of a video block in terms of vertical and horizontal dimensions, e.g., 16x16 pixels or 16 by 16 pixels. Generally, a 16x16 block will have 16 pixels in the vertical direction (y=16) and 16 pixels in the horizontal direction (x=16). Similarly, an NxN block generally has N pixels in the vertical direction and N pixels in the horizontal direction, where N represents a non-negative integer value. The pixels in a block may be arranged in rows and columns. Furthermore, a block need not necessarily have the same number of pixels in the horizontal direction as in the vertical direction. For example, a block may comprise NxM pixels, where M is not necessarily equal to N.

After intra-predictive or inter-predictive coding using a PU of a CU, video encoder 20 may calculate residual data for the TUs of the CU. The PU may include syntax data that describes a method or mode of generating predictive pixel data in the spatial domain (also called the pixel domain), and the TU may include coefficients in the transform domain after applying a transform (e.g., a discrete cosine transform (DCT), an integer transform, a wavelet transform, or a conceptually similar transform) to the residual video data. The residual data may correspond to pixel differences between pixels of an unencoded picture and prediction values corresponding to the PU. Video encoder 20 may form TUs including the residual data for the CU, and then transform the TUs to produce transform coefficients for the CU.

After performing any transforms to produce transform coefficients, video encoder 20 may perform quantization of the transform coefficients. Quantization generally refers to a process in which transform coefficients are quantized to potentially reduce the amount of data used to represent the coefficients, thereby providing further compression. The quantization process may reduce the bit depth associated with some or all of the coefficients. For example, an n-bit value may be truncated to an m-bit value during quantization, where n is greater than m.

After quantization, the video encoder may scan the transform coefficients, generating a one-dimensional vector from the two-dimensional matrix including the quantized transform coefficients. The scan may be designed to place higher energy (and therefore lower frequency) coefficients at the front of the array and lower energy (and therefore higher frequency) coefficients at the back of the array. In some examples, video encoder 20 may utilize a predefined scan order to scan the quantized transform coefficients to generate a serialized vector that can be entropy encoded. In other examples, video encoder 20 may perform adaptive scanning. After scanning the quantized transform coefficients to form a one-dimensional vector, video encoder 20 may entropy encode the one-dimensional vector, for example, according to context-adaptive variable length coding (CAVLC), context-adaptive binary arithmetic coding (CABAC), syntax-based context-adaptive binary arithmetic coding (SBAC), probability interval partitioning entropy (PIPE) coding, or another entropy encoding method. Video encoder 20 may also entropy encode syntax elements associated with the encoded video data for use by video decoder 30 in decoding the video data.

To perform CABAC, video encoder 20 may assign context within a context model to a symbol to be transmitted. The context may relate to, for example, whether neighboring values of the symbol are non-zero. To perform CAVLC, video encoder 20 may select a variable length code for the symbol to be transmitted. Codewords in VLC may be constructed such that relatively shorter codes correspond to more likely symbols, while longer codes correspond to less likely symbols. In this way, using VLC may achieve bit savings compared to, for example, using equal-length codewords for each symbol to be transmitted. Probability determinations may be made based on the context assigned to the symbol.

Video encoder 20 may further send syntax data (e.g., block-based syntax data, frame-based syntax data, and GOP-based syntax data) to video decoder 30 (e.g., in a frame header, block header, slice header, or GOP header). The GOP syntax data may describe the number of frames in the corresponding GOP, and the frame syntax data may indicate the encoding/prediction mode used to encode the corresponding frame.

HEVC is designed to be universal in the sense that it is intended to serve (e.g., be compatible with) a wide range of applications, bit rates, resolutions, qualities, and services. Among these, applications potentially served by HEVC include digital storage media, television broadcasting, and real-time communications. In developing HEVC, various requirements from typical applications were considered, the necessary algorithmic elements were developed, and these were integrated into a single syntax. Thus, HEVC should facilitate the interchange of video data among different applications. However, given the practicality of implementing the full syntax of HEVC, a limited number of subsets of the syntax are also agreed upon by means of "profiles" and "levels."

A "profile" is defined as a subset of the full bitstream syntax specified by HEVC. Within the boundaries imposed by the syntax of a given profile, it is still possible to require very large variations in the performance of the encoder and decoder depending on the values taken by syntax elements in the bitstream (e.g., the specified size of decoded pictures). In many applications, it is currently neither practical nor economical to implement a decoder capable of handling all hypothetical uses of the syntax within a particular profile.

To address this issue, "tiers" and "levels" are specified within each profile. A tier of a hierarchy is a set of specified constraints imposed on the values of syntax elements in the bitstream. These constraints can be simple restrictions on the values. Alternatively, they can take the form of constraints on arithmetic combinations of values (e.g., picture width multiplied by picture height multiplied by the number of pictures decoded per second). Tiers specified for lower tiers are more constrained than tiers specified for higher tiers. The same set of tiers is defined for all profiles, with most aspects of the definition of each tier being common across different profiles. Within the specified constraints, individual implementations may support different tiers for each supported profile. In different contexts, a tier is the value of a transform coefficient before scaling. Profiles and tiers are described in more detail in Annex A of High Efficiency Video Coding (HEVC) Working Draft 8 (WD8).

Coded video content conforming to HEVC WD8 uses a common syntax.To implement a subset of the full syntax, flags, parameters, and other syntax elements are included in the bitstream that signal the presence or absence of syntax elements that appear later in the bitstream.

HEVC WD8 defines a sub-layer as a temporally scalable layer of a temporally scalable bitstream, consisting of a Video Coding Layer (VCL) Network Abstraction Layer (NAL) unit with a specific value of the TemporalId variable and associated non-VCL NAL units. HEVC WD8 further defines a sub-layer representation as a subset of the bitstream consisting of NAL units of a specific sub-layer and lower sub-layers.

Subclause 10.1 of HEVC 8 describes bitstream subsets and the extraction process used to generate sub-bitstreams. Subclause 10.1 is described below.

10.1 Sub-bitstream extraction process

The bitstream conformance requirement is that any sub-bitstream contained in the output of the process specified in this subclause shall conform to this Recommendation | International Standard, where tIdTarget is equal to any value in the range of 0 to 6 (inclusive), and where targetDecLayerIdSet contains the value 0.

NOTE—A conforming bitstream contains one or more coded slice NAL units with nuh_reserved_zero_6bits equal to 0 and TemporalId equal to 0.

The inputs to this process are the variable tIdTarget and the list targetDecLayerIdSet.

The output of this process is a sub-bitstream.

The sub-bitstream is derived by removing from the bitstream all NAL units whose TemporalId is greater than tIdTarget or whose nuh_reserved_zero_6bits is not in the targetDecLayerIdSet.

In general, HEVC WD8 describes extracting a sub-bitstream from a bitstream based on the values of a layer identifier and a temporal sub-layer identifier that identify an operation point of the bitstream.

