Information technology — Coding of audio-visual objects — Part 32: File format reference software and conformance

This document describes the reference software and conformance suite for the file format documents in MPEG-4 and MPEG-H. Since these documents share a lot of technology, their reference software and conformance program are being handled together. These documents are: ISO/IEC 14496-12, ISO/IEC 14496-14, ISO/IEC 14496-15, ISO/IEC 14496-30 and ISO/IEC 23008-12. The purpose of the conformance suite is to cover the set of valid features that can be exercised in the file format. Media conformance is not covered, though of course in order to exercise the file format features, media will be stored.

Technologies de l'information — Codage des objets audiovisuels — Partie 32: Titre manque

General Information

Status
Published
Publication Date
04-Jan-2021
Current Stage
6060 - International Standard published
Start Date
05-Jan-2021
Completion Date
05-Jan-2021
Ref Project

Buy Standard

Standard
ISO/IEC 14496-32:2021 - Information technology -- Coding of audio-visual objects
English language
22 pages
sale 15% off
Preview
sale 15% off
Preview
Draft
ISO/IEC PRF 14496-32:Version 21-nov-2020 - Information technology -- Coding of audio-visual objects
English language
22 pages
sale 15% off
Preview
sale 15% off
Preview

Standards Content (sample)

INTERNATIONAL ISO/IEC
STANDARD 14496-32
First edition
2021-01
Information technology — Coding of
audio-visual objects —
Part 32:
File format reference software and
conformance
Reference number
ISO/IEC 14496-32:2021(E)
ISO/IEC 2021
---------------------- Page: 1 ----------------------
ISO/IEC 14496-32:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO/IEC 2021

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO/IEC 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/IEC 14496-32:2021(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Reference software ............................................................................................................................................................................................ 2

5 Conformance ............................................................................................................................................................................................................. 2

5.1 Overview ...................................................................................................................................................................................................... 2

5.2 Standard specific considerations ............................................................................................................................................ 2

5.2.1 Considerations for ISO/IEC 14496-12, 14496-14 and 14496-15 ......................................... 2

5.2.2 Considerations for ISO/IEC 14496-30 .......................................................................................................... 2

5.2.3 Considerations for ISO/IEC 23008-12 .......................................................................................................... 3

5.3 File documentation ............................................................................................................................................................................. 3

5.3.1 Files from related conformance programs ................................................................................................ 3

5.3.2 Files unique to this conformance program ............................................................................................... 4

Annex A (informative) Other tools .......................................................................................................................................................................21

Bibliography .............................................................................................................................................................................................................................22

© ISO/IEC 2021 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO/IEC 14496-32:2021(E)
Foreword

ISO (the International Organization for Standardization) and IEC (the International Electrotechnical

Commission) form the specialized system for worldwide standardization. National bodies that

are members of ISO or IEC participate in the development of International Standards through

technical committees established by the respective organization to deal with particular fields of

technical activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other

international organizations, governmental and non-governmental, in liaison with ISO and IEC, also

take part in the work.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for

the different types of document should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject

of patent rights. ISO and IEC shall not be held responsible for identifying any or all such patent

rights. Details of any patent rights identified during the development of the document will be in the

Introduction and/or on the ISO list of patent declarations received (see www .iso .org/ patents) or the IEC

list of patent declarations received (see http:// patents .iec .ch).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/

iso/ foreword .html.

This document was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,

Subcommittee SC 29, Coding of audio, picture, multimedia and hypermedia information.

A list of all parts in the ISO/IEC 14496 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO/IEC 2021 – All rights reserved
---------------------- Page: 4 ----------------------
INTERNATIONAL STANDARD ISO/IEC 14496-32:2021(E)
Information technology — Coding of audio-visual
objects —
Part 32:
File format reference software and conformance
1 Scope

This document describes the reference software and conformance suite for the file format documents

in MPEG-4 and MPEG-H. Since these documents share a lot of technology, their reference software

and conformance program are being handled together. These documents are: ISO/IEC 14496-12,

ISO/IEC 14496-14, ISO/IEC 14496-15, ISO/IEC 14496-30 and ISO/IEC 23008-12.

The purpose of the conformance suite is to cover the set of valid features that can be exercised in the

file format. Media conformance is not covered, though of course in order to exercise the file format

features, media will be stored.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO/IEC 14496-12, Information technology — Coding of audio-visual objects — Part 12: ISO base media

file format

ISO/IEC 14496-14, Information technology — Coding of audio-visual objects — Part 14: MP4 file format

ISO/IEC 14496-15, Information technology — Coding of audio-visual objects — Part 15: Carriage of

network abstraction layer (NAL) unit structured video in the ISO base media file format

ISO/IEC 14496-30, Information technology — Coding of audio-visual objects — Part 30: Timed text and

other visual overlays in ISO base media file format

ISO/IEC 23008-12, Information technology — High efficiency coding and media delivery in heterogeneous

environments — Part 12: Image File Format
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO/IEC 14496-12,

ISO/IEC 14496-14, ISO/IEC 14496-15, ISO/IEC 14496-30 and ISO/IEC 23008-12 apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at https:// www .iso .org/ obp
© ISO/IEC 2021 – All rights reserved 1
---------------------- Page: 5 ----------------------
ISO/IEC 14496-32:2021(E)
4 Reference software

The reference software for ISO/IEC 14496-12, ISO/IEC 14496-14, ISO/IEC 14496-15, ISO/IEC 14496-30

and ISO/IEC 23008-12 is provided at:

https:// standards .iso .org/ iso -iec/ 14496/ -32/ ed -1/ en/ reference _software/

Additional tools exercising features of the ISO base media file format (ISOBMFF) are described in

Annex A.
5 Conformance
5.1 Overview

The conformance suite for ISO/IEC 14496-12, ISO/IEC 14496-14, ISO/IEC 14496-15, ISO/IEC 14496-30

and ISO/IEC 23008-12 is provided at:
https:// standards .iso .org/ iso -iec/ 14496/ -32/ ed -1/ en/ conformance/

The suite of conformance tests does not currently cover deliberately errored files. However, such files

do occur in practice and implementations should be written to be resilient.

There is no official reference tool provided to check the conformance of files. However, such tools do

exist (see Annex A). The reference software can be used to open files in ‘debug’ mode and provide a

listing of what it finds, and other trade associations and standards bodies may have validation tools

tailored to their areas.

