[whatwg] Video feedback

Eric Carlson eric.carlson at apple.com
Wed Jun 8 08:33:53 PDT 2011

On Jun 8, 2011, at 3:35 AM, Silvia Pfeiffer wrote:

>> Nothing exposed via the current API would change, AFAICT.
> Thus, after a change mid-stream to, say,  a smaller video width and
> height, would the video.videoWidth and video.videoHeight attributes
> represent the width and height of the previous stream or the current
> one?
>> I agree that if we
>> start exposing things like sampling rate or want to support arbitrary
>> chained Ogg, then there is a problem.
> I think we already have a problem with width and height for chained
> Ogg and we cannot stop people from putting chained Ogg into the @src.
> I actually took this discussion away from MPEG PTM, which is where
> Eric's question came from, because I don't understand how it works
> with MPEG. But I can see that it's not just a problem of MPEG, but
> also of Ogg (and possibly of WebM which can have multiple Segments).
> So, I think we need a generic solution for it.
  The characteristics of an Apple HTTP live stream can change on the fly. For example if the user's bandwidth to the streaming server changes, the video width and height can change as the stream resolution is switched up or down, or the number of tracks can change when a stream switches from video+audio to audio only. In addition, a server can insert segments with different characteristics into a stream on the fly, eg. inserting an ad or emergency announcement.

  It is not possible to predict these changes before they occur.


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