Convert M4V to ALAC — Free Online Tool
Convert M4V video files to ALAC (Apple Lossless Audio Codec) .m4a files, extracting and losslessly re-encoding the AAC audio track into a bit-perfect lossless format. Ideal for archiving iTunes video purchases or iOS content as high-quality audio files compatible with Apple Music, iTunes, and all Apple devices.
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FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
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Note: Browser-based encoding uses approximate quality targets. For precise CRF compression, copy the FFmpeg command above and run it on your desktop.
Estimated output:
Conversion Complete!
DownloadHow It Works
M4V files contain video streams (typically H.264 or H.265) alongside AAC or MP3 audio tracks wrapped in an MPEG-4 container. During this conversion, FFmpeg discards the video stream entirely and re-encodes the audio track using Apple's ALAC codec, storing the result in an .m4a container — also MPEG-4 based, making the transition structurally clean. Unlike simply copying the AAC stream, ALAC is a lossless codec, meaning the output audio is mathematically reconstructable to a high-quality PCM representation. Note that if the source audio was AAC (lossy), the ALAC output will be a lossless encoding of that lossy audio — it won't recover detail lost during the original AAC encoding, but it will perfectly preserve whatever audio data exists in the M4V without introducing any additional generation loss.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg binary — the open-source multimedia processing engine running here as FFmpeg.wasm compiled to WebAssembly, executing entirely in your browser without any server upload. |
-i input.m4v
|
Specifies the input M4V file. FFmpeg reads and demuxes the MPEG-4 container, identifying the video stream (H.264/H.265) and the audio stream (typically AAC) for processing. |
-c:a alac
|
Sets the audio codec to ALAC (Apple Lossless Audio Codec), instructing FFmpeg to re-encode the M4V's AAC audio track into a lossless ALAC stream for the output file. This flag appears twice in the resolved command, which is redundant but does not change the result. |
-c:a alac
|
A duplicate of the preceding audio codec flag — FFmpeg processes the last valid instance, so the behavior is identical to specifying it once. The output audio will still be encoded as ALAC. |
output.m4a
|
Defines the output filename with the .m4a extension, signaling an MPEG-4 audio container. FFmpeg automatically drops the video stream since the .m4a format is audio-only, and wraps the ALAC-encoded audio in the container alongside any supported metadata and chapter markers from the source M4V. |
Common Use Cases
- Archive the audio from iTunes movie or TV show purchases as lossless .m4a files for long-term preservation without re-encoding losses
- Extract high-quality audio from a music video downloaded in M4V format to create an archival master for an Apple Music library
- Convert iOS-recorded video content to ALAC for use in professional audio workflows on a Mac where lossless source material is required
- Prepare audio from an M4V lecture or educational video for lossless editing in GarageBand or Logic Pro before further processing
- Strip video from M4V content to create ALAC audio files compatible with Apple TV playback via Home Sharing or local media libraries
- Convert M4V audiobook content with multiple audio tracks into a lossless format while retaining chapter metadata for structured playback
Frequently Asked Questions
No — ALAC is a lossless codec, but it cannot recover audio information that was discarded when the original AAC track was encoded. If your M4V contains AAC audio at 128k, converting to ALAC will produce a lossless representation of that 128k AAC signal, not a higher-fidelity version. The benefit is that no additional quality is lost in this conversion and all future processing starts from the same baseline without accumulating further lossy encoding artifacts.
ALAC uses lossless compression, which by definition retains all audio data and cannot achieve the same file size reductions as lossy codecs like AAC. AAC typically compresses audio to a fraction of its uncompressed size by discarding perceptually irrelevant data; ALAC simply compresses losslessly, resulting in files significantly larger than equivalent AAC content but smaller than raw PCM (WAV/AIFF). The video stream is removed entirely, but the ALAC audio alone will be larger than just the AAC stream from the original M4V.
ALAC in an .m4a container does support chapter metadata, and FFmpeg will attempt to carry over chapter markers from the M4V during conversion. However, M4V chapters are stored as QuickTime-style text tracks, and compatibility in the output depends on your playback software. iTunes and Apple Music on macOS tend to handle ALAC chapter markers well, making this a good workflow for audiobook-style content originally packaged as M4V.
By default, FFmpeg selects the first or 'best' audio stream according to its internal stream selection logic, which is typically the default audio track. ALAC .m4a does not support multiple simultaneous audio tracks, so only one stream will be encoded. If your M4V contains alternate language tracks or commentary audio and you want a specific track, you would need to add a stream selector like '-map 0:a:1' to the FFmpeg command to target the second audio stream explicitly.
ALAC is a lossless codec, so there are no bitrate or quality parameters to tune — the codec always produces a mathematically lossless result. Unlike AAC with '-b:a' or Vorbis with '-q:a', the '-c:a alac' flag produces output at full lossless fidelity by design. The only meaningful variation would be the sample rate or bit depth of the source audio, which FFmpeg preserves from the M4V input automatically unless you explicitly resample with '-ar' or '-sample_fmt'.
On macOS or Linux, you can batch convert all M4V files in a directory using a shell loop: 'for f in *.m4v; do ffmpeg -i "$f" -c:a alac "${f%.m4v}.m4a"; done'. On Windows Command Prompt, use: 'for %f in (*.m4v) do ffmpeg -i "%f" -c:a alac "%~nf.m4a"'. This applies the same lossless ALAC extraction to every M4V in the folder, which is especially useful since the browser-based tool handles files up to 1GB but desktop FFmpeg has no such limit.
Technical Notes
Both M4V and the ALAC output .m4a share the MPEG-4 container foundation, which makes this a structurally compatible conversion — FFmpeg is writing into a format from the same container family. The ALAC codec ('alac' in FFmpeg) was open-sourced by Apple in 2011 and is natively supported across all Apple platforms, meaning the output .m4a files will play in iTunes, Apple Music, QuickTime, iOS, tvOS, and macOS without any additional codec installation. One important limitation: if the M4V file is DRM-protected (FairPlay DRM, common on iTunes Store purchases), FFmpeg cannot read the encrypted streams and the conversion will fail — only DRM-free M4V files are processable. Metadata tags such as title, artist, and album are generally preserved through the MPEG-4 container, but M4V-specific video metadata (resolution, frame rate tags) is naturally dropped since the output is audio-only. The duplicate '-c:a alac' flag in the resolved command is redundant but harmless — a single '-c:a alac' is sufficient and is what FFmpeg acts on.