[daala] Curious about progress of codec

Jarek Duda dudajar at gmail.com
Wed Apr 27 18:41:41 UTC 2016

Ok, you are right here (I haven't thought that they have different 
statistics) ... I only wanted to express that anything is better than 
always starting with flat probability distribution.


On 16/04/27 19:49, Jean-Marc Valin wrote:
> On 04/27/2016 01:08 PM, Jarek Duda wrote:
>> Regarding using probability distribution from the last I-frame, I have
>> meant remembering probability distribution at the end of this I-frame
>> (not updated further) - additional buffer which is updated every
>> I-frame, P-frames use it as the initial probability distribution.
> While it would be technically possible to do that without hurting
> robustness to losses too much (what if you lost *part* of the keyframe),
> the main problem is that it likely wouldn't actually help either. The
> statistics of symbols on a keyframe are very very different from the
> statistics of those on a P-frame. Not to mention that keyframes don't
> have things like motion vectors which eat up a lot of the bits in P-frames.
> You *could* have the keyframe explicitly send initial probabilities for
> all subsequent P-frames, but it's a lot of work and it's not clear how
> much gain there would be. Not to mention that the statistics again
> change depending on how far your P-frame is from your keyframe.
> Cheers,
> 	Jean-Marc

dr Jarosław Duda
Institute of Computer Science and Computer Mathematics,
Jagiellonian University, Cracow, Poland

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