[whatwg] How to handle multitrack media resources in HTML

Eric Carlson eric.carlson at apple.com
Mon Apr 11 08:55:51 PDT 2011

On Apr 10, 2011, at 12:36 PM, Mark Watson wrote:

> In the case of in-band tracks it may still be the case that they are retrieved independently over the network. This could happen two ways:
> - some file formats contain headers which enable precise navigation of the file, for example using HTTP byte ranges, so that the tracks could be retrieved independently. mp4 files would be an example. I don't know that anyone does this, though.

  QuickTime has supported tracks with external media samples in .mov files for more than 15 years. This type of file is most commonly used during editing, but they are occasionally found on the net.

> - in the case of adaptive streaming based on a manifest, the different tracks may be in different files, even though they appear as in-band tracks from an HTML perspective.
> In these cases it *might* make sense to expose separate buffer and network states for the different in-band tracks in just the same way as out-of-band tracks.

  I strongly disagree. Having different tracks APIs for different container formats will be extremely confusing for developers, and I don't think it will add anything. A UA that chooses to support non-self contained media files should account for all samples when reporting readyState and networkState.


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