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This specification defines a Media Source Extensions byte stream format specification based on the ISO Base Media File Format.
This document is merely a W3C-internal document. It has no official standing of any kind and does not represent consensus of the W3C Membership.
This specification defines segment formats for implementations that choose to support the ISO Base Media File Format ISO/IEC 14496-12 (ISO BMFF).
It defines the MIME-type parameters used to signal codecs, and provides the necessary format specific definitions for initialization segments, media segments, and random access points required by the byte stream formats section of the Media Source Extensions spec.This section specifies the parameters that can be used in the MIME-type passed to isTypeSupported()
or addSourceBuffer()
.
MIME-types for this specification must conform to the rules outlined for "audio/mp4" and "video/mp4" in RFC 6381.
An ISO BMFF initialization segment is defined in this specification as a single File Type Box (ftyp) followed by a single Movie Header Box (moov).
The user agent must run the end of stream algorithm with the error parameter set to "decode"
if any of the following conditions are met:
The user agent must support setting the offset from media composition time to movie presentation time by handling an Edit Box (edts) containing a single Edit List Box (elst) that contains a single edit with media rate one. This edit may have a duration of 0 (indicating that it spans all subsequent media) or may have a non-zero duration (indicating the total duration of the movie including fragments).
The user agent must support parameter sets (e.g., PPS/SPS) stored in the sample entry (as defined for avc1/avc2), and should support parameter sets stored inband in the samples themselves (as defined for avc3/avc4).
For maximum content interoperability, user agents are strongly advised to support both inband and out-of-band storage of the SPS and PPS.
Valid top-level boxes such as pdin, free, and sidx are allowed to appear before the moov box. These boxes must be accepted and ignored by the user agent and are not considered part of the initialization segment in this specification.
An ISO BMFF media segment is defined in this specification as one optional Segment Type Box (styp) followed by a single Movie Fragment Box (moof) followed by one or more Media Data Boxes (mdat). If the Segment Type Box is not present, the segment must conform to the brands listed in the File Type Box (ftyp) in the initialization segment.
Valid top-level boxes defined in ISO/IEC 14496-12 other than ftyp, moov, styp, moof, and mdat are allowed to appear between the end of an initialization segment or media segment and before the beginning of a new media segment. These boxes must be accepted and ignored by the user agent and are not considered part of the media segment in this specification.
The user agent must run the end of stream algorithm with the error parameter set to "decode"
if any of the following conditions are met:
A Movie Fragment Box uses movie-fragment relative addressing when the first Track Fragment Run(trun) box in each Track Fragment Box has the data-offset-present flag set and either of the following conditions are met:
This implies that the base-data-offset-present flag is not set.
A random access point as defined in this specification corresponds to a Stream Access Point of type 1 or 2 as defined in Annex I of ISO/IEC 14496-12.
Version | Comment |
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20 June 2014 |
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03 March 2014 |
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02 December 2013 | Initial CR version. |