[theora] Theora/Thusnelda features questions.

Christopher Blizzard blizzard at mozilla.com
Thu Jul 23 17:44:21 PDT 2009


On 7/23/2009 9:57 AM, xiphmont at xiph.org wrote:
>> >  It is said that Theora performs really well with low-resolution
>> >  content, but less with high-def content. How and why is Theora's
>> >  performance related to the size of the video? Is it an aspect of the
>> >  Theora spec (or of the VP3 spec), or is this caused by the
>> >  implementation?
>>      
>
> The two biggest reasons Theora is said to be best for low res content
> is becasue Theora's maximum motion vector size is relatively small
> (+/-31 halfpel) and the minimum quantizer of DCT coefficients
> relatively coarse compared to codecs designed for HD.
To the untrained eye these seem like knobs that could be adjusted pretty 
easily, but maybe with changes to the format.  Would they need changes 
to the Theora format (i.e. a Theora 2) to bridge the gap to HD content?

--Chris
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