4 5GMS codecs and formats capabilities

26.5113GPP5G Media Streaming (5GMS)Profiles, codecs and formatsTS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

4.1 Introduction

This clause defines codecs and formats capabilities for video, audio, speech and subtitles for 5G Media Streaming.

For each media type, decoding and encoding capabilities are defined. These capabilities are a combination of codecs, profiles, tiers (if applicable), levels and format restrictions. In order to use the codecs in 5G Media Streaming for each capability the following functionalities are defined:

– Mapping to the ISO Base Media File Format defining a track format.

– The definition of a CMAF Track

– The definition of a CMAF Switching Set and the media profile

– The playback requirements for this media profile

– The content generation requirements for this media profile

4.2 Video

4.2.1 H.264 (AVC)

4.2.1.1 Decoding

The following H.264 (AVC) media decoding capabilities are defined:

– AVC-HD-Dec: the capability to decode H.264 (AVC) Progressive High Profile Level 3.1 [2] bitstreams, for which the maximum VCL Bit Rate is constrained to be 14 Mbps with cpbBrVclFactor and cpbBrNalFactor being fixed to be 1,000 and 1,200, respectively.

– AVC-FullHD-Dec: the capability to decode H.264 (AVC) Progressive High Profile Level 4.0 [2] bitstreams.

– AVC-UHD-Dec: the capability to decode H.264/AVC Progressive High Profile Level 5.1 [2] bitstreams for H.264/AVC with the following additional restrictions and requirements:

– the maximum VCL Bit Rate is constrained to be 120 Mbps with cpbBrVclFactor and cpbBrNalFactor being fixed to be 1250 and 1500, respectively.

– the bitstream does not contain more than 10 slices per picture.

NOTE: High Profile for H.264/AVC excludes Flexible macro-block order, Arbitrary slice ordering, Redundant slices, Data partition.

4.2.1.2 Encoding

The following H.264 (AVC) media encoding capabilities are defined:

– AVC-HD-Enc: the capability to encode a video signal with:

– up to 108,000 macroblocks per second;

– up to a frame size of 3,600 macroblocks;

– up to 120 frames per second;

– the chroma format being 4:2:0; and

– the bit depth being 8 bit;

to a bitstream that is decodable by a decoder that is AVC-HD-Dec capable as defined in clause 4.2.1.1.

– AVC-FullHD-Enc: the capability to encode a video signal with:

– up to 245,760 macroblocks per second;

– up to a frame size of 8,192 macroblocks;

– up to 240 frames per second;

– the chroma format being 4:2:0; and

– the bit depth being 8 bit;

to a bitstream that is decodable by a decoder that is AVC-FullHD-Dec capable as defined in clause 4.2.1.1.

– AVC-UHD-Enc: the capability to encode a video signal with:

– up to 983,040 macroblocks per second;

– up to a frame size of 36,864 macroblocks;

– up to 480 frames per second;

– the chroma format being 4:2:0; and

– the bit depth being 8 bit;

to a bitstream that is decodable by a decoder that is AVC-UHD-Dec capable as defined in clause 4.2.1.1.

4.2.1.3 Media Profiles: Mapping to 5GMS Delivery

4.2.1.3.1 AVC-HD

4.2.1.3.1.1 ISO BMFF File Format

If AVC-HD media is provided in a bitstream that is decodable by a decoder capable of the AVC-HD-Dec decoding capabilities as defined in clause 4.2.1.1 and the media is encapsulated in an ISO BMFF Track [14], then the file format track shall conform with the requirements of the codec entry ‘avc1’ or ‘avc3’ as defined in ISO/IEC 14496-15 [15].

4.2.1.3.1.2 CMAF Track Definition

If AVC-HD media is provided in an CMAF track, then the CMAF track shall conform with:

– the requirements of the ISO BMFF File format track defined in clause 4.2.1.3.1.1;

– the general CMAF Track constraints in ISO/IEC 23000-19, clause 7;

– the general video track constraints defined in ISO/IEC 23000-19; clause 9.

