[FFmpeg-user] How to set histogram size?

Dave Rice dave at dericed.com
Tue Apr 7 02:01:49 CEST 2015

> On Apr 6, 2015, at 4:32 PM, Pedro <ffmpeg at 11.to> wrote:
> I'm trying to add a waveform histogram to a video. I'm following this <https://trac.ffmpeg.org/wiki/FancyFilteringExamples#waveform> example but I'm having trouble setting the size of the histogram, this is code I'm using:
> *ffmpeg -y -report -i input.mp4 -vf "split[a][b];[a]format=gray,histogram=mode=waveform:waveform_mode=column,vflip,split[c][d];[b]pad=iw:ih+256[padded];[c]geq=g=1:b=1[red];[d]geq=r=1:b=1,crop=in_w:220:0:16[mid];[red][mid]overlay=0:16[wave];[padded][wave]overlay=0:H-h" output.mp4*

Maybe unrelated, but you're forcing [a] to grayscale and then splitting that to [c] and [d], then using geq to extract red from [c] and green from [d]. Taking red and green from a grayscale image should give the same result. Can you explain what you are hoping to achieve?
Dave Rice

> I've tried to play around with the *|pad|***and *|crop|***values without luck.
> How can I set the size of histogram to 100 pixels only?
> Thank you!
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