An HTML report (conformance_report.html) indicates which code points (e.g. box codes and track

reference types) defined in these documents are used in which conformance file.
5.2 Standard specific considerations
5.2.1 Considerations for ISO/IEC 14496-12, 14496-14 and 14496-15

For ISOBMFF conformance, an associated file (ff-conformance.xls) is used to list the features in groups,

and to document which files exercise each feature. Features not currently covered by any file are

marked with the sign “---“.

The file ff-conformance.xls has two spreadsheets. The first briefly lists the areas and features covered,

and then has a column for each proposed file. The second sheet provides a brief description of each area

and feature, by line.
5.2.2 Considerations for ISO/IEC 14496-30
Two files are proposed regarding:
— WebVTT;
— TTML.

There are several general features of ISO/IEC 14496-30 which are not exercised in the above files,

specifically:
— a track with 'mul' language;

— a track sharing resources (images, …) between samples through the use of a MetaBox;

— file with a subtitle and a font track.
2 © ISO/IEC 2021 – All rights reserved
---------------------- Page: 6 ----------------------
ISO/IEC 14496-32:2021(E)

There are several features specific to the carriage of TTML in MP4 which are not exercised:

— timing:
— 'empty' sample;

— sample with a document containing a larger time range than the sample presentation range;

— sample with a document whose time range is smaller than the sample range;
— sample entry format:
— with multiple namespace values;
— with schema location;
— with auxiliary mime types;
— sample format:
— with additional resources.
5.2.3 Considerations for ISO/IEC 23008-12

For HEIF conformance, an associated file (HEIF_conformance.xlsx) is used to describe the current files,

associated input bitstreams, and a specification coverage analysis of the conformance.

The spreadsheet "HEIF_conformance.xlsx" contains information of the tested features and their

mapping to the provided conformance files. It was created by picking all normative statements (shall,

shall not, etc.) in the HEIF specification. These are collected in the "Areas tested" column of the sheet.

The column "Description" presents a brief description of the tested feature, exercising the associated

normative statement in the specification.
The column "File ID" provides the file name.

The column "brands" indicates the HEIF brands that are included in FileTypeBox of the respective file

(in the "Test Content" sheet) or concern the respective test case (in the "Test Cases" sheet. The aim of

the column is to help implementers to pick files that concern the brand of their interest. For example,

implementers of the 'heic' brand should only consider the files with that brand included.

Note that the spreadsheet enables filtering by content, e.g. by selecting only a particular File ID (at cell

A1), one can see which features are exercised by a particular file.
5.3 File documentation
5.3.1 Files from related conformance programs
5.3.1.1 Overview

Some files provided in this suite originate from external conformance programs, from other ISO

documents or external specifications. The latest version should be obtained from their original source

as indicated in the following sections.
5.3.1.2 Audio-based conformance files

ISO/IEC 14496-26 provides several MP4 files containing MPEG-4 AAC, MPEG-D MPS, and MPEG-D USAC

streams and exercising features of the ISOBMFF. Within these files, only some are necessary to cover

all the ISOBMFF features. These files are from the "AAC-Conformance" part. The features specifically

exercised by these files compared to existing files are: "padb" and "m4ae".
© ISO/IEC 2021 – All rights reserved 3
---------------------- Page: 7 ----------------------
ISO/IEC 14496-32:2021(E)
The following files are also included for ISOBMFF conformance:
— ./mpeg-audio-conformance/ac01.mp4 (padb)
— ./mpeg-audio-conformance/sls2100_aot02_048_16.mp4 (m4ae)
Original files can be obtained from ISO/IEC 14496-26.
5.3.1.3 Timed text conformance files

DECE produced a set of Timed Text test vector files with video and audio tracks. Some of these files

exercise features of ISO/IEC 14496-12 and ISO/IEC 14496-30. The following files are added as part of

ISOBMFF conformance:
— ./uvvu/Solekai002_1280_23_1x1_v7clear.uvvu
— ./uvvu/Solekai007_1920_29_1x1_v7clear.uvvu

Original files can be obtained from http:// uvvuwiki .com/ cff/ cff -test -files .html.

5.3.1.4 DASH-based conformance files

The ISO/IEC 23009 series specifies the use of ISOBMFF files for adaptive streaming. ISO/IEC 23009-2

contains the following files that exercise specific features of the ISOBMFF:
— ./green/video_2500000bps_0.mp4
— ./green/meta_2500000bps_0.mp4m
— ./nalu/svc/mp4-onDemand-LastTime-depRep.mp4
— ./nalu/mvc/DDF_10s_25fps.mp4
Original files can be obtained from http:// testassets .dashif .org/ .
5.3.1.5 MAF-based conformance files

The ISO/IEC 23000 series uses the ISOBMFF standard at its core and contains some files (related to the

PAAF and VSAF standards). None of these files exercise new features, but they exercise some features

differently. The following files are copied in this ISOBMFF conformance:
— ./maf/vsaf/1.mp4
— ./maf/paaf/01_output_a.paf
Original files can be obtained from ISO/IEC 23000-6 and ISO/IEC 23000-10.
5.3.2 Files unique to this conformance program
5.3.2.1 a1-foreman-QCIF.mp4

This file is about as simple as it gets. It has an MPEG-4 video part 2 visual track, and an AAC track,

interleaved; and a minimal BIFS scene and OD track, with an IOD.
5.3.2.2 a2-foreman-QCIF-hinted.mp4

This file is basically the same as a1-foreman-QCIF.mp4 but hinted for RTP transmission.

4 © ISO/IEC 2021 – All rights reserved
---------------------- Page: 8 ----------------------
ISO/IEC 14496-32:2021(E)
5.3.2.3 a3-tone-protected.mp4

This file uses the protected stream structures. The keys are also supplied (a3c-prot-keys.txt), and the

result of de-protection (a3b-tone-deprot.mp4, for comparison).
5.3.2.4 a4-tone-fragmented.mp4

This file uses movie fragments. The initial 1-second movie is followed by a 1-second movie fragment.

Fragment-aware readers should play 2 second of content, fragment-unaware readers only 1 second.

5.3.2.5 a5-foreman-AVC.mp4

This is a very simple video-only main profile AVC file. Since it is main profile, composition offsets are used.

5.3.2.6 a6_tone_multifile.mp4

This is the same tone as used in test a4-tone-fragmented.mp4, but the actual access units are stored in

a separate file, referenced by a relative URL “./myData.dat” from the main file.
5.3.2.7 a7-tone-oddities.mp4
This file also uses the 1-second tone. However, it has:
— a UUID,
— a non-standard ‘junk’ atom in it (which should be ignored),
— a free space box (also ignored),
— the compact sample size table,
— a padding bits table (though the padding bits are all set to zero).

