diff --git a/index.html b/index.html new file mode 100644 index 0000000..fb3072b --- /dev/null +++ b/index.html @@ -0,0 +1,639 @@ + + + + + + + + +MPEG-2 TS Byte Stream Format + + + + + + + + + + +
+

+

MPEG-2 TS Byte Stream Format

+

W3C Editor's Draft

+
+ More details about this document +
+
This version:
+ https://w3c.github.io/mse-byte-stream-format-mp2t/ +
+
Latest published version:
+ https://www.w3.org/TR/mse-byte-stream-format-mp2t/ +
+
Latest editor's draft:
https://w3c.github.io/mse-byte-stream-format-mp2t/
+
History:
+ https://www.w3.org/standards/history/mse-byte-stream-format-mp2t/ +
+ Commit history +
+ + + + + +
Editor:
+ Mark Watson (Netflix Inc.) +
+
+ Former editors: +
+ (W3C Invited Expert) (Until February 2024) +
+ Jerry Smith (Microsoft Corporation) (Until September 2017) +
+ Aaron Colwell (Google Inc.) (Until April 2015) +
+ Adrian Bateman (Microsoft Corporation) (Until April 2015) +
+ +
Feedback:
+ GitHub w3c/mse-byte-stream-format-mp2t + (pull requests, + new issue, + open issues) +
public-media-wg@w3.org with subject line [mse-byte-stream-format-mp2t] … message topic … (archives)
+ + +
+
+ + +

+ Copyright + © + 2024 + + World Wide Web Consortium. + W3C® + liability, + trademark and + permissive document license rules apply. +

+
+
+

Abstract

+ This specification defines a Media Source Extensions™ [MEDIA-SOURCE] byte stream format specification based on MPEG-2 Transport Streams [MPEG2TS]. +
+ +

Status of This Document

This section describes the status of this + document at the time of its publication. A list of current W3C + publications and the latest revision of this technical report can be found + in the W3C technical reports index at + https://www.w3.org/TR/.

+

The working group maintains a list of all bug reports that the editors have not yet tried to address; + there may also be related open bugs in the GitHub repository of the Media Source Extensions™ specification.

+

+ This document was published by the Media Working Group as + an Editor's Draft. +

Publication as an Editor's Draft does not + imply endorsement by W3C and its Members.

+ This is a draft document and may be updated, replaced or obsoleted by other + documents at any time. It is inappropriate to cite this document as other + than work in progress. + +

+ + This document was produced by a group + operating under the + W3C Patent + Policy. + + + W3C maintains a + public list of any patent disclosures + made in connection with the deliverables of + the group; that page also includes + instructions for disclosing a patent. An individual who has actual + knowledge of a patent which the individual believes contains + Essential Claim(s) + must disclose the information in accordance with + section 6 of the W3C Patent Policy. + +

+ This document is governed by the + 03 November 2023 W3C Process Document. +

+ +

1. Introduction

+ +

This specification defines segment formats for implementations of Media Source Extensions™ [MEDIA-SOURCE] that choose to support MPEG-2 Transport Streams [MPEG2TS].

+

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™ specification. This document also defines extra behaviors and state that only apply to this byte stream format.

+
+ +

2. MIME-type info

+ +

The MIME-type/subtype pair of "video/MP2T", as specified in [RFC3551], MUST be used for byte streams that conform + to this specification.

+ +

The following parameter can be used in the MIME-type passed to isTypeSupported() or addSourceBuffer().

+
+
codecs
+
+ A comma separated list of codec IDs used to specify what codecs will be used in the byte stream. Implementations SHOULD accept IDs in the form specified by [RFC6381]. +
Note
Implementations MAY only implement a subset of the codecs and profiles mentioned in the RFC.
+
+
+
+ +

3. General Transport Stream Requirements

+ +

MPEG-2 TS media segments and initialization segments MUST conform to the MPEG-2 TS Adaptive Profile [MPEG2TS].

+ +

The user agent MUST run the append error algorithm if any of the following conditions are met:

+
    +
  1. Segments do not contain complete MPEG-2 TS packets.
    2. +
  2. Segments do not contain complete PES packets and sections.
    3. +
  3. Segments contain more than one program.
    4. +
  4. At least one MPEG-2 TS packet has a non-zero transport_error_indicator.
    5. +
+
+

4. Initialization Segments

+ +

An MPEG-2 TS initialization segment consists of a single PAT and a single PMT.

