[Bug 18642] Handle timestamp overflow in append(data)

https://www.w3.org/Bugs/Public/show_bug.cgi?id=18642

Bob Lund <b.lund@cablelabs.com> changed:

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--- Comment #3 from Bob Lund <b.lund@cablelabs.com> 2012-08-28 21:44:12 UTC ---
(In reply to comment #0)
> http://dvcs.w3.org/hg/html-media/raw-file/tip/media-source/media-source.html#dom-append
> 
> There's already a check to trigger MEDIA_ERR_DECODE when any modified timestamp
> would underflow (< 0) but nothing about how to handle overflow. This is
> particularly likely with 32-bit timestamp fields, but can of course happen
> regardlessly.
> 
> Suggestion: If any modified timestamp would overflow in the representation used
> in the byte stream, trigger a MEDIA_ERR_DECODE.
> 
> In addition, the byte stream specs could place the necessary requirements to
> make this situation as unlikely as possible.

The MPEG-2 TS Presentation Time Stamp and Decode Time Stamp fields are 33bit
counts of a 90KHz clock, which will rollover every 26.5 hours. This is a normal
event in a linear (e.g. broadcast) video channel. This does not represent a
decode error.

It is not clear if/how a receiver could make this situation unlikely while
still remaining compliant with the transport stream specification.

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Received on Tuesday, 28 August 2012 21:44:13 UTC