Convert MOV to CAVS — Free Online Tool
Convert MOV files to CAVS format directly in your browser, encoding video with H.264 (libx264) and audio with AAC to meet the Chinese Audio Video Standard used in Chinese broadcast and distribution pipelines. This tool is especially useful when you need to repackage Apple QuickTime footage into a CAVS-compliant container without professional encoding software.
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FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
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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
MOV is Apple's QuickTime container and can hold a wide variety of codecs including H.264, H.265, VP9, MJPEG, and lossless formats. CAVS, the Chinese Audio Video Standard, is a far more constrained format that only supports H.264 video and AAC audio in its FFmpeg implementation. During this conversion, if your MOV source already uses H.264 video and AAC audio, the streams still cannot simply be remuxed — they must be re-encoded into the CAVS container structure, which does not support transparency, chapter markers, multiple audio tracks, or subtitle streams. Any of those features present in your MOV file will be silently dropped. The video is re-encoded using libx264 at CRF 23 (a visually transparent quality level for most content) and audio is encoded to AAC at 128k bitrate, producing a lossy output in both cases.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg multimedia processing engine. In this browser-based tool, FFmpeg runs as a WebAssembly (FFmpeg.wasm) binary entirely within your browser — no data is sent to a server. The same command can be run identically on a desktop FFmpeg installation for files over 1GB. |
-i input.mov
|
Specifies the input file as a MOV (QuickTime) container. FFmpeg will detect all streams inside — which may include H.264, H.265, ProRes, or other video codecs alongside various audio formats — and use them as the source for re-encoding into CAVS. |
-c:v libx264
|
Sets the video encoder to libx264, FFmpeg's H.264 encoder, which is the only video codec supported by the CAVS container in FFmpeg's implementation. Regardless of what video codec the source MOV uses, the video will be fully re-encoded to H.264. |
-c:a aac
|
Sets the audio encoder to AAC (Advanced Audio Coding), the only audio codec supported by the CAVS container. Any source audio format in the MOV — including FLAC, Opus, MP3, or Vorbis — will be transcoded to lossy AAC. |
-crf 23
|
Sets the Constant Rate Factor for libx264 to 23, which is the default quality level for H.264 encoding. Lower values (e.g., 18) produce higher quality and larger files; higher values (e.g., 28–35) produce smaller files with more visible compression artifacts. This value controls the visual quality of the CAVS output video. |
-b:a 128k
|
Sets the AAC audio bitrate to 128 kilobits per second, a standard quality level suitable for most speech and general video content. If your MOV source contains high-fidelity music or broadcast-quality audio, consider increasing this to 192k or 256k for better audio fidelity in the CAVS output. |
output.cavs
|
Specifies the output filename with the .cavs extension, which tells FFmpeg to write the result into a CAVS container. The .cavs extension is the standard file extension for Chinese Audio Video Standard files and is required for downstream CAVS-compatible playback systems to recognize the format. |
Common Use Cases
- Preparing Apple ProRes or H.264 footage shot on a Mac or iPhone for submission to a Chinese broadcaster that requires CAVS-compliant video files.
- Converting finished video edits exported from Final Cut Pro (which defaults to MOV) into CAVS format for distribution on Chinese streaming or VOD platforms.
- Transcoding archival QuickTime recordings into CAVS for compatibility with Chinese government or institutional media systems that mandate the national standard.
- Testing CAVS output quality and file size before committing to a large batch conversion of MOV master files destined for a Chinese distribution partner.
- Generating the correct FFmpeg command to run locally on a desktop for batch-converting large MOV libraries (over 1GB) to CAVS without uploading sensitive footage to a cloud service.
Frequently Asked Questions
No. CAVS is a much more limited container than MOV and does not support transparency (alpha channels), chapter markers, or multiple audio tracks. If your MOV source contains any of these features — for example, a Final Cut Pro export with chapter markers or a multi-language audio track layout — they will be discarded during conversion. Only the first video stream and the first audio stream will be encoded into the output CAVS file.
Yes. Unlike an MKV-to-MP4 remux where an H.264 stream can be copied without re-encoding, CAVS requires full re-encoding through FFmpeg's libx264 encoder. This means even an H.264 MOV source will undergo a generation loss — the video is decoded and re-encoded at CRF 23 by default. For most content this is visually acceptable, but if you are working with high-value master footage you should consider lowering the CRF value (e.g., to 18) for higher quality at the cost of a larger file.
CAVS stands for Chinese Audio Video Standard, a codec and container format developed by China as a domestic alternative to internationally standardized formats like H.264/AVC. In practice, FFmpeg's CAVS container implementation encodes video using H.264 (libx264) and audio