Underflow in YUV to RGB conversion

[Memotech-Bill]

In routine parse_im (file "video_capture.c") you protect against the calculated values of RGB being greater than 255, and clip them to this maximum value. However you do not protect against them going negative (which can happen in dark areas of the image).

The code needs to be extended as:

        if(B > UCHAR_MAX){
            B = UCHAR_MAX;
        } else if(B < 0){
            B = 0;
        }
        if(G > UCHAR_MAX){
            G = UCHAR_MAX;
        } else if(G < 0){
            G = 0;
        }
        if(R > UCHAR_MAX){
            R = UCHAR_MAX;
        } else if(R < 0){
            R = 0;
        }