4.2.1.3.1.3 CMAF Switching Set Definition

If AVC-HD media is provided in an CMAF Switching Set; then

– every CMAF track in the CMAF Switching Set shall conform with the requirements of CMAF Track in clause 4.2.1.3.1.2;

– the general CMAF Switching Set constraints in ISO/IEC 23000-19 [7], clause 7; and

– the general CMAF video track Switching Set constraints defined in ISO/IEC 23000-19 [7]; clause 9.

4.2.1.3.1.4 Playback Requirements

For a receiver supporting the AVC-HD media profile the following applies:

– It shall support the AVC-HD-Dec decoding capabilities as defined in clause 4.2.1.1.

– It shall support the following playback requirements as documented in clause 8 of CTA-WAVE 5003 [9] for any content conforming to a CMAF Switching Set as defined in clause 4.2.1.3.1.3 namely:

– 8.2 Sequential Track Playback

– 8.3 Random Access to Fragment

– 8.4 Random Access to Time

– 8.5 Switching Set Playback

– 8.6 Regular Playback of Chunked Content

– 8.7 Regular Playback of Chunked Content, non-aligned append

– It should support the following playback requirements as documented in clause 8 of CTA-WAVE 5003 [9] for any content conforming to a CMAF Switching Set as defined in clause 4.2.1.3.1.3 namely:

– 8.9 Out-Of-Order Loading

– 8.10 Overlapping Fragments

– 8.12 Playback of Encrypted Content

4.2.1.3.1.5 Content Generation Requirements

For a transmitter supporting the AVC-HD media profile the following applies:

– It shall support the AVC-HD-Enc encoding capabilities as defined in clause 4.2.1.2.

– It shall support the generation of a CMAF Track that conforms to the requirements in clause 4.2.1.3.1.2.

– If used for Adaptive Bit Rate (ABR) distribution, it shall support the generation of a CMAF Switching Set as defined in clause 4.2.1.3.1.3.

4.2.1.3.2 AVC-FullHD

4.2.1.3.2.1 ISO BMFF File Format

If AVC-FullHD media is provided in a bitstream that is decodable by a decoder capable of the AVC-FullHD-Dec decoding capabilities as defined in clause 4.2.1.1 and the media is encapsulated in an ISO BMFF Track [14], then the file format track shall conform with the requirements of the codec entry ‘avc1’ or ‘avc3’ as defined in ISO/IEC 14496-15 [15].

4.2.1.3.2.2 CMAF Track Definition

If AVC-FullHD media is provided in an CMAF track, then the CMAF track shall conform with

– the requirements of the ISO BMFF File format track defined in clause 4.2.1.3.2.1;

– the general CMAF Track constraints in ISO/IEC 23000-19, clause 7; and

– the general video track constraints defined in ISO/IEC 23000-19, clause 9.

4.2.1.3.2.3 CMAF Switching Set Definition

If AVC-FullHD media is provided in an CMAF Switching Set, then:

– every CMAF track in the CMAF Switching Set shall conform with the requirements of CMAF Track in clause 4.2.1.3.2.2;

– the general CMAF Switching Set constraints in ISO/IEC 23000-19 [27], clause 7; and

– the general CMAF video track Switching Set constraints defined in ISO/IEC 23000-19 [7], clause 9.

4.2.1.3.2.4 Playback Requirements

For a receiver supporting the AVC-FullHD media profile the following applies:

– It shall support the AVC-FullHD-Dec decoding capabilities as defined in clause 4.2.1.1.

– It shall support the following playback requirements as documented in clause 8 of CTA-WAVE 5003 [9] for any content conforming to a CMAF Switching Set as defined in clause 4.2.1.3.2.3 namely:

– 8.2 Sequential Track Playback

– 8.3 Random Access to Fragment

– 8.4 Random Access to Time

– 8.5 Switching Set Playback

– 8.6 Regular Playback of Chunked Content

– 8.7 Regular Playback of Chunked Content, non-aligned append

– It should support the following playback requirements as documented in clause 8 of CTA-WAVE 5003 [9] for any content conforming to a CMAF Switching Set as defined in clause 4.2.1.3.2.3 namely:

– 8.9 Out-Of-Order Loading

– 8.10 Overlapping Fragments

– 8.12 Playback of Encrypted Content

4.2.1.3.2.5 Content Generation Requirements

For a transmitter supporting the AVC-FullHD media profile the following applies:

– It shall support the AVC-FullHD-Enc encoding capabilities as defined in clause 4.2.1.2.

