Extract Audio from CAVS to OGG — Free Online Tool
Extract audio from CAVS (Chinese Audio Video Standard) files and convert it to OGG format using the open Vorbis codec. CAVS files carry AAC audio, which gets re-encoded to libvorbis inside an OGG container — ideal for open-format archiving or web audio playback.
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FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
Drop your CAVS file here
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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
CAVS files store audio as AAC streams alongside video encoded with a codec based on the Chinese national standard. This tool discards the video stream entirely (-vn) and re-encodes only the AAC audio track into Vorbis (libvorbis), placing it inside an OGG container. Because AAC and Vorbis use fundamentally different psychoacoustic models, a full re-encode is required — there is no lossless remux path between these two codecs. The default quality setting (-q:a 4) uses Vorbis's variable bitrate mode, targeting roughly 128–160 kbps, which provides transparent quality for most source material while keeping file sizes manageable.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg program, the open-source multimedia processing engine that powers this conversion entirely within your browser via WebAssembly. |
-i input.cavs
|
Specifies the input file in CAVS format. FFmpeg will demux this file to access its video and audio streams, including the AAC audio track that will be re-encoded. |
-vn
|
Disables video output entirely, instructing FFmpeg to discard the CAVS video stream and produce an audio-only file. This is essential since OGG is being used here purely as an audio container. |
-c:a libvorbis
|
Selects the libvorbis encoder to transcode the CAVS file's AAC audio into Vorbis format. Vorbis is the native and most widely compatible audio codec for OGG containers. |
-q:a 4
|
Sets the Vorbis variable bitrate quality level to 4 on a 0–10 scale, targeting approximately 128–160 kbps. This is the recommended default that balances audio fidelity with file size when extracting audio from CAVS broadcast content. |
output.ogg
|
Defines the output filename with the .ogg extension, telling FFmpeg to wrap the encoded Vorbis audio stream in an OGG container — an open, royalty-free format maintained by Xiph.Org. |
Common Use Cases
- Extracting dialogue, commentary, or narration from Chinese broadcast CAVS recordings for use in open-source multimedia projects that require patent-free audio formats.
- Converting CAVS audio tracks to OGG Vorbis for playback in open-source games or applications built on engines like Godot that natively favor OGG over AAC.
- Archiving the audio from CAVS broadcast content in an open, royalty-free container format for long-term digital preservation without codec licensing concerns.
- Stripping the audio from CAVS video files to create standalone music or soundtrack files for use in Linux-based environments where OGG has broader native support than AAC.
- Preparing audio extracted from CAVS source material for upload to platforms like Wikipedia/Wikimedia Commons, which require open, patent-unencumbered formats like OGG Vorbis.
- Separating the audio from a CAVS broadcast clip to edit or process it independently in open-source audio editors like Audacity, which handle OGG Vorbis natively.
Frequently Asked Questions
Yes, there is a generation loss because this conversion re-encodes from one lossy format (AAC) to another (Vorbis). The original CAVS file's AAC audio was already compressed, and Vorbis re-encodes it using a different psychoacoustic algorithm. At the default -q:a 4 setting, the quality loss is typically inaudible for speech and subtle for music, but for critical listening applications you should use a higher quality setting like -q:a 7 or -q:a 9.
OGG is a container that supports multiple audio codecs including Vorbis, Opus, and FLAC. This tool defaults to libvorbis because it is the historically standard codec for OGG and has the broadest compatibility with players and platforms that support OGG files. Opus is technically superior at low bitrates, but Vorbis is better recognized as the 'native' OGG codec and remains more universally supported in older software.
The video stream is completely discarded. The -vn flag tells FFmpeg to ignore all video data in the CAVS file, and the OGG container does not support video streams in typical use anyway. Only the audio track is processed, making the output a pure audio OGG file with no video component.
Replace the value after -q:a in the command. Vorbis quality uses a scale from 0 (lowest, ~64 kbps) to 10 (highest, ~500 kbps), with 4 being the default (roughly 128–160 kbps). For example, use 'ffmpeg -i input.cavs -vn -c:a libvorbis -q:a 7 output.ogg' for higher quality output at around 224–320 kbps. For near-lossless quality from your CAVS source, use -q:a 9 or -q:a 10.
Yes, on Linux or macOS you can use a shell loop: 'for f in *.cavs; do ffmpeg -i "$f" -vn -c:a libvorbis -q:a 4 "${f%.cavs}.ogg"; done'. On Windows Command Prompt, use: 'for %f in (*.cavs) do ffmpeg -i "%f" -vn -c:a libvorbis -q:a 4 "%~nf.ogg"'. This is particularly useful for processing large collections of CAVS broadcast recordings where the browser-based tool's 1GB file limit might be a constraint.
FFmpeg will attempt to copy any metadata tags present in the CAVS file into the OGG output automatically. OGG Vorbis supports metadata via Vorbis Comment tags (title, artist, album, etc.), which is a well-supported open standard. However, CAVS files from Chinese broadcast sources may carry minimal or non-standard metadata, so the presence of tags in the output depends entirely on what was embedded in the source file.
Technical Notes
CAVS (Chinese Audio Video Standard) files encode audio exclusively as AAC in typical broadcast implementations, meaning there is no shortcut to losslessly extract audio into an OGG container — OGG does not support AAC streams, so a full transcode through libvorbis is mandatory. The Vorbis codec uses variable bitrate (VBR) encoding by default when the -q:a parameter is used, which is more efficient than CBR for most content types. The OGG container's chapter support is available in the output format spec, but since CAVS does not support chapters, no chapter data will be transferred. Similarly, CAVS does not support multiple audio tracks, so this conversion always processes a single mono or stereo audio stream. One known limitation: if the CAVS source contains non-standard or proprietary audio extensions specific to certain Chinese broadcast systems, FFmpeg may not decode them cleanly, which would result in audio artifacts or decoding errors before the Vorbis encode even begins. The OGG format's open, patent-free status makes these output files suitable for distribution in contexts where codec licensing is a concern, unlike the AAC-bearing CAVS originals.