[Bug 22134] New: When do multiple SourceBuffers have to be used

https://www.w3.org/Bugs/Public/show_bug.cgi?id=22134

            Bug ID: 22134
           Summary: When do multiple SourceBuffers have to be used
    Classification: Unclassified
           Product: HTML WG
           Version: unspecified
          Hardware: PC
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Media Source Extensions
          Assignee: adrianba@microsoft.com
          Reporter: oipfjon@gmail.com
        QA Contact: public-html-bugzilla@w3.org
                CC: mike@w3.org, public-html-media@w3.org

The specification is unclear about when multiple SourceBuffers have to be used
(i.e. when using a single SourceBuffer will fail) and when they may be used
(i.e. using a single SourceBuffer will not fail but may not be recommended).

We request that this be clarified and that the clarification cover at least the
following scenarios;
1.    Video and audio are each delivered separately (e.g. DASH ISOBMFF content
where each representation contains only one media component).
2.    One video track and multiple audio tracks (e.g. multiple languages or
accessible audio) are each delivered separately (e.g. DASH ISOBMFF content
where each representation contains only one media component).
3.    The audio is encoded such that part of the audio it does not meet the
requirements of section 11 of MSE to form a single logical byte stream, e.g.
the audio in the main content is Dolby but a number of adverts are to be
inserted where the audio is HE-AAC. There are two variations on this, 
i) where the video during the adverts also does not meet the requirements of
section 11 and
ii) where the video during the adverts does meet the requirements of section
11.
4.    A new initialization segment is needed that has a different number and/or
type of tracks and/or different track IDs.
5.    The byte stream format changes, e.g. from MPEG-2 transport stream to ISO
BMFF or vice-versa.

NOTE: This issue arises from joint discussions between the Open IPTV Forum,
HbbTV and the UK DTG. These organizations originally sent a liaison statement
to the W3C Web & TV IG which is archived here;

https://lists.w3.org/Archives/Member/member-web-and-tv/2013Jan/0000.html (W3C
member only link)

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Received on Wednesday, 22 May 2013 14:09:17 UTC