Thank you for the contribution. You might be interested to read this old report I did testing a/v sync of the DVEO SDI consumer, drivers, and hardware: http://www.mltframework.org/bin/view/MLT/LinsysSyncTest
The challenge now is to figure out if the problems lie more in the avformat consumer or producer, or at least how to isolate one to fine tune it. Do you have any thoughts about that? At least with raw DV output, we can check it with the dvthumbs.c I used in that study. Also, how did you come up with the 3ms number? Why is 33ms - one frame at 30 Hz - not acceptable? On Mon, Feb 25, 2013 at 8:45 PM, Brian Matherly <pez4br...@yahoo.com> wrote: > Dan, > > I added a new module: avsync. It has one producer and one consumer. The > producer generates a stream with a classic blip/flash pattern. The consumer > attempts to detect the blip/flash and calculate the audio/video sync. The > consumer will report the caluclated lipsync in milliseconds. A positive > number indicates that audio leads video. A negative number indicates that > audio lags video. > > The module can test itself: > > melt -silent -profile atsc_720p_30 blipflash -consumer blipflash > avsync = 0.00 > > Obviously, 0 is perfect sync. > > It is interesting to round-trip the pattern through some various encodings: > > melt -profile atsc_720p_30 blipflash -consumer avformat:test.avi > melt -silent test.avi -consumer blipflash > avsync = -23.02 > > melt -profile atsc_720p_30 blipflash -consumer avformat:test.mpg > melt -silent test.mpg -consumer blipflash > avsync = -10.02 > > melt -profile atsc_720p_30 blipflash -consumer avformat:test.mkv > melt -silent test.mkv -consumer blipflash > avsync = 0.00 > > melt -profile atsc_720p_30 blipflash -consumer avformat:test.mov acodec=ac3 > melt -silent test.mov -consumer blipflash > avsync = -5.33 > > melt blipflash -consumer libdv:test.dv > melt -silent test.dv -consumer blipflash > avsync = -40.00 > > A sync worse than +/-3ms is pretty bad, in my opinion. Some of these might be > worth looking in to. > > Anyway, the module is obviously up for debate. Let me know your thoughts. I > can add, modify or delete as appropriate. > > ~Brian ------------------------------------------------------------------------------ Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_feb _______________________________________________ Mlt-devel mailing list Mlt-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mlt-devel