– It shall support the generation of a CMAF Track that conforms to the requirements in clause 4.2.1.3.2.2.

– If used for Adaptive Bit Rate (ABR) distribution, it shall support the generation of a CMAF Switching Set as defined in clause 4.2.1.3.2.3.

4.2.1.3.3 AVC-UHD

4.2.1.3.3.1 ISO BMFF File Format

If AVC-UHD media is provided in a bitstream that is decodable by a decoder capable of the AVC-UHD-Dec decoding capabilities as defined in clause 4.2.1.1 and the media is encapsulated in an ISO BMFF Track [14], then the file format track shall conform with the requirements of the codec entry ‘avc1’ or ‘avc3’ as defined in ISO/IEC 14496-15 [15].

4.2.1.3.3.2 CMAF Track Definition

If AVC-UHD media is provided in an CMAF track, then the CMAF track shall conform with

– the requirements of the ISO BMFF File format track defined in clause 4.2.1.3.3.1;

– the general CMAF Track constraints in ISO/IEC 23000-19, clause 7; and

– the general video track constraints defined in ISO/IEC 23000-19, clause 9.

4.2.1.3.3.3 CMAF Switching Set Definition

If AVC-UHD media is provided in an CMAF Switching Set, then

– every CMAF track in the CMAF Switching Set shall conform with the requirements of CMAF Track in clause 4.2.1.3.3.2;

– the general CMAF Switching Set constraints in ISO/IEC 23000-19 [27], clause 7; and

– the general CMAF video track Switching Set constraints defined in ISO/IEC 23000-19 [7], clause 9.

4.2.1.3.3.4 Playback Requirements

For a receiver supporting the AVC-UHD media profile the following applies:

– It shall support the AVC-UHD-Dec decoding capabilities as defined in clause 4.2.1.1.

– It shall support the following playback requirements as documented in clause 8 of CTA-WAVE 5003 [9] for any content conforming to a CMAF Switching Set as defined in clause 4.2.1.3.3.3 namely:

– 8.2 Sequential Track Playback

– 8.3 Random Access to Fragment

– 8.4 Random Access to Time

– 8.5 Switching Set Playback

– 8.6 Regular Playback of Chunked Content

– 8.7 Regular Playback of Chunked Content, non-aligned append

– It should support the following playback requirements as documented in clause 8 of CTA-WAVE 5003 [9] for any content conforming to a CMAF Switching Set as defined in clause 4.2.1.3.3.3 namely:

– 8.9 Out-Of-Order Loading

– 8.10 Overlapping Fragments

– 8.12 Playback of Encrypted Content

4.2.1.3.3.5 Content Generation Requirements

For a transmitter supporting the AVC-UHD media profile the following applies:

– It shall support the AVC-UHD-Enc encoding capabilities as defined in clause 4.2.1.2.

– It shall support the generation of a CMAF Track that conforms to the requirements in clause 4.2.1.3.3.2.

– If used for Adaptive Bit Rate (ABR) distribution, it shall support the generation of a CMAF Switching Set as defined in clause 4.2.1.3.3.3.

4.2.2 H.265 (HEVC)

4.2.2.1 Decoding

The following H.265 (HEVC) media decoding capabilities are defined:

– HEVC-HD-Dec: the capability to decode H.265 (HEVC) Main Profile, Main Tier, Level 3.1[3] bitstreams that have general_progressive_source_flag equal to 1, general interlaced_source_flag equal to 0, general_non_packed_constraint_flag equal to 1, and general_frame_only_constraint_flag equal to 1.

