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

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

--- Comment #6 from Cyril Concolato <cyril.concolato@telecom-paristech.fr> ---
(In reply to comment #3)
> Bytestream format changes are not allowed within a single SourceBuffer
> because when an application calls addSourceBuffer() to create a SourceBuffer
> it needs to specify the mimetype of the bytestream format it intends to
> append to the SourceBuffer object. Obviously MPEG-2 TS data does not conform
> to ISOBMFF bytestream spec rules so you can expect a changing to MPEG2 TS in
> a SourceBuffer created for ISOBMFF would trigger a decode error in step 2 of
> the Segment Parser Loop. If you need to support different bytestreams then
> you need to use seperate SourceBuffers for that.
> 
> I hope this clarifies things.
Actually, the spec isn't very clear about that. In Segment Parser Loop it says:
"If the input buffer starts with bytes that violate the byte stream format
specifications, then run the end of stream algorithm with the error parameter
set to "decode" and abort this algorithm."
Note the 's' at the end of "byte stream format specifications". So strictly
speaking, MPEG-2 TS could be allowed in an ISO BMF SourceBuffer. This should
probably be fixed. 

Additionally, the MIME type provided to the addSourceBuffer call is never
referred to. The fix should probably mention it. 

Also, it is unclear if the codec parameters passed to the addSourceBuffer call
(in any) should be used to reject input data in the Segment Parser Loop (i.e.
if initialization segments declaring additional tracks compared to what was
passed to the addSourceBuffer call should be accepted).

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Received on Tuesday, 11 June 2013 13:25:06 UTC