[FFmpeg-trac] #8871(swscale:new): swsscale crops image on yuv2rgb

[FFmpeg]

#8871: swsscale crops image on yuv2rgb
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             Reporter:  xlp      |                     Type:  defect
               Status:  new      |                 Priority:  normal
            Component:  swscale  |                  Version:  unspecified
             Keywords:           |               Blocked By:
             Blocking:           |  Reproduced by developer:  0
Analyzed by developer:  0        |
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 Summary of the bug:
 swscale leaves a small right portion of the image out on yuv2rgb
 conversion. aka "crops it", so a bar of the destination-image on right
 side stays unwritten. this seems to effect only certain
 resolutions/linesizes - below is one given that seems to cause issues

 How to reproduce:
 {{{
 // HAS NO ISSUES
 // int32_t width = 1600;
 // int32_t height = 900;
 // int srcLinesize[8] = {1664, 832, 832, 0, 0, 0, 0, 0};

 // HAS ISSUES
 int32_t width = 1220;
 int32_t height = 1200;
 int srcLinesize[8] = {1280, 640, 640, 0, 0, 0, 0, 0};

 struct SwsContext* sws_scaler_ctx = sws_getContext(width, height,
 AV_PIX_FMT_YUV420P,
                                 width, height, AV_PIX_FMT_RGB0,
                                 SWS_FAST_BILINEAR, 0, 0, 0);

 size_t destBufferSize = width * 4 * height;
 uint8_t* destBuffer = (uint8_t*) malloc(destBufferSize);
 memset(destBuffer, 0x00, destBufferSize);
 uint8_t* destLines[4] = {destBuffer, 0, 0, 0};
 int destData[4] = {width * 4, 0, 0, 0};

 // Make a dummy source with green footage
 uint8_t* srcData[8];
 for (int i = 0; i < 8; i++) {
     if (srcLinesize[i] > 0) {
         size_t srcBufferSize = srcLinesize[i]*height;
         srcData[i] = (uint8_t*) malloc(srcBufferSize);
         memset(srcData[i], 0x00, srcBufferSize);
     } else {
         srcData[i] = 0x00;
     }
 }

 sws_scale(sws_scaler_ctx, (const uint8_t* const*)srcData, srcLinesize, 0,
 height, destLines, destData);
 }}}

 Produced Result:

 Green area with unwritten gap at the right side (here in the size of
 4x1200)

 Expected result:

 Completely green area, as the provided YUV source contains

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Ticket URL: <https://trac.ffmpeg.org/ticket/8871>
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