Preview: Fit to screen introduces grid pattern in waveform

[pjotrek-b]

Hi everyone!

Not necessarily an issue, but maybe good to know (*)? The mechanism used to rescale the preview window size may add grid-like artefacts into the waveform filter (and maybe others, too?)

Example here:

• On the left side: "fit to screen"
• On the right side: "100%"

The red box is just to indicate one square of the slightly "ghosty" grid. Do you see it?

(*) I just noticed this, assuming these were "interesting" compression artefacts :wink:

In case someone's interested, here are the full, original screenshots:

[dericed]

Hi @pjotrek-b, when scaling I used the neighbor scalar as I thought this would be the most authentic, however the downside is that a grid can be introduced depending on the amount of scale.

Potentially another scalar could be used, recommendations welcome.

For instance, this command:

ffplay -f lavfi -i mandelbrot -vf "format=yuv444p,waveform=i=0.1,crop=w=120:h=120,split[a][b];[a]scale=300:300:sws_flags=neighbor[a1];[b]scale=300:300[b1];[a1][b1]xstack"

Takes the center 120x120 of the waveform of the mandelbrot filter and scales two copies of it to 300x300 with neighbor and the default scalar (bicubic).