M4A → AC3

Yes, and it is worth planning around. Both formats are lossy, so the AC3 encoder is working from audio that has already been through one psychoacoustic pass, and its own decisions compound the first set. At 192 kbps or above the result is still transparent for most listening. If you have a lossless master anywhere, encoding the AC3 from that instead avoids the double pass entirely. An M4A holds AAC in most cases, or Apple Lossless (ALAC) when it came from a lossless rip. AC-3 is lossy multichannel audio, normally 5.1 at 384 or 448 kbps, with metadata for dialogue normalisation and downmixing.

Not intact. M4A carries a proper metadata block, but AC3 has no standard place for artist, album, track number or cover art, so tags are dropped rather than mangled. Keep the M4A as the tagged copy, or re-tag afterwards with a tool like Mp3tag or MusicBrainz Picard. AC-3 is inefficient by modern standards and is not accepted by browsers, phones or most web players without a downmix to stereo.

DRM. A subset of M4A files are encrypted by the store or the software that issued them, and encrypted audio cannot be decoded by any converter. Anything you ripped yourself, recorded, or bought without protection converts normally; a licensed purchase will not. M4A hides two very different things behind one extension — lossy AAC and lossless ALAC — and non-Apple hardware support is inconsistent.

If M4A is lossy and AC3 is lossless (e.g. MP3 → WAV), the AC3 is no better than the M4A — you cannot recover information already discarded. If M4A is lossless and AC3 is lossy, the AC3 codec recompresses; at 192 kbps the result is transparent for most content.

Several files in one job need a paid plan. Free use is one file per conversion, one conversion an hour. On a paid plan you can add several files to one job, then download each result on its own or all of them in one ZIP.

By default yes — 48 kHz M4A stays 48 kHz in AC3. If you need to downsample for compatibility (96 kHz → 44.1 kHz for CD burning), the sample-rate option applies high-quality resampling in the same encode pass.

Not in this step. The converter has no loudness setting and leaves the level as it is. To even out the volume, run the finished AC3 through a Normalize tool on this site.

MP3 plays almost everywhere. AAC plays on Apple devices, most Android phones and Sonos. FLAC plays on Sonos and Android but not on older iPods, and WAV plays on nearly everything but makes large files. There are no device presets on this page, so choose the target format your player supports. AC-3 is the surround track every AV receiver, DVD player and TV decodes natively, which is why it is still the broadcast baseline.

Yes. Uploaded M4A files are processed on our own conversion servers, no person reviews them, and they are never shared. The upload and the converted AC3 are both deleted automatically about 24 hours after the conversion, which leaves time to download the result. See /privacy/ for the full policy.