Convert M4V to FLAC — Free Online Tool
Extract lossless audio from an M4V video file and save it as FLAC. This tool strips the video stream entirely and re-encodes the AAC or MP3 audio track from your iTunes or iOS-compatible M4V into a lossless FLAC file — ideal for archiving or high-fidelity playback.
to
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 typically carry AAC audio (sometimes MP3) alongside an H.264 or H.265 video stream inside an MPEG-4 container. Because FLAC is a pure audio format, the video stream is discarded entirely — not remuxed or re-encoded, simply dropped. The audio track is then decoded from its original lossy AAC compression and re-encoded into FLAC's lossless compression. It is important to understand that FLAC is lossless in the sense that it preserves every bit of the decoded PCM audio — but it cannot recover detail that AAC already discarded during its original lossy encoding. The result is a bit-perfect archive of whatever audio quality was present in the M4V source. FLAC then applies its own lossless compression (level 5 by default) to reduce file size without any further quality degradation.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg tool, which handles the reading, decoding, and re-encoding pipeline for this M4V-to-FLAC conversion. |
-i input.m4v
|
Specifies the input M4V file. FFmpeg reads the MPEG-4 container, identifying all streams — including H.264/H.265 video and AAC audio — before applying the output mapping rules. |
-c:a flac
|
Sets the audio codec to FLAC for the output. FFmpeg decodes the M4V's AAC audio to raw PCM and then re-encodes it using FLAC's lossless compression algorithm, producing a bit-perfect audio archive. |
-compression_level 5
|
Sets FLAC's lossless compression effort to level 5 on a scale of 0 to 8. This affects only encode speed and output file size — not audio quality, which is always bit-perfect regardless of the level chosen. Level 5 is the FLAC default and offers a practical balance between speed and compression ratio. |
output.flac
|
Defines the output filename and format. The .flac extension tells FFmpeg to use the FLAC container. Because FLAC is audio-only, the video stream from the M4V is automatically dropped — no explicit video discard flag is needed since the FLAC muxer simply does not accept video streams. |
Common Use Cases
- Archiving the audio from purchased iTunes movie or TV downloads in a lossless format that isn't tied to Apple's ecosystem or DRM restrictions on non-protected files
- Extracting a musical score or soundtrack embedded in an M4V video for high-quality listening without re-encoding through another lossy stage
- Preparing M4V audio tracks for mastering or audio editing workflows where FLAC's lossless PCM-accurate output is required by the DAW or editor
- Stripping audio from iOS-recorded video (saved as M4V) to produce a clean lossless audio file for podcast production or voice-over archiving
- Converting M4V lecture or conference recordings into FLAC so the audio can be stored long-term in a format supported by music library managers like Roon, Plex, or MusicBrainz Picard
- Feeding M4V audio into a lossless comparison workflow to evaluate the quality of the original AAC encode without introducing additional codec artifacts
Frequently Asked Questions
The FLAC file will be a lossless representation of the audio as it exists in the M4V — but AAC itself is a lossy codec, so any detail discarded during the original AAC encoding is permanently gone. FLAC cannot recover that lost information. What you get is a bit-perfect, uncompressed-equivalent capture of the decoded AAC signal, which is useful for archiving and further processing without introducing any new quality loss.
The video stream — whether H.264 or H.265 — is completely discarded. FFmpeg reads the M4V container, ignores all video packets, and only processes the audio track. The output FLAC file contains no video data whatsoever. If you need to keep the video, you would need to choose a different output format such as MKV or MP4.
FFmpeg will attempt to copy compatible metadata tags — such as title, artist, album, and track number — from the M4V container's iTunes-style atoms into FLAC's Vorbis comment metadata block. However, M4V-specific metadata like chapter markers, multiple audio track labels, and iTunes cover art may not transfer cleanly or completely, since FLAC does not support chapters or multiple audio tracks. Basic tags generally carry over reliably.
Replace the value after -compression_level with any integer from 0 to 8. Level 0 is the fastest but produces the largest file, while level 8 is the slowest but achieves maximum compression. Crucially, all levels produce identical audio quality — only encode speed and file size differ. The default of 5 is a well-balanced midpoint. For example: ffmpeg -i input.m4v -c:a flac -compression_level 8 output.flac for maximum compression.
Yes. On Linux or macOS, you can use a shell loop: for f in *.m4v; do ffmpeg -i "$f" -c:a flac -compression_level 5 "${f%.m4v}.flac"; done. On Windows Command Prompt, use: for %f in (*.m4v) do ffmpeg -i "%f" -c:a flac -compression_level 5 "%~nf.flac". The browser-based tool processes one file at a time, so the FFmpeg command is especially useful for batch workflows on large collections.
AAC is a highly efficient lossy codec that achieves small file sizes by permanently removing audio data the encoder deems perceptually unimportant. FLAC, being lossless, must store the full decoded PCM audio waveform (just compressed without loss), which is inherently much larger than a lossy AAC stream at the same duration. Expect FLAC files to be significantly larger than the audio-only portion of the source M4V — this is expected and correct behavior.
Technical Notes
M4V is structurally very close to MP4, and its audio is almost universally AAC encoded at bitrates between 128 kbps and 256 kbps for iTunes content. The conversion process involves full AAC decoding to raw PCM followed by FLAC lossless encoding — this is a transcode, not a remux, because FLAC cannot natively carry AAC streams. The -compression_level parameter in FLAC controls only the efficiency of the lossless compression algorithm (affecting encode speed and output file size) and has zero effect on audio fidelity. M4V files may contain multiple audio tracks (e.g., stereo and surround), but FLAC supports only a single audio track — FFmpeg will select the default or first audio stream. If your M4V has a 5.1 surround track, FFmpeg will encode all six channels into a multi-channel FLAC file, which is valid but has limited player support compared to stereo FLAC. M4V chapter data and subtitle tracks are incompatible with FLAC and are silently dropped. DRM-protected M4V files (FairPlay-encrypted iTunes purchases) cannot be processed by FFmpeg or this tool — only DRM-free M4V files are supported.