Hi, On Sun, Dec 4, 2011 at 11:15 AM, Derek Buitenhuis < [email protected]> wrote:
> On 04/12/2011 2:03 PM, Kostya Shishkov wrote: > >> It's better to amend the entry with ProRes decoder (also notice the >> capitalisation) IMO. >> > > All right. > > > For the record I find it hard to believe it's a real name and not a >> pseudonym. >> Actually I sent a letter to the author asking about it (got no reply >> though). >> > > Ir most probably is a pseudonym, but I do not think that should > stop Libav from having it. A ProRes encoder is something that's > -very- beneficial, IMO. > > > > this can be shared between decoder and encoder >> > > Okay. > > > makes me wonder where those matrices come from >> > > Well it IS a reverse engineered codec... > They're made up. The codec allows setting custom qmats in the frame header. A good encoder will do some sort of rate distortion optimization to find the best quantizers for each coefficient index in the 8x8 square that gives best quality for the requested compression (or the other way around). This one just hardcodes 4 profiles with fixed quantizer tables, which is a little bit lame. Reminds me of Mike's VP8 encoder [1][2]. Ronald [1] http://multimedia.cx/eggs/the-big-vp8-debug/ [2] http://multimedia.cx/eggs/the-worst-vp8-encoder/
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