[FFmpeg-devel] [PATCH] ljpegdec: support non zero MCU for RGB.

[Michael Niedermayer]

Fixes Ticket875

Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
---
 libavcodec/mjpegdec.c |   17 +++++++++++++----
 1 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/libavcodec/mjpegdec.c b/libavcodec/mjpegdec.c
index 7c27f5d..be7ad83 100644
--- a/libavcodec/mjpegdec.c
+++ b/libavcodec/mjpegdec.c
@@ -684,24 +684,28 @@ static int ljpeg_decode_rgb_scan(MJpegDecodeContext *s, int nb_components, int p
     int left[3], top[3], topleft[3];
     const int linesize= s->linesize[0];
     const int mask= (1<<s->bits)-1;
+    int resync_mb_y= 0;
+    int resync_mb_x= 0;
 
     av_fast_malloc(&s->ljpeg_buffer, &s->ljpeg_buffer_size, (unsigned)s->mb_width * 4 * sizeof(s->ljpeg_buffer[0][0]));
     buffer= s->ljpeg_buffer;
 
-    for(i=0; i<3; i++){
-        buffer[0][i]= 1 << (s->bits - 1);
-    }
     for(mb_y = 0; mb_y < s->mb_height; mb_y++) {
-        const int modified_predictor= mb_y ? predictor : 1;
         uint8_t *ptr = s->picture.data[0] + (linesize * mb_y);
 
         if (s->interlaced && s->bottom_field)
             ptr += linesize >> 1;
 
         for(i=0; i<3; i++){
+            if(mb_y == resync_mb_y || mb_y == resync_mb_y+1 && 0 < resync_mb_x)
+                buffer[0][i]= 1 << (s->bits - 1);
             top[i]= left[i]= topleft[i]= buffer[0][i];
         }
         for(mb_x = 0; mb_x < s->mb_width; mb_x++) {
+            int modified_predictor = predictor;
+            if(mb_y == resync_mb_y || mb_y == resync_mb_y+1 && mb_x < resync_mb_x)
+                modified_predictor = 1;
+
             if (s->restart_interval && !s->restart_count)
                 s->restart_count = s->restart_interval;
 
@@ -724,6 +728,11 @@ static int ljpeg_decode_rgb_scan(MJpegDecodeContext *s, int nb_components, int p
             if (s->restart_interval && !--s->restart_count) {
                 align_get_bits(&s->gb);
                 skip_bits(&s->gb, 16); /* skip RSTn */
+                resync_mb_x = mb_x;
+                resync_mb_y = mb_y;
+                for(i=0; i<3; i++){
+                    top[i]= left[i]= topleft[i]= 1 << (s->bits - 1);
+                }
             }
         }
 
-- 
1.7.5.4