+

The user agent MUST run the append error algorithm if any of the following conditions are met:

+
    +
  1. A PAT is not present in the initialization segment
    2. +
  2. A PMT is not present in the initialization segment
    3. +
+ +

The user agent MUST accept and ignore other SI, such as CAT, that are invariant for all subsequent media segments.

+

The user agent MUST source attribute values for id, kind, label and language for AudioTrack, VideoTrack and + TextTrack objects as described for MPEG-2 Transport Streams in the in-band tracks spec [INBANDTRACKS].

+
+ +

5. Media Segments

+ + +

The user agent MUST run the append error algorithm if any of the following conditions are met:

+
    +
  1. A media segment relies on initialization information in another media segment.
    2. +
  2. At least one PES packet does not have a PTS timestamp.
    3. +
  3. PCR is not present in the Segment prior to the first byte of a TS packet payload containing media data.
    4. +
+ + The user agent will accept and ignore PSI that is identical to the information in the last initialization segment which may appear repeatedly throughout the segment. +
+ +

6. Random Access Points

+ +

A random access point as defined in this specification corresponds to Elementary Stream Random Access Point as defined in + [MPEG2TS].

+
+

7. Timestamp Rollover & Discontinuities

+ +

Timestamp rollovers and discontinuities MUST be handled by the UA. The UA's MPEG-2 TS implementation MUST maintain an internal offset + variable, MPEG2TS_timestampOffset, to keep track of the offset that needs to be applied to timestamps + that have rolled over or are part of a discontinuity. MPEG2TS_timestampOffset is initially set to 0 when the SourceBuffer is + created. This offset MUST be applied to the timestamps as part of the conversion process from MPEG-2 TS packets + into coded frames for the coded frame processing algorithm. This results in the coded frame timestamps + for a packet being computed by the following equations:

+ 
Coded Frame Presentation Timestamp = (MPEG-2 TS presentation timestamp) + MPEG2TS_timestampOffset
+Coded Frame Decode Timestamp = (MPEG-2 TS decode timestamp) + MPEG2TS_timestampOffset
+ +

MPEG2TS_timestampOffset is updated in the following ways:

+ +
+ +

8. Conformance

As well as sections marked as non-normative, all authoring guidelines, diagrams, examples, and notes in this specification are non-normative. Everything else in this specification is normative.

+ The key words MAY, MUST, and SHOULD in this document + are to be interpreted as described in + BCP 14 + [RFC2119] [RFC8174] + when, and only when, they appear in all capitals, as shown here. +

+ +

9. Acknowledgments

+ + The editors would like to thank + Alex Giladi, + Bob Lund, + David Singer, + Duncan Rowden, + Glenn Adams, + Mark Vickers, + and Michael Thornburgh for their contributions to this specification. +
+ + +

A. References

A.1 Normative references

+ +
[html]
+ HTML Standard. Anne van Kesteren; Domenic Denicola; Ian Hickson; Philip Jägenstedt; Simon Pieters. WHATWG. Living Standard. URL: https://html.spec.whatwg.org/multipage/ +
[INBANDTRACKS]
+ Sourcing In-band Media Resource Tracks from Media Containers into HTML. Silvia Pfeiffer; Bob Lund. W3C. 26 April 2015. Unofficial Draft. URL: https://dev.w3.org/html5/html-sourcing-inband-tracks/ +
[MEDIA-SOURCE]
+ Media Source Extensions™. Jean-Yves Avenard; Mark Watson. W3C. 4 July 2024. W3C Working Draft. URL: https://www.w3.org/TR/media-source-2/ +
[MPEG2TS]
+ Information technology — Generic coding of moving pictures and associated audio information — Part 1: Systems. ISO/IEC. December 2023. Published. URL: https://www.iso.org/standard/87619.html +
[RFC2119]
+ Key words for use in RFCs to Indicate Requirement Levels. S. Bradner. IETF. March 1997. Best Current Practice. URL: https://www.rfc-editor.org/rfc/rfc2119 +
[RFC3551]
+ RTP Profile for Audio and Video Conferences with Minimal Control. H. Schulzrinne; S. Casner. IETF. July 2003. Internet Standard. URL: https://www.rfc-editor.org/rfc/rfc3551 +
[RFC6381]
+ The 'Codecs' and 'Profiles' Parameters for "Bucket" Media Types. R. Gellens; D. Singer; P. Frojdh. IETF. August 2011. Proposed Standard. URL: https://www.rfc-editor.org/rfc/rfc6381 +
[RFC8174]
+ Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words. B. Leiba. IETF. May 2017. Best Current Practice. URL: https://www.rfc-editor.org/rfc/rfc8174 +
+
\ No newline at end of file