avidec: Factor out the sync fucntionality.

libavformat/avidec.c

@@ -836,13 +836,137 @@ static int get_stream_idx(int *d){
     }
 }
 
-static int avi_read_packet(AVFormatContext *s, AVPacket *pkt)
+static int avi_sync(AVFormatContext *s)
 {
     AVIContext *avi = s->priv_data;
     AVIOContext *pb = s->pb;
     int n, d[8];
     unsigned int size;
     int64_t i, sync;
+
+start_sync:
+    memset(d, -1, sizeof(int)*8);
+    for(i=sync=avio_tell(pb); !pb->eof_reached; i++) {
+        int j;
+
+        for(j=0; j<7; j++)
+            d[j]= d[j+1];
+        d[7]= avio_r8(pb);
+
+        size= d[4] + (d[5]<<8) + (d[6]<<16) + (d[7]<<24);
+
+        n= get_stream_idx(d+2);
+//av_log(s, AV_LOG_DEBUG, "%X %X %X %X %X %X %X %X %"PRId64" %d %d\n", d[0], d[1], d[2], d[3], d[4], d[5], d[6], d[7], i, size, n);
+        if(i + (uint64_t)size > avi->fsize || d[0]<0)
+            continue;
+
+        //parse ix##
+        if(  (d[0] == 'i' && d[1] == 'x' && n < s->nb_streams)
+        //parse JUNK
+           ||(d[0] == 'J' && d[1] == 'U' && d[2] == 'N' && d[3] == 'K')
+           ||(d[0] == 'i' && d[1] == 'd' && d[2] == 'x' && d[3] == '1')){
+            avio_skip(pb, size);
+//av_log(s, AV_LOG_DEBUG, "SKIP\n");
+            goto start_sync;
+        }
+
+        //parse stray LIST
+        if(d[0] == 'L' && d[1] == 'I' && d[2] == 'S' && d[3] == 'T'){
+            avio_skip(pb, 4);
+            goto start_sync;
+        }
+
+        n= get_stream_idx(d);
+
+        if(!((i-avi->last_pkt_pos)&1) && get_stream_idx(d+1) < s->nb_streams)
+            continue;
+
+        //detect ##ix chunk and skip
+        if(d[2] == 'i' && d[3] == 'x' && n < s->nb_streams){
+            avio_skip(pb, size);
+            goto start_sync;
+        }
+
+        //parse ##dc/##wb
+        if(n < s->nb_streams){
+            AVStream *st;
+            AVIStream *ast;
+            st = s->streams[n];
+            ast = st->priv_data;
+
+            if(s->nb_streams>=2){
+                AVStream *st1  = s->streams[1];
+                AVIStream *ast1= st1->priv_data;
+                //workaround for broken small-file-bug402.avi
+                if(   d[2] == 'w' && d[3] == 'b'
+                   && n==0
+                   && st ->codec->codec_type == AVMEDIA_TYPE_VIDEO
+                   && st1->codec->codec_type == AVMEDIA_TYPE_AUDIO
+                   && ast->prefix == 'd'*256+'c'
+                   && (d[2]*256+d[3] == ast1->prefix || !ast1->prefix_count)
+                  ){
+                    n=1;
+                    st = st1;
+                    ast = ast1;
+                    av_log(s, AV_LOG_WARNING, "Invalid stream + prefix combination, assuming audio.\n");
+                }
+            }
+
+
+            if(   (st->discard >= AVDISCARD_DEFAULT && size==0)
+               /*|| (st->discard >= AVDISCARD_NONKEY && !(pkt->flags & AV_PKT_FLAG_KEY))*/ //FIXME needs a little reordering
+               || st->discard >= AVDISCARD_ALL){
+                ast->frame_offset += get_duration(ast, size);
+                avio_skip(pb, size);
+                goto start_sync;
+            }
+
+            if (d[2] == 'p' && d[3] == 'c' && size<=4*256+4) {
+                int k = avio_r8(pb);
+                int last = (k + avio_r8(pb) - 1) & 0xFF;
+
+                avio_rl16(pb); //flags
+
+                for (; k <= last; k++)
+                    ast->pal[k] = avio_rb32(pb)>>8;// b + (g << 8) + (r << 16);
+                ast->has_pal= 1;
+                goto start_sync;
+            } else if(   ((ast->prefix_count<5 || sync+9 > i) && d[2]<128 && d[3]<128) ||
+                         d[2]*256+d[3] == ast->prefix /*||
+                         (d[2] == 'd' && d[3] == 'c') ||
+                         (d[2] == 'w' && d[3] == 'b')*/) {
+
+//av_log(s, AV_LOG_DEBUG, "OK\n");
+                if(d[2]*256+d[3] == ast->prefix)
+                    ast->prefix_count++;
+                else{
+                    ast->prefix= d[2]*256+d[3];
+                    ast->prefix_count= 0;
+                }
+
+                avi->stream_index= n;
+                ast->packet_size= size + 8;
+                ast->remaining= size;
+
+                if(size || !ast->sample_size){
+                    uint64_t pos= avio_tell(pb) - 8;
+                    if(!st->index_entries || !st->nb_index_entries || st->index_entries[st->nb_index_entries - 1].pos < pos){
+                        av_add_index_entry(st, pos, ast->frame_offset, size, 0, AVINDEX_KEYFRAME);
+                    }
+                }
+                return 0;
+            }
+        }
+    }
+
+    return AVERROR_EOF;
+}
+
+static int avi_read_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    AVIContext *avi = s->priv_data;
+    AVIOContext *pb = s->pb;
+    int err;
     void* dstr;
 
     if (CONFIG_DV_DEMUXER && avi->dv_demux) {
@@ -993,121 +1117,9 @@ resync:
         return size;
     }
 
