Hello Ross,
Thanks for your reply.
Le 06/09/2010 20:40, Ross Finlayson a écrit :
I'm using liveMedia library to implement an audio / video RTSP receiver.
To do so, I have created a minimal MediumSink subclass, in which I do
my decoding stuff (using libav* code).
It works really fine with streamed audio, but I can't decode videos
properly.
I noticed that the frames I'm receiving have really small sizes (sth
like 2000 bytes), and should be more around 60000 bytes to contain an
'image'.
You haven't said anything about what RTP payload format (codec) the
video is using. Please post an example of the SDP description
returned by the server (in response to the RTSP "DESCRIBE" command).
Here's the complete SDP :
******************* SDP message ********************
v=0
o=- 1283760697113531 1 IN IP4 127.0.1.1
s=MPEG-1 or 2 Program Stream, streamed by MultimediaRTSPServer
i=video:f24.mpg
t=0 0
a=tool:LIVE555 Streaming Media v2008.07.24
a=type:broadcast
a=control:*
a=range:npt=0-105.379
a=x-qt-text-nam:MPEG-1 or 2 Program Stream, streamed by MultimediaRTSPServer
a=x-qt-text-inf:video:f24.mpg
m=video 0 RTP/AVP 32
c=IN IP4 0.0.0.0
a=control:track1
m=audio 0 RTP/AVP 14
c=IN IP4 0.0.0.0
a=control:track2
******************* End of SDP ********************
This video has (on purpose) no audio track, so I can focus on video
stream only.
Payload of value 32 is an MPEG1 or MPEG2 video, if I refer to FFmpeg RTP
sources.
The thing is, with frames this small (~2000 bytes), I iterate video
decoding on it until libavcodec tells me we have a complete frame : it
seems to work fine with the first frame (I can't display it though),
afterwards, the video decoder seems completely lost.
Then, I inserted some traces into FileSink.cpp, and just using openRTSP,
I noticed that frames sizes were identical to mine... And i can read the
resulting video file perfectly with FFmpeg or VLC.
If you have any more ideas, they are of course welcomed, but liveMedia
seems not guilty on this one :)
Best regards,
Guillaume.
PS : some interesting insight : when I try to read one of those
videos with ffplay (small player contained in ffmpeg sources), it
works just fine.
Have you tried using VLC?
Also fine with VLC...
--
Guillaume FERRY
Bertin Technologies
Département Bertin Conseil
Activité Traitement de l'Information et du Contenu
/Tél/ 01.39.30.62.09
/Fax/ 01.39.30.62.45
/Mail/ [email protected]
/Web/ www.bertin.fr <http://www.bertin.fr>
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