[foms] WebM Manifest

Jeroen Wijering jeroen at longtailvideo.com
Thu Mar 17 04:24:57 PDT 2011

On Mar 17, 2011, at 9:35 AM, Philip Jägenstedt wrote:

> My approximate solution for the low-level API is something like this:
> * XMLHttpRequest is used to get a data Blob for a resource.
> * We have some mechanism to concatenate several Blobs into a Stream object
> * setting video.src to the Stream object just works, similar to how video  
> conferencing is defined.
> What's missing here is to make XMLHttpRequest byte range aware, so that  
> one could do the kind of thing you mention above.

Do note a few additional JavaScript APIs are required in order for such a low level API to work:

*) Byte-level access to the data fetched using XMLHttpRequests. For example, to read and parse the seek index and to read and store the codec configurations.
*) A means to detect decoding load (e.g. CPU load, frames painted/dropped, pixel throughput), so processing constraints can be taken into account.

I'm not up to date with all functionalities XMLHttpRequests, but I presume there's events like initialization (to calculate latency) and progress (to calculate bandwidth)?

Next, the Stream API needs to be very strictly defined in terms of how provided A/V frames should be formatted, and how and when codec initialization data must be (re)sent.

Basically, javascript handles the demuxing. This would be a great API, allowing for much flexibility. At the same time, the amount of knowledge required for such an API would be so staggering (e.g. full understanding of video containers) that few people would be able to work with it. 

Kind regards,


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