[foms] Proposal: adaptive streaming using open codecs

[James Courtier-Dutton]

>
> Conrad had related questions on the specification of chunks:
>
>> For at least Vorbis and Theora tracks in Ogg, including the headers to
>> make a valid file would require a complete copy of the codebooks,
>> adding ~3-4kB of overhead per track to the start of each chunk. I
>> assume this also applies to Vorbis in WebM (but not VP8?).
>>
>> We would also need to specify where in the available chunks global
>> information goes, such as Ogg Skeleton or Matroska Chapters, and how
>> (or if) to handle seek tables, cueing data etc.
>>
>> It might defeat some of the point of adaptive streaming to have
>> repeated information at the start of each chunk. Perhaps it would be
>> cheaper to just specify that chunks are a sequence of video frames
>> (ie. a sequence of pages/clusters beginning with a keyframe)?
> Perhaps somebody could setup a proposal for this side of the system? Are chained Ogg / WebM / ContainerX files indeed preferred? In the case of WebM, what would they look like? Would it still be possible for "smart servers" to parse a regular Ogg/WebM file and push out a chain-chunk on the fly? The latter is important for legacy content (no need to re-encode) and for simultaneous streaming/download offerings of a single file. 
>
> - Jeroen
Perhaps the manifest could contain two links.
One for the video metadata (i.e. codebooks, sequence start, video size
info for the decoder) and one for video stream itself.
This would allow the client to only download the codebooks once if the
url is the same for multiple chunks.
This would help with reducing the bandwidth for low bandwidth adaptive
streams.