- From: Bob Lund <B.Lund@CableLabs.com>
- Date: Wed, 8 Jun 2011 09:57:00 -0600
> -----Original Message----- > From: whatwg-bounces at lists.whatwg.org [mailto:whatwg- > bounces at lists.whatwg.org] On Behalf Of Eric Carlson > Sent: Wednesday, June 08, 2011 9:34 AM > To: Silvia Pfeiffer; Philip J?genstedt > Cc: whatwg at lists.whatwg.org > Subject: Re: [whatwg] Video feedback > > > 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. > > eric For commercial video providers, the tracks in a live stream change all the time; this is not limited to audio and video tracks but would include text tracks as well. Bob Lund
Received on Wednesday, 8 June 2011 08:57:00 UTC