jpegdec: better rst skiping

Fixes Ticket426

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit 94c2478d90c1b8c007591b8daba13e65d393d2e8)

1 files changed, 8 insertions, 4 deletions

diff --git a/libavcodec/mjpegdec.c b/libavcodec/mjpegdec.c
index 5c6d84a07d..cb5bc2387f 100644
--- a/libavcodec/mjpegdec.c
+++ b/libavcodec/mjpegdec.c
@@ -881,14 +881,18 @@ static int mjpeg_decode_scan(MJpegDecodeContext *s, int nb_components, int Ah, i
                 }
             }
 
+            if (s->restart_interval) --s->restart_count;
             if (s->restart_interval && show_bits(&s->gb, 8) == 0xFF){ /* skip RSTn */
-                --s->restart_count;
+                int pos= get_bits_count(&s->gb);
                 align_get_bits(&s->gb);
                 while(show_bits(&s->gb, 8) == 0xFF)
                     skip_bits(&s->gb, 8);
-                skip_bits(&s->gb, 8);
-                for (i=0; i<nb_components; i++) /* reset dc */
-                    s->last_dc[i] = 1024;
+                if((get_bits(&s->gb, 8)&0xF8) == 0xD0){
+                    for (i=0; i<nb_components; i++) /* reset dc */
+                        s->last_dc[i] = 1024;
+                }else{
+                    skip_bits_long(&s->gb, pos - get_bits_count(&s->gb));
+                }
             }
         }
     }