Convert MKV to FLAC Online Free
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Extract the audio track from your Matroska MKV video and save it as lossless FLAC. Perfect for archiving soundtracks, ripping anime audio, and preserving high-quality audio from MKV media collections.
By ChangeThisFile Team · Last updated: March 2026
ChangeThisFile extracts the audio track from your Matroska MKV video and encodes it as lossless FLAC using FFmpeg on our secure servers. MKV files often contain high-quality audio tracks ideal for lossless archiving. Files are auto-deleted, free with no signup required.
Matroska vs FLAC: Format Comparison
Key differences between the two formats
| Feature | MKV (Matroska) | FLAC |
|---|---|---|
| Type | Open video container (audio + video) | Lossless audio-only format |
| Developer | Matroska.org (open standard) | Xiph.Org Foundation |
| Audio codec | AC-3, DTS, AAC, FLAC, TrueHD, or PCM | FLAC lossless codec |
| File size | Large (HD video included) | Moderate — lossless audio compression only |
| Audio quality | Often high or lossless (DTS, TrueHD) | Bit-perfect reproduction of decoded audio |
| Multiple tracks | Yes — multiple audio/subtitle tracks | Single audio stream |
| Use case | HD media files, rips, anime, films | Audiophile libraries, DAW editing, archiving |
When to Convert
Common scenarios where this conversion is useful
Extract lossless audio from HD film or anime MKV rips
MKV files from Blu-ray rips often contain DTS-HD, TrueHD, or lossless PCM audio tracks. Converting to FLAC decodes these streams into a lossless, portable format suitable for audiophile playback without a Blu-ray player.
Rip and archive video game soundtrack MKV files
Extracted video game cutscenes and trailers are often MKV files. Converting the audio to FLAC creates a lossless archive of game soundtracks that can be organized in a music library and played on any device.
Create FLAC versions of anime episodes' audio tracks
Anime MKV files frequently include multiple audio tracks (Japanese, English dub). Extract your preferred audio track as FLAC to create a lossless audio collection from anime series you enjoy.
Prepare MKV dialogue for professional audio editing
Extract dialogue or voice-over tracks from MKV source files as FLAC for lossless audio editing in a DAW. Starting with FLAC preserves maximum quality throughout the editing and export process.
Build a lossless music library from concert MKV recordings
Concert recordings distributed in MKV format often contain high-quality audio. Extract to FLAC to add them to a lossless music library managed by Plex, Kodi, or Foobar2000 with full metadata.
Who Uses This Conversion
Tailored guidance for different workflows
Podcasters
- Pull the audio from a recorded Matroska interview or webinar and publish it as a FLAC episode
- Convert a Matroska livestream recording to FLAC so listeners can catch up on the go
Musicians & Producers
- Extract a performance take from a Matroska video into FLAC to edit in your DAW
- Rip reference audio from a Matroska clip to FLAC for sampling or transcription
Content Creators
- Convert a Matroska recording to FLAC to reuse the soundtrack as background audio or a voiceover
- Turn a Matroska talk into a FLAC audiogram or clip for social platforms
How to Convert Matroska to FLAC
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1
Upload your MKV file
Drag and drop your .mkv file onto the converter or click to browse and select it. The free tier accepts files up to 25MB; eligible paid browser access accepts up to 100MB.
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2
Server-side FLAC extraction
Your MKV is uploaded over HTTPS and FFmpeg extracts the default audio track. Lossless audio (FLAC, PCM) is re-wrapped or decoded into FLAC. Lossy audio (AAC, AC-3) is decoded and stored losslessly in FLAC. The video stream is discarded.
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3
Download your FLAC file
Click Download to save the .flac file. The original MKV and converted FLAC are automatically deleted from our servers after download.
Developers: convert via API →
Frequently Asked Questions
MKV is an extremely flexible container that supports virtually any audio codec. Common codecs in MKV files include AAC, MP3, AC-3 (Dolby Digital), DTS, DTS-HD, TrueHD, FLAC, and uncompressed PCM. FFmpeg handles all of these during FLAC extraction.
The converter extracts the default (first) audio track from the MKV. MKV files sometimes contain multiple language tracks or commentary. To extract a specific track, consider using FFmpeg directly with the -map flag to select the desired stream.
Yes. If the MKV already contains FLAC audio, FFmpeg can stream-copy it directly into a standalone FLAC file with zero re-encoding and zero quality loss.
DTS audio is decoded from a lossy DTS stream, then stored losslessly in FLAC. The FLAC will contain an exact representation of the DTS audio data without further quality loss — but DTS itself is lossy, so perfect PCM quality cannot be recovered.
FLAC extracts only the audio stream and compresses it losslessly. For typical HD video MKV files, the FLAC will be dramatically smaller (a fraction of the size) since the video stream is removed.
FLAC is supported by VLC, Foobar2000, Kodi, Plex, Winamp, Android natively, and macOS/iOS since version 10.13/iOS 11. It is one of the most widely supported audio formats outside of MP3 and AAC.
Yes. FLAC supports up to 8 channels of audio. 5.1 or 7.1 surround audio from MKV files will be preserved in the FLAC output with all channels intact.
Yes. ChangeThisFile is completely free. No signup, no limits, and no fees.
Audio-only extraction is fast — typically under 30 seconds for most videos. For very long MKV files, it may take up to a minute. Only the audio stream is processed, not the video.
Yes. All uploads use HTTPS encryption. Files are automatically deleted from servers immediately after conversion. We never store or access your content.
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