[FFmpeg-devel] [PATCH] lavfi: port mcdeint filter from libmpcodecs

[Stefano Sabatini]

On date Thursday 2013-05-30 15:36:08 +0200, Stefano Sabatini encoded:
[...]
> Updated mcdeint patch. I tracked the inconsistent output to
> uninitialiazed buffer reading which happens in the CHECK(j) macro:
> 
> #define CHECK(j)\
>     {   int score = FFABS(srcp[-srcs-1+(j)] - srcp[+srcs-1-(j)]) +\
>                     FFABS(srcp[-srcs  +(j)] - srcp[+srcs  -(j)]) +\
>                     FFABS(srcp[-srcs+1+(j)] - srcp[+srcs+1-(j)]);\
>         if (score < spatial_score) {\
>             spatial_score = score;\
>             diff0 = filp[-fils+(j)] - srcp[-srcs+(j)];\
>             diff1 = filp[+fils-(j)] - srcp[+srcs-(j)];
> 
> which is reading padded data if x<2 && x>=w-2, and out-of-buffer data
> in case x=2 and y=1 or x=w-3 and y=h-1.
> 
> A possible way to fix it would be to change:
> -                    if((x-2)+(y-1)*w>=0 && (x+2)+(y+1)*w<w*h){ //FIXME either alloc larger images or optimize this
> +                    if(y>0 && y<h-1 && x>2 && x<w-3){
> 
> but Michael suggested to adopt the same logic used in yadif. I suspend
> my port of mcdeint until the problem is fixed in libmpcodecs.
> 
> Note: CHECK(j) macro restored to initial form for consistency with
> yadif code.

Patch update mirroring the same fix in the mp/mcdeint patch. Now
mcdeint and mp=mcdeint are bit-exact equivalent, and native mcdeint
performs faster.

I'll push the port and drop the wrapper at the same time as the
mcdeint fix is approved&committed.
-- 
FFmpeg = Freak & Fast Multipurpose Perfectionist Elected Gadget
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