[FFmpeg-devel] [PATCH] Binary identicity for ffvc1 (was Re: [PATCH] VC-1 MMX DSP functions)

Christophe GISQUET christophe.gisquet
Sun Jul 8 20:57:34 CEST 2007


Pascal Massimino a ?crit :
>   Hi everybody,
>  may i recall some remarks about compliance of the code you're presently
> optimizing?
> http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/2006-November/019051.html

Indeed, I tested with wmv dll decoder and the output (whether using
plain C or MMX) is different. Running tiny_psnr (not perfectly adapted
but...) on the reference (dll codec) and ffvc1 outputs, I got a standard
deviation of 0.5 and a PSNR of ~54dB.

And applying what you describe as the actual filtering process does
indeed fix the problem: for one file, output is binary identical to dll
codec output.

You'll find a patch against vc1dsp.c attached. That also means of course
I have to redo some of the MMX code.

Thanks for reminding us again, Pascal!

Best regards,
Christophe GISQUET
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