– HEVC-FullHD-Dec: the capability to decode H.265 (HEVC) Main10 Profile, Main Tier, Level 4.1[3] bitstreams that have general_progressive_source_flag equal to 1, general interlaced_source_flag equal to 0, general_non_packed_constraint_flag equal to 1, and general_frame_only_constraint_flag equal to 1.

– HEVC-UHD-Dec: the capability to decode H.265 (HEVC) Main10 Profile, Main Tier, Level 5.1[3] bitstreams that have general_progressive_source_flag equal to 1, general interlaced_source_flag equal to 0, general_non_packed_constraint_flag equal to 1, and general_frame_only_constraint_flag equal to 1.

– HEVC-8K-Dec: the capability to decode H.265 (HEVC) Main10 Profile, Main Tier, Level 6.1[3] bitstreams that have general_progressive_source_flag equal to 1, general interlaced_source_flag equal to 0, general_non_packed_constraint_flag equal to 1, and general_frame_only_constraint_flag equal to 1 with the following further limitations:

– the bitstream does not exceed the maximum luma picture size in samples of 33,554,432,

– the maximum VCL Bit Rate is constrained to be 80 Mbps with CpbVclFactor and CpbNalFactor being fixed to be 1000 and 1100, respectively.

4.2.2.2 Encoding

The following H.265 (HEVC) media encoding capabilities are defined:

– HEVC-HD-Enc: the capability to encode a video signal with

– up to 33,177,600 luma samples per second;

– up to a luma picture size of 983,040 samples;

– up to 120 frames per second;

– the Chroma format being 4:2:0; and

– the bit depth being 8 bit;

to a bitstream that is decodable by a decoder that is HEVC-HD-Dec capable as defined in clause 4.2.2.1.

– HEVC-FullHD-Enc: the capability to encode a video signal with

– up to 133,693,440 luma samples per second;

– up to a luma picture size of 2,228,224 samples;

– up to 240 frames per second;

– the Chroma format being 4:2:0; and

– the bit depth being either 8 or 10 bit;

to a bitstream that is decodable by a decoder that is HEVC-FullHD-Dec capable as defined in clause 4.2.2.1.

– HEVC-UHD-Enc: the capability to encode a video signal with

– up to 534,773,760 luma samples per second;

– up to a luma picture size of 8,912,896 samples;

– up to 480 frames per second;

– the Chroma format being 4:2:0; and

– the bit depth being either 8 or 10 bit;

to a bitstream that is decodable by a decoder that is HEVC-UHD-Dec capable as defined in clause 4.2.2.1.

4.2.2.3 Media Profiles: Mapping to 5G Media Streaming

4.2.2.3.1 HEVC-HD

4.2.2.3.1.1 ISO BMFF File Format

If HEVC-HD media is provided in a bitstream that is decodable by a decoder capable of the HEVC-HD-Dec decoding capabilities as defined in clause 4.2.1.1 and the media is encapsulated in an ISO BMFF Track [14], then the file format track shall conform with the requirements of the codec entry ‘hvc1’ or ‘hev1’ as defined in ISO/IEC 14496-15 [15].

4.2.2.3.1.2 CMAF Track Definition

If HEVC-HD media is provided in an CMAF track, then the CMAF track shall conform with

– the requirements of the ISO BMFF File format track defined in clause 4.2.2.3.1.1;

– the general CMAF Track constraints in ISO/IEC 23000-19, clause 7; and

– the general video track constraints defined in ISO/IEC 23000-19; clause 9.

4.2.2.3.1.3 CMAF Switching Set Definition

If HEVC-HD media is provided in an CMAF Switching Set, then

– every CMAF track in the CMAF Switching Set shall conform with the requirements of CMAF Track in clause 4.2.2.3.1.2;

– the general CMAF Switching Set constraints in ISO/IEC 23000-19 [27], clause 7; and

– the general CMAF video track Switching Set constraints defined in ISO/IEC 23000-19 [7], clause 9.

4.2.2.3.1.4 Playback Requirements

For a receiver supporting the HEVC-HD media profile the following applies:

– It shall support the HEVC-HD-Dec decoding capabilities as defined in clause 4.2.1.1.

