Add your MTS file
Drop one or more .mts files onto the converter above, or browse for them. They load into browser memory only — nothing is uploaded, so there is no size-based pricing and no server queue.
MTS to ALAC
Pulling the soundtrack out of a .mts video into .alac audio keeps what you can hear and drops the picture entirely. Free, private, and validated — the file never leaves your browser.
Private for supported formats — processed in your browser
Runs on your deviceConvert supported files
Drop MTS files here
Batch files can each use a different output. Nothing uploads for local conversions.
Working inputs include camera RAW, browser-local audio/video, PDF, CBZ/CBR comics, office documents, ebooks, markup, 3D models, structured text, images, and archives.About converting AVCHD video to Apple Lossless audio
Pulling the soundtrack out of a .mts video into .alac audio keeps what you can hear and drops the picture entirely. An .mts file is AVCHD footage as written to a camcorder's memory card, containing H.264 video inside an MPEG transport stream. Sony and Panasonic camcorders from the late 2000s onward filled SD cards with .mts clips, so the extension is familiar to anyone importing family or event video.
ALAC, the Apple Lossless Audio Codec, compresses music with zero quality sacrifice, and the .alac extension is occasionally used to label such files explicitly even though the codec normally travels inside an .m4a container. Decoding reproduces the original samples exactly, making it Apple's counterpart to FLAC. For this route the practical draw is native on every Apple platform from iOS to HomePod and mathematically lossless reconstruction — balanced against compresses slightly worse than FLAC on average, which is worth knowing before you commit a large batch.
Why convert MTS to ALAC?
The usual reason to take .alac audio out of a .mts file is that only the sound matters — a talk, interview, song, or podcast segment. Keeping the video stream would waste storage, and a dedicated audio file is easier to trim, tag, and play. On the source side, transport-stream packet overhead makes files larger than the same video in MP4; on the target side, the payoff is native on every Apple platform from iOS to HomePod, which is exactly what you want for building a lossless library that syncs cleanly to iPhones and the Music app.
MTS vs ALAC at a glance
| Aspect | AVCHD video (.mts) | Apple Lossless audio (.alac) |
|---|---|---|
| Format type | Container — quality depends on the codecs and settings inside | Lossless — every pixel or sample is preserved exactly |
| How it stores data | uses 192-byte transport packets, standard 188-byte packets plus a 4-byte arrival timestamp, matching Blu-ray's BDAV layout | linear-prediction compression conceptually similar to FLAC, typically reaching 40 to 60 percent of PCM size |
| Strongest at | importing camcorder footage into Premiere, Resolve, or Final Cut | building a lossless library that syncs cleanly to iPhones and the Music app |
| Weak spot | transport-stream packet overhead makes files larger than the same video in MP4 | compresses slightly worse than FLAC on average |
| Metadata | recording date, camera settings, and GPS coordinates on some models are stored in the AVCHD folder's clip-info files rather than in the .mts stream itself | inherits the full iTunes metadata atom set from its MPEG-4 container, including artwork, composer, and grouping fields |
Pick ALAC as the output
Select .alac in the output menu next to each file. The menu only offers targets this engine can genuinely produce, so if ALAC is selectable, the route is real and validated.
Convert on your device
Press Convert. A WebAssembly FFmpeg build demuxes the audio track and re-encodes it locally; the video stream is simply discarded.
Verify and download
Each result is signature-checked before the download unlocks, so a failed encode can never masquerade as a valid ALAC file. Outputs keep the original filename with the .alac extension.
MTS to ALAC questions, answered
Will converting MTS to ALAC lose quality?
Since mts is container-oriented and alac is lossless-oriented, the conversion preserves the source content exactly as stored; no additional compression pass is applied beyond what .alac itself requires.
Is it private to convert MTS files here?
Yes — the .mts file is processed inside your browser tab and never uploaded. A WebAssembly FFmpeg build demuxes the audio track and re-encodes it locally; the video stream is simply discarded. Close the tab and the file is gone from memory.
Where will the ALAC file work?
Every Apple device and application plays ALAC natively, and cross-platform players such as VLC and foobar2000 handle it on Windows, Linux, and Android. Outside the Apple world support varies by player, which is why cross-platform archives still tend to favor FLAC.
Will the ALAC file be bigger or smaller than my MTS?
Much smaller — the video stream is usually 80–95% of a .mts file's weight, and it is discarded entirely. The remaining audio is re-encoded at the bitrate implied by your quality setting.
What happens to the metadata in my MTS file?
This converter strips container metadata deliberately (the FFmpeg command runs with metadata mapping disabled) so exported files do not leak recording details. In the source, recording date, camera settings, and GPS coordinates on some models are stored in the AVCHD folder's clip-info files rather than in the .mts stream itself; none of it is transmitted anywhere because the file never leaves your browser.