> On Apr 9, 2018, at 4:12 PM, Dave Rice <d...@dericed.com> wrote: > > Hi ffmpeg-user, > > I’m using drawgraph with slide=picture in order to make some still images of > audiovisual metrics upon a timeline. I’d like to use drawgraph and drawtext > in order to overlay some x-axis markers and label the timeline; however I’m > unclear how the x-axis is represented in this mode. For instance, the example > below plots lavfi.astats.1.Min_level for a 60 second sample, but the > resulting image appears to have a x-axis that represents more than 60 > seconds. The result appears to roughly plot about 80 seconds with the 60-80 > second range being blank. > > ffmpeg -f lavfi -i > "aevalsrc=d=60:exprs=sin(PI*t):s=48000,aformat=sample_fmts=dbl,astats=metadata=1:reset=1,adrawgraph=m1=lavfi.astats.1.Min_level:max=1:min=-1:slide=picture:s=1920x240" > -y test.png > > Is there some math that I can use to determine the maximum value of the > x-axis from the plotted image?
Responding to myself here, but the max of the x-axis in this drawgraph example is found via: variables from the command: sample_rate = 48000 duration = 60 number_of_sample_in_audio_frame = 2048 drawgraph_width = 1920 temp variables: TILE_FLOOR= floor ( ( ( sample_rate * duration ) / number_of_sample_in_audio_frame ) / drawgraph_width ) TILE_MOD= modulo ( ( ( sample_rate * duration ) / number_of_sample_in_audio_frame ) / drawgraph_width , drawgraph_width) TILE_CEILING=ceiling ( ( ( sample_rate * duration ) / number_of_sample_in_audio_frame ) / drawgraph_width ) result: X-AXIS-MAX=duration / ( TILE_FLOOR * drawgraph_width + TILE_MOD ) / ( TILE_CEILING * drawgraph_width ) or TILE_FLOOR=0 TILE_MOD=1,406.25 TILE_CEILING=1 or X-AXIS-MAX=81.9194174619 seconds So my guess of 80 seconds was close. Best Regards, Dave Rice _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
