AAC to MP3 for Podcasts

Podcasters hit this specific conversion because HLS streaming segments is where the AAC came from — a remote guest, a field recording, a clip — and a bare .aac stream lacks the container index that tells software its duration, so players won't list it and editors import it wrong. For a show you need MP3, so the AAC-to-MP3 step is part of the edit, not an afterthought.

MP3 is what you publish — Apple Podcasts, Spotify, and every RSS-based host expect it. The order matters more than the format: record and edit on a lossless file, and encode the MP3 once, from the finished episode. Converting early means every later edit sits on top of lossy audio and your export adds another generation on top of that.

Podcast bitrates are lower than most people assume, deliberately. 128 kbps stereo is the widely used standard, and 64–96 kbps mono is entirely respectable for pure speech — it roughly halves the download for every listener, which adds up across a back catalogue and matters to anyone on limited mobile data. Reserve 192 kbps and above for shows where music genuinely carries the experience.

Mono is the decision most worth revisiting. If your episode is voices with no meaningful stereo image — which describes most interview and solo shows — mono at 96 kbps is perceptually equivalent to stereo at 192 and half the size. Publishing stereo by default is a habit, not a requirement. And archive the lossless edit: social clips, best-of segments, and fixes should always be cut from that, never from the published file.

Sizes are comparable: AAC and MP3 both sit near 1.2–1.4 MB per stereo minute, so this conversion is about compatibility, not storage. You're stacking a second lossy generation. At a generous bitrate that's inaudible, but if you still have a lossless original, encode from that instead: one generation always beats two.

AAC files come from HLS streaming segments, broadcast pipelines, Android recording apps, and hardware recorders. A bare .aac stream lacks the container index that tells software its duration, so players won't list it and editors import it wrong — which is the whole reason this conversion exists. MP3 is the destination because it plays essentially everywhere — downloads and every ordinary phone, browser, and player. File size stays in the same ballpark — both formats land around 1.2–1.4 MB per minute. Both AAC and MP3 are lossy, so this pair stacks a second encode — at a generous bitrate it stays inaudible, but if a lossless original of the AAC exists, encode the MP3 from that instead.