An operation point is generally identified by a set of nuh_reserved_zero_6bits values (denoted as OpLayerIdSet) and a TemporalId value (denoted as OpTid), and the associated bitstream subset derived as the output of the sub-bitstream extraction process (as specified in subclause 10.1 of HEVC WD8, with OpTid and OpLayerIdSet as input) is independently decodable. A simple operation point mode is generally considered to be an operation point mode where, for each operation point, OpLayerIdSet includes and only includes a specific value of nuh_reserved_zero_6bits and all other values of nuh_reserved_zero_6bits (less than the specific value of nuh_reserved_zero_6bits).

Table 1 below shows an example of VPS Raw Byte Sequence Payload (RBSP) syntax and semantics.

Table 1

The syntax element "vps_simple_op_mode_flag[i]" set equal to 1 specifies that the simple operation point mode is used for the i-th operation_point_layer_ids() syntax structure. The syntax element "vps_simple_op_mode_flag[i]" equal to 0 specifies that the simple operation point mode is not used for the i-th operation_point() syntax structure.

Any two instances of the syntax structures hrd_parameters(i, vps_max_sub_layers_minus1) and hrd_parameters(j, vps_max_sub_layers_minus1), where i is not equal to j, may not have the same content.

Table 2 below shows examples of profile, hierarchy, and level syntax and semantics.

Table 2

When ProfilePresentFlag is equal to 1, the syntax element "sub_layer_profile_present_flag[i]" set to 1 specifies that profile information is present in the profile_tier_level() syntax structure for the representation of the sub-layer with TemporalId equal to i. sub_layer_profile_present_flag[i] set to 0 specifies that profile information is not present in the profile_tier_level() syntax structure for the representation of the sub-layer with TemporalId equal to i. When not present, the value of sub_layer_profile_present_flag[i] is inferred to be equal to 0.

The syntax element "sub_layer_level_present_flag[i]" set equal to 1 specifies that for the representation of the sublayer with TemporalId equal to i, the tier information is present in the profile_tier_level() syntax structure. sub_layer_level_present_flag[i] equal to 0 specifies that for the representation of the sublayer with TemporalId equal to i, the tier information is not present in the profile_tier_level() syntax structure.

The syntax elements "sub_layer_profile_idc[i]" and "sub_layer_level_idc[i]" have the same semantics as general_profile_idc and general_level_idc, respectively, but still apply to the representation of the sub-layer with TemporalId equal to i.

Table 3 below shows an example of operation point syntax and semantics.

Table 3

The operation_point(opIdx) syntax structure specifies the set of nuh_reserved_zero_6bits values contained in the OpLayerIdSet of the operation point to which the opIdx-th hrd_parameters() syntax structure in the video parameter set applies.

When vps_simple_op_mode_flag[opIdx] is set equal to 0, the syntax element "op_first_present_layer_id[opIdx]" specifies the first (i.e., 0th) value of nuh_reserved_zero_6bits contained in the OpLayerIdSet of the operation point to which the opIdxth hrd_parameters() syntax structure in the video parameter set applies. When vps_simple_op_mode_flag[opIdx] is equal to 1, op_first_present_layer_id[opIdx] specifies the maximum value of nuh_reserved_zero_6bits contained in the OpLayerIdSet of the operation point to which the opIdxth hrd_parameters() syntax structure in the video parameter set applies.

When vps_simple_op_mode_flag[opIdx] is equal to 0, the syntax element "op_num_layer_id_values_minus1[opIdx]"+1 specifies the number of nuh_reserved_zero_6bits values contained in the OpLayerIdSet of the operation point to which the opIdx-th hrd_parameters() syntax structure in the video parameter set applies. op_num_layer_id_values_minus1[opIdx] is less than or equal to 63.

When vps_simple_op_mode_flag[opIdx] is equal to 0, the syntax element "op_layer_id_delta_minus1[opIdx][i]"+1 specifies the difference between the i-th value of nuh_reserved_zero_6bits and the (i-1)-th value of nuh_reserved_zero_6bits in the OpLayerIdSet contained in the operation point to which the opIdx-th hrd_parameters() syntax structure in the video parameter set applies. The value of op_layer_id_delta_minus1[opIdx][i] is in the range of 0 to 63, inclusive.

The variable NumOpLayerIdsMinus1[opIdx] is derived as follows.

NumOpLayerIdsMinus1[0] is inferred to be equal to 0.

For i in the range of 0 to NumOpLayerIdsMinus1[opIdx] (inclusive), the variable OpLayerId[opIdx][i] is derived as follows.

The value of OpLayerId[0][0] is inferred to be equal to 0.

When i is not equal to j and both i and j are in the range of 0 to NumOpLayerIdsMinus1[opIdx] (inclusive), then the value of OpLayerId[opIdx][i] is equal to OpLayerId[opIdx][j].

Any two sets OpLayerId[opIdx1] and OpLayerId[opIdx2] (where opIdx1 is not equal to opIdx2) do not contain the same set of nuh_reserved_zero_6bits values.

For i in the range of 0 to NumOpLayerIdsMinus1[opIdx], inclusive, the OpLayerIdSet of the operation point to which the opIdx-th hrd_parameters() syntax structure in the video parameter set applies is set to include and only include a nuh_reserved_zero_6bits value equal to OpLayerId[opIdx][i].

Table 4 and below describe the alternative operation point syntax and semantics.

Table 4

The syntax element "op_num_layer_id_values_minus1[opIdx]"+1 specifies the number of nuh_reserved_zero_6bits values contained in the OpLayerIdSet of the operation point to which the opIdx-th hrd_parameters() syntax structure in the video parameter set applies. op_num_layer_id_values_minus1[opIdx] is less than or equal to 63. When not present, the value of op_num_layer_id_values_minus1[opIdx] is inferred to be equal to 0.

In bitstreams conforming to this specification, op_num_layer_id_values_minus1[opIdx] is equal to 0. Although the value of op_num_layer_id_values_minus1[opIdx] is required to be equal to 0 in this version of this specification, a decoder allows other values to appear in the op_num_layer_id_values_minus1[opIdx] syntax.

The syntax element "op_layer_id[opIdx][i]" specifies the i-th value of nuh_reserved_zero_6bits contained in the OpLayerIdSet of the operation point to which the opIdx-th hrd_parameters() syntax structure in the video parameter set applies.

The variable NumOpLayerIdsMinus1[opIdx] is derived as follows.

NumOpLayerIdsMinus1[0] is inferred to be equal to 0.

for(i＝0;i<=NumOpLayerIdsMinus1[opIdx];i++)

OpLayerId[opIdx][i]=vps_simple_op_mode_flag[opIdx]? i:

op_layer_id[opIdx][i]

The value of OpLayerId[0][0] is inferred to be equal to 0.

Any two sets OpLayerId[opIdx1] and OpLayerId[opIdx2] do not contain the same set of nuh_reserved_zero_6bits values, where opIdx1 is not equal to opIdx2.

