Convert MTS to FLAC — Free Online Converter
Convert AVCHD Video (.mts) to Free Lossless Audio Codec (.flac) online for free. Fast, secure video conversion with no watermarks or registration....
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How to Convert
Upload your .mts 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.
About MTS to FLAC Conversion
AVCHD camcorders record audio as either AC3 (Dolby Digital) at 256-640 kbps or LPCM at 1536 kbps — both substantially higher quality than typical consumer audio recordings. FLAC (Free Lossless Audio Codec) compresses audio by 30-50% without losing a single sample. Converting MTS to FLAC extracts the camcorder's high-quality audio track into a compact lossless format suitable for archiving, editing, and cross-platform distribution.
Why Convert MTS to FLAC?
Camcorder audio often contains irreplaceable recordings — wedding ceremonies, live performances, family milestones, nature soundscapes. FLAC provides the safest archival format because it is lossless (no degradation over any number of accesses), open-source (no vendor lock-in), and compressed (half the size of WAV/AIFF). Unlike AAC or MP3, FLAC guarantees that every future use of the audio starts from the best possible quality.
FLAC is also the preferred format for music archives, radio stations, and institutional sound collections. The format's built-in integrity checking (MD5 fingerprint) ensures that stored files have not been corrupted — an essential feature for long-term audio preservation.
Common Use Cases
- Archiving wedding and family event audio from AVCHD camcorder recordings
- Extracting live performance recordings from camcorder footage for lossless music archives
- Creating lossless audio masters from documentary camcorder footage
- Building nature sound libraries from camcorder ambient recordings
- Preserving interview audio from camcorder recordings for institutional archives
How It Works
FFmpeg discards video and encodes audio to FLAC: `-vn -c:a flac -compression_level 8 -ar 48000 -ac 2`. For 5.1 AC3 sources, FLAC supports up to 8 channels: `-ac 6` preserves all surround channels. FLAC compression levels (0-12) affect only encoding speed — decoded quality is identical at all levels. Level 8 provides good compression with reasonable encoding speed.
Quality & Performance
FLAC is mathematically lossless. If the MTS contains LPCM audio, the FLAC file is a bit-perfect compressed copy. If the source is AC3, the decoded AC3 audio is preserved exactly in FLAC without any further loss. File sizes are roughly 15-20 MB per minute for stereo 48 kHz content.
Device Compatibility
| Device | MTS | FLAC |
|---|---|---|
| Windows PC | Partial | Partial |
| macOS | Partial | Partial |
| iPhone/iPad | Partial | Partial |
| Android | Partial | Native |
| Linux | Partial | Native |
| Web Browser | No | No |
Recommended Settings by Platform
YouTube
Resolution: 1920x1080
Bitrate: 8-12 Mbps
H.264 recommended for fast processing
Resolution: 1080x1080
Bitrate: 3.5 Mbps
Square or 9:16 for Reels
TikTok
Resolution: 1080x1920
Bitrate: 4 Mbps
9:16 vertical, under 60s ideal
Twitter/X
Resolution: 1280x720
Bitrate: 5 Mbps
Under 140s, 512MB max
Resolution: 960x540
Bitrate: 2 Mbps
16MB limit for standard, 64MB for document
Discord
Resolution: 1280x720
Bitrate: 4 Mbps
8MB free, 50MB Nitro
Tips for Best Results
- 1Use compression level 5-8 for the best balance of file size and encoding speed — higher levels save trivial additional space
- 2Preserve 5.1 surround channels in FLAC if the MTS has AC3 audio — you can always downmix later, but you cannot recreate surround from stereo
- 3Verify FLAC integrity after archiving with `flac --test` to ensure no corruption during storage or transfer
- 4Tag FLAC files with recording date, location, and event metadata for organized archive browsing
- 5Use FLAC as your master format, then derive AAC, MP3, or other formats from it as needed — lossless masters future-proof your audio archive
Related Conversions
MTS to FLAC conversion preserves camcorder audio in the best possible format for long-term archival — lossless, open-source, and compact enough for practical storage of large recording collections.