MP3 to AAC

Re-encode an MP3 file as raw AAC. AAC generally sounds better than MP3 at the same bitrate and is the default codec for the iTunes/Apple ecosystem and most modern streaming. Because the source is already lossy, expect some quality loss in the re-encode — pick a higher bitrate if you care. Runs entirely in your browser using ffmpeg.wasm; nothing is uploaded. Expect a few seconds for a 5-minute song.