support decoding of the last mpeg "packet" even if no startcode is immedeatly...

support decoding of the last mpeg "packet" even if no startcode is immedeatly afterwards (fixes bugs with mpeg in avi)
new behavior is only activated if CODEC_FLAG_NOT_TRUNCATED is set

Originally committed as revision 909 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/avcodec.h

@@ -119,6 +119,7 @@ static const int Motion_Est_QTab[] = { ME_ZERO, ME_PHODS, ME_LOG,
 #define CODEC_FLAG_GRAY  0x2000  /* only decode/encode grayscale */
 #define CODEC_FLAG_EMU_EDGE 0x4000/* dont draw edges */
 #define CODEC_FLAG_DR1    0x8000 /* dr1 */
+#define CODEC_FLAG_NOT_TRUNCATED  0x00010000 /* input bitstream is not truncated, except before a startcode */
 /* codec capabilities */
 
 /* decoder can use draw_horiz_band callback */

libavcodec/mpeg12.c

@@ -584,7 +584,7 @@ static VLC mb_ptype_vlc;
 static VLC mb_btype_vlc;
 static VLC mb_pat_vlc;
 
-void mpeg1_init_vlc(MpegEncContext *s)
+static void init_vlcs(MpegEncContext *s)
 {
     static int done = 0;
 
@@ -1260,6 +1260,7 @@ static int mpeg_decode_init(AVCodecContext *avctx)
     
     s->mpeg_enc_ctx.flags= avctx->flags;
     common_init(&s->mpeg_enc_ctx);
+    init_vlcs(&s->mpeg_enc_ctx);
 
     s->header_state = 0xff;
     s->mpeg_enc_ctx_allocated = 0;
@@ -1468,7 +1469,7 @@ static int mpeg_decode_slice(AVCodecContext *avctx,
 
     start_code = (start_code - 1) & 0xff;
     if (start_code >= s->mb_height){
-        fprintf(stderr, "slice below image\n");
+        fprintf(stderr, "slice below image (%d >= %d)\n", start_code, s->mb_height);
         return -1;
     }
     s->last_dc[0] = 1 << (7 + s->intra_dc_precision);
@@ -1590,7 +1591,6 @@ static int mpeg1_decode_sequence(AVCodecContext *avctx,
         
         if (MPV_common_init(s) < 0)
             return -1;
-        mpeg1_init_vlc(s);
         s1->mpeg_enc_ctx_allocated = 1;
     }
 
@@ -1711,7 +1711,17 @@ static int mpeg_decode_frame(AVCodecContext *avctx,
         } else {
             memcpy(s->buf_ptr, buf_start, len);
             s->buf_ptr += len;
-            
+            if(   (s2->flags&CODEC_FLAG_NOT_TRUNCATED) && (!start_code_found) 
+               && s->buf_ptr+4<s->buffer+s->buffer_size){
+                start_code_found= 1;
+                code= 0x1FF;
+                s->header_state=0xFF;
+                s->buf_ptr[0]=0;
+                s->buf_ptr[1]=0;
+                s->buf_ptr[2]=1;
+                s->buf_ptr[3]=0xFF;
+                s->buf_ptr+=4;
+            }
             if (start_code_found) {
                 /* prepare data for next start code */
                 input_size = s->buf_ptr - s->buffer;