move frame header reading into its own function

Originally committed as revision 7649 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/asf.c

@@ -530,45 +530,17 @@ static int asf_get_packet(AVFormatContext *s)
     return 0;
 }
 
-static int asf_read_packet(AVFormatContext *s, AVPacket *pkt)
-{
+/**
+ *
+ * @return <0 if error
+ */
+static int asf_read_frame_header(AVFormatContext *s){
     ASFContext *asf = s->priv_data;
-    ASFStream *asf_st = 0;
     ByteIOContext *pb = &s->pb;
-    //static int pc = 0;
-    for (;;) {
-        int rsize = 0;
-        if (asf->packet_size_left < FRAME_HEADER_SIZE
-            || asf->packet_segments < 1) {
-            //asf->packet_size_left <= asf->packet_padsize) {
-            int ret = asf->packet_size_left + asf->packet_padsize;
-            //printf("PacketLeftSize:%d  Pad:%d Pos:%"PRId64"\n", asf->packet_size_left, asf->packet_padsize, url_ftell(pb));
-            assert(ret>=0);
-            /* fail safe */
-            url_fskip(pb, ret);
-
-            ret= (url_ftell(&s->pb) - s->data_offset) % asf->packet_size;
-            if(asf->hdr.max_pktsize == asf->hdr.min_pktsize && ret){
-                av_log(s, AV_LOG_ERROR, "packet end missaligned skiping %d\n", ret);
-                url_fskip(pb, asf->packet_size - ret);
-            }
-
-            asf->packet_pos= url_ftell(&s->pb);
-            if (asf->data_object_size != (uint64_t)-1 &&
-                (asf->packet_pos - asf->data_object_offset >= asf->data_object_size))
-                return AVERROR_IO; /* Do not exceed the size of the data object */
-            ret = asf_get_packet(s);
-            //printf("READ ASF PACKET  %d   r:%d   c:%d\n", ret, asf->packet_size_left, pc++);
-            if (ret < 0 || url_feof(pb))
-                return AVERROR_IO;
-            asf->packet_time_start = 0;
-            continue;
-        }
-        if (asf->packet_time_start == 0) {
-            /* read frame header */
+    int rsize = 1;
     int num = get_byte(pb);
+
     asf->packet_segments--;
-            rsize++;
     asf->packet_key_frame = num >> 7;
     asf->stream_index = asf->asfid2avid[num & 0x7f];
     // sequence should be ignored!
@@ -580,7 +552,7 @@ static int asf_read_packet(AVFormatContext *s, AVPacket *pkt)
         asf->packet_obj_size = get_le32(pb);
         if(asf->packet_obj_size >= (1<<24) || asf->packet_obj_size <= 0){
             av_log(s, AV_LOG_ERROR, "packet_obj_size invalid\n");
-                    continue;
+            return -1;
         }
         asf->packet_frag_timestamp = get_le32(pb); // timestamp
         url_fskip(pb, asf->packet_replic_size - 8);
@@ -595,11 +567,10 @@ static int asf_read_packet(AVFormatContext *s, AVPacket *pkt)
         rsize++;
     }else if(asf->packet_replic_size!=0){
         av_log(s, AV_LOG_ERROR, "unexpected packet_replic_size of %d\n", asf->packet_replic_size);
-                continue;
+        return -1;
     }
     if (asf->packet_flags & 0x01) {
         DO_2BITS(asf->packet_segsizetype >> 6, asf->packet_frag_size, 0); // 0 is illegal
-#undef DO_2BITS
         //printf("Fragsize %d\n", asf->packet_frag_size);
     } else {
         asf->packet_frag_size = asf->packet_size_left - rsize;
@@ -607,14 +578,53 @@ static int asf_read_packet(AVFormatContext *s, AVPacket *pkt)
     }
     if (asf->packet_replic_size == 1) {
         asf->packet_multi_size = asf->packet_frag_size;
-                if (asf->packet_multi_size > asf->packet_size_left) {
-                    asf->packet_segments = 0;
-                    continue;
-                }
+        if (asf->packet_multi_size > asf->packet_size_left)
+            return -1;
     }
     asf->packet_size_left -= rsize;
     //printf("___objsize____  %d   %d    rs:%d\n", asf->packet_obj_size, asf->packet_frag_offset, rsize);
 
+    return 0;
+}
+
+static int asf_read_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    ASFContext *asf = s->priv_data;
+    ASFStream *asf_st = 0;
+    ByteIOContext *pb = &s->pb;
+    //static int pc = 0;
+    for (;;) {
+        if (asf->packet_size_left < FRAME_HEADER_SIZE
+            || asf->packet_segments < 1) {
+            //asf->packet_size_left <= asf->packet_padsize) {
+            int ret = asf->packet_size_left + asf->packet_padsize;
+            //printf("PacketLeftSize:%d  Pad:%d Pos:%"PRId64"\n", asf->packet_size_left, asf->packet_padsize, url_ftell(pb));
+            assert(ret>=0);
+            /* fail safe */
+            url_fskip(pb, ret);
+
+            ret= (url_ftell(&s->pb) - s->data_offset) % asf->packet_size;
+            if(asf->hdr.max_pktsize == asf->hdr.min_pktsize && ret){
+                av_log(s, AV_LOG_ERROR, "packet end missaligned skiping %d\n", ret);
+                url_fskip(pb, asf->packet_size - ret);
+            }
+
+            asf->packet_pos= url_ftell(&s->pb);
+            if (asf->data_object_size != (uint64_t)-1 &&
+                (asf->packet_pos - asf->data_object_offset >= asf->data_object_size))
+                return AVERROR_IO; /* Do not exceed the size of the data object */
+            ret = asf_get_packet(s);
+            //printf("READ ASF PACKET  %d   r:%d   c:%d\n", ret, asf->packet_size_left, pc++);
+            if (ret < 0 || url_feof(pb))
+                return AVERROR_IO;
+            asf->packet_time_start = 0;
+            continue;
+        }
+        if (asf->packet_time_start == 0) {
+            if(asf_read_frame_header(s) < 0){
+                asf->packet_segments= 0;
+                continue;
+            }
             if (asf->stream_index < 0
                 || s->streams[asf->stream_index]->discard >= AVDISCARD_ALL
                 || (!asf->packet_key_frame && s->streams[asf->stream_index]->discard >= AVDISCARD_NONKEY)
@@ -624,7 +634,7 @@ static int asf_read_packet(AVFormatContext *s, AVPacket *pkt)
                 url_fskip(pb, asf->packet_frag_size);
                 asf->packet_size_left -= asf->packet_frag_size;
                 if(asf->stream_index < 0)
-                    av_log(s, AV_LOG_ERROR, "ff asf skip %d  %d\n", asf->packet_frag_size, num & 0x7f);
+                    av_log(s, AV_LOG_ERROR, "ff asf skip %d (unknown stream)\n", asf->packet_frag_size);
                 continue;
             }
             asf->asf_st = s->streams[asf->stream_index]->priv_data;