JCTVC-K0204 (which is incorporated herein by reference and available at http://phenix.int-evry.fr/jct/doc_end_user/documents/11_Shanghai/wg11/JCTVC-K0204-v1.zip) provides revised signaling of operation points as described by the following syntax and semantics:

Table 5

The syntax element “layer_present_in_op_flag[opIdx][i]” set equal to 1 specifies that layer i is present in the operation point opIdx, and the syntax element “layer_present_in_op_flag[opIdx][i]” set equal to 0 specifies that layer i is not present in the operation point opIdx.

Existing methods for signaling operation points may have some potential drawbacks. For example, existing methods for signaling operation points may have entropy coded syntax elements using ue(v) coding as specified in HEVC WD8, or may not support signaling of nuh_reserved_zero_6bits values (i.e., layer IDs) greater than max_num_layers_minus1, which is signaled in the video parameter set (VPS).

This disclosure proposes various techniques that can potentially address some of these potential drawbacks. In one such technique, the maximum value of nuh_reserved_zero_6bits (i.e., the maximum layer ID value) is first signaled, followed by a list of flags, each of which specifies whether a layer with a particular layer ID value less than the maximum layer ID value is included in the OpLayerIdSet of the operation point to which the opIdx-th hrd_parameters() syntax structure in the video parameter set applies. In another technique, a list of M flags is signaled, each of which specifies whether a layer with a particular possible layer ID value is included in the OpLayerIdSet of the operation point to which the opIdx-th hrd_parameters() syntax structure in the video parameter set applies. The value of M is equal to the total number of possible different layer IDs in any bitstream. For example, M may be equal to ^2N , where N is the number of bits used to represent nuh_reserved_zero_6bits (i.e., the layer ID). In yet another technique, the maximum value of the nuh_reserved_zero_6bits value (i.e., the maximum layer ID value) is signaled. If simple operation point mode is not used, a list of flags is signaled, where each flag specifies whether a layer with a particular layer ID value less than the maximum layer ID value is included in the OpLayerIdSet of the operation point to which the opIdx-th hrd_parameters() syntax structure in the video parameter set applies.

Some detailed examples of the above techniques will now be described. The examples described below are generally consistent with HEVC WD8, and therefore, aspects that are not fully described below can be assumed to be the same as those in HEVC WD8.

The operation point syntax and semantics for the first example are shown in Table 6 below.

Table 6

The operation_point(opIdx) syntax structure specifies that the set of nuh_reserved_zero_6bits values is contained in the OpLayerIdSet of the operation point to which the opIdx-th hrd_parameters() syntax structure in the video parameter set applies.

The syntax element "op_max_layer_id[opIdx]" specifies the maximum value of nuh_reserved_zero_6 bits contained in the OpLayerIdSet of the operation point to which the opIdx-th hrd_parameters() syntax structure in the video parameter set applies. Although Table 6 shows that the syntax element "op_max_layer_id[opIdx]" is signaled for each operation point, it can also be signaled elsewhere in the coded bitstream, for example, in a sequence parameter set or VPS.

The syntax element "op_layer_id_incuded_flag[opIdx][i]" set equal to 0 specifies that the value of nuh_reserved_zero_6bits equal to i is not included in the OpLayerIdSet of the operation point to which the opIdx-th hrd_parameters() syntax structure in the video parameter set applies. op_layer_id_incuded_flag[opIdx][i] equal to 1 specifies that the value of nuh_reserved_zero_6bits equal to i is included in the OpLayerIdSet of the operation point to which the opIdx-th hrd_parameters() syntax structure in the video parameter set applies. The sum of all op_layer_id_incuded_flag[opIdx][i] is less than or equal to max_num_layers_minus1, where i is in the range from 0 to op_max_layer_id[opIdx]-1, inclusive.

The variables NumOpLayerIdsMinus1[opIdx] and OpLayerId[opIdx][i] are derived as follows, where i is in the range of 0 to NumOpLayerIdsMinus1[opIdx] (inclusive).

The inferred value of NumOpLayerIdsMinus1[0] is equal to 0. The inferred value of OpLayerId[0][0] is equal to 0.

The OpLayerIdSet of the operation point to which the opIdx-th hrd_parameters() syntax structure in the video parameter set applies is set to include and only include the nuh_reserved_zero_6bits value equal to OpLayerId[opIdx][i], where i is in the range of 0 to NumOpLayerIdsMinus1[opIdx] (inclusive).

Referring back to the above example, assume that the bitstream includes six substreams with various temporal and spatial resolutions, each with a layer ID. For the operation point identified by opIdx, the maximum layer ID value can be signaled in the bitstream as the value of the syntax element "op_max_layer_id[opIdx]." For the purposes of this example, assume that the maximum layer ID value is 9, such that op_max_layer_id[opIdx] is equal to 9. Nine flags can be used to signal the remaining layer ID values, with the first flag indicating whether a layer ID value of 0 is present, the second flag indicating whether a layer ID value of 1 is present, and so on. Thus, to signal layer ID values of 2, 5, and 10, the value 10 can be signaled first, followed by the flag sequence 001001000, where a 1 in the third bit indicates the presence of a layer ID value of 2, and a 1 in the sixth bit indicates the presence of a layer ID value of 5. Using the syntax of Table 6, the flag sequence 001001000 is obtained as follows. For i=0, the flag value for op_layer_id_included_flag[opIdx][i] is 0. For i=1, the flag value for op_layer_id_included_flag[opIdx][i] is 0. For i=3, the flag value for op_layer_id_included_flag[opIdx][i] is 0. For i=4, the flag value for op_layer_id_included_flag[opIdx][i] is 0. For i=5, the flag value for op_layer_id_included_flag[opIdx][i] is 1. For i=6, the flag value for op_layer_id_included_flag[opIdx][i] is 0. For i=7, the flag value for op_layer_id_included_flag[opIdx][i] is 0. For i=8, the flag value for op_layer_id_included_flag[opIdx][i] is 0. For i=9, the value of i is not less than op_max_layer_id[opIdx], which is also equal to 9. Therefore, the video decoder can determine that the last flag has been received.

The operation point syntax and semantics for the second example technique are shown in Table 7 below.

Table 7

The syntax element "op_layer_id_incuded_flag[opIdx][i]" set equal to 0 specifies that the value of nuh_reserved_zero_6bits equal to i is not included in the OpLayerIdSet of the operation point to which the opIdx-th hrd_parameters() syntax structure in the video parameter set applies. op_layer_id_incuded_flag[opIdx][i] equal to 1 specifies that the value of nuh_reserved_zero_6bits equal to i is included in the OpLayerIdSet of the operation point to which the opIdx-th hrd_parameters() syntax structure in the video parameter set applies. The sum of all op_layer_id_incuded_flag[opIdx][i] is less than or equal to max_num_layers_minus1, where i is in the range from 0 to 63, inclusive.

The operation point syntax and semantics for the third example are shown below in Table 8. In this example, the VPS syntax and semantics are also changed, as shown in Table 8 and described below.

Table 8

The syntax element "vps_simple_op_mode_flag[i]" set equal to 1 specifies that the simple operation point mode is used for the i-th operation_point() syntax structure. vps_simple_op_mode_flag[i] equal to 0 specifies that the simple operation point mode is not used for the i-th operation_point() syntax structure.

