Merge Audio: MP3 Joiner

Merge Audio combines several audio files into one and, when the sources are compatible with each other, copies the sound as it is: no second compression and no quality loss.

The verdict appears before you export, not after. If re-encoding is needed, the app names the track that causes it and the reason: a different sample rate, a different channel count, another codec, or a setting that requires processing. The choice stays with you.

LOSSLESS JOIN
- MP3 frames are copied one by one, and AAC or ALAC packets move into a new container.
- The result sounds the same as the originals.
- An honest note: every seam keeps the padding added by the original encoder, a few hundredths of a second. It is inaudible in speech, chapters and podcasts; truly gapless music is better re-encoded.

TRIM ON THE REAL WAVEFORM
- Tap a track and set its start and end with two handles over its waveform.
- Trimming does not re-encode either: whole frames are dropped and the rest is copied byte for byte.
- The cut snaps to the nearest complete frame.

OUTPUT FORMATS
MP3, M4A (AAC), M4B audiobook, WAV, FLAC and Ogg Opus. Automatic mode keeps the source format, which is what makes the lossless path possible. Bitrate, sample rate and channels can also be set by hand.

M4B AUDIOBOOKS
Each track becomes a chapter with an editable title. Title, author, album and cover art can be added.

PER-TRACK ADJUSTMENTS
- Gain in decibels.
- Fade in and fade out.
- Transition into the next track: direct join, silence or crossfade.
- Loudness matching at -16 LUFS with true peaks limited to -1 dBTP, per track or treating everything as one program.

WORKFLOW
- Reorder by dragging, with undo.
- Listen to the mix and to the result inside the app.
- Export with progress and cancellation at any point.
- Save the file or share it.
- Local history with date, tracks, duration, size and whether the join was lossless.

EVERYTHING ON YOUR DEVICE
Audio is processed entirely on your iPhone or iPad. No files, names, paths or history are uploaded. It works without a connection, contains no advertising and sends no analytics or tracking data. Only the files you pick are read. No account is required.

MADE FOR
Podcasts and interviews, audiobooks and chapters, voice notes and long messages, recorded lectures and talks, music takes that run one into the next.

Open-source components: LAME, FLAC, Opus and libopusenc, with their licenses and source included in the project.
Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Privacy Policy: https://www.freeprivacypolicy.com/live/6709a492-0082-4d37-b246-397c3cdc06a5