[MPlayer-dev-eng] [PATCH] vop eq2 with gamma correction

[Milan Cutka]

HH> Milan Cutka wrote:

>> > for (j = 0; j < h; j++) {
>> >    for (i = 0; i < w; i++) {
>> >      *(dst++) = lut[*(src++)];
>> >    }
>> > }
>> 
>> You could try this:
>> 
>> for (j = 0; j < h; j++) {
>>    for (i = 0; i < w; i+=4,src+=4,dst+=4) {
>>      *(unsigned int*)dst=
>>        (lut[src[3]]<<24)|(lut[src[2]]<<16)|(lut[src[1]]<<8)|lut[src[0]];
>>    }
>> }

HH> The problem is that this is highly non-portable. There are at least
HH> three issues here (endianness, alignment and sizeof(int)).

Sorry, but I've never needed to care about portability. Maybe I should
try to port some of ffdshow image filters to mplayer to learn that.

>> It works faster for me in ffdshow. Of course the best would be to add
>> some MMX optimizations, but I don't know how it would be possible to use MMX here.
>> For faster but not precise MMX optimized gamma correction look here:
>> http://www.stereopsis.com/polygamma.html.

HH> The main reason for me to use a LUT is that it is possible to combine
HH> multiple filters in a single LUT.

Maybe I will try this too in ffdshow.

    Milan