macOS Multimedia Apps

Multimedia software is the broad group for working with audio and video — playing it, converting it, organizing it, and preparing it for other devices. It overlaps with several narrower categories on the site, so treat this as the general shelf and the codec, video-player, and audio sections as the focused ones.
Playback is the most common need, and modern media players have made it simple. A capable player carries its own decoders and will open almost any file you give it without extra installation. If a video plays sound but shows no picture, trying a different player is usually quicker than chasing down a codec.
Conversion is the other frequent job. Files often need to change format because a phone, a television, or an editing program expects something specific. A converter re-encodes the file, and that takes processing time — large videos can take a while, and the result is only as good as the settings you choose. Higher quality means larger files, with no way around the trade.
The category also includes library tools for tagging and sorting media, and suites that bundle playback, conversion, and burning together. When you choose, start from the task — play, convert, organize — rather than from the largest program available. A focused tool is faster to learn and lighter on the system than a suite you use one corner of.