[Live-devel] doubled framerate necessary to correctly capture RTSP stream using openRTSP

[VTMusicAdmin]

I am experiencing an issue with openRTSP for which I've not yet 
been able to find an explanation.  If there is a more 
appropriate forum for this or a FAQ I have missed, please let me 
know.  I'm attempting to use openRTSP to capture and record the 
RTSP stream from an Extron SME-100 live streaming hardware 
encoder.  The encoder is configured with a frame rate / GOP 
length of 30 fps, yet if I set openRTSP with a frame rate of 30 
like this:

     openRTSP -d 300 -4 -w 640 -h 360 -f 30 -Q rtsp://URL > 
test.mp4 (or)
     openRTSP -d 300 -q -w 640 -h 360 -f 30 -Q rtsp://URL > test.mov

The video is the incorrect speed and does not match the audio.  
If however, I set openRTSP with a frame rate of 60 with:

     openRTSP -d 300 -4 -w 640 -h 360 -f 60 -Q rtsp://URL > 
test.mp4 (or)
     openRTSP -d 300 -q -w 640 -h 360 -f 60 -Q rtsp://URL > test.mov

The video is captured correctly and is synchronous with the 
audio for the duration of the capture.  This is a perfectly 
viable work-around, but I'm curious about why openRTSP only 
seems to work as expected when set to capture at a 2x (actual) 
frame rate.  Am I misunderstanding something about the use of 
openRTSP or the process by any chance?   Anny insight that can 
be offered into this situation would be greatly appreciated; 
thank you!

-- 
-- Michael Dunston
-- Music and Technology
-- School of Performing Arts
-- Music | Theatre | Cinema
-- <http://www.music.vt.edu/technology/>
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