video-editor

Remux instead of reencoding: run ffmpeg -i input.mkv -c copy output.mp4. This moves the streams into a new container without re-compression, so quality is preserved exactly and the operation completes in seconds.

CRF 18-20 gives visually lossless to high quality for archival, while 23 is the general-use default. Lower CRF means higher quality and larger files; note that x265 CRF values are not directly comparable to x264.

Hardware encoders such as NVENC and QuickSync prioritize speed over compression efficiency, producing worse quality at the same bitrate than x264 or x265. Use them for live streaming or quick transcodes, not quality-focused archival.

Washed-out colors usually mean a color range mismatch, where Limited range video is treated as Full. Check color metadata with MediaInfo and explicitly set -colorspace, -color_primaries, and -color_trc flags in your ffmpeg command.

Use the subtitles filter: ffmpeg -i input.mkv -vf "subtitles=subs.ass" -c:v libx264 -preset slower -crf 20 output.mkv. For complex ASS styling, mpv handles positioning and fonts more accurately than ffmpeg.

Remux whenever you only need to change the container format, since stream copying is lossless and nearly instant. Reencode only when you must change the codec, reduce file size, or meet platform compatibility requirements.