How this Discord video compressor works
This compressor re-encodes a video so it aims under 10 MB, the size that fits Discord's free upload limit. Discord has changed that limit more than once, so check the current figure for your account if the file matters. The result is an MP4 with H.264 video and AAC sound.
VimCut works out a bitrate from the length of the clip, so a short clip keeps more detail and a longer one gets less. When the budget is tight the picture is scaled down so the file still fits. Sound is set to 64 kbps. If your file is already under 10 MB, it is returned unchanged and nothing is encoded. When your browser supports it, the work uses the built-in hardware encoder. Otherwise it falls back to WebAssembly (ffmpeg.wasm). The result is a normal MP4 that you download and drop into Discord yourself.