Convert Video to GIF

What a GIF can hold, and what it costs

Frames are sampled at fixed moments rather than blended together: ten a second means the nearest decoded frame at every tenth of a second, so a 30 fps source has two frames in three discarded. Motion that was smooth strobes a little, and there is no way around it short of raising the rate — which raises the file in direct proportion, because a GIF pays for each frame separately.

Colour is where the format shows its age most plainly. Each frame is reduced to 256 colours chosen from that frame, and nothing is dithered, so a sky, a gradient or a skin tone arrives in visible bands — and because the palette is recomputed for every frame, those bands shift slightly from one frame to the next, which reads as a faint shimmer across the loop. Flat material has no such trouble: a screen recording, a terminal session or line animation often contains fewer than 256 colours to begin with and comes out exact.

Timing is stored as a delay per frame in hundredths of a second, so only some frame rates are exactly representable. Ten a second is 10 hundredths exactly; fifteen would be 6.67, so frames alternate between 7 and 6 with the rounding carried along, which keeps the whole loop the length you asked for instead of letting it drift short.

When you want something else

ffmpeg makes better GIFs than this does, and on photographic material it is not close: its palettegen and paletteuse filters build one palette for the whole clip and then dither against it, which removes the banding and the shimmer that per-frame palettes cause. gifsicle will optimise the result further, and its lossy setting further still. Neither is reachable from a browser, and if you make GIFs regularly they are worth the two commands.