[whatwg] <source>s in <video> by quality as well as codec

Silvia Pfeiffer silviapfeiffer1 at gmail.com
Wed Jun 6 01:32:05 PDT 2012

I believe right now there are two proposals under discussion that are
trying to address the adaptive streaming issues:

I believe both are still somewhat at the experimental level and need
harmonization, but they are both being worked on at the W3C.



On Wed, Jun 6, 2012 at 8:23 AM, Charles Pritchard <chuck at jumis.com> wrote:
> On Jun 5, 2012, at 2:54 PM, Ian Hickson <ian at hixie.ch> wrote:
>> On Tue, 21 Feb 2012, Rodger Combs wrote:
>>> I propose that <source> add a quality, bitrate, or filesize attribute to
>>> allow the UA to decide between multiple streams by choosing the maximum
>>> quality file that it can download within a reasonable amount of time
>>> (e.g. it will download faster than it will play) or based on a user
>>> preference (e.g. prefer SD quality, or always use HD when provided). It
>>> should also be possible to retrieve a list of the <source>s the UA can
>>> play in JS, and switch between them by user action (either a JS call for
>>> a custom UI or a dropdown in the builtin UI), loading the new file and
>>> switching to it with minimal skipping. This way, a site like YouTube,
>>> which presents several files in various bitrates and codecs, can allow
>>> the user to choose to use a higher quality without having to force an
>>> src attribute on the video, and a mobile UA that roams from 3G to WiFi
>>> or moves close to a base station can increase the quality of its stream.
>>> I think it fits in well with the purpose of the source element. This is
>>> certainly open for modification, but I think it's a good concept in
>>> essence.
>> If this is for a site like YouTube, I think an adaptive network channel
>> would be a more effective solution (i.e. one where the download adapts in
>> real time to changing network conditions, with the endpoints negotiating
>> with each other regarding what to transmit).
> I'd like to see strawman proposals for resource description markup.
> Presently, magnet+BitTorrent is the only mature and implemented tech in this field that I've found with wide support. And it's not even meant for adaptive streaming.
> I know that markup for subtitles happened in this group. I'd like to see an effort for markup for resources, with the same experimental atmosphere.
> The hope being that we can copy and paste some kind of text markup which describes various endpoints and metadata sufficient for streaming strategies for media.
> -Charles

More information about the whatwg mailing list