– It shall support the following playback requirements as documented in clause 8 of CTA-WAVE 5003 [9] for any content conforming to a CMAF Switching Set as defined in clause 4.2.2.3.1.3 namely:

– 8.2 Sequential Track Playback

– 8.3 Random Access to Fragment

– 8.4 Random Access to Time

– 8.5 Switching Set Playback

– 8.6 Regular Playback of Chunked Content

– 8.7 Regular Playback of Chunked Content, non-aligned append

– It should support the following playback requirements as documented in clause 8 of CTA-WAVE 5003 [9] for any content conforming to a CMAF Switching Set as defined in clause 4.2.2.3.1.3 namely:

– 8.9 Out-Of-Order Loading

– 8.10 Overlapping Fragments

– 8.12 Playback of Encrypted Content

4.2.2.3.1.5 Content Generation Requirements

For a transmitter supporting the HEVC-HD media profile the following applies:

– It shall support the HEVC-HD-Enc encoding capabilities as defined in clause 4.2.2.2.

– It shall support the generation of a CMAF Track that conforms to the requirements in clause 4.2.2.3.1.2.

– If used for Adaptive Bit Rate (ABR) distribution, it shall support the generation of a CMAF Switching Set as defined in clause 4.2.2.3.1.3.

4.2.2.3.2 HEVC-FullHD

4.2.2.3.2.1 ISO BMFF File Format

If HEVC-FullHD media is provided in a bitstream that is decodable by a decoder capable of the HEVC-FullHD-Dec decoding capabilities as defined in clause 4.2.1.1 and the media is encapsulated in an ISO BMFF Track [14], then the file format track shall conform with the requirements of the codec entry ‘hvc1’ or ‘hev1’ as defined in ISO/IEC 14496-15 [15].

4.2.2.3.2.2 CMAF Track Definition

If HEVC-FullHD media is provided in an CMAF track, then the CMAF track shall conform with

– the requirements of the ISO BMFF File format track defined in clause 4.2.2.3.2.1;

– the general CMAF Track constraints in ISO/IEC 23000-19, clause 7; and

– the general video track constraints defined in ISO/IEC 23000-19, clause 9.

4.2.2.3.2.3 CMAF Switching Set Definition

If HEVC-FullHD media is provided in an CMAF Switching Set, then

– every CMAF track in the CMAF Switching Set shall conform with the requirements of CMAF Track in clause 4.2.2.3.2.2,

– the general CMAF Switching Set constraints in ISO/IEC 23000-19 [27], clause 7; and

– the general CMAF video track Switching Set constraints defined in ISO/IEC 23000-19 [7], clause 9.

4.2.2.3.2.4 Playback Requirements

For a receiver supporting the HEVC-FullHD media profile the following applies:

– It shall support the HEVC-FullHD-Dec decoding capabilities as defined in clause 4.2.1.1.

– It shall support the following playback requirements as documented in clause 8 of CTA-WAVE 5003 [9] for any content conforming to a CMAF Switching Set as defined in clause 4.2.2.3.2.3 namely:

– 8.2 Sequential Track Playback

– 8.3 Random Access to Fragment

– 8.4 Random Access to Time

– 8.5 Switching Set Playback

– 8.6 Regular Playback of Chunked Content

– 8.7 Regular Playback of Chunked Content, non-aligned append

– It should support the following playback requirements as documented in clause 8 of CTA-WAVE 5003 [9] for any content conforming to a CMAF Switching Set as defined in clause 4.2.2.3.2.3 namely:

– 8.9 Out-Of-Order Loading

– 8.10 Overlapping Fragments

– 8.12 Playback of Encrypted Content

4.2.2.3.2.5 Content Generation Requirements

For a transmitter supporting the HEVC-FullHD media profile the following applies:

– It shall support the HEVC-FullHD-Enc encoding capabilities as defined in clause 4.2.2.2.

– It shall support the generation of a CMAF Track that conforms to the requirements in clause 4.2.2.3.2.2.

