[theora-dev] Theora Decoder

xiphmont at xiph.org xiphmont at xiph.org
Thu Apr 24 23:04:14 PDT 2008

On Fri, Apr 25, 2008 at 1:27 AM, Asanka Dilruk <adilruk at gmail.com> wrote:
> Theora can encode video with several quality parameters. So when that
> encoded video is decoding it should be looked at quality value. For a single
> video, decoder get first frame quality value for all video frame or decoder
> get each quality value for each frame?

Each frame transmits and uses up to three different qi (quantizer
indexes) pre frame.  The macroblocks in each frame may use any of the
three transmitted values.

The qi are not really 'quality' parameters, although they are chosen
by the encoder to implement the requested quality constraint.  The
quality and bitrate constraints may change from frame to frame.


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