Convert OGG to FLAC — Free Online Tool
Convert OGG audio files (Vorbis or Opus encoded) to FLAC, a lossless format that preserves every detail of your audio without compression artifacts. This tool is especially useful for archiving OGG files encoded with FLAC streams, or for transcoding lossy Vorbis/Opus content into a universally compatible lossless container.
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FFmpeg Command
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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:
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DownloadHow It Works
OGG is a container format that most commonly holds Vorbis or Opus audio streams — both of which are lossy codecs. When converting OGG to FLAC, FFmpeg decodes the compressed audio stream back to raw PCM audio, then re-encodes it using the FLAC lossless codec. This means the output FLAC file will be a lossless representation of the decoded audio — no further lossy degradation occurs during the conversion itself. However, if the source OGG contained a lossy Vorbis or Opus stream, any artifacts introduced during the original encoding are already baked into the audio and cannot be recovered. The exception is OGG files that contain a native FLAC stream (ogg/flac), which can be remuxed with minimal processing. The output FLAC file uses compression level 5 by default, which balances file size reduction against encoding speed without affecting audio quality.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg command-line tool, which handles decoding the OGG container and its audio stream, then re-encoding and muxing the output FLAC file. |
-i input.ogg
|
Specifies the input OGG file. FFmpeg automatically detects the container format and the audio codec inside (Vorbis, Opus, or FLAC) and prepares the appropriate decoder. |
-c:a flac
|
Tells FFmpeg to encode the audio stream using the FLAC lossless codec. The decoded PCM audio from the OGG source is passed directly to the FLAC encoder, ensuring no additional lossy processing occurs. |
-compression_level 5
|
Sets the FLAC compression level to 5 out of a maximum of 8. This controls only the efficiency of the lossless compression algorithm — higher values produce slightly smaller files but take longer to encode. Audio quality is identical at every level. |
output.flac
|
Specifies the output filename with the .flac extension. FFmpeg uses this extension to confirm the output container format, producing a standard FLAC file compatible with virtually all audio players and editing software. |
Common Use Cases
- Archiving a music collection originally distributed in OGG Vorbis format into FLAC for long-term storage in a lossless container
- Preparing OGG audio files for import into a DAW (like Audacity or Reaper) that handles FLAC more reliably than OGG for editing workflows
- Converting OGG audiobook or podcast files to FLAC for playback on hardware players or home theater systems that support FLAC but not OGG
- Standardizing a mixed audio library to a single lossless format (FLAC) for use with music players like foobar2000, Roon, or Plex
- Extracting and converting a lossless OGG/FLAC stream into a standalone FLAC file for compatibility with software that requires the dedicated FLAC container
- Preserving game audio assets distributed in OGG format by converting them to FLAC before editing or re-using them in a project
Frequently Asked Questions
No — if your OGG file contains a lossy Vorbis or Opus stream, converting it to FLAC will not recover any quality that was lost during the original OGG encoding. FLAC is a lossless format, meaning it will preserve the decoded audio exactly as-is, including any artifacts from the original compression. The benefit is that no additional quality loss occurs during or after this conversion, making FLAC a better container for archiving or further processing.
OGG files (typically containing Vorbis or Opus audio) use lossy compression, which achieves small file sizes by discarding audio information the encoder deems imperceptible. FLAC uses lossless compression, which retains all audio data and therefore produces larger files. A high-quality OGG Vorbis file at around 192 kbps might expand to several times its size when losslessly encoded as FLAC, since FLAC must store the full PCM audio data with only lossless compression applied.
OGG supports chapter markers and rich metadata tags, but the FLAC format does not support chapters. During this conversion, chapter information will be lost. Standard metadata tags such as title, artist, album, and track number stored in OGG Vorbis Comment format are compatible with FLAC's Vorbis Comment metadata block, so those tags should be preserved by FFmpeg during the conversion.
No. FLAC supports only a single audio track per file. If your OGG container holds multiple audio streams (for example, multiple language tracks), FFmpeg will by default select only the first (or best-ranked) audio stream for the FLAC output. If you need a specific track, you can modify the FFmpeg command to add '-map 0:a:1' (for the second audio track, zero-indexed) before the output filename.
The '-compression_level 5' flag controls how aggressively FLAC compresses the audio data. You can set it to any integer from 0 (fastest encoding, largest file) to 8 (slowest encoding, smallest file). Importantly, this setting has no effect on audio quality — all compression levels produce bit-for-bit identical audio output. For example, use 'ffmpeg -i input.ogg -c:a flac -compression_level 8 output.flac' for the smallest possible FLAC file, at the cost of slower encoding.
Yes. On Linux or macOS, you can use a shell loop: 'for f in *.ogg; do ffmpeg -i "$f" -c:a flac -compression_level 5 "${f%.ogg}.flac"; done'. On Windows Command Prompt, use: 'for %f in (*.ogg) do ffmpeg -i "%f" -c:a flac -compression_level 5 "%~nf.flac"'. This applies the same conversion settings to every OGG file in the current directory, outputting a corresponding FLAC file for each.
Technical Notes
OGG is a container that most commonly carries Vorbis (lossy, variable bitrate) or Opus (lossy, low-latency optimized) audio, though it can also encapsulate a native FLAC stream (sometimes called OGG FLAC or .oga). FFmpeg's decoding pipeline handles all three transparently before re-encoding to FLAC. The output uses FFmpeg's 'flac' encoder, which is fully compliant with the FLAC specification. FLAC compression level 5 is the default and represents a widely used middle ground — encoding is fast enough for real-time use and file sizes are reasonable. Note that FLAC does not support subtitles, and unlike OGG, it is limited to a single audio stream per file. The FLAC format does support cue sheets and ReplayGain tags, which can be embedded separately using tagging tools if needed after conversion. If your OGG source file contains a lossless FLAC audio stream natively, the decoded PCM will be perfectly reconstructed and re-encoded to FLAC with no generational loss of any kind.