Convert MPEG-4 Part 14 (.mp4) to Free Lossless Audio Codec (.flac) online for free. Fast, secure video conversion with no watermarks or registration.
Conversion settings — add a file to adjust
Upload your .mp4 file by dragging it into the upload area or clicking to browse.
Choose your output settings. The default settings work great for most files.
Click Convert and download your .flac file when it's ready.
MP4 to FLAC conversion extracts the audio track from an MPEG-4 video and encodes it as a Free Lossless Audio Codec file. FLAC is the most widely supported open-source lossless audio format, compatible with Android, Windows, Linux, most car stereos, and a growing number of Apple devices (since iOS 11). Unlike lossy formats, FLAC compresses audio without discarding any data, achieving 40-60% size reduction compared to raw PCM.
Our converter decodes the audio from your MP4 and re-encodes it with the reference FLAC encoder. Metadata including title, artist, and album can be carried through if present in the source file.
FLAC is the standard for lossless audio outside the Apple ecosystem. Audiophiles, music producers, and archivists choose FLAC for its perfect fidelity, open-source nature, and universal support. Extracting audio from video as FLAC ensures you have the highest quality master for future use — you can always transcode FLAC to MP3 or AAC later without going back to the video file. Streaming services like Tidal and Amazon Music HD use FLAC for their lossless tiers.
FFmpeg decodes the MP4 audio stream and feeds PCM samples to the FLAC encoder. Compression level defaults to 5 (on a 0-8 scale), balancing encoding speed with file size. Higher levels (7-8) produce slightly smaller files but take significantly longer. FLAC supports up to 32-bit depth and 655,350 Hz sample rate, though typical output is 16-bit or 24-bit at 44.1 or 48 kHz. The FLAC container stores Vorbis comments for metadata and supports embedded album art.
FLAC is bit-perfect lossless. The decoded output is identical to the PCM audio input. However, since most MP4 files contain lossy AAC audio, the FLAC preserves the decoded AAC stream perfectly but cannot recover data lost during AAC encoding. The value is in preventing any further quality degradation and providing a format suitable for critical listening equipment.
| Device | MP4 | FLAC |
|---|---|---|
| Windows PC | Native | Partial |
| macOS | Native | Partial |
| iPhone/iPad | Native | Partial |
| Android | Native | Native |
| Linux | Partial | Native |
| Web Browser | Native |
Resolution: 1920x1080
Bitrate: 8-12 Mbps
H.264 recommended for fast processing
Resolution: 1080x1080
Bitrate: 3.5 Mbps
Square or 9:16 for Reels
Resolution: 1080x1920
Bitrate: 4 Mbps
9:16 vertical, under 60s ideal
Resolution: 1280x720
Bitrate: 5 Mbps
Under 140s, 512MB max
Resolution: 960x540
Bitrate: 2 Mbps
16MB limit for standard, 64MB for document
Resolution: 1280x720
Bitrate: 4 Mbps
8MB free, 50MB Nitro
FLAC is the gold standard for lossless audio preservation. Converting MP4 to FLAC gives you the highest quality audio extraction in a format supported by virtually every non-Apple platform.
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| No |
| 特徴 | MP4 | FLAC |
|---|---|---|
| 正式名称 | MPEG-4 Part 14 | Free Lossless Audio Codec |
| 拡張子 | .mp4 | .flac |
| 最適な用途 | Universal compatibility | Lossless compression |