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[Bug 18921] New: append(data) should accept any part of media segment

From: <bugzilla@jessica.w3.org>
Date: Wed, 19 Sep 2012 19:03:50 +0000
To: public-html-media@w3.org
Message-ID: <bug-18921-5436@http.www.w3.org/Bugs/Public/>
https://www.w3.org/Bugs/Public/show_bug.cgi?id=18921

           Summary: append(data) should accept any part of media segment
           Product: HTML WG
           Version: unspecified
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Media Source Extensions
        AssignedTo: adrianba@microsoft.com
        ReportedBy: whadar@gmail.com
         QAContact: public-html-bugzilla@w3.org
                CC: mike@w3.org, public-html-media@w3.org


>From step 6 of the append method, as defined in the spec:
If data is part of a media segment and timestampOffset is not 0:
1.Find all timestamps inside data and add timestampOffset to them.
2.If any of the modified timestamps are earlier than the presentation start
time, then call endOfStream("decode"), and abort these steps.
3.Copy the contents of data, with the modified timestamps, into the source
buffer.

The definition of "part of a media segment" have several conditions that needs
to be addressed. In particular, a part of a media segment that is not
continuous to a previously appended buffer.

In seeking scenario, after the current source buffer is aborted, a user might
append a buffer which is not a beginning of a segment. In that case, the
browser should discard all the bytes that are prior to a beginning of a
segment. This will protect the playback from failing. In some cases, there can
be several "small" appends which are part of previous segment which should all
be discarded, until the append of buffer the contain the start of a segment.

Without that, js developers must employ parsers to have the accurate offset of
all segments.

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Received on Wednesday, 19 September 2012 19:03:52 GMT

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