Any two instances of the syntax structures hrd_parameters(i, vps_max_sub_layers_minus1) and hrd_parameters(j, vps_max_sub_layers_minus1), where i is not equal to j, do not have the same content.

Table 9

The operation_point(opIdx) syntax structure shown in Table 9 specifies that the nuh_reserved_zero_6bits value set is included in the OpLayerIdSet of the operation point to which the opIdx-th hrd_parameters() syntax structure in the video parameter set applies.

The syntax element "op_max_layer_id[opIdx]" specifies the maximum value of nuh_reserved_zero_6bits contained in the OpLayerIdSet of the operation point to which the opIdx-th hrd_parameters() syntax structure in the video parameter set applies.

When vps_simple_op_mode_flag[opIdx] is equal to 0, the syntax element "op_layer_id_incuded_flag[opIdx][i]" set equal to 0 specifies that the value of nuh_reserved_zero_6bits equal to i is not included in the OpLayerIdSet of the operation point to which the opIdx-th hrd_parameters() syntax structure in the video parameter set applies. When vps_simple_op_mode_flag[opIdx] is equal to 0, op_layer_id_incuded_flag[opIdx][i] equal to 1 specifies that the value of nuh_reserved_zero_6bits equal to i is included in the OpLayerIdSet of the operation point to which the opIdx-th hrd_parameters() syntax structure in the video parameter set applies. The sum of all op_layer_id_incuded_flag[opIdx][i] is less than or equal to max_num_layers_minus1, where i is in the range from 0 to op_max_layer_id[opIdx]-1, inclusive.

FIG2 is a block diagram illustrating an example of a video encoder 20 that may implement the techniques described in this disclosure. Video encoder 20 may perform intra- and inter-coding of video blocks within a video slice. Intra-coding relies on spatial prediction to reduce or remove spatial redundancy in video within a given video frame or picture. Inter-coding relies on temporal prediction to reduce or remove temporal redundancy in video within adjacent frames or pictures of a video sequence. Intra-mode (I-mode) may refer to any of several spatially-based coding modes. Inter-mode (e.g., unidirectional prediction (P-mode) or bidirectional prediction (B-mode)) may refer to any of several temporally-based coding modes.

As shown in FIG2 , video encoder 20 receives a current video block within a video frame to be encoded. In the example of FIG2 , video encoder 20 includes a mode selection unit 40, a reference frame memory 64, a summer 50, a transform processing unit 52, a quantization unit 54, and an entropy encoding unit 56. Mode selection unit 40, in turn, includes a motion compensation unit 44, a motion estimation unit 42, an intra-prediction processing unit 46, and a partitioning unit 48. To achieve video block reconstruction, video encoder 20 also includes an inverse quantization unit 58, an inverse transform processing unit 60, and summer 62. A deblocking filter may also be included to filter block boundaries, thereby removing blocking artifacts from the reconstructed video. If necessary, the deblocking filter will typically filter the output of summer 62. In addition to the deblocking filter, additional filters (in-loop or post-loop) may also be used. Such filters are not shown for brevity, but if necessary, such filters can filter the output of summer 50 (as in-loop filters).

During the encoding process, video encoder 20 receives a video frame or slice to be coded. The frame or slice may be divided into multiple video blocks. Motion estimation unit 42 and motion compensation unit 44 perform inter-predictive coding of the received video block relative to one or more blocks in one or more reference frames to provide temporal prediction. Intra-prediction processing unit 46 may alternatively perform intra-predictive coding of the received video block relative to one or more neighboring blocks in the same frame or slice as the block to be coded to provide spatial prediction. Video encoder 20 may perform multiple coding passes, for example, to select an appropriate coding mode for each block of video data.

Furthermore, partition unit 48 may partition blocks of video data into sub-blocks based on evaluation of previous partitioning schemes in previous coding passes. For example, partition unit 48 may initially partition a frame or slice into LCUs and, based on rate-distortion analysis (e.g., rate-distortion optimization), partition each of the LCUs into sub-CUs. Mode select unit 40 may further generate a quadtree data structure indicating the partitioning of the LCUs into sub-CUs. A leaf node CU of the quadtree may include one or more PUs and one or more TUs.

Mode select unit 40 may select one of the coding modes (intra or inter) based on the error result, for example, and provide the resulting intra- or inter-coded block to summer 50 to generate residual block data and to summer 62 to reconstruct the encoded block for use as a reference frame. Mode select unit 40 also provides syntax elements, such as motion vectors, intra-mode indicators, partition information, and other such syntax information, to entropy encoding unit 56.

Motion estimation unit 42 and motion compensation unit 44 may be highly integrated, but are described separately for conceptual purposes. Motion estimation, performed by motion estimation unit 42, is the process of generating motion vectors, which estimate the motion of video blocks. For example, a motion vector may indicate the displacement of a PU of a video block within a current video frame or picture relative to a predictive block within a reference frame (or other coded unit) relative to the current block being coded within the current frame (or other coded unit). A predictive block is a block that is found to closely match the block to be coded in terms of pixel difference, which may be determined by sum of absolute difference (SAD), sum of squared difference (SSD), or other difference metrics. In some examples, video encoder 20 may calculate values for sub-integer pixel positions of a reference picture stored in reference frame memory 64. For example, video encoder 20 may interpolate values for quarter-pixel positions, eighth-pixel positions, or other fractional pixel positions of the reference picture. Thus, motion estimation unit 42 may perform motion searches relative to full-pixel positions and fractional pixel positions and output motion vectors with fractional pixel precision.

Motion estimation unit 42 calculates a motion vector for a PU of a video block in an inter-coded slice by comparing the position of the PU to the position of a predictive block of a reference picture. The reference picture may be selected from a first reference picture list (List 0) or a second reference picture list (List 1), each of which identifies one or more reference pictures stored in reference frame memory 64. Motion estimation unit 42 sends the calculated motion vector to entropy encoding unit 56 and motion compensation unit 44.

Motion compensation performed by motion compensation unit 44 may involve extracting or generating the predictive block based on the motion vector determined by motion estimation unit 42. Furthermore, in some examples, motion estimation unit 42 and motion compensation unit 44 may be functionally integrated. Upon receiving the motion vector for the PU of the current video block, motion compensation unit 44 may locate the predictive block to which the motion vector points in one of the reference picture lists. Summer 50 forms a residual video block by subtracting the pixel values of the predictive block from the pixel values of the current video block being coded, thereby forming pixel difference values, as discussed below. In general, motion estimation unit 42 performs motion estimation with respect to the luma component, and motion compensation unit 44 uses the motion vector calculated based on the luma component for both chroma and luma components. Mode select unit 40 may also generate syntax elements associated with the video block and video slice for use by video decoder 30 in decoding the video block of the video slice.

