[FFmpeg-user] Timing control?

Spencer Graves spencer.graves at prodsyse.com
Thu Mar 20 20:29:32 CET 2014

       What's the preferred method for controlling the timing of 
individual frames?

       This list previously recommended the concat demuxer with a 
control file (thread "[FFmpeg-user] concatenate png files for different 
durations?").  Unfortunately, that failed to control the timing as 
advertised:  A toy example played "duration 6" in less than 1 second 
followed by 5 seconds for a frame at "duration 1".  (I want to mate 
frames with audio timed to hundreths of a second.) I've not been able to 
control the times even if all frames have officially the same time.  
Other posts suggest that I'm not the only person with this problem.

       It looks to me like there is a bug in the FFmpeg concat demuxer.  
However, another question asked about keyframes. Researching that led me 
to documentation saying that, "forcing too many keyframes is very 
harmful for the lookahead algorithms of certain encoders: using 
fixed-GOP options or similar would be more efficient." 


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