Extract Audio from MKV to OGG — Free Online Tool
Extract and convert audio from MKV video files to OGG format using the open-source Vorbis codec, entirely in your browser. This tool strips the video stream and re-encodes the audio to OGG Vorbis — the ideal open-standard format for web audio, Linux applications, and royalty-free distribution.
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FFmpeg Command
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Settings
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
MKV files commonly carry audio encoded in AAC, MP3, Opus, or FLAC. During this conversion, the video stream is completely discarded (using the -vn flag) and the audio stream is re-encoded using the libvorbis encoder into an OGG container. This is a full audio transcode — the audio is decoded from its original codec and re-encoded as Vorbis using a variable bitrate quality scale. If the MKV already contains a Vorbis audio stream, the re-encoding still occurs to ensure clean OGG output. The resulting OGG file retains basic metadata tags and chapter markers if present in the source MKV, but subtitles and multiple audio tracks are not carried over — only the primary audio stream is extracted.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg command-line tool, the open-source multimedia processing engine that powers this conversion. In the browser-based version of this tool, FFmpeg runs as a WebAssembly binary (FFmpeg.wasm) with no server involvement. |
-i input.mkv
|
Specifies the input file, an MKV (Matroska) container that may contain video, audio, subtitles, and chapter data. FFmpeg reads all available streams from this file and makes them available for processing or discarding. |
-vn
|
Disables video output entirely, telling FFmpeg to ignore all video streams from the MKV. This is the core of the audio extraction — no video data is written to the OGG output file, which is a audio-only format anyway. |
-c:a libvorbis
|
Specifies the Vorbis encoder (libvorbis) for the audio stream, producing audio compatible with the OGG container. Vorbis is the default and most widely supported codec for OGG files, and unlike MP3 or AAC, it is completely patent-free. |
-q:a 4
|
Sets the Vorbis variable bitrate quality to level 4 on a 0–10 scale, which targets approximately 128–160 kbps. This is the default balance between file size and audio fidelity — raise this value toward 8–10 for music or high-quality audio, or lower it toward 1–2 for voice-only content like podcasts. |
output.ogg
|
Defines the output filename and format. The .ogg extension tells FFmpeg to wrap the encoded Vorbis audio stream in an OGG container, the open standard developed by Xiph.Org for streaming and storing Vorbis, Opus, and FLAC audio. |
Common Use Cases
- Extract the audio commentary track from an MKV film rip to create a standalone OGG file for listening on a Linux media player like Rhythmbox or Audacious
- Convert MKV game cutscene files to OGG for use as background music or sound assets in open-source game engines like Godot, which natively support OGG Vorbis
- Strip the audio from an MKV lecture recording to produce a royalty-free, patent-free OGG podcast episode for hosting on open platforms
- Extract a Vorbis-compatible audio track from an MKV screencast so it can be embedded directly in a web page using the HTML5 audio element without licensing concerns
- Convert MKV anime episodes to OGG to extract Japanese audio tracks for language learning applications that accept open audio formats
- Pull audio from an MKV music concert video to create an OGG archive that is smaller than FLAC but higher quality than heavily compressed MP3 at equivalent bitrates
Frequently Asked Questions
Yes, unless the source MKV already contains FLAC or uncompressed audio, there will be some generational quality loss because Vorbis is a lossy codec and the audio is being decoded and re-encoded. If the MKV audio is already AAC or MP3, you are transcoding from one lossy format to another, which compounds compression artifacts. At the default quality setting of -q:a 4, Vorbis produces approximately 128–160 kbps variable bitrate audio, which is generally transparent for most listeners, but for archival purposes you should consider keeping the original MKV if source quality matters.
By default, FFmpeg selects only the first (or best-ranked) audio stream from the MKV and encodes it into the OGG file. OGG does support multiple audio streams technically, but this tool's command does not explicitly map additional tracks. If your MKV has separate language tracks or commentary streams you need, you would need to modify the command with explicit -map flags to target the desired audio stream by index, such as -map 0:a:1 for the second audio track.
OGG Vorbis has excellent support on Linux, Android, and all major modern browsers except Safari, which historically has had limited native OGG support without plugins. Windows and macOS do not natively support OGG playback in the operating system's built-in media players, though applications like VLC, foobar2000, and Firefox handle it without issues. If cross-platform compatibility with Apple devices is a priority, you may want to consider MP3 or AAC output instead.
Yes. You can modify the command to target a specific audio stream using the -map flag. For example, to extract the second audio track (index 1), run: ffmpeg -i input.mkv -vn -map 0:a:1 -c:a libvorbis -q:a 4 output.ogg. You can first inspect your MKV's streams by running ffmpeg -i input.mkv without any output file, which will list all available video, audio, and subtitle tracks with their indices.
The -q:a flag controls Vorbis variable bitrate quality on a scale from 0 (lowest, roughly 64 kbps) to 10 (highest, roughly 500 kbps), with 4 being the default and approximating 128–160 kbps. To increase quality, raise the value — for example, -q:a 6 targets approximately 192 kbps and is a good choice for music, while -q:a 8 approaches archival quality near 256 kbps. To reduce file size at the cost of quality, lower the value to -q:a 2 or -q:a 1, which is still acceptable for voice content like podcasts or lectures.
OGG does support chapter metadata, and FFmpeg will attempt to carry over chapter information from the MKV during this conversion. However, OGG chapter support is less standardized than in MKV, and not all OGG-compatible players will read or display chapter markers correctly. Metadata tags such as title, artist, and album are generally preserved as Vorbis comment tags in the OGG output, but complex MKV metadata structures may not map perfectly to the simpler Vorbis comment format.
Technical Notes
OGG is a container format developed by Xiph.Org, and in this conversion it carries a Vorbis audio stream — one of the few major audio codecs that is entirely free of patents and royalties. The libvorbis encoder used here implements variable bitrate encoding governed by the -q:a quality scale, meaning the actual bitrate fluctuates based on the complexity of the audio signal rather than being fixed. This makes Vorbis particularly efficient for content with varying dynamics. A known limitation is that the OGG format does not support subtitles, so any subtitle streams in the source MKV are silently dropped. Additionally, if the MKV contains multiple audio tracks — common in multi-language releases — only one track is extracted unless the FFmpeg command is modified with explicit stream mapping. For MKV files that contain FLAC audio, this conversion introduces lossy compression for the first time; to preserve lossless quality, consider using the libopus codec at high bitrates or outputting to OGG FLAC with -c:a flac instead. The resulting OGG files are broadly compatible with web deployment via the HTML5 audio element, though a fallback format is advisable for Safari users.