As described above, intra-prediction processing unit 46 may intra-predict a current block, as an alternative to the inter-prediction performed by motion estimation unit 42 and motion compensation unit 44. In particular, intra-prediction processing unit 46 may determine an intra-prediction mode to use to encode the current block. In some examples, intra-prediction processing unit 46 may encode the current block using various intra-prediction modes, e.g., during separate encoding passes, and intra-prediction processing unit 46 (or, in some examples, mode select unit 40) may select an appropriate intra-prediction mode to use from the tested modes.

For example, intra-prediction processing unit 46 may calculate rate-distortion values using a rate-distortion analysis for various tested intra-prediction modes and select the intra-prediction mode with the best rate-distortion characteristics among the tested modes. The rate-distortion analysis generally determines the amount of distortion (or error) between an encoded block and the original, unencoded block that was encoded to produce the encoded block, as well as the bit rate (i.e., the number of bits) used to produce the encoded block. Intra-prediction processing unit 46 may calculate a ratio of the distortion and rate for the various encoded blocks to determine which intra-prediction mode exhibits the best rate-distortion value for the block.

After selecting an intra-prediction mode for a block, intra-prediction processing unit 46 may provide information indicating the intra-prediction mode selected for the block to entropy encoding unit 56. Entropy encoding unit 56 may encode the information indicating the selected intra-prediction mode. Video encoder 20 may include in the transmitted bitstream configuration data a definition of the contexts in which the various blocks are encoded, and an indication of the most probable intra-prediction mode to be used for each of the contexts, an intra-prediction mode index table, and a modified intra-prediction mode index table, which may include multiple intra-prediction mode index tables and multiple modified intra-prediction mode index tables (also referred to as codeword mapping tables).

Video encoder 20 forms a residual video block by subtracting the prediction data from mode select unit 40 from the original video block being coded. Summer 50 represents the one or more components that perform this subtraction operation. Transform processing unit 52 applies a transform, such as a discrete cosine transform (DCT) or a conceptually similar transform, to the residual block, producing a video block comprising residual transform coefficient values. Transform processing unit 52 may perform other transforms conceptually similar to DCT. Wavelet transforms, integer transforms, subband transforms, or other types of transforms may also be used. In any case, transform processing unit 52 applies a transform to the residual block, producing a block of residual transform coefficients. The transform may convert the residual information from a pixel value domain to a transform domain (e.g., a frequency domain). Transform processing unit 52 may send the resulting transform coefficients to quantization unit 54.

Quantization unit 54 quantizes the transform coefficients to further reduce the bit rate. The quantization process may reduce the bit depth associated with some or all of the coefficients. The degree of quantization may be modified by adjusting a quantization parameter. In some examples, quantization unit 54 may then perform a scan of the matrix containing the quantized transform coefficients. Alternatively, entropy encoding unit 56 may perform the scan.

After quantization, entropy encoding unit 56 entropy codes the quantized transform coefficients. For example, entropy encoding unit 56 may perform context adaptive variable length coding (CAVLC), context adaptive binary arithmetic coding (CABAC), syntax-based context adaptive binary arithmetic coding (SBAC), probability interval partitioning entropy (PIPE) coding, or another entropy coding technique. In the case of context-based entropy coding, the context may be based on neighboring blocks. After entropy coding by entropy encoding unit 56, the encoded bitstream may be transmitted to another device (e.g., video decoder 30) or archived for later transmission or retrieval.

Inverse quantization unit 58 and inverse transform processing unit 60 apply inverse quantization and inverse transform, respectively, to reconstruct the residual block in the pixel domain, e.g., for later use as a reference block. Motion compensation unit 44 may calculate a reference block by adding the residual block to a predictive block of one of the frames of reference frame memory 64. Motion compensation unit 44 may also apply one or more interpolation filters to the reconstructed residual block to calculate sub-integer pixel values for use in motion estimation. Summer 62 adds the reconstructed residual block to the motion compensated prediction block produced by motion compensation unit 44 to produce a reconstructed video block for storage in reference frame memory 64. The reconstructed video block may be used by motion estimation unit 42 and motion compensation unit 44 as a reference block for inter-coding a block in a subsequent video frame.

3 is a block diagram illustrating an example of a video decoder 30 that may implement the techniques described in this disclosure. In the example of FIG3 , video decoder 30 includes an entropy decoding unit 70, a motion compensation unit 72, an intra-prediction processing unit 74, an inverse quantization unit 76, an inverse transform processing unit 78, a reference frame memory 82, and a summer 80. In some examples, video decoder 30 may perform a decoding pass that is generally reciprocal to the encoding pass described with respect to video encoder 20 (as shown in FIG2 ).

During the decoding process, video decoder 30 receives an encoded video bitstream representing video blocks and associated syntax elements of an encoded video slice from video encoder 20. Video decoder 30 may receive the encoded video bitstream from network entity 29. Network entity 29 may, for example, be a server, a media-aware network element (MANE), a video editor/splicer, or other such device configured to implement one or more of the techniques described above. Network entity 29 may include an external device configured to perform the techniques of this disclosure. As described above, some of the techniques described in this disclosure may be implemented by network entity 29 before network entity 29 transmits the encoded video bitstream to video decoder 30. In some video decoding systems, network entity 29 and video decoder 30 may be parts of separate devices, while in other instances, the functionality described with respect to network entity 29 may be performed by the same device including video decoder 30.

In one example, network entity 29 may store or receive a raw bitstream of video data that is scalable and/or includes multiple layers or views. In the raw bitstream, a parameter set (e.g., a VPS) may include the operation point syntax discussed above. The operation point syntax may be used by network entity 29 to identify which layers are present in the operation point. Network entity 29 may select one of multiple operation points (i.e., sub-bitstreams) from the raw bitstream based on the operation point syntax included in the VPS and based on content required by or requested by video decoder 30. For the sub-bitstream corresponding to the selected operation point, network entity 29 may forward the VLC NAL units and non-VCL NAL units comprising the bitstream to video decoder 30 and not forward other NAL units.

For a particular operation point identified in the VPS, network entity 29 may receive an indication of the maximum layer ID value for the bitstream and a series of flags for layers with layer ID values less than the maximum layer ID value. Based on the values of the flags, network entity 29 may determine which layers are included in the operation point. For example, if the maximum layer ID value is M, then layer M is included in the operation point. For layer M-1, network entity 29 receives a flag, wherein a first value of the flag (e.g., 1 or 0) indicates that layer M-1 is included in the operation point, and a second value of the flag (e.g., 0 or 1) indicates that layer M-1 is not included in the operation point. For layer M-2, network entity 29 receives a second flag, wherein a first value of the second flag (e.g., 1 or 0) indicates that layer M-2 is included in the operation point, and a second value of the second flag (e.g., 0 or 1) indicates that layer M-2 is not included in the operation point. Network entity 29 may similarly receive flags for all remaining layers up to layer 0. Thus, if the value of the maximum layer ID is M, the network entity 29 may receive flags for all layers 0 through M-1.

