[Live-devel] openRTSP producing bad video files

Ross Finlayson finlayson at live555.com
Fri Sep 5 12:47:30 PDT 2008

>On Tue, Sep 02, 2008 at 01:43:54PM -0700, Ross Finlayson wrote:
>>  We don't make available old versions of the code, and offer absolutely no
>>  support for old versions.  Everyone should work with the newest version
>>  of the code.
>Ok Ross, one more question... Can openRTSP cope with a variable
>framerate stream?  If, for example, my encoding hardware can't keep up
>and is sending out a stream that changes framerates, is it possible that
>openRTSP would produce a file that plays at the wrong speed?

The problem is not openRTSP, or RTP/RTSP in general.  The problem is 
the ".mp4"/".mov" file format.  This file format is badly designed 
for what openRTSP is trying to do: record - into the file - incoming 
RTP streams.  The code - for recording into ".mp4"/".mov" files - 
assumes that the frame rate is fixed (and specified in advance with 
the "-f" flag to openRTSP).  If the frame rate is actually variable, 
then I'm not sure the resulting file will play properly.

If, however, your stream really does have a fixed frame rate, but 
packets just happen to be sent at non-fixed intervals, then that 
should be OK.

Ross Finlayson
Live Networks, Inc.

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