[Libav-user] JPEG YUV->RGB

[Jeremy Mordkoff]

On Thu, 2011-05-12 at 18:09 +0400, Dmitriy K wrote:

> Is there any examples of this conversion? 
> I've found YUV_TO_RGB1 and YUV_TO_RGB2 in libavcodec/colorspace.h in documentation, but there is no this file in my system.
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here's a snippet from our code that does the conversion. Note how we
clamp the range from 0 to 255. Sorry about the integer math. Also be
careful as I'm not positive we're RGB...I have this vague recollection
that the next step in our process expects BGRA  data. Your mileage may
vary....


        res = ((Y * 1000) + (1574 * Pr)) / 1000;
        if ( res > 255 ) res = 255;
        if ( res < 0 ) res = 0;
        *(bufptr+(i*4))   = res;
        res = ((Y * 1000) - (187 * Pb) - (468 * Pr)) / 1000; 
        if ( res > 255 ) res = 255;
        if ( res < 0 ) res = 0;
        *(bufptr+(i*4)+1) = res;
        res = ((Y * 1000) + (1855 * Pb)) / 1000;
        if ( res > 255 ) res = 255;
        if ( res < 0 ) res = 0;
        *(bufptr+(i*4)+2) = res;

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