The mdat atom has an implied length (the length in the file is zero, meaning to end of file).

5.3.2.8 a8-foreman_QCIF_edit.mp4

This file has the "foreman" 10 second of video, with 5 seconds before and after, of the “container” video.

However, the edit list should select only foreman. The container ship should not appear. Note that the

I-frames do not land on the edit boundaries. A player will have to pre-roll the video from an I-frame to

work correctly.
5.3.2.9 a9-aac-samplegroups-edit.mp4

This file demonstrates the suggested way of handling AAC: it has a pre-roll sample group, and a track

edit that is not aligned at either start or end with an AAC sample boundary.
5.3.2.10 a10-foreman_QCIF-raw.mp4

This file contains ‘raw’ (YUV420) video. Since this is an unregistered codec type (it’s actually supported

in QuickTime movie files) this is an unrecognized codec type from an ISOBMFF reader’s point of view.

5.3.2.11 LargerThan4GB.mp4
This file tests handling of very large (>4GB) files.

The ‘mdat’ atom has a large (64-bit) size, and all the samples are at the end, preceded by 4GB of zeroes.

Therefore, the chunk offset table is also a co64, not an stco. The actual media data is a simple AAC tone.

© ISO/IEC 2021 – All rights reserved 5
---------------------- Page: 9 ----------------------
ISO/IEC 14496-32:2021(E)
5.3.2.12 f1.mp4

This file is a simple AVC + AAC file. It has an MPEG-4 AVC Baseline visual track (including the optional

BitrateBox), and an AAC track.
5.3.2.13 f2.mp4

This file is a protected AVC + AAC file. The 128-bit key for the decryption process is 0x01020304050607

080102030405060708 for both tracks. The salt (counter offset) is 0x0000000000000001 for the audio

and 0x0000000000000002. Because of the usage of protected streams, “isom” was replace with “iso2”

in the list of compatible brands.
5.3.2.14 male_amr122.3gp

This file and the following 3GP files contain AMR speech at 12.2 or 6.7 kbps, with or without DTX

(silence frames). In addition, 3GP files with hint tracks are provided.
AMR 12.2kbps, no DTX
5.3.2.15 male_amr122DTX.3gp
AMR 12.2kbps, DTX
5.3.2.16 female_amr67_hinted.3gp
AMR 6.7kbps, no DTX, hint track
5.3.2.17 female_amr67DTX_hinted.3gp
AMR 6.7kbps, DTX, hint track
5.3.2.18 pdin_example.3gp

This file contains one video track with AVC and a progressive download information box specifying

required initial delays for six different download rates. The download rates 5106, 7659, 10213,

12766, 15319 and 20426 bytes per second require initial delays of 20808, 7206, 1089, 652, 396 and

200 seconds, respectively.
5.3.2.19 rs_example_r1.3gp

This file contains three video tracks with AVC at different bitrates, three audio tracks with HE-AACv2

at different bitrates, track selection box, and rate share information with two operation points. For

the first operation point (100 kilobits per second), the target rate shares are 20 % for audio and 80 %

for video. For the second operation point (160 kilobits per second), the target rate share weights are

20 and 140 for audio and video, respectively. As the sum is not 100 for the second case, the numbers

correspond to weights that need to be normalized by the server/player. Depending on the available

bitrate, the server selects which tracks to stream/play.
5.3.2.20 01-simple.mp4

Simple AV file (MPEG-4 ASP video, AAC audio), BIFS+OD scene, 2 timelines (BIFS/OD and A/V),

interleaved.
5.3.2.21 02-dref_edts_img.mp4

Image track, audio track with edit list, with media data located outside the file.

6 © ISO/IEC 2021 – All rights reserved
---------------------- Page: 10 ----------------------
ISO/IEC 14496-32:2021(E)
5.3.2.22 03-hinted.mp4

Simple video file with MPEG-4 ASP visual, hinted for RTP (IETF RFC 3640 payload).

5.3.2.23 04-bifs_video.mp4

Video (MPEG-4 ASP visual) + BIFS text (reading 'unprotected video'), with a single timeline.

5.3.2.24 05-bifs_video_protected_v2.mp4

Protected video (MPEG-4 ASP visual) + BIFS text (reading 'protected video'), with a single timeline.

Keys are described in an item located in a meta box at the file root level, ISMA KMS URI referring to this

item. Keys are:
— key 0x2b7e151628aed2a6abf7158809cf4f3c
— salt 0xf8f9fafbfcfdfeff
Only video I-frames are encrypted.
5.3.2.25 06-bifs.mp4

Simple animation with a single BIFS track. File moov box is located after mdat box.

5.3.2.26 07-bifs_sprite.mp4

Simple looping animation with two BIFS tracks, exercising decoding dependency and synchronization

track references.
Animation track uses ShadowSync samples in-between regular samples.
5.3.2.27 08-bifs_carousel_v2.mp4

Simple animation with a single BIFS track. Random access samples are inserted in-between the samples

for the BIFS carrousel and signalled with a sample dependency type box.
5.3.2.28 09-text.mp4

Sample MPEG-4 streaming text file, stored in 3GPP text track format, with 2 sample descriptions.

5.3.2.29 10-fragments.mp4

Simple AV file (MPEG-4 ASP video, AAC audio), BIFS+OD scene, stored as a sequence of 500 ms fragments.

5.3.2.30 12_metas_v2.mp4

File with a single image track, containing 3 metas (root, moov and track level). Meta at moov level has

an item referencing the whole file.
5.3.2.31 13_long.mp4

Long duration file, with MPEG-4 ASP track (only I-frames present). Total file duration is 5000000000 sec.

