fix mjpega bitfilter when dht, dqt, sof0 are not ordered as expected, patch by Jay Freeman, saurik at saurik com

Originally committed as revision 16074 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/mjpega_dump_header_bsf.c

@@ -35,6 +35,7 @@ static int mjpega_dump_header(AVBitStreamFilterContext *bsfc, AVCodecContext *av
                               const uint8_t *buf, int buf_size, int keyframe)
 {
     uint8_t *poutbufp;
+    unsigned dqt = 0, dht = 0, sof0 = 0;
     int i;
 
     if (avctx->codec_id != CODEC_ID_MJPEG) {
@@ -59,12 +60,13 @@ static int mjpega_dump_header(AVBitStreamFilterContext *bsfc, AVCodecContext *av
     for (i = 0; i < buf_size - 1; i++) {
         if (buf[i] == 0xff) {
             switch (buf[i + 1]) {
-            case DQT:  /* quant off */
+            case DQT:  dqt  = i + 46; break;
-            case DHT:  /* huff  off */
+            case DHT:  dht  = i + 46; break;
-            case SOF0: /* image off */
+            case SOF0: sof0 = i + 46; break;
-                bytestream_put_be32(&poutbufp, i + 46);
-                break;
             case SOS:
+                bytestream_put_be32(&poutbufp, dqt); /* quant off */
+                bytestream_put_be32(&poutbufp, dht); /* huff off */
+                bytestream_put_be32(&poutbufp, sof0); /* image off */
                 bytestream_put_be32(&poutbufp, i + 46); /* scan off */
                 bytestream_put_be32(&poutbufp, i + 46 + AV_RB16(buf + i + 2)); /* data off */
                 bytestream_put_buffer(&poutbufp, buf + 2, buf_size - 2); /* skip already written SOI */