Entropy decoding unit 70 of video decoder 30 entropy decodes the bitstream provided by network entity 29 to generate quantized coefficients, motion vectors or intra-prediction mode indicators, and other syntax elements (e.g., the operation point syntax described above). Entropy decoding unit 70 forwards the motion vectors and other syntax elements to motion compensation unit 72. Video decoder 30 may receive different syntax elements at different parts of the encoded bitstream. For example, some syntax elements may be received at the VPS level, the SPS level, or the APS level, while other syntax elements are received at the video slice level and/or the video block level.

When the video slice is coded as an intra-coded (I) slice, intra-prediction processing unit 74 may generate prediction data for the video block of the current video slice based on the signaled intra-prediction mode and data from previously decoded blocks of the current frame or picture. When the video frame is coded as an inter-coded (i.e., B, P, or GPB) slice, motion compensation unit 72 generates a predictive block for the video block of the current video slice based on the motion vectors and other syntax elements received from entropy decoding unit 70. The predictive block may be generated from one of the reference pictures within one of the reference picture lists. Video decoder 30 may construct the reference frame lists (List 0 and List 1) using a default construction technique based on the reference pictures stored in reference frame memory 82.

Motion compensation unit 72 determines prediction information for a video block of the current video slice by parsing motion vectors and other syntax elements, and uses the prediction information to produce a predictive block for the current video block being decoded. For example, motion compensation unit 72 uses some of the received syntax elements to determine a prediction mode (e.g., intra-prediction or inter-prediction) used to code the video block of the video slice, an inter-prediction slice type (e.g., a B slice or a P slice), construction information for one or more of the reference picture lists for the slice, a motion vector for each inter-coded video block of the slice, an inter-prediction state for each inter-coded video block of the slice, and other information to decode the video blocks in the current video slice.

Motion compensation unit 72 may also perform interpolation based on interpolation filters. Motion compensation unit 72 may calculate interpolated values for sub-integer pixels of a reference block using interpolation filters as used by video encoder 20 during encoding of the video block. In this case, motion compensation unit 72 may determine the interpolation filters used by video encoder 20 from received syntax elements and use the interpolation filters to produce a predictive block.

Inverse quantization unit 76 inverse quantizes (i.e., de-quantizes) the quantized transform coefficients provided in the bitstream and decoded by entropy decoding unit 70. The inverse quantization process may include determining the degree of quantization and, likewise, the degree of inverse quantization that should be applied, using a quantization parameter QP _Y calculated for each video block in the video slice by video decoder 30. Inverse transform processing unit 78 applies an inverse transform (e.g., an inverse DCT, an inverse integer transform, or a conceptually similar inverse transform process) to the transform coefficients to produce residual blocks in the pixel domain.

After motion compensation unit 72 generates a predictive block for the current video block based on the motion vector and other syntax elements, video decoder 30 forms a decoded video block by summing the residual block from inverse transform processing unit 78 with the corresponding predictive block generated by motion compensation unit 72. Summer 90 represents the one or more components that perform this summation operation. If necessary, a deblocking filter may also be applied to filter the decoded block to remove blocking artifacts. Other loop filters (in the decoding loop or after the decoding loop) may also be used to smooth pixel transitions or otherwise improve video quality. The decoded video blocks in a given frame or picture are then stored in reference frame memory 82, which stores reference pictures used for subsequent motion compensation. Reference frame memory 82 also stores decoded video for later presentation on a display device (e.g., display device 32 of FIG. 1 ).

4 is a block diagram illustrating an example set of devices that form part of network 100. In this example, network 100 includes routing devices 104A, 104B (routing devices 104) and transcoding device 106. Routing devices 104 and transcoding device 106 are intended to represent a small number of devices that may form part of network 100. Other network devices (e.g., switches, hubs, gateways, firewalls, bridges, and other such devices) may also be included within network 100. Furthermore, additional network devices may be provided along the network path between server device 102 and client device 108. In some examples, server device 102 may correspond to source device 12 (FIG. 1), while client device 108 may correspond to destination device 14 (FIG. 1).

Generally speaking, routing device 104 implements one or more routing protocols to exchange network data through network 100. In some examples, routing device 104 may be configured to perform proxy or cache operations. Therefore, in some examples, routing device 104 may be referred to as a proxy device. Generally speaking, routing device 104 executes routing protocols to discover paths through network 100. By executing such routing protocols, routing device 104B can discover a network path from itself via routing device 104A to server device 102.

Routing device 104 and transcoding device 106 are examples of devices that may implement the techniques described in this disclosure. For example, as part of delivering video data from server device 102 to client device 108, routing device 104 and/or transcoding device 106 may receive VPS syntax that includes operation point syntax. The operation point syntax may, for example, include a maximum layer ID value for the bitstream. Routing device 104 and transcoding device 106 may additionally receive one or more flags in the operation point syntax for layers with layer IDs that are less than the maximum layer ID value. Based on the maximum layer ID value and the flags, routing device 104 and transcoding device 106 may determine that the layer is included in the operation point and, therefore, may identify the NAL unit of the sub-bitstream that includes the operation point.

FIG5 shows an example method of encoding video data according to the techniques of this disclosure. The techniques of FIG5 will be described with reference to a video encoder, such as video encoder 20. Video encoder 20 may generate, in a bitstream of encoded video data, an indication of a maximum layer ID value for the bitstream (152). Video encoder 20 may also generate a flag for the first layer having a layer ID value that is less than the maximum layer ID value (154). The indication of the maximum layer ID and the flag may, for example, be part of operation point syntax contained in a VPS.

FIG6 shows an example method of processing video data according to the techniques of this disclosure. The techniques of FIG6 will be described with reference to a video processing device, which may correspond to a video decoder (e.g., video decoder 30 of FIG1 and FIG3 ) or may correspond to a network device or network entity (e.g., network device 13 of FIG1 , network entity 29 of FIG3 , or routing device 104 or transcoding device 106 of FIG4 ). The video processing device may receive, in a bitstream of encoded video data, an indication of a maximum layer ID value for the bitstream (162). The video processing device may also receive a flag for a first layer having a layer ID value that is less than the maximum layer ID value (164). Based on the value of the flag, the video processing device may determine, based on the value of the flag, whether the first layer is included in the operation point (166).

It should be appreciated that, depending on the example, certain actions or events of any of the techniques described herein may be performed in a different sequence, may be added, combined, or omitted entirely (e.g., not all described actions or events are necessary to practice the techniques). Furthermore, in some examples, actions or events may be performed concurrently rather than sequentially, for example, through multithreading, interrupt processing, or multiple processors.

In one or more examples, the described functions may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted via a computer-readable medium as one or more instructions or codes and executed by a hardware-based processing unit. Computer-readable media may include computer-readable storage media (which corresponds to tangible media such as data storage media) or communication media, which includes, for example, any media that facilitates the transfer of a computer program from one place to another according to a communication protocol. In this manner, computer-readable media may generally correspond to: (1) a non-transitory, tangible computer-readable storage medium; or (2) a communication medium such as a signal or carrier wave. Data storage media may be any available media that can be accessed by one or more computers or one or more processors to retrieve instructions, codes, and/or data structures for implementing the techniques described in this disclosure. A computer program product may include computer-readable media.

