[whatwg] Video playback quality metric

Michael A. Puls II shadow2531 at gmail.com
Tue Feb 10 01:54:18 PST 2009

On Tue, 10 Feb 2009 04:38:01 -0500, James Graham <jgraham at opera.com> wrote:

> Jeremy Doig wrote:
>> Measuring the rate at which the playback buffer is filling/emptying  
>> gives a
>> fair indication of network goodput, but there does not appear to be a  
>> way to
>> measure just how well the client is playing the video itself. If I have  
>> a
>> wimpy machine behind a fat network connection, you may flood me with HD  
>> that
>> I just can't play very well. The cpu or video card may just not be able  
>> to
>> render the video well.Exposing a metric (eg: Dropped Frame count,  
>> rendered
>> frame rate) would allow sites to dynamically adjust the video which is  
>> being
>> sent to a client [eg: switch the url to a differently encoded file] and
>> thereby optimize the playback experience.
>> Anyone else think this would be good to have ?
> It seems like, in the short term at least, the "worse is better"  
> solution to this problem is for content providers to provide links to  
> resources at different quality levels, and allow users to choose the  
> most appropriate resource based on their internet connection and their  
> computer rather than having the computer try to work it out for them.  
> Assuming that the majority of users use a relatively small number of  
> sites with the resources to provide multiple-quality versions of their  
> videos and use a small number of computing devices with roughly  
> unchanging network conditions (I imagine this scenario applies to the  
> majority of non-technical), they will quickly learn which versions of  
> the media works best for them on each site. Therefore the burden of this  
> simple approach on end users does not seem to be very high.
> Given this, I would prefer automatic quality negotiation be deferred to  
>   HTML6.

Flash has low, medium and high quality that the user can change (although a lot of sites/players seem to rudely disable that option in the menu for some reason). This helps out a lot and can allow a video to play better. I could imagine an "Auto" option too that automatically switched quality as necessary to get decent playback.

As an event, a site could use it like:

video.onplaybacktooslow = function() {
    this.quality = "low";
    this.setToNativeSize(); // stretched videos use more cpu

Or, something like that.


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