(158 Years 81 Days 08:53:20).
5.3.2.32 14_large.mp4
Large file exercising 64 bits chunk offset.
© ISO/IEC 2021 – All rights reserved 7
---------------------- Page: 11 ----------------------
ISO/IEC 14496-32:2021(E)
5.3.2.33 16_vtt.mp4
The file 16_vtt.mp4 contains the following boxes:
— wvtt
— vttC
— vttc
— ctim
— iden
— sttg
— payl
— vtte
— vtta
5.3.2.34 17_negative_ctso.mp4

This file contains a single AVC video track with a ctts box using version 1. The box declares negative

composition offset such that the offset of the first frame is 0.
5.3.2.35 18_pssh_v2.mp4

This file contains an encrypted video track. The file also contains 2 pssh boxes: one with only opaque

data and the other one with KID information.
5.3.2.36 19_ttml.mp4
This file contains a simple TTML track.
5.3.2.37 20_stxt.mp4

This file contains a track of type 'stxt' whose content is SVG, the mime type is image/svg+xml. The SVG

content is distributed over 4 samples. The configuration of the track contains the header of the SVG

content.
5.3.2.38 21_segment.mp4

This file contains a self-initializing DASH media segment with the following boxes: 'sdix', 'prft', trun

v1, sgpd.
5.3.2.39 22_tx3g.mp4
The file provides a simple 3GPP Timed Text stream stored in an mp4 file.
5.3.2.40 compact-no-code-fec-1.iso3

This file contains one JPEG file stored as an item. Compact No-Code FEC is used and the file is partitioned

into one source block. The file contains also one hint track for FLUTE transmission.

5.3.2.41 compact-no-code-fec-2.iso3

This file contains one JPEG file stored as items. Compact No-Code FEC is used and the file is partitioned

into three source blocks. The file contains also one hint track for FLUTE transmission.

8 © ISO/IEC 2021 – All rights reserved
---------------------- Page: 12 ----------------------
ISO/IEC 14496-32:2021(E)
5.3.2.42 mbms-fec.iso3

This file contains two JPEG files stored as items. MBMS-FEC is used and both files are partitioned into

one source block and several sub-blocks. Parity symbols for the source block are stored as an FEC

reservoir item. The file contains also three hint tracks for FLUTE transmission with FEC overheads

10 %, 20 % and 40 %. Each hint track defines transmission of both JPEG files over one FLUTE channel.

5.3.2.43 fragment-random-access-1+AF8-rev1.mp4

This uses movie fragment random access boxes (movie fragment random access, track fragment random

access, movie fragment random access offset in ISO/IEC 14496-12). These boxes help readers to search

where random access points are.
There are random access points at 1-sec interval.

For the purpose of reference, the initial 1-second movie is followed by a 14-second movie fragment. The

movie consists of audio and video tracks. Fragment aware readers should play 15.3 seconds of content,

fragment-unaware readers only 1 second.
5.3.2.44 fragment_random_access-2.mp4
This uses movie fragment random access boxes as 1.4.
There are random access points at 5-sec interval.

For the purpose of reference, the initial 1-second movie is followed by a 10.1-second movie fragment.

The movie consists of audio and video tracks. Fragment aware readers should play 15,1 seconds of

content, fragment-unaware readers only 5 seconds.
5.3.2.45 timed-metadata.mp4
Simple audio file with a timed-metadata track.
5.3.2.46 restricted.mp4
Features — Post-decoder requirements on media
— ‘resv’ box
— ‘rinf’ box
— ‘stvi’ box
— ‘schi’ box

This bitstream exercises the method of restricting access to video media. The media itself is in

stereoscopic 3D format with side-by-side frame packing.
© ISO/IEC 2021 – All rights reserved 9
---------------------- Page: 13 ----------------------
ISO/IEC 14496-32:2021(E)
5.3.2.47 sg-tl-st.mp4
Features — Level assignment
— ‘leva’ box
— Sub-tracks
— ‘strk’ box
— ‘stri’ box
— ‘strd’ box
— ‘stsg’ box
— Segment index box
— ‘sidx’ box
— Sub-segment index box
— ‘ssix’ box
— Temporal level sample group
— Contained in ‘sgpd’ box
— Sample groups
— ‘spgd’ box
— ‘sbgp’ box

This bitstream exercises a method of splitting video media data such that it can be efficiently

transmitted, decoded, and played back at full framerate or half framerate.

The first M samples in the ‘mdat’ box (sample group 1) give an independently decodable media segment,

and the remaining samples (sample group 2) are not referenced by any samples in group 1.

Sample groups 1 and 2 are assigned to temporal levels 1 and 2 respectively. Each level is referenced

as a byte range in the sub-segment index. Two sub-tracks are defined, the first of which applies just to

sample group 1, and the second of which applies to the full range of samples.
5.3.2.48 subs_tile_hvc1.mp4
Features — sub-sample information
— ‘subs’ box
— hvc1 sample entry
— ‘hvc1’ box

This file contains HEVC video track with associated tile-based sub-sample (flags = 2). The sub-sample

information box (‘subs’) is used to provide information such as sub-sample sizes in bytes, priority, etc.

without having to decode HEVC data. The sub-samples are derived by using entry point offsets found

from the HEVC slice header. The values of discardable and subsample_priority fields in the ‘subs’ box

are set to 0 and the field subsample_size is set to the entry point offset value.

10 © ISO/IEC 2021 – All rights reserved
---------------------- Page: 14 ----------------------
ISO/IEC 14496-32:2021(E)
5.3.2.49 subs_slice_hvc1.mp4
Features — sub-sample information
— ‘subs’ box
— hvc1 sample entry
— ‘hvc1’ box

The file contains HEVC video track with associated slice-based sub-sample (flags = 4). Sub-sample is

constructed by using the sizes of the slices. The values of discardable and subsample_priority fields in

the ‘subs’ box are set to 0 and the field subsample_size is set to the slice size in bytes.

5.3.2.50 aggr_hvc1.mp4
Features — aggregators
— Aggregator container in the HEVC bit stream
— Aggregates SHVC enchancement layer
— hvc1 sample entry
— ‘hvc1’ box

This file includes an aggregator container around SHVC enhancement layer NAL units so that the video

can be viewed and decoded as normal HEVC. Decoder supporting aggregators can increase video

resolution by extracting the enhancement layer. Aggregator is a special type of NAL unit including or

referring to a set of data. In this coded bit stream, the aggregator includes the aggregated data.

5.3.2.51 trgr_hvc1.mp4
Features — track groups
— ‘trgr’ box
— hvc1 sample entry
— ‘hvc1’ box

This bit stream includes a ‘trgr’ box that groups related tracks together and a ‘hvc1’ box that contains

the HEVC video configurations.
© ISO/IEC 2021 – All rights reserved 11
---------------------- Page: 15 ----------------------
ISO/IEC 14496-32:2021(E)
5.3.2.52 alst_hvc1.mp4
Features — alternative startup (alst) sequences sample group
— ‘sgpd’ box
— ‘sbgp’ box
— RAP sample group
— ‘sgpd’ box
— ‘sbgp’ box
— hvc1 sample entry
— ‘hvc1’ box

The alternative startup sequences sample group is indicated by two parameters: roll_count and first_

output_sample, which specify the number of samples in the group and the first sample in the sequence

to be sent to the output, respectively. In addition, the random access point (RAP) sample group is used

to point the location of the sync samples where alst sample group could be found in the stream. The

RAP sample group is composed of CRA/BLA/IDR/IRAP pictures. A position in the stream is sought

among the RAP samples preceding the position of interest
...

