[foms] Proposal: adaptive streaming using open codecs

[Jeroen Wijering]

On Oct 18, 2010, at 5:49 PM, Steve Heffernan wrote:

>> So the bigger question is whether we would prefer codec selection inside the sources tags or inside the manifest.
> 
> Seems like inside the source tags would be the better route, so you don't have to parse the m3u8 file to check for compatibility.
> 
> i.e. videoElement.canPlayType("video/m3u8") wouldn't be reliable.

Yes, that makes sense. Although there's also a difference between, say, "video/webm" and "manifest/webm". The first plays in FF4.0, the latter not.

- Jeroen




>>>> User-agents
>>>> ===========
>>>> 
>>>> The root manifest serves as the single, unique reference point for a adaptive stream. Therefore, user agents need solely its URL to playback the stream.
>>>> 
>>>> Here's an example for loading a root manifest: through the *src* attribute of the <video> tag in an HTML page:
>>>> 
>>>>  <video width="480" height="270" src="http://example.com/video.m3u8">
>>>>    <a href="http://example.com/video_low.webm">Download the video</a>
>>>>  </video>
>>>> 
>>>> In this variation, the manifest is loaded through the <source> tag, to provide fallback logic:
>>>> 
>>>>  <video width="480" height="270" >
>>>>    <source src="http://example.com/video.m3u8" type="video/m3u8">
>>>>    <source src="http://example.com/video_low.webm" type="video/webm">
>>>>    <a href="http://example.com/video_low.webm">Download the video</a>
>>>>  </video>
>>> 
>>> Shouldn't the m3u8 file have the mime type of the video data being
>>> inside it? i.e. it should be type="video/webm" rather than
>>> "video/m3u8"? How would the browser otherwise know which m3u8 file to
>>> use for mp4, ogg or webm?
>> 
>> That could be. However, nothing seems to prevent a single M3U8 file from providing both WebM and M2TS quality levels. So the bigger question is whether we would prefer codec selection inside the sources tags or inside the manifest.
>> 
>> If an M3U8 file always contains a single container, I think it makes sense indeed to use video/webm.
>> 
>> Kind regards,
>> 
>> Jeroen
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