W3C home > Mailing lists > Public > whatwg@whatwg.org > April 2007

[whatwg] on codecs in a 'video' tag.

From: Dave Singer <singer@apple.com>
Date: Mon, 2 Apr 2007 13:33:19 -0700
Message-ID: <p06230924c237184ca7cb@[]>
At 22:27  +0200 2/04/07, Maik Merten wrote:
>Dave Singer schrieb:
>>  are you telling us that all implementations of Ogg and Theora can play
>>  audio and video up to any bitrate, screensize, channel count etc.,
>>  without dropping frames, getting behind, decoding badly, or other
>>  limits?   That would be quite an achievement...more impressive than
>>  getting a quart out of a pint pot...
>I'd bet that no MPEG implementation can play audio and video up to any
>bitrate, screensize, channel count etc. either - the profiles which
>define different sets of coding features definately add to the
>interoperability complexity in a different way than those factors.

You miss the point.  MPEG defines levels exactly so that bitstreams 
can say "you need to be level X to be able to play this" and players 
can implement "up to level X" and interoperability is well-defined 
and assured.  Levels *improve* the interoperability, not make it 
worse.  Without formal level definitions, you never know for sure 
what you can 'get away with' in your encodings if you want it to play 
on a set of devices.

David Singer
Apple Computer/QuickTime
Received on Monday, 2 April 2007 13:33:19 UTC

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