INTERNATIONAL ISO
STANDARD 14496-32
First edition
Information technology — Coding of
audio-visual objects —
Part 32:
File format reference software and
conformance
PROOF/ÉPREUVE
Reference number
ISO 14496-32:2020(E)
ISO 2020
---------------------- Page: 1 ----------------------
ISO 14496-32:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO/IEC 2020

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii PROOF/ÉPREUVE © ISO/IEC 2020 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 14496-32:2020(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Reference software ............................................................................................................................................................................................ 2

5 Conformance ............................................................................................................................................................................................................. 2

5.1 Overview ...................................................................................................................................................................................................... 2

5.2 Standard specific considerations ............................................................................................................................................ 2

5.2.1 Considerations for ISO/IEC 14496-12, 14496-14 and 14496-15 ......................................... 2

5.2.2 Considerations for ISO/IEC 14496-30 .......................................................................................................... 2

5.2.3 Considerations for ISO/IEC 23008-12 .......................................................................................................... 3

5.3 File documentation ............................................................................................................................................................................. 3

5.3.1 Files from related conformance programs ................................................................................................ 3

5.3.2 Files unique to this conformance program ............................................................................................... 4

Annex A (informative) Other tools .......................................................................................................................................................................21

Bibliography .............................................................................................................................................................................................................................22

© ISO/IEC 2020 – All rights reserved PROOF/ÉPREUVE iii
---------------------- Page: 3 ----------------------
ISO 14496-32:2020(E)
Foreword

ISO (the International Organization for Standardization) and IEC (the International Electrotechnical

Commission) form the specialized system for worldwide standardization. National bodies that

are members of ISO or IEC participate in the development of International Standards through

technical committees established by the respective organization to deal with particular fields of

technical activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other

international organizations, governmental and non-governmental, in liaison with ISO and IEC, also

take part in the work.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for

the different types of document should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject

of patent rights. ISO and IEC shall not be held responsible for identifying any or all such patent

rights. Details of any patent rights identified during the development of the document will be in the

Introduction and/or on the ISO list of patent declarations received (see www .iso .org/ patents) or the IEC

list of patent declarations received (see http:// patents .iec .ch).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/

iso/ foreword .html.

This document was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,

Subcommittee SC 29, Coding of audio, picture, multimedia and hypermedia information.

A list of all parts in the ISO/IEC 14496 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
iv PROOF/ÉPREUVE © ISO/IEC 2020 – All rights reserved
---------------------- Page: 4 ----------------------
INTERNATIONAL STANDARD ISO 14496-32:2020(E)
Information technology — Coding of audio-visual
objects —
Part 32:
File format reference software and conformance
1 Scope

This document describes the reference software and conformance suite for the file format documents

in MPEG-4 and MPEG-H. Since these documents share a lot of technology, their reference software

and conformance program are being handled together. These documents are: ISO/IEC 14496-12,

ISO/IEC 14496-14, ISO/IEC 14496-15, ISO/IEC 14496-30 and ISO/IEC 23008-12.

The purpose of the conformance suite is to cover the set of valid features that can be exercised in the

file format. Media conformance is not covered, though of course in order to exercise the file format

features, media will be stored.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO/IEC 14496-12, Information technology — Coding of audio-visual objects — Part 12: ISO base media

file format

ISO/IEC 14496-14, Information technology — Coding of audio-visual objects — Part 14: MP4 file format

ISO/IEC 14496-15, Information technology — Coding of audio-visual objects — Part 15: Carriage of

network abstraction layer (NAL) unit structured video in the ISO base media file format

ISO/IEC 14496-30, Information technology — Coding of audio-visual objects — Part 30: Timed text and

other visual overlays in ISO base media file format

ISO/IEC 23008-12, Information technology — High efficiency coding and media delivery in heterogeneous

environments — Part 12: Image File Format
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO/IEC 14496-12,

ISO/IEC 14496-14, ISO/IEC 14496-15, ISO/IEC 14496-30 and ISO/IEC 23008-12 apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at https:// www .iso .org/ obp
© ISO/IEC 2020 – All rights reserved PROOF/ÉPREUVE 1
---------------------- Page: 5 ----------------------
ISO 14496-32:2020(E)
4 Reference software

The reference software for ISO/IEC 14496-12, ISO/IEC 14496-14, ISO/IEC 14496-15, ISO/IEC 14496-30

and ISO/IEC 23008-12 is provided at:

https:// standards .iso .org/ iso -iec/ 14496/ -32/ ed -1/ en/ reference _software/

Additional tools exercising features of the ISO base media file format (ISOBMFF) are described in

Annex A.
5 Conformance
5.1 Overview

The conformance suite for ISO/IEC 14496-12, ISO/IEC 14496-14, ISO/IEC 14496-15, ISO/IEC 14496-30

and ISO/IEC 23008-12 is provided at:
https:// standards .iso .org/ iso -iec/ 14496/ -32/ ed -1/ en/ conformance/

The suite of conformance tests does not currently cover deliberately errored files. However, such files

do occur in practice and implementations should be written to be resilient.

There is no official reference tool provided to check the conformance of files. However, such tools do

exist (see Annex A). The reference software can be used to open files in ‘debug’ mode and provide a

listing of what it finds, and other trade associations and standards bodies may have validation tools

tailored to their areas.

An HTML report (conformance_report.html) indicates which code points (e.g. box codes and track

reference types) defined in these documents are used in which conformance file.
5.2 Standard specific considerations
5.2.1 Considerations for ISO/IEC 14496-12, 14496-14 and 14496-15

For ISOBMFF conformance, an associated file (ff-conformance.xls) is used to list the features in groups,

and to document which files exercise each feature. Features not currently covered by any file are

marked with the sign “---“.

The file ff-conformance.xls has two spreadsheets. The first briefly lists the areas and features covered,

and then has a column for each proposed file. The second sheet provides a brief description of each area

and feature, by line.
5.2.2 Considerations for ISO/IEC 14496-30
Two files are proposed regarding:
— WebVTT;
— TTML.

