[Bug 22139] New: MSE and ISOBMFF interoperability

https://www.w3.org/Bugs/Public/show_bug.cgi?id=22139

            Bug ID: 22139
           Summary: MSE and ISOBMFF interoperability
    Classification: Unclassified
           Product: HTML WG
           Version: unspecified
          Hardware: PC
                OS: Windows NT
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Media Source Extensions
          Assignee: adrianba@microsoft.com
          Reporter: cyril.concolato@telecom-paristech.fr
        QA Contact: public-html-bugzilla@w3.org
                CC: mike@w3.org, public-html-media@w3.org

MSE requires that media segments use the "default-base-is-moof" flag in the
movie fragment. However, conformant ISOBMF parsers require that an ftyp box
with a compatible brand 'iso5' be declared to process the flag. While MSE ISO
parsers can be modified to assume that a correct ftyp has been declared (or
modified to ignore that rule), this can create ISO interoperability problems if
MSE byte streams are stored in files. A conformant ISO parser will have no
means to tell if the file is the result of storing an MSE byte stream or if it
is an ISO v1 file (no ftyp). An ISO validator might also declare the file
invalid.

To avoid these interoperability problems, MSE should:
- define a brand for initialization segments and media segments (e.g. msei,
msem)
- recommend that an ftyp (with the right brand) be added if an MSE
initialization segment byte streams is stored in a file
- recommend that if an MSE media segment is stored in a file, and if an styp
box is used, that the styp box uses the above brand

No change to the MSE parsing behavior is required.

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Received on Wednesday, 22 May 2013 15:04:35 UTC