Reducing GIF Dithering with ffmpeg

TODO: collapasable, copyable, download, etc

I have a screen recording. I process it with ffmpeg -i ~/Desktop/Screen\ Recording\ 2023-10-11\ at\ 1.26.59\ PM.mov -pix_fmt rgb8 -r 10 output.gif && gifsicle -O3 output.gif -o output.gif

The gif has grey dots all over it in a regular grid. Why is that?The grey dots you're seeing in the GIF are likely a result of dithering. Dithering is a technique used to simulate colors or tones in an image that aren't present in the limited color palette of the format. The GIF format supports a maximum of 256 colors, so when you convert a video (which likely has thousands or millions of colors) to a GIF, some form of dithering is often applied to approximate the colors of the original video.

The -pix_fmt rgb8 flag in your ffmpeg command is instructing ffmpeg to output an 8-bit RGB palette, which further reduces the number of colors available in the resulting image, making the dithering more pronounced.

If you want to reduce the appearance of these dots:

1. Increase the palette size: Instead of using -pix_fmt rgb8, use the palettegen and paletteuse filters in ffmpeg to generate and use a custom 256-color palette. This can help to create a GIF that better matches the original video's colors:

ffmpeg -i ~/Desktop/Screen\ Recording\ 2023-10-11\ at\ 1.26.59\ PM.mov -vf "fps=10,palettegen" palette.png
ffmpeg -i ~/Desktop/Screen\ Recording\ 2023-10-11\ at\ 1.26.59\ PM.mov -i palette.png -filter_complex "fps=10,paletteuse" output.gif

2. Reduce dithering: If you still notice unwanted dithering, you can modify the paletteuse filter to reduce it. For example:

-filter_complex "fps=10,paletteuse=dither=none"

However, reducing dithering can sometimes result in banding or color inaccuracies.

3. Post-process with gifsicle: Continue using gifsicle as you've been doing to optimize the GIF size:

gifsicle -O3 output.gif -o output_optimized.gif

Remember, GIFs inherently have limitations with color due to their restricted palette. While these steps can help improve the appearance, some loss of color fidelity is expected when converting full-color videos to GIF format.How can I get ffmpeg to not ask if palette.png already exists Y/N to overwrite. it should just always overwriteYou can use the -y flag with ffmpeg to automatically overwrite the output file if it already exists without prompting for confirmation.

For example:

ffmpeg -y -i ~/Desktop/Screen\ Recording\ 2023-10-11\ at\ 1.26.59\ PM.mov -vf "fps=10,palettegen" palette.png

By adding -y before specifying the input file (or anywhere in the command), ffmpeg will overwrite palette.png (or any other output file) without asking.

Reducing GIF Dithering with ffmpeg created at Tue Jan 20 1970 15:24:16 GMT+0000 (Coordinated Universal Time)