There are several general features of ISO/IEC 14496-30 which are not exercised in the above files,

specifically:
— a track with 'mul' language;

— a track sharing resources (images, …) between samples through the use of a MetaBox;

— file with a subtitle and a font track.
2 PROOF/ÉPREUVE © ISO/IEC 2020 – All rights reserved
---------------------- Page: 6 ----------------------
ISO 14496-32:2020(E)

There are several features specific to the carriage of TTML in MP4 which are not exercised:

— timing:
— 'empty' sample;

— sample with a document containing a larger time range than the sample presentation range;

— sample with a document whose time range is smaller than the sample range;
— sample entry format:
— with multiple namespace values;
— with schema location;
— with auxiliary mime types;
— sample format:
— with additional resources.
5.2.3 Considerations for ISO/IEC 23008-12

For HEIF conformance, an associated file (HEIF_conformance.xlsx) is used to describe the current files,

associated input bitstreams, and a specification coverage analysis of the conformance.

The spreadsheet "HEIF_conformance.xlsx" contains information of the tested features and their

mapping to the provided conformance files. It was created by picking all normative statements (shall,

shall not, etc.) in the HEIF specification. These are collected in the "Areas tested" column of the sheet.

The column "Description" presents a brief description of the tested feature, exercising the associated

normative statement in the specification.
The column "File ID" provides the file name.

The column "brands" indicates the HEIF brands that are included in FileTypeBox of the respective file

(in the "Test Content" sheet) or concern the respective test case (in the "Test Cases" sheet. The aim of

the column is to help implementers to pick files that concern the brand of their interest. For example,

implementers of the 'heic' brand should only consider the files with that brand included.

Note that the spreadsheet enables filtering by content, e.g. by selecting only a particular File ID (at cell

A1), one can see which features are exercised by a particular file.
5.3 File documentation
5.3.1 Files from related conformance programs
5.3.1.1 Overview

Some files provided in this suite originate from external conformance programs, from other ISO

documents or external specifications. The latest version should be obtained from their original source

as indicated in the following sections.
5.3.1.2 Audio-based conformance files

ISO/IEC 14496-26 provides several MP4 files containing MPEG-4 AAC, MPEG-D MPS, and MPEG-D USAC

streams and exercising features of the ISOBMFF. Within these files, only some are necessary to cover

all the ISOBMFF features. These files are from the "AAC-Conformance" part. The features specifically

exercised by these files compared to existing files are: "padb" and "m4ae".
© ISO/IEC 2020 – All rights reserved PROOF/ÉPREUVE 3
---------------------- Page: 7 ----------------------
ISO 14496-32:2020(E)
The following files are also included for ISOBMFF conformance:
— ./mpeg-audio-conformance/ac01.mp4 (padb)
— ./mpeg-audio-conformance/sls2100_aot02_048_16.mp4 (m4ae)
Original files can be obtained from ISO/IEC 14496-26.
5.3.1.3 Timed text conformance files

DECE produced a set of Timed Text test vector files with video and audio tracks. Some of these files

exercise features of ISO/IEC 14496-12 and ISO/IEC 14496-30. The following files are added as part of

ISOBMFF conformance:
— ./uvvu/Solekai002_1280_23_1x1_v7clear.uvvu
— ./uvvu/Solekai007_1920_29_1x1_v7clear.uvvu

Original files can be obtained from http:// uvvuwiki .com/ cff/ cff -test -files .html.

5.3.1.4 DASH-based conformance files

The ISO/IEC 23009 series specifies the use of ISOBMFF files for adaptive streaming. ISO/IEC 23009-2

contains the following files that exercise specific features of the ISOBMFF:
— ./green/video_2500000bps_0.mp4
— ./green/meta_2500000bps_0.mp4m
— ./nalu/svc/mp4-onDemand-LastTime-depRep.mp4
— ./nalu/mvc/DDF_10s_25fps.mp4
Original files can be obtained from http:// testassets .dashif .org/ .
5.3.1.5 MAF-based conformance files

The ISO/IEC 23000 series uses the ISOBMFF standard at its core and contains some files (related to the

PAAF and VSAF standards). None of these files exercise new features, but they exercise some features

differently. The following files are copied in this ISOBMFF conformance:
— ./maf/vsaf/1.mp4
— ./maf/paaf/01_output_a.paf
Original files can be obtained from ISO/IEC 23000-6 and ISO/IEC 23000-10.
5.3.2 Files unique to this conformance program
5.3.2.1 a1-foreman-QCIF.mp4

This file is about as simple as it gets. It has an MPEG-4 video part 2 visual track, and an AAC track,

interleaved; and a minimal BIFS scene and OD track, with an IOD.
5.3.2.2 a2-foreman-QCIF-hinted.mp4

This file is basically the same as a1-foreman-QCIF.mp4 but hinted for RTP transmission.

4 PROOF/ÉPREUVE © ISO/IEC 2020 – All rights reserved
---------------------- Page: 8 ----------------------
ISO 14496-32:2020(E)
5.3.2.3 a3-tone-protected.mp4

This file uses the protected stream structures. The keys are also supplied (a3c-prot-keys.txt), and the

result of de-protection (a3b-tone-deprot.mp4, for comparison).
5.3.2.4 a4-tone-fragmented.mp4

This file uses movie fragments. The initial 1-second movie is followed by a 1-second movie fragment.

Fragment-aware readers should play 2 second of content, fragment-unaware readers only 1 second.

5.3.2.5 a5-foreman-AVC.mp4

This is a very simple video-only main profile AVC file. Since it is main profile, composition offsets are used.

5.3.2.6 a6_tone_multifile.mp4

This is the same tone as used in test a4-tone-fragmented.mp4, but the actual access units are stored in

a separate file, referenced by a relative URL “./myData.dat” from the main file.
5.3.2.7 a7-tone-oddities.mp4
This file also uses the 1-second tone. However, it has:
— a UUID,
— a non-standard ‘junk’ atom in it (which should be ignored),
— a free space box (also ignored),
— the compact sample size table,
— a padding bits table (though the padding bits are all set to zero).

The mdat atom has an implied length (the length in the file is zero, meaning to end of file).

5.3.2.8 a8-foreman_QCIF_edit.mp4

This file has the "foreman" 10 second of video, with 5 seconds before and after, of the “container” video.