-    memset(d, -1, sizeof(int)*8);
-    for(i=sync=avio_tell(pb); !pb->eof_reached; i++) {
-        int j;
-
-        for(j=0; j<7; j++)
-            d[j]= d[j+1];
-        d[7]= avio_r8(pb);
-
-        size= d[4] + (d[5]<<8) + (d[6]<<16) + (d[7]<<24);
-
-        n= get_stream_idx(d+2);
-//av_log(s, AV_LOG_DEBUG, "%X %X %X %X %X %X %X %X %"PRId64" %d %d\n", d[0], d[1], d[2], d[3], d[4], d[5], d[6], d[7], i, size, n);
-        if(i + (uint64_t)size > avi->fsize || d[0]<0)
-            continue;
-
-        //parse ix##
-        if(  (d[0] == 'i' && d[1] == 'x' && n < s->nb_streams)
-        //parse JUNK
-           ||(d[0] == 'J' && d[1] == 'U' && d[2] == 'N' && d[3] == 'K')
-           ||(d[0] == 'i' && d[1] == 'd' && d[2] == 'x' && d[3] == '1')){
-            avio_skip(pb, size);
-//av_log(s, AV_LOG_DEBUG, "SKIP\n");
-            goto resync;
-        }
-
-        //parse stray LIST
-        if(d[0] == 'L' && d[1] == 'I' && d[2] == 'S' && d[3] == 'T'){
-            avio_skip(pb, 4);
-            goto resync;
-        }
-
-        n= get_stream_idx(d);
-
-        if(!((i-avi->last_pkt_pos)&1) && get_stream_idx(d+1) < s->nb_streams)
-            continue;
-
-        //detect ##ix chunk and skip
-        if(d[2] == 'i' && d[3] == 'x' && n < s->nb_streams){
-            avio_skip(pb, size);
-            goto resync;
-        }
-
-        //parse ##dc/##wb
-        if(n < s->nb_streams){
-            AVStream *st;
-            AVIStream *ast;
-            st = s->streams[n];
-            ast = st->priv_data;
-
-            if(s->nb_streams>=2){
-                AVStream *st1  = s->streams[1];
-                AVIStream *ast1= st1->priv_data;
-                //workaround for broken small-file-bug402.avi
-                if(   d[2] == 'w' && d[3] == 'b'
-                   && n==0
-                   && st ->codec->codec_type == AVMEDIA_TYPE_VIDEO
-                   && st1->codec->codec_type == AVMEDIA_TYPE_AUDIO
-                   && ast->prefix == 'd'*256+'c'
-                   && (d[2]*256+d[3] == ast1->prefix || !ast1->prefix_count)
-                  ){
-                    n=1;
-                    st = st1;
-                    ast = ast1;
-                    av_log(s, AV_LOG_WARNING, "Invalid stream + prefix combination, assuming audio.\n");
-                }
-            }
-
-
-            if(   (st->discard >= AVDISCARD_DEFAULT && size==0)
-               /*|| (st->discard >= AVDISCARD_NONKEY && !(pkt->flags & AV_PKT_FLAG_KEY))*/ //FIXME needs a little reordering
-               || st->discard >= AVDISCARD_ALL){
-                ast->frame_offset += get_duration(ast, size);
-                avio_skip(pb, size);
-                goto resync;
-            }
-
-            if (d[2] == 'p' && d[3] == 'c' && size<=4*256+4) {
-                int k = avio_r8(pb);
-                int last = (k + avio_r8(pb) - 1) & 0xFF;
-
-                avio_rl16(pb); //flags
-
-                for (; k <= last; k++)
-                    ast->pal[k] = avio_rb32(pb)>>8;// b + (g << 8) + (r << 16);
-                ast->has_pal= 1;
-                goto resync;
-            } else if(   ((ast->prefix_count<5 || sync+9 > i) && d[2]<128 && d[3]<128) ||
-                         d[2]*256+d[3] == ast->prefix /*||
-                         (d[2] == 'd' && d[3] == 'c') ||
-                         (d[2] == 'w' && d[3] == 'b')*/) {
-
-//av_log(s, AV_LOG_DEBUG, "OK\n");
-                if(d[2]*256+d[3] == ast->prefix)
-                    ast->prefix_count++;
-                else{
-                    ast->prefix= d[2]*256+d[3];
-                    ast->prefix_count= 0;
-                }
-
-                avi->stream_index= n;
-                ast->packet_size= size + 8;
-                ast->remaining= size;
-
-                if(size || !ast->sample_size){
-                    uint64_t pos= avio_tell(pb) - 8;
-                    if(!st->index_entries || !st->nb_index_entries || st->index_entries[st->nb_index_entries - 1].pos < pos){
-                        av_add_index_entry(st, pos, ast->frame_offset, size, 0, AVINDEX_KEYFRAME);
-                    }
-                }
-                goto resync;
-            }
-        }
-    }
-
-    return AVERROR_EOF;
+    if ((err = avi_sync(s)) < 0)
+        return err;
+    goto resync;
 }
 
 /* XXX: We make the implicit supposition that the positions are sorted