On 11/26/19, Michael Koch <astroelectro...@t-online.de> wrote: > >>> Thanks for your suggestion. Adding -r 25 does indeed solve the problem. >>> Although I don't understand why it is required. The input framerate is >>> 25 and it's detected correctly when I use the simpler filter chain. >>> >> Ah, I know why this happens, you need to use settb=1/FPS filter after >> vstack. >> This happens because adrawgraph filter it order to not drop output >> frames need to have same timebase as input audio. Otherwise you would >> get different metadata values. >> Also note that your FPS in this case is 48000/1024. ~= 46.xxx > > 48000 is the audio sample rate, but where does the 1024 come from?
From astats i think. > > I have a new example with testsrc2 and anoisesrc. There is no input file > required for reproducing. > There are two graphs: The first one uses signalstats and drawgraph, and > the second one uses astats and adrawgraph. The problem is that the two > graphs don't advance with the same speed in X direction. Do you have an > idea how to make them synchrone?The video width is the same in both > cases, otherwise vstack wouldn't work. > The speed of drawgraph is correct, 1 pixel per frame. The speed of > adrawgraph is too fast. > > Other question: reset=1 in astats means that the calculation result is > reset after each frame. But how does the filter know when a frame ends, > if the input of this filter is only an audio signal? > > c://ffmpeg/ffmpeg -f lavfi -i testsrc2=size=hd1080:duration=10:rate=25 > -f lavfi -i anoisesrc=d=10:c=pink:r=48000 -lavfi > [0]signalstats,drawgraph=m1=lavfi.signalstats.YAVG:mode=line:slide=scroll:min=0:max=255,settb=1/25[G1];[1]astats=metadata=1:reset=1,adrawgraph=m1=lavfi.astats.1.RMS_level:mode=line:slide=scroll:min=-90:max=0,settb=1/25[G2];[G1][G2]vstack,settb=1/25 > -r 25 -y test.mp4 > Use asetnsamples, to change size of audio frame to match you video FPS. > Michael > > _______________________________________________ > ffmpeg-user mailing list > ffmpeg-user@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-user > > To unsubscribe, visit link above, or email > ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe". _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