However, the edit list should select only foreman. The container ship should not appear. Note that the

I-frames do not land on the edit boundaries. A player will have to pre-roll the video from an I-frame to

work correctly.
5.3.2.9 a9-aac-samplegroups-edit.mp4

This file demonstrates the suggested way of handling AAC: it has a pre-roll sample group, and a track

edit that is not aligned at either start or end with an AAC sample boundary.
5.3.2.10 a10-foreman_QCIF-raw.mp4

This file contains ‘raw’ (YUV420) video. Since this is an unregistered codec type (it’s actually supported

in QuickTime movie files) this is an unrecognized codec type from an ISOBMFF reader’s point of view.

5.3.2.11 LargerThan4GB.mp4
This file tests handling of very large (>4GB) files.

The ‘mdat’ atom has a large (64-bit) size, and all the samples are at the end, preceded by 4GB of zeroes.

Therefore, the chunk offset table is also a co64, not an stco. The actual media data is a simple AAC tone.

© ISO/IEC 2020 – All rights reserved PROOF/ÉPREUVE 5
---------------------- Page: 9 ----------------------
ISO 14496-32:2020(E)
5.3.2.12 f1.mp4

This file is a simple AVC + AAC file. It has an MPEG-4 AVC Baseline visual track (including the optional

BitrateBox), and an AAC track.
5.3.2.13 f2.mp4

This file is a protected AVC + AAC file. The 128-bit key for the decryption process is 0x01020304050607

080102030405060708 for both tracks. The salt (counter offset) is 0x0000000000000001 for the audio

and 0x0000000000000002. Because of the usage of protected streams, “isom” was replace with “iso2”

in the list of compatible brands.
5.3.2.14 male_amr122.3gp

This file and the following 3GP files contain AMR speech at 12.2 or 6.7 kbps, with or without DTX

(silence frames). In addition, 3GP files with hint tracks are provided.
AMR 12.2kbps, no DTX
5.3.2.15 male_amr122DTX.3gp
AMR 12.2kbps, DTX
5.3.2.16 female_amr67_hinted.3gp
AMR 6.7kbps, no DTX, hint track
5.3.2.17 female_amr67DTX_hinted.3gp
AMR 6.7kbps, DTX, hint track
5.3.2.18 pdin_example.3gp

This file contains one video track with AVC and a progressive download information box specifying

required initial delays for six different download rates. The download rates 5106, 7659, 10213,

12766, 15319 and 20426 bytes per second require initial delays of 20808, 7206, 1089, 652, 396 and

200 seconds, respectively.
5.3.2.19 rs_example_r1.3gp

This file contains three video tracks with AVC at different bitrates, three audio tracks with HE-AACv2

at different bitrates, track selection box, and rate share information with two operation points. For

the first operation point (100 kilobits per second), the target rate shares are 20 % for audio and 80 %

for video. For the second operation point (160 kilobits per second), the target rate share weights are

20 and 140 for audio and video, respectively. As the sum is not 100 for the second case, the numbers

correspond to weights that need to be normalized by the server/player. Depending on the available

bitrate, the server selects which tracks to stream/play.
5.3.2.20 01-simple.mp4

Simple AV file (MPEG-4 ASP video, AAC audio), BIFS+OD scene, 2 timelines (BIFS/OD and A/V),

interleaved.
5.3.2.21 02-dref_edts_img.mp4

Image track, audio track with edit list, with media data located outside the file.

6 PROOF/ÉPREUVE © ISO/IEC 2020 – All rights reserved
---------------------- Page: 10 ----------------------
ISO 14496-32:2020(E)
5.3.2.22 03-hinted.mp4

Simple video file with MPEG-4 ASP visual, hinted for RTP (IETF RFC 3640 payload).

5.3.2.23 04-bifs_video.mp4

Video (MPEG-4 ASP visual) + BIFS text (reading 'unprotected video'), with a single timeline.

5.3.2.24 05-bifs_video_protected_v2.mp4

Protected video (MPEG-4 ASP visual) + BIFS text (reading 'protected video'), with a single timeline.

Keys are described in an item located in a meta box at the file root level, ISMA KMS URI referring to this

item. Keys are:
— key 0x2b7e151628aed2a6abf7158809cf4f3c
— salt 0xf8f9fafbfcfdfeff
Only video I-frames are encrypted.
5.3.2.25 06-bifs.mp4

Simple animation with a single BIFS track. File moov box is located after mdat box.

5.3.2.26 07-bifs_sprite.mp4

Simple looping animation with two BIFS tracks, exercising decoding dependency and synchronization

track references.
Animation track uses ShadowSync samples in-between regular samples.
5.3.2.27 08-bifs_carousel_v2.mp4

Simple animation with a single BIFS track. Random access samples are inserted in-between the samples

for the BIFS carrousel and signalled with a sample dependency type box.
5.3.2.28 09-text.mp4

Sample MPEG-4 streaming text file, stored in 3GPP text track format, with 2 sample descriptions.

5.3.2.29 10-fragments.mp4

Simple AV file (MPEG-4 ASP video, AAC audio), BIFS+OD scene, stored as a sequence of 500 ms fragments.

5.3.2.30 12_metas_v2.mp4

File with a single image track, containing 3 metas (root, moov and track level). Meta at moov level has

an item referencing the whole file.
5.3.2.31 13_long.mp4

Long duration file, with MPEG-4 ASP track (only I-frames present). Total file duration is 5000000000 sec.

(158 Years 81 Days 08:53:20).
5.3.2.32 14_large.mp4
Large file exercising 64 bits chunk offset.
© ISO/IEC 2020 – All rights reserved PROOF/ÉPREUVE 7
---------------------- Page: 11 ----------------------
ISO 14496-32:2020(E)
5.3.2.33 16_vtt.mp4
The file 16_vtt.mp4 contains the following boxes:
— wvtt
— vttC
— vttc
— ctim
— iden
— sttg
— payl
— vtte
— vtta
5.3.2.34 17_negative_ctso.mp4

This file contains a single AVC video track with a ctts box using version 1. The box declares negative

composition offset such that the offset of the first frame is 0.
5.3.2.35 18_pssh_v2.mp4

This file contains an encrypted video track. The file also contains 2 pssh boxes: one with only opaque

data and the other one with KID information.
5.3.2.36 19_ttml.mp4
This file contains a simple TTML track.
5.3.2.37 20_stxt.mp4

This file contains a track of type 'stxt' whose content is SVG, the mime type is image/svg+xml. The SVG

content is distributed over 4 samples. The configuration of the track contains the header of the SVG

content.
5.3.2.38 21_segment.mp4

This file contains a self-initializing DASH media segment with the following boxes: 'sdix', 'prft', trun

v1, sgpd.
5.3.2.39 22_tx3g.mp4
The file provides a simple 3GPP Timed Text stream stored in an mp4 file.
5.3.2.40 compact-no-code-fec-1.iso3

This file contains one JPEG file stored as an item. Compact No-Code FEC is used and the file is partitioned

into one source block. The file contains also one hint track for FLUTE transmission.

