On Mon, Feb 25, 2013 at 10:20 PM, Dan Dennedy <d...@dennedy.org> wrote: > 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 >> > > It is interesting to note that > > melt blipflash -consumer libdv:test.dv
excuse me, I meant melt -silent libdv:test.dv -consumer blipflash using the libdv producer instead of avformat. > gives 0.00, which lends itself to a possible off-by-one error in the > avformat producer since this is PAL, which is 40ms per frame. I started to look into this, but like the other isolation problem, now I am not sure whether to look at audio or video initially! -- +-DRD-+ ------------------------------------------------------------------------------ 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
