[Ffmpeg-devel] rtsp problem with ffplay

chris.2.dobbs at bt.com chris.2.dobbs
Tue Mar 7 19:53:21 CET 2006

Slight update to this after some more poking around....

I notice that in rtp.c the /AVFormatContext/ structure looks to be
something that holds all he recognised codec types for audio and video
ove rtp...I notice there is none for AMR NB. My payload type seems to
come thru ok as 96 (which is correct for AMR NB) so am I correct in
thinking that I just need to add a line for this payload type to reflect
AMR NB codec?

-----Original Message-----
From: ffmpeg-devel-bounces at mplayerhq.hu
[mailto:ffmpeg-devel-bounces at mplayerhq.hu] On Behalf Of
chris.2.dobbs at bt.com
Sent: 07 March 2006 18:04
To: ffmpeg-devel at mplayerhq.hu
Subject: [Ffmpeg-devel] rtsp problem with ffplay

I have a problem using ffplay to read an rtsp amr-nb stream (streamed
out using the LIVE555 media code).

ffplay can read and play this stream if presented as a local file i.e
ffplay test.amr

Quicktime can play this stream across rtsp but ffplay cannot. It seems
after looking into the code that is not managing to populate the 
Ic->streams[0]->codec structure  - in fact it continually loops around
inside av_find_stream_info() looking at each media header to see if it
can understand the stream and thus never feeds the audio play thread.

The codec id picked up by the file based ffplay session is x012000 (AMR
narrowband as expected)

To sumarize:
%ffplay -vn -nodisp /temp/test.amr   (works fine)

%ffplay -vn -nodisp rtsp://<hostname>:<port>/test.amr (doesn't work) All
the RTSP chatter on port 544 works fine and the server side even starts
streaming, it's just that ffplay can't understand the stream I think. 

I wanted to ask in this forum befire I start hacking around inside the
code as this looks to be a very simple problem but the code is rather
hairy at this level and I would rather someone who is more familiar with
the code base take a look.

Any help would be greatly appreciated.
-Chris Dobbs

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