5.3.2.41 compact-no-code-fec-2.iso3

This file contains one JPEG file stored as items. Compact No-Code FEC is used and the file is partitioned

into three source blocks. The file contains also one hint track for FLUTE transmission.

8 PROOF/ÉPREUVE © ISO/IEC 2020 – All rights reserved
---------------------- Page: 12 ----------------------
ISO 14496-32:2020(E)
5.3.2.42 mbms-fec.iso3

This file contains two JPEG files stored as items. MBMS-FEC is used and both files are partitioned into

one source block and several sub-blocks. Parity symbols for the source block are stored as an FEC

reservoir item. The file contains also three hint tracks for FLUTE transmission with FEC overheads

10 %, 20 % and 40 %. Each hint track defines transmission of both JPEG files over one FLUTE channel.

5.3.2.43 fragment-random-access-1+AF8-rev1.mp4

This uses movie fragment random access boxes (movie fragment random access, track fragment random

access, movie fragment random access offset in ISO/IEC 14496-12). These boxes help readers to search

where random access points are.
There are random access points at 1-sec interval.

For the purpose of reference, the initial 1-second movie is followed by a 14-second movie fragment. The

movie consists of audio and video tracks. Fragment aware readers should play 15.3 seconds of content,

fragment-unaware readers only 1 second.
5.3.2.44 fragment_random_access-2.mp4
This uses movie fragment random access boxes as 1.4.
There are random access points at 5-sec interval.

For the purpose of reference, the initial 1-second movie is followed by a 10.1-second movie fragment.

The movie consists of audio and video tracks. Fragment aware readers should play 15,1 seconds of

content, fragment-unaware readers only 5 seconds.
5.3.2.45 timed-metadata.mp4
Simple audio file with a timed-metadata track.
5.3.2.46 restricted.mp4
Features — Post-decoder requirements on media
— ‘resv’ box
— ‘rinf’ box
— ‘stvi’ box
— ‘schi’ box

This bitstream exercises the method of restricting access to video media. The media itself is in

stereoscopic 3D format with side-by-side frame packing.
© ISO/IEC 2020 – All rights reserved PROOF/ÉPREUVE 9
---------------------- Page: 13 ----------------------
ISO 14496-32:2020(E)
5.3.2.47 sg-tl-st.mp4
Features — Level assignment
— ‘leva’ box
— Sub-tracks
— ‘strk’ box
— ‘stri’ box
— ‘strd’ box
— ‘stsg’ box
— Segment index box
— ‘sidx’ box
— Sub-segment index box
— ‘ssix’ box
— Temporal level sample group
— Contained in ‘sgpd’ box
— Sample groups
— ‘spgd’ box
— ‘sbgp’ box

This bitstream exercises a method of splitting video media data such that it can be efficiently

transmitted, decoded, and played back at full framerate or half framerate.

The first M samples in the ‘mdat’ box (sample group 1) give an independently decodable media segment,

and the remaining samples (sample group 2) are not referenced by any samples in group 1.

Sample groups 1 and 2 are assigned to temporal levels 1 and 2 respectively. Each level is referenced

as a byte range in the sub-segment index. Two sub-tracks are defined, the first of which applies just to

sample group 1, and the second of which applies to the full range of samples.
5.3.2.48 subs_tile_hvc1.mp4
Features — sub-sample information
— ‘subs’ box
— hvc1 sample entry
— ‘hvc1’ box

This file contains HEVC video track with associated tile-based sub-sample (flags = 2). The sub-sample

information box (‘subs’) is used to provide information such as sub-sample sizes in bytes, priority, etc.

without having to decode HEVC data. The sub-samples are derived by using entry point offsets found

from the HEVC slice header. The values of discardable and subsample_priority fields in the ‘subs’ box

are set to 0 and the field subsample_size is set to the entry point offset value.

10 PROOF/ÉPREUVE © ISO/IEC 2020 – All rights reserved
---------------------- Page: 14 ----------------------
ISO 14496-32:2020(E)
5.3.2.49 subs_slice_hvc1.mp4
Features — sub-sample information
— ‘subs’ box
— hvc1 sample entry
— ‘hvc1’ box

The file contains HEVC video track with associated slice-based sub-sample (flags = 4). Sub-sample is

constructed by using the sizes of the slices. The values of discardable and subsample_priority fields in

the ‘subs’ box are set to 0 and the field subsample_size is set to the slice size in bytes.

5.3.2.50 aggr_hvc1.mp4
Features — aggregators
— Aggregator container in the HEVC bit stream
— Aggregates SHVC enchancement layer
— hvc1 sample entry
— ‘hvc1’ box

This file includes an aggregator container around SHVC enhancement layer NAL units so that the video

can be viewed and decoded as normal HEVC. Decoder supporting aggregators can increase video

resolution by extracting the enhancement layer. Aggregator is a special type of NAL unit including or

referring to a set of data. In this coded bit stream, the aggregator includes the aggregated data.

5.3.2.51 trgr_hvc1.mp4
Features — track groups
— ‘trgr’ box
— hvc1 sample entry
— ‘hvc1’ box

This bit stream includes a ‘trgr’ box that groups related tracks together and a ‘hvc1’ box that contains

the HEVC video configurations.
© ISO/IEC 2020 – All rights reserved PROOF/ÉPREUVE 11
---------------------- Page: 15 ----------------------
ISO 14496-32:2020(E)
5.3.2.52 alst_hvc1.mp4
Features — alternative startup (alst) sequences sample group
— ‘sgpd’ box
— ‘sbgp’ box
— RAP sample group
— ‘sgpd’ box
— ‘sbgp’ box
— hvc1 sample entry
— ‘hvc1’ box

The alternative startup sequences sample group is indicated by two parameters: roll_count and first_

output_sample, which specify the number of samples in the group and the first sample in the sequence

to be sent to the output, respectively. In addition, the random access point (RAP) sample group is used

to point the location of the sync samples where alst sample group could be found in the stream. The

RAP sample group is composed of CRA
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.