mpegtsmux: Initialize PES packet before getting the header size.

The PES header length is calculated before setting the dynamic flags, returning
a wrong value. Small frames that should be sent in a single TS packet are
spawned to a new packet because of that error. For audio streams where a single
frame can cope in one TS packet it introduces a huge overhead.

For a 100B packet, we prepare a TS packet with a payload of(100+9)B. Then, we
write the TS header using this value in tsmux_write_ts_header, and call
tsmux_stream_get_data(). The dynamic flags where not set yet and now
tsmux_stream_pes_header_length() returns 14B instead of 9B. The payload of the
TS packet is 114B, 5B more than what was calculated. 109B are sent in a first
packet and the remaining 5B are sent in another one.

Fixes bug #628548.

gst/mpegtsmux/tsmux/tsmux.c

@@ -767,8 +767,10 @@ tsmux_write_stream_packet (TsMux * mux, TsMuxStream * stream)
     }
   }
 
-  pi->stream_avail = tsmux_stream_bytes_avail (stream);
   pi->packet_start_unit_indicator = tsmux_stream_at_pes_start (stream);
+  if (pi->packet_start_unit_indicator)
+    tsmux_stream_initialize_pes_packet (stream);
+  pi->stream_avail = tsmux_stream_bytes_avail (stream);
 
   if (!tsmux_write_ts_header (mux->packet_buf, pi, &payload_len, &payload_offs))
     return FALSE;

gst/mpegtsmux/tsmux/tsmuxstream.c

@@ -332,23 +332,18 @@ tsmux_stream_bytes_in_buffer (TsMuxStream * stream)
 }
 
 /**
- * tsmux_stream_get_data:
+ * tsmux_stream_initialize_pes_packet:
  * @stream: a #TsMuxStream
- * @buf: a buffer to hold the result
- * @len: the length of @buf
  *
- * Copy up to @len available data in @stream into the buffer @buf.
+ * Initializes the PES packet.
  *
- * Returns: TRUE if @len bytes could be retrieved.
+ * Returns: TRUE if we the packet was initialized.
  */
 gboolean
-tsmux_stream_get_data (TsMuxStream * stream, guint8 * buf, guint len)
+tsmux_stream_initialize_pes_packet (TsMuxStream * stream)
 {
-  g_return_val_if_fail (stream != NULL, FALSE);
+  if (stream->state != TSMUX_STREAM_STATE_HEADER)
-  g_return_val_if_fail (buf != NULL, FALSE);
+    return TRUE;
-
-  if (stream->state == TSMUX_STREAM_STATE_HEADER) {
-    guint8 pes_hdr_length;
 
   if (stream->pes_payload_size != 0) {
     /* Use prescribed fixed PES payload size */
@@ -377,6 +372,28 @@ tsmux_stream_get_data (TsMuxStream * stream, guint8 * buf, guint len)
       stream->pi.flags |= TSMUX_PACKET_FLAG_PES_WRITE_PTS;
   }
 
+  return TRUE;
+}
+
+/**
+ * tsmux_stream_get_data:
+ * @stream: a #TsMuxStream
+ * @buf: a buffer to hold the result
+ * @len: the length of @buf
+ *
+ * Copy up to @len available data in @stream into the buffer @buf.
+ *
+ * Returns: TRUE if @len bytes could be retrieved.
+ */
+gboolean
+tsmux_stream_get_data (TsMuxStream * stream, guint8 * buf, guint len)
+{
+  g_return_val_if_fail (stream != NULL, FALSE);
+  g_return_val_if_fail (buf != NULL, FALSE);
+
+  if (stream->state == TSMUX_STREAM_STATE_HEADER) {
+    guint8 pes_hdr_length;
+
     pes_hdr_length = tsmux_stream_pes_header_length (stream);
 
     /* Submitted buffer must be at least as large as the PES header */

gst/mpegtsmux/tsmux/tsmuxstream.h

@@ -212,6 +212,7 @@ void 		tsmux_stream_get_es_descrs 	(TsMuxStream *stream, guint8 *buf, guint16 *l
 
 gint 		tsmux_stream_bytes_in_buffer 	(TsMuxStream *stream);
 gint 		tsmux_stream_bytes_avail 	(TsMuxStream *stream);
+gboolean 	tsmux_stream_initialize_pes_packet (TsMuxStream *stream);
 gboolean 	tsmux_stream_get_data 		(TsMuxStream *stream, guint8 *buf, guint len);
 
 guint64 	tsmux_stream_get_pts 		(TsMuxStream *stream);