– If used for Adaptive Bit Rate (ABR) distribution, it shall support the generation of a CMAF Switching Set as defined in clause 4.2.2.3.2.3.

4.2.2.3.3 HEVC-UHD

4.2.2.3.3.1 ISO BMFF File Format

If HEVC-UHD media is provided in a bitstream that is decodable by a decoder capable of the HEVC-UHD-Dec decoding capabilities as defined in clause 4.2.1.1 and the media is encapsulated in an ISO BMFF Track [14], then the file format track shall conform with the requirements of the codec entry ‘hvc1’ or ‘hev1’ as defined in ISO/IEC 14496-15 [15].

4.2.2.3.3.2 CMAF Track Definition

If HEVC-UHD media is provided in an CMAF track, then the CMAF track shall conform with

– the requirements of the ISO BMFF File format track defined in clause 4.2.2.3.3.1;

– the general CMAF Track constraints in ISO/IEC 23000-19, clause 7; and

– the general video track constraints defined in ISO/IEC 23000-19, clause 9.

4.2.2.3.3.3 CMAF Switching Set Definition

If HEVC-UHD media is provided in an CMAF Switching Set, then

– every CMAF track in the CMAF Switching Set shall conform with the requirements of CMAF Track in clause 4.2.2.3.3.2;

– the general CMAF Switching Set constraints in ISO/IEC 23000-19 [27], clause 7; and

– the general CMAF video track Switching Set constraints defined in ISO/IEC 23000-19 [7], clause 9.

4.2.2.3.3.4 Playback Requirements

For a receiver supporting the HEVC-UHD media profile the following applies:

– It shall support the HEVC-UHD-Dec decoding capabilities as defined in clause 4.2.1.1.

– It shall support the following playback requirements as documented in clause 8 of CTA-WAVE 5003 [9] for any content conforming to a CMAF Switching Set as defined in clause 4.2.2.3.3.3 namely:

– 8.2 Sequential Track Playback

– 8.3 Random Access to Fragment

– 8.4 Random Access to Time

– 8.5 Switching Set Playback

– 8.6 Regular Playback of Chunked Content

– 8.7 Regular Playback of Chunked Content, non-aligned append

– It should support the following playback requirements as documented in clause 8 of CTA-WAVE 5003 [9] for any content conforming to a CMAF Switching Set as defined in clause 4.2.2.3.3.3 namely:

– 8.9 Out-Of-Order Loading

– 8.10 Overlapping Fragments

– 8.12 Playback of Encrypted Content

4.2.2.3.3.5 Content Generation Requirements

For a transmitter supporting the HEVC-UHD media profile the following applies:

– It shall support the HEVC-UHD-Enc encoding capabilities as defined in clause 4.2.2.2.

– It shall support the generation of a CMAF Track that conforms to the requirements in clause 4.2.2.3.3.2.

– If used for Adaptive Bit Rate (ABR) distribution, it shall support the generation of a CMAF Switching Set as defined in clause 4.2.2.3.3.3.

4.2.2.3.4 HEVC-8K

4.2.2.3.4.1 ISO BMFF File Format

If HEVC-8K media is provided in a bitstream that is decodable by a decoder capable of the HEVC-8K-Dec decoding capabilities as defined in clause 4.2.2.1 and the media is encapsulated in an ISO BMFF Track [14], then the file format track shall conform with the requirements of the codec entry ‘hvc1’ or ‘hev1’ as defined in ISO/IEC 14496-15 [15].

4.2.2.3.4.2 CMAF Track Definition

If HEVC-UHD media is provided in a CMAF track, then the CMAF track shall conform with

– the requirements of the ISO BMFF File format track defined in clause 4.2.2.3.4.1;

– the general CMAF Track constraints in ISO/IEC 23000-19, clause 7, and

– the general video track constraints defined in ISO/IEC 23000-19, clause 9.

4.2.2.3.4.3 CMAF Switching Set Definition

If HEVC-UHD media is provided in a CMAF Switching Set, then

– every CMAF track in the CMAF Switching Set shall conform with the requirements of CMAF Track in clause 4.2.2.3.4.2;

– the general CMAF Switching Set constraints in ISO/IEC 23000-19 [27], clause 7; and

– the general CMAF video track Switching Set constraints defined in ISO/IEC 23000-19 [7], clause 9.

