Convert AAC to MP3
Drop a .aac file and download an MP3 at 192 kbps. Sample rate and channel count carry through unchanged.
Raw .aac files usually come out of stream capture, broadcast tooling, or an encoder configured to write ADTS rather than MP4. They hold good audio in a container that many players and editors will not touch.
ADTS has no metadata
An ADTS stream is a sequence of frames with small headers and nothing else: no title, no artist, no embedded seek table. Players that rely on container metadata to build a timeline often refuse to open it or report the wrong duration.
MP3 carries its own frame headers and accepts ID3 tags, which is why it survives this kind of pipeline better.
The re-encode
AAC decodes to PCM, then MP3 encodes that. At 192 kbps the added loss stays minor. If the .aac was captured at a low bitrate, that ceiling still applies to the MP3, so the output will not sound better than the capture did.