ISO/IEC 14496-12:2005/Amd 1:2007
(Amendment)Information technology — Coding of audio-visual objects — Part 12: ISO base media file format — Amendment 1: Support for timed metadata, non-square pixels and improved sample groups
Information technology — Coding of audio-visual objects — Part 12: ISO base media file format — Amendment 1: Support for timed metadata, non-square pixels and improved sample groups
Technologies de l'information — Codage des objets audiovisuels — Partie 12: Format ISO de base pour les fichiers médias — Amendement 1: Support pour métadonnées temporisées, pixels "non-square" et groupes d'échantillons améliorés
General Information
Relations
Standards Content (Sample)
INTERNATIONAL ISO/IEC
STANDARD 14496-12
Second edition
2005-04-01
Corrected version
2005-10-01
AMENDMENT 1
2007-04-01
Information technology — Coding of
audio-visual objects —
Part 12:
ISO base media file format
AMENDMENT 1: Support for timed
metadata, non-square pixels and improved
sample groups
Technologies de l'information — Codage des objets audiovisuels —
Partie 12: Format ISO de base pour les fichiers médias
AMENDEMENT 1: Support pour métadonnées temporisées, pixels
«non-square» et groupes d'échantillons améliorés
Reference number
ISO/IEC 14496-12:2005/Amd.1:2007(E)
©
ISO/IEC 2007
---------------------- Page: 1 ----------------------
ISO/IEC 14496-12:2005/Amd.1:2007(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
© ISO/IEC 2007
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO/IEC 2007 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/IEC 14496-12:2005/Amd.1:2007(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. In the field of information
technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of the joint technical committee is to prepare International Standards. Draft International
Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as
an International Standard requires approval by at least 75 % of the national bodies casting a vote.
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.
Amendment 1 to ISO/IEC 14496-12:2005 was prepared by Joint Technical Committee ISO/IEC JTC 1,
Information technology, Subcommittee SC 29, Coding of audio, picture, multimedia and hypermedia
information.
© ISO/IEC 2007 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO/IEC 14496-12:2005/Amd.1:2007(E)
Information technology — Coding of audio-visual objects —
Part 12:
ISO base media file format
AMENDMENT 1: Support for timed metadata, non-square pixels and
improved sample groups
Add the following to Clause 2, Normative references:
ISO/IEC 15938-1, Information technology — Multimedia content description interface — Part 1: Systems
ISO/IEC 23001-1, Information technology — MPEG systems technologies — Part 1: Binary MPEG format for
XML
Add to 8.5.1:
The width and height in the track header are measured on a notional ‘square’ (uniform) grid. Track video data
is normalized to these dimensions (logically) before any transformation or placement caused by a layup or
composition system. Track (and movie) matrices, if used, also operate in this uniformly-scaled space.
Add to the narrative in 8.9.1:
There is a general handler for metadata streams of any type; the specific format is identified by the sample
entry, as for video or audio, for example. If they are in text, then a MIME format is supplied to document their
format; if in XML, each sample is a complete XML document, and the namespace of the XML is also supplied.
Note that MPEG-7 streams, which are a specific kind of metadata stream, have their own handler
declared, documented in the MP4 file format [ISO/IEC 14496-14].
Note that metadata tracks are linked to the track they describe using a track-reference of type ‘cdsc’.
Metadata tracks use a null media header (‘nmhd’), as defined in sub-clause 8.9.1.
Add to the handler types in 8.9.3 the ‘meta’ handler:
handler_type when present in a media box, is an integer containing one of the following values, or a
value from a derived specification:
‘vide’ Video track
‘soun’ Audio track
‘hint’ Hint track
‘meta’ Timed Metadata track
Clarify the narrative in 8.11.5:
Streams other than visual and audio (e.g., timed metadata streams) may use a null Media Header Box, as
defined here.
© ISO/IEC 2007 – All rights reserved 1
---------------------- Page: 4 ----------------------
ISO/IEC 14496-12:2005/Amd.1:2007(E)
Amend 8.16.1 as follows:
change:
For video tracks, a VisualSampleEntry is used; for audio tracks, an AudioSampleEntry. Hint tracks use an
entry format specific to their protocol, with an appropriate name.
to:
For video tracks, a VisualSampleEntry is used, for audio tracks, an AudioSampleEntry and for metadata
tracks, a MetaDataSampleEntry. Hint tracks use an entry format specific to their protocol, with an appropriate
name.
Add at the end of the section:
An optional BitRateBox may be present at the end of any MetaDataSampleEntry to signal the bit rate
information of a stream. This can be used for buffer configuration. In case of XML metadata it can be used to
choose the appropriate memory representation format (DOM, STX).
The width and height in the video sample entry document the pixel counts that the codec will deliver; this
enables the allocation of buffers. Since these are counts they do not take into account pixel aspect ratio.
The pixel aspect ratio and clean aperture of the video may be specified using the ‘pasp’ and ‘clap’ sample
entry boxes, respectively. These are both optional; if present, they over-ride the declarations (if any) in
structures specific to the video codec, which structures should be examined if these boxes are absent.
In the PixelAspectRatioBox, hSpacing and vSpacing have the same units, but those units are unspecified:
only the ratio matters. hSpacing and vSpacing may or may not be in reduced terms, and they may reduce
to 1/1. Both of them must be positive.
They are defined as the aspect ratio of a pixel, in arbitrary units. If a pixel appears H wide and V tall, then
hSpacing/vSpacing is equal to H/V. This means that a square on the display that is n pixels tall needs to be
n*vSpacing/hSpacing pixels wide to appear square.
Note: When adjusting pixel aspect ratio, normally, the horizontal dimension of the video is
scaled, if needed (i.e. if the final display system has a different pixel aspect ratio from the
video source).
Note: It is recommended that the original pixels, and the composed transform, be carried
through the pipeline as far as possible. If the transformation resulting from ‘correcting’ pixel
aspect ratio to a square grid, normalizing to the track dimensions, composition or placement
(e.g. track and/or movie matrix), and normalizing to the display characteristics, is a unity
matrix, then no re-sampling need be done. In particular, video should not be re-sampled more
than once in the process of rendering, if
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.