- Looks a tiny bit harder in mpegps_probe() for a valid start code. This is

needed to detect some files produced by pvr-250/350 capture cards.
- Adds AC3 audio support to the mpegts demuxer, and makes it a little more
tolerant of bad files.
patch by (Isaac Richards <ijr at po dot cwru dot edu>)

Originally committed as revision 2028 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/mpeg.c

@@ -405,9 +405,10 @@ static int mpeg_mux_end(AVFormatContext *ctx)
 
 static int mpegps_probe(AVProbeData *p)
 {
-    int code;
+    int code, c, i;
     const uint8_t *d;
 
+    code = 0xff;
     /* we search the first start code. If it is a packet start code,
        then we decide it is mpeg ps. We do not send highest value to
        give a chance to mpegts */
@@ -416,20 +417,23 @@ static int mpegps_probe(AVProbeData *p)
 
     if (p->buf_size < 6)
         return 0;
-    d = p->buf;
-    code = (d[0] << 24) | (d[1] << 16) | (d[2] << 8) | (d[3]);
-    if ((code & 0xffffff00) == 0x100) {
-        if (code == PACK_START_CODE ||
-            code == SYSTEM_HEADER_START_CODE ||
-            (code >= 0x1e0 && code <= 0x1ef) ||
-            (code >= 0x1c0 && code <= 0x1df) ||
-            code == PRIVATE_STREAM_2 ||
-            code == PROGRAM_STREAM_MAP ||
-            code == PRIVATE_STREAM_1 ||
-            code == PADDING_STREAM)
-            return AVPROBE_SCORE_MAX - 1;
-        else
-            return 0;
+
+    for (i = 0; i < 20; i++) {
+        c = p->buf[i];
+        code = (code << 8) | c;
+        if ((code & 0xffffff00) == 0x100) {
+            if (code == PACK_START_CODE ||
+                code == SYSTEM_HEADER_START_CODE ||
+                (code >= 0x1e0 && code <= 0x1ef) ||
+                (code >= 0x1c0 && code <= 0x1df) ||
+                code == PRIVATE_STREAM_2 ||
+                code == PROGRAM_STREAM_MAP ||
+                code == PRIVATE_STREAM_1 ||
+                code == PADDING_STREAM)
+                return AVPROBE_SCORE_MAX - 1;
+            else
+                return 0;
+        }
     }
     return 0;
 }

libavformat/mpegts.c

@@ -387,6 +387,7 @@ static void pmt_cb(void *opaque, const uint8_t *section, int section_len)
         case STREAM_TYPE_AUDIO_MPEG2:
         case STREAM_TYPE_VIDEO_MPEG1:
         case STREAM_TYPE_VIDEO_MPEG2:
+        case STREAM_TYPE_AUDIO_AC3:
             add_pes_stream(ts->stream, pid);
             break;
         default:
@@ -613,16 +614,19 @@ static void mpegts_push_data(void *opaque,
                 if (pes->header[0] == 0x00 && pes->header[1] == 0x00 &&
                     pes->header[2] == 0x01) {
                     /* it must be an mpeg2 PES stream */
-                    /* XXX: add AC3 support */
                     code = pes->header[3] | 0x100;
                     if (!((code >= 0x1c0 && code <= 0x1df) ||
-                          (code >= 0x1e0 && code <= 0x1ef)))
+                          (code >= 0x1e0 && code <= 0x1ef) ||
+                          (code == 0x1bd)))
                         goto skip;
                     if (!pes->st) {
                         /* allocate stream */
                         if (code >= 0x1c0 && code <= 0x1df) {
                             codec_type = CODEC_TYPE_AUDIO;
                             codec_id = CODEC_ID_MP2;
+                        } else if (code == 0x1bd) {
+                            codec_type = CODEC_TYPE_AUDIO;
+                            codec_id = CODEC_ID_AC3;
                         } else {
                             codec_type = CODEC_TYPE_VIDEO;
                             codec_id = CODEC_ID_MPEG1VIDEO;
@@ -805,6 +809,8 @@ static int handle_packets(AVFormatContext *s, int nb_packets)
     ByteIOContext *pb = &s->pb;
     uint8_t packet[TS_FEC_PACKET_SIZE];
     int packet_num, len;
+    int i, found = 0;
+    int64_t pos;
 
     ts->stop_parse = 0;
     packet_num = 0;
@@ -814,13 +820,32 @@ static int handle_packets(AVFormatContext *s, int nb_packets)
         packet_num++;
         if (nb_packets != 0 && packet_num >= nb_packets)
             break;
+        pos = url_ftell(pb);
         len = get_buffer(pb, packet, ts->raw_packet_size);
         if (len != ts->raw_packet_size)
             return AVERROR_IO;
         /* check paquet sync byte */
-        /* XXX: accept to resync ? */
         if (packet[0] != 0x47)
-            return AVERROR_INVALIDDATA;
+        {
+           //printf("bad packet: 0x%x\n", packet[0]);
+           found = 0;
+           for (i = 0; i < ts->raw_packet_size; i++)
+           {
+               if (packet[i] == 0x47)
+               {
+                   found = 1;
+                   //printf("packet start at: %d\n", i);
+                   break;
+               }
+           }
+           
+           if (found)
+           {
+               url_fseek(pb, pos + i, SEEK_SET);
+               continue;
+           }
+           return AVERROR_INVALIDDATA;
+        }
         handle_packet(s, packet);
     }
     return 0;

libavformat/mpegts.h

@@ -38,5 +38,7 @@
 #define STREAM_TYPE_PRIVATE_SECTION 0x05
 #define STREAM_TYPE_PRIVATE_DATA    0x06
 
+#define STREAM_TYPE_AUDIO_AC3       0x81
+
 unsigned int mpegts_crc32(const uint8_t *data, int len);
 extern AVOutputFormat mpegts_mux;