ISO/IEC 14496-32:2021
(Main)Information technology — Coding of audio-visual objects — Part 32: File format reference software and conformance
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
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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
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ISO/IEC 14496-32:2021(E)
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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
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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.
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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
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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.
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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".
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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
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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
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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
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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.
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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
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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.
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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".
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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
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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
...
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