mpegtspacketizer: be more tolerant when parsing the adaptation field

According to the specification, the adaptation field length must be 183 if
there is no payload data and < 183 if the packet contains an adaptation
field and payload data.

Unfortunately some payloaders always set the flag for payload data, even if
the adaptation field length is 183.

Don't return with an error in this case. Clear the payload data flag
instead and parse the adaptation field as usual. This avoids visual
artefacts for such streams.

diff --git a/gst/mpegtsdemux/mpegtspacketizer.c b/gst/mpegtsdemux/mpegtspacketizer.c
index b793f85..7dde696 100644 (file)
--- a/gst/mpegtsdemux/mpegtspacketizer.c
+++ b/gst/mpegtsdemux/mpegtspacketizer.c
@@ -354,6 +354,17 @@ mpegts_packetizer_parse_adaptation_field_control (MpegTSPacketizer2 *
       GST_MEMDUMP ("Unknown payload", packet->data + length,
           packet->data_end - packet->data - length);
     }
+  } else if (length == 183) {
+    /* Note: According to the specification, the adaptation field length
+     * must be 183 if there is no payload data and < 183 if the packet
+     * contains an adaptation field and payload data.
+     * Some payloaders always set the flag for payload data, even if the
+     * adaptation field length is 183. This just means a zero length
+     * payload so we clear the payload flag here and continue.
+     */
+    GST_WARNING ("PID 0x%04x afc == 0x%02x and length %d == 183 (ignored)",
+        packet->pid, packet->scram_afc_cc & 0x30, length);
+    packet->scram_afc_cc &= ~0x10;
   } else if (length > 182) {
     GST_WARNING ("PID 0x%04x afc == 0x%02x and length %d > 182",
         packet->pid, packet->scram_afc_cc & 0x30, length);
@@ -482,7 +493,7 @@ mpegts_packetizer_parse_packet (MpegTSPacketizer2 * packetizer,
       return FALSE;
   }
 
-  if (FLAGS_HAS_PAYLOAD (tmp))
+  if (FLAGS_HAS_PAYLOAD (packet->scram_afc_cc))
     packet->payload = packet->data;
   else
     packet->payload = NULL;