Change function prototype of the sdp_parse_a_line in DynamicProtocolHandler.

This function is called in rtsp.c for each a= line in the SDP of the Describe
response after m= RTSP stream descriptors. The function prototype used to
take an AVStream argument. For RDT, however, every RTSPStream represents
a set of streams of identical content, and can thus represent multiple
AVStreams. Therefore, it should not take an AVStream as argument. This
patch modifies it to accept a AVFormatContext (of the RTSP/SDP demuxer)
instead. See discussion in "[PATCH/RFC] change function prototype of
parse_sdp_a_line" thread on ML.

Originally committed as revision 16024 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/rtp_internal.h

@@ -66,7 +66,8 @@ struct RTPDynamicProtocolHandler_s {
     enum CodecID codec_id;
 
     // may be null
-    int (*parse_sdp_a_line) (AVStream * stream,
+    int (*parse_sdp_a_line) (AVFormatContext *s,
+                             int st_index,
                              PayloadContext *priv_data,
                              const char *line); ///< Parse the a= line from the sdp field
     PayloadContext *(*open) (); ///< allocate any data needed by the rtp parsing for this dynamic data.