[foms] Proposal: adaptive streaming using open codecs

[Steve Heffernan]

Ah, good point. I like the "manifest/webm" approach, or basically a Type attribute where you could know that it's a manifest and whether or not the referenced files are compatible.

<source src="video.m3u8" type='manifest/webm; codecs="vp8, vorbis"'>

Though the mime type I see being used for m3u8 files in apple streaming is application/x-mpegURL, so not sure how that comes into play.

On Oct 18, 2010, at 11:23 AM, Jeroen Wijering wrote:

> 
> 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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>> 
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