On Tue, Oct 12, 2021 at 10:55 AM Michael Koch <astroelectro...@t-online.de> wrote:
> I have a question about the "fftfilt" filter. What's the default value > of the weight_U and weight_V options? I'm asking because I get an > unexpected result. > > This command line creates my input image for testing: > > ffmpeg -f lavfi -i color=black:s=300x50 -lavfi > drawgrid=c=white:y=-1:w=2:h=51,split[a][b];[b]crop=iw/2:x=0,scale=2*iw:ih:flags=neighbor,split[b][c];[c]crop=iw/2:x=0,scale=2*iw:ih:flags=neighbor,split[c][d];[d]crop=iw/2:x=0,scale=2*iw:ih:flags=neighbor,split[d][e];[e]crop=iw/2:x=0,scale=2*iw:ih:flags=neighbor,split[e][f];[f]crop=iw/2:x=0,scale=2*iw:ih:flags=neighbor[f];[a][b][c][d][e][f]vstack=6,split[h][v];[v]transpose[v];[v][h]hstack > > -frames 1 -y test.png > > This is the fftfilt lowpass example from the official documentation: > > ffmpeg -i test.png -vf fftfilt=dc_Y=0:weight_Y='squish((Y+X)/100-1)' -y > out1.png > > Problem: The output has a greenish tint. > Expressions by default for U and V are copied from Y if are unset. filter works only in YUV or gray space thus in above combination one gets green tint. > > If I set the weight_U and weight_V options to 1, then the greenish tint > disappears: > > ffmpeg -i test.png -vf > fftfilt=dc_Y=0:weight_Y='squish((Y+X)/100-1)':weight_U=1:weight_V=1 -y > out2.png > > 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".