4.2.2.3.4.4 Playback Requirements

For a receiver supporting the HEVC-UHD media profile the following applies:

– It shall support the HEVC-8K-Dec decoding capabilities as defined in clause 4.2.2.1.

– It shall support the following playback requirements as documented in clause 8 of CTA-WAVE 5003 [9] for any content conforming to a CMAF Switching Set as defined in clause 4.2.2.3.4.3 namely:

– 8.2 Sequential Track Playback

– 8.3 Random Access to Fragment

– 8.4 Random Access to Time

– 8.5 Switching Set Playback

– 8.6 Regular Playback of Chunked Content

– 8.7 Regular Playback of Chunked Content, non-aligned append

– It should support the following playback requirements as documented in clause 8 of CTA-WAVE 5003 [9] for any content conforming to a CMAF Switching Set as defined in clause 4.2.2.3.4.3 namely:

– 8.9 Out-Of-Order Loading

– 8.10 Overlapping Fragments

– 8.12 Playback of Encrypted Content

4.3 Audio

4.3.1 Decoding

Audio decoding capabilities are defined in 3GPP TS 26.117 [4] clause 5.3.

4.3.2 Encoding

Audio encoding capabilities are defined in 3GPP TS 26.117 [4] clause 5.3.

4.4 Speech

4.4.1 Decoding

Speech decoding capabilities are defined in 3GPP TS 26.117 [4] clause 5.2.

4.4.2 Encoding

Speech encoding capabilities are defined in 3GPP TS 26.117 [4] clause 5.3.4.5.

4.5 Subtitles

4.5.1 IMSC1.1. Text Track

4.5.1.1 Decoding Capability

The IMSC1.1. Text Track decoding capability is defined as IMSC1.1-TEXT-DEC. Support for IMSC1.1-TEXT-DEC requires the support of an IMSC1.1 text processor as defined in W3C IMSC1.1 [16].

4.5.1.2 ISO BMFF File Format

If an IMSC1.1 Text Track is provided in a bitstream that is decodable by a decoder capable of the IMSC1.1-TEXT-DEC decoding capabilities as defined in clause 4.5.1.1 and the media is encapsulated in an ISO BMFF Track [14], then the file format track shall conform with the requirements of the codec entry ‘imt2’as defined in ISO/IEC 14496-30 [17].

4.5.1.3 CMAF Track Definition

If IMSC1.1-TEXT-DEC media is provided in an CMAF track, then the CMAF track shall conform with

– the requirements of the ISO BMFF File format track defined in clause 4.5.1.2;

– the general CMAF Track constraints in ISO/IEC 23000-19, clause 7;

– the general subtitle track constraints defined in ISO/IEC 23000-19, clause 11; and

– the IMSC1.1. text track constraints defined in ISO/IEC 23000-19, Annex L.2.

4.5.1.4 CMAF Switching Set Definition

If IMSC1.1-TEXT-DEC media is provided in an CMAF Switching Set, then:

– only a single CMAF track according to the requirements in clause 4.5.1.3 shall be present.

4.5.1.5 Playback Requirements

For a receiver supporting the IMSC1.1. Text Track media profile the following applies:

– It shall support the IMSC1.1-TEXT-DEC decoding capabilities as defined in clause 4.5.1.1.

– It shall support the following playback requirements as documented in clause 8 of CTA-WAVE 5003 [9] for any content conforming to a CMAF Switching Set as defined in clause 4.5.1.4, namely:

– 8.2 Sequential Track Playback

– 8.3 Random Access to Fragment

– 8.4 Random Access to Time

– It should support the following playback requirements as documented in clause 8 of CTA-WAVE 5003 [9] for any content conforming to a CMAF Switching Set as defined in clause 4.2.1.4 namely:

– 8.9 Out-Of-Order Loading

– 8.10 Overlapping Fragments

– 8.12 Playback of Encrypted Content