By way of example, and not limitation, such computer-readable storage media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer. Furthermore, any connection is properly termed a computer-readable medium. For example, if instructions are transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies (such as infrared, radio, and microwave), the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies (such as infrared, radio, and microwave) are included in the definition of medium. However, it should be understood that computer-readable storage media and data storage media do not include connections, carrier waves, signals, or other transitory media, but rather refer to non-transitory, tangible storage media. As used herein, disk and disc include compact disc (CD), laser disc, optical disc, digital video disc (DVD), floppy disk, and Blu-ray disc. Disks typically reproduce data magnetically, while discs reproduce data optically using lasers. Combinations of the above should also be included within the scope of computer-readable media.

Instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs), general-purpose microprocessors, application-specific integrated circuits (ASICs), field-programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuitry. Thus, as used herein, the term "processor" may refer to any of the aforementioned structures or any other structure suitable for implementing the techniques described herein. Additionally, in some aspects, the functionality described herein may be provided within dedicated hardware and/or software modules configured for encoding and decoding, or incorporated into a combined codec. Moreover, the techniques may be fully implemented in one or more circuits or logic elements.

The techniques of this disclosure may be implemented in a wide variety of devices or apparatuses, including wireless handsets, integrated circuits (ICs), or sets of ICs (e.g., chipsets). Various components, modules, or units are described in this disclosure to emphasize functional aspects of devices configured to perform the disclosed techniques, but do not necessarily require implementation by different hardware units. Specifically, as described above, the various units may be combined in a codec hardware unit, or provided by a collection of interoperable hardware units (including one or more processors as described above) in conjunction with appropriate software and/or firmware.

Various embodiments have been described. These and other embodiments are within the scope of the following claims.

Method, apparatus and device for processing and encoding multi-layer video data

Technical Field

Background Art

Summary of the Invention

BRIEF DESCRIPTION OF THE DRAWINGS

DETAILED DESCRIPTION

10.1 Sub-bitstream extraction process

The output of this process is a sub-bitstream.

Table 1

Table 2

Table 3 below shows an example of operation point syntax and semantics.

Table 3

The variable NumOpLayerIdsMinus1[opIdx] is derived as follows.

NumOpLayerIdsMinus1[0] is inferred to be equal to 0.

The value of OpLayerId[0][0] is inferred to be equal to 0.

Table 4

The variable NumOpLayerIdsMinus1[opIdx] is derived as follows.

NumOpLayerIdsMinus1[0] is inferred to be equal to 0.

for(i＝0;i<=NumOpLayerIdsMinus1[opIdx];i++)

OpLayerId[opIdx][i]=vps_simple_op_mode_flag[opIdx]? i:

op_layer_id[opIdx][i]

The value of OpLayerId[0][0] is inferred to be equal to 0.

Table 5

Table 6

Table 7

Table 8

Table 9

Technical Field

Background Art

Summary of the Invention

BRIEF DESCRIPTION OF THE DRAWINGS

DETAILED DESCRIPTION

10.1 Sub-bitstream extraction process

The output of this process is a sub-bitstream.

Table 1

Table 2

Table 3 below shows an example of operation point syntax and semantics.

Table 3

The variable NumOpLayerIdsMinus1[opIdx] is derived as follows.

NumOpLayerIdsMinus1[0] is inferred to be equal to 0.

The value of OpLayerId[0][0] is inferred to be equal to 0.

Table 4

The variable NumOpLayerIdsMinus1[opIdx] is derived as follows.

NumOpLayerIdsMinus1[0] is inferred to be equal to 0.

for(i＝0;i<=NumOpLayerIdsMinus1[opIdx];i++)

OpLayerId[opIdx][i]=vps_simple_op_mode_flag[opIdx]? i:

op_layer_id[opIdx][i]

The value of OpLayerId[0][0] is inferred to be equal to 0.

Table 5

Table 6

Table 7

Table 8

Table 9

Claims

1. A method for processing multi-layer video data, the method comprising:

A syntax element is received in the video parameter set, the syntax element specifying a maximum layer identification ID value for any NAL unit associated with the first layer set, wherein the multi-layer video data includes two or more layer sets, each of the two or more layer sets being associated with at least one independently decodeable bitstream of the multi-layer video data and including two or more layers.

For the first layer set of the at least one layer set, a one-bit layer ID flag is received in the video parameter set for the first layer having a layer ID value less than the maximum layer ID value;

The first layer is determined to be included in the first layer set based on the value of the one-bit layer ID flag.

Receive a plurality of NAL units, each of the plurality of NAL units having a NAL unit header, the NAL unit header containing a layer ID syntax element, the layer ID syntax element specifying the layer to which the respective NAL unit belongs; and

The NAL units of the plurality of NAL units are determined to be included in the first layer based on the layer ID syntax element corresponding to the NAL unit of the first layer.

2. The method according to claim 1, further comprising:

The video parameter set receives a layer ID flag with an extra bit for each layer ID value that is different from the layer ID associated with the first layer and is between 1 and the maximum layer ID value, wherein the value of each layer ID flag with an extra bit indicates whether the layer associated with each layer ID value is included in the first layer set.

3. The method of claim 1, wherein the first value of the one-bit layer ID flag indicates that the first layer is included in the first layer set, and the second value of the one-bit layer ID flag indicates that the first layer is not included in the first layer set.

4. The method of claim 1, wherein the first layer set includes operation points.

5. The method of claim 1, wherein the method is performed by a Media Aware Network Element (MANE), and wherein the method further comprises:

In response to the first layer being included in the first layer set, one or more NAL units having a layer ID value less than the maximum layer ID value are identified from the plurality of NAL units;

Extract one or more NAL units from the multi-layer video data that have a layer ID value less than the maximum layer ID value.

6. The method of claim 1, wherein the video parameter set includes a syntax applicable to multiple layers.

7. The method of claim 1, wherein the syntax element specifying the maximum layer ID value and the one-bit layer ID flag are each a fixed-length syntax element that is not entropy-encoded.

8. An apparatus for processing multi-layer video data, the apparatus comprising:

A memory, configured to store the multi-layer video data; and

One or more processors, said one or more processors being configured to:

For the first layer set of the at least one layer set, a one-bit layer ID flag for the first layer having a layer ID value less than the maximum layer ID value is received in the video parameter set; and

9. The apparatus of claim 8, wherein the one or more processors are further configured to receive, in the video parameter set, a layer ID flag with an additional bit for each layer ID value between 1 and the maximum layer ID value, which is different from the layer ID associated with the first layer, wherein the value for each layer ID flag with an additional bit indicates whether the layer associated with the respective layer ID value is included in the first layer set.

10. The apparatus of claim 8, wherein the first value of the one-bit layer ID flag indicates that the first layer is included in the first layer set, and the second value of the one-bit layer ID flag indicates that the first layer is not included in the first layer set.

11. The apparatus of claim 8, wherein the first layer set includes operating points.

12. The apparatus of claim 8, wherein the apparatus includes a Media Aware Network Element (MANE), and wherein the one or more processors are further configured to:

13. The apparatus of claim 8, wherein the apparatus comprises at least one of the following:

integrated circuit;

microprocessor; or

Wireless communication device.

