A library with MP3s mixed in among AAC tracks can be inconsistent to manage. Filemorph converts an MP3 to M4A on your iPhone so it matches the format the rest of an Apple-native library already uses.
M4A (AAC) is the format Apple Music, Voice Memos and most iOS recording tools already use, so folding an older MP3 collection into M4A keeps a whole library in one consistent format instead of a mix of two.
This conversion decodes the MP3 and re-encodes it as AAC using Apple's AVFoundation. Because MP3 is already a lossy format, re-encoding it to another lossy format does not restore anything the MP3 lost, and it adds a small amount of additional generation loss on top. For a track you still have in a lossless source, converting from that source instead gives a cleaner result.
In the app: Transcode (Output Format: M4A).
A library split between MP3 and AAC files behaves inconsistently in some apps and syncs oddly across devices. Standardizing older MP3s to M4A brings them in line with everything already recorded or purchased in Apple's format.
Yes. Unlike web converters that upload your files to a server, Filemorph converts every file locally using Apple's frameworks. Nothing leaves your device, and it works with no internet connection. This operation is part of Filemorph Pro ($29.99/year, 7-day free trial on monthly and annual plans).
No, and it can add a small amount of additional loss. MP3 and M4A are both lossy formats, so re-encoding from one to the other cannot recover detail the MP3 already discarded — it only changes the container and codec for consistency.
If you still have the track in a lossless format like WAV or FLAC, converting from that instead avoids the extra lossy re-encode. Convert from MP3 only when it is the only copy you have.
No, audio Transcode is part of Filemorph Pro ($29.99 a year, 7-day free trial on monthly and annual plans).
On-device, no upload. Plus 300+ more file operations.
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