RTP封装格式：H.265/HEVC视频编码标准

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"H265 RFC标准描述了一种用于传输H.265/HEVC视频的RTP负载格式，支持NAL单元的打包和分片，适用于多种网络环境下的视频通信、流媒体和高比特率娱乐质量视频传输。" 本文档（RFC标准）详细阐述了在互联网工程任务组（IETF）下制定的RTP（实时传输协议）负载格式，旨在支持国际电信联盟电信标准部门（ITU-T）建议H.265以及国际标准化组织/国际电工委员会（ISO/IEC）国际标准23008-2，两者都被称为高效视频编码（HEVC）。这一编码标准由联合视频编码团队（JCT-VC）开发，旨在显著提高视频压缩效率。 RTP负载格式的主要特性包括： 1. **NAL单元的打包**：每个RTP数据包的负载可以包含一个或多个网络抽象层（NAL）单元。NAL单元是HEVC编码的基本传输单位，包含视频帧的不同部分，如图像块、切片等。 2. **NAL单元的分片**：对于较大的NAL单元，该格式允许将其分割成多个RTP数据包进行传输。这种分片机制确保了在网络条件不佳时，仍能有效地恢复视频数据。 3. **单个或多个RTP流的传输**：支持在一个或多个RTP流上发送HEVC码流，这允许根据网络状况和应用场景灵活选择传输策略。例如，在多路传输中，可以使用单个传输或多个并发传输来提高可靠性。 4. **广泛应用**：该RTP负载格式适应性强，广泛应用于视频会议、互联网视频流媒体以及高比特率的娱乐级视频服务中。它为各种网络环境提供了可靠的视频传输解决方案。状态说明：该文档是互联网草案，表明其内容还在讨论和修改中，但意图是将其发展为标准轨道的正式标准。此RFC标准的发布对于实现高效、可靠的H.265/HEVC视频传输具有重要意义，特别是在互联网和移动通信环境中，它有助于优化带宽使用，提升视频服务质量，同时降低了网络拥塞的可能性。随着视频内容的不断增长，这种高效编码和传输技术的重要性日益凸显。

Internet-Draft RTP Payload Format for HEVC November 5, 2015

fragmentation mechanism described in this memo in that they need

the cooperation of the encoder. As a dependent slice segment

necessarily contains an integer number of CTUs, a decoder using

multiple cores operating on CTUs can process a dependent slice

segment without communicating parts of the slice segment’s

bitstream to other cores. Fragmentation, as specified in this

memo, in contrast, does not guarantee that a fragment contains an

integer number of CTUs.

In wavefront parallel processing (WPP), the picture is

partitioned into rows of CTUs. Entropy decoding and prediction

are allowed to use data from CTUs in other partitions. Parallel

processing is possible through parallel decoding of CTU rows,

where the start of the decoding of a row is delayed by two CTUs,

so to ensure that data related to a CTU above and to the right of

the subject CTU is available before the subject CTU is being

decoded. Using this staggered start (which appears like a

wavefront when represented graphically), parallelization is

possible with up to as many processors/cores as the picture

contains CTU rows.

Because in-picture prediction between neighboring CTU rows within

a picture is allowed, the required inter-processor/inter-core

communication to enable in-picture prediction can be substantial.

The WPP partitioning does not result in the creation of more NAL

units compared to when it is not applied, thus WPP cannot be used

for MTU size matching, though slices can be used in combination

for that purpose.

Tiles define horizontal and vertical boundaries that partition a

picture into tile columns and rows. The scan order of CTUs is

changed to be local within a tile (in the order of a CTU raster

scan of a tile), before decoding the top-left CTU of the next

tile in the order of tile raster scan of a picture. Similar to

slices, tiles break in-picture prediction dependencies (including

entropy decoding dependencies). However, they do not need to be

included into individual NAL units (same as WPP in this regard),

hence tiles cannot be used for MTU size matching, though slices

can be used in combination for that purpose. Each tile can be

processed by one processor/core, and the inter-processor/inter-

core communication required for in-picture prediction between

Wang, et al Expires May 5, 2016 [Page 16]

Internet-Draft RTP Payload Format for HEVC November 5, 2015

nal_unit_type. This field specifies the NAL unit type as

defined in Table 7-1 of [

HEVC]. If the most significant bit

of this field of a NAL unit is equal to 0 (i.e. the value of

this field is less than 32), the NAL unit is a VCL NAL unit.

Otherwise, the NAL unit is a non-VCL NAL unit. For a

reference of all currently defined NAL unit types and their

semantics, please refer to Section 7.4.1 in [

HEVC].

LayerId: 6 bits

nuh_layer_id. Required to be equal to zero in [

HEVC]. It is

anticipated that in future scalable or 3D video coding

extensions of this specification, this syntax element will be

used to identify additional layers that may be present in the

CVS, wherein a layer may be, e.g. a spatial scalable layer, a

quality scalable layer, a texture view, or a depth view.

TID: 3 bits

nuh_temporal_id_plus1. This field specifies the temporal

identifier of the NAL unit plus 1. The value of TemporalId is

equal to TID minus 1. A TID value of 0 is illegal to ensure

that there is at least one bit in the NAL unit header equal to

1, so to enable independent considerations of start code

emulations in the NAL unit header and in the NAL unit payload

data.

1.2 Overview of the Payload Format

This payload format defines the following processes required for

transport of HEVC coded data over RTP [

RFC3550]:

o Usage of RTP header with this payload format

o Packetization of HEVC coded NAL units into RTP packets using

three types of payload structures, namely single NAL unit

packet, aggregation packet, and fragment unit

o Transmission of HEVC NAL units of the same bitstream within a

single RTP stream or multiple RTP streams (within one or more

RTP sessions), where within an RTP stream transmission of NAL

units may be either non-interleaved (i.e. the transmission

Wang, et al Expires May 5, 2016 [Page 18]

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RTP封装格式：H.265/HEVC视频编码标准

H.264标准详解：rfc3984中文版

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H.264 RFC标准文档(中文版)

rfc3984标准文档

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RFC 5415协议标准

rfc3984 for h264

h264编码的RFC3984传输实现

rfc6184_h264.pdf

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