14. The apparatus of claim 8, wherein the video parameter set includes a syntax applicable to multiple layers.

15. The apparatus of claim 8, wherein the syntax element specifying the maximum layer ID value and the one-bit layer ID flag are each a fixed-length and non-entropy-encoded syntax element.

16. An apparatus for processing multi-layer video data, the apparatus comprising:

A means for receiving syntax elements in a video parameter set, the syntax elements specifying a maximum layer identification ID value for any NAL unit associated with a first layer set, wherein the multi-layer video data includes two or more layer sets, each of the two or more layer sets being associated with at least one independently decodeable bitstream of the multi-layer video data and including two or more layers.

For receiving, in the video parameter set, a means for receiving, the first layer set of the at least one layer set, a one-bit layer ID flag for the first layer having a layer ID value less than the maximum layer ID value;

A means for determining, based on the value of the layer ID flag containing a single layer ID, that the first layer is included in the first layer set;

A means for receiving a plurality of NAL units, each of the plurality of NAL units having a NAL unit header, the NAL unit header including a layer ID syntax element specifying the layer to which the respective NAL unit belongs; and

A means for determining, based on the layer ID syntax element corresponding to the NAL unit of the first layer, that the NAL unit of the plurality of NAL units is included in the first layer.

17. The device according to claim 16, further comprising:

Means for receiving, in the video parameter set, a flag with an extra bit for each layer ID value, between 1 and the maximum layer ID value, that is different from the layer ID associated with the first layer, wherein the value of each flag with an extra bit indicates whether the layer associated with each layer ID value is included in the first layer set.

18. The device of claim 16, wherein the first value for the one-bit layer ID flag indicates that the first layer is included in the first layer set, and the second value for the one-bit layer ID flag indicates that the first layer is not included in the first layer set.

19. The device of claim 16, wherein the first layer set includes operating points.

20. The apparatus of claim 16, wherein the apparatus includes a Media Aware Network Element (MANE), and wherein the apparatus further includes means for identifying one or more NAL units having a layer ID value less than the maximum layer ID value from the plurality of NAL units; and means for extracting the one or more NAL units having a layer ID value less than the maximum layer ID value from the multi-layer video data.

21. The device of claim 16, wherein the video parameter set includes a syntax applicable to multiple layers.

22. The device of claim 16, wherein the syntax element specifying the maximum layer ID value and the one-bit layer ID flag are each a fixed-length and non-entropy-encoded syntax element.

23. A non-volatile computer-readable storage medium for processing multi-layer video data, wherein the storage instructions, when executed by one or more processors, cause the one or more processors to perform the following operations:

24. The non-volatile computer-readable storage medium of claim 23, wherein other instructions are stored, said other instructions being configured to cause the one or more processors to perform the following operations:

25. The non-volatile computer-readable storage medium of claim 23, wherein the first value of the layer ID flag indicates that the first layer is included in the first layer set, and the second value of the layer ID flag indicates that the first layer is not included in the first layer set.

26. The non-volatile computer-readable storage medium of claim 23, wherein the first layer set includes operating points.

27. The non-volatile computer-readable storage medium of claim 23, wherein other instructions are stored, said other instructions causing the one or more processors to perform the following operations:

In response to the first layer being included in the first layer set, one or more NAL units having a layer ID value less than the maximum layer ID value are identified;

28. The non-volatile computer-readable storage medium of claim 23, wherein the video parameter set includes a syntax applicable to multiple layers.

29. The non-volatile computer-readable storage medium of claim 23, wherein the syntax element specifying the maximum layer ID value and the syntax element containing a one-bit layer ID flag are each a fixed-length and non-entropy-encoded syntax element.

30. A method for encoding multi-layer video data, the method comprising:

A set of layers is determined for the multi-layer video data, wherein the set of layers corresponds to at least one independently decodeable bitstream of the multi-layer video data and includes two or more layers;

A syntax element is generated to be included in the video parameter set, the syntax element specifying a maximum layer identification ID value for any NAL unit associated with a first layer set, wherein the multi-layer video data includes two or more layer sets, each of the two or more layer sets being associated with at least one independently decodeable bitstream of the multi-layer video data and including two or more layers.

Generate a one-bit layer ID flag for a first layer having a layer ID value less than the maximum layer ID value to be included in the video parameter set, wherein the value of the one-bit layer ID flag indicates whether the first layer is included in the first layer set; and

The output is an encoded bitstream containing the multi-layer video data.

31. The method of claim 30, further comprising:

Generate an extra-bit layer ID flag for each layer ID value between 1 and the maximum layer ID value to be included in the video parameter set, wherein the value of each extra-bit layer ID flag indicates whether the layer associated with the respective layer ID value is included in the layer set.

32. The method of claim 30, wherein the first value of the one-bit layer ID flag indicates that the first layer is included in the layer set, and the second value of the one-bit layer ID flag indicates that the first layer is not included in the layer set.

33. The method of claim 30, wherein the first layer set includes operation points.

34. The method of claim 30, wherein the method is performed by a video encoder.

35. The method of claim 30, wherein the video parameter set includes a syntax applicable to multiple layers.

36. The method of claim 30, wherein the syntax element specifying the maximum layer ID value and the one-bit layer ID flag are each a fixed-length and non-entropy-encoded syntax element.

37. A video decoding apparatus for processing multi-layer video data, the apparatus comprising:

A memory, configured to store the multi-layer video data; and

One or more processors, said one or more processors being configured to:

For the multi-layer video data, a layer set is determined, wherein the layer set corresponds to at least one independently decodeable bitstream comprising the multi-layer video data and includes two or more layers;

A syntax element is generated to be included in the video parameter set, the syntax element specifying a maximum layer identification ID value for any NAL unit associated with a first layer set, wherein the multi-layer video data comprises two or more layer sets, each of the two or more layer sets being associated with at least one independently decodeable bitstream of the multi-layer video data and comprising two or more layers; and,

The output is an encoded bitstream containing the multi-layer video data.

38. The video decoding apparatus of claim 37, wherein the one or more processors are further configured to generate an additional layer ID flag for each layer ID value between 1 and the maximum layer ID value to be included in the video parameter set, wherein the value for each additional layer ID flag indicates whether the layer associated with the respective layer ID value is included in the layer set.

39. The video decoding apparatus of claim 37, wherein the first value of the layer ID flag indicates that the first layer is included in the layer set, and the second value of the layer ID flag indicates that the first layer is not included in the layer set.

40. The video decoding apparatus of claim 37, wherein the first layer set includes operation points.

41. The video decoding apparatus of claim 37, wherein the apparatus comprises a video encoder.

42. The video decoding apparatus of claim 37, wherein the video parameter set includes a syntax applicable to multiple layers.

43. The video decoding apparatus of claim 37, wherein the syntax element specifying the maximum layer ID value and the one-bit layer ID flag are both fixed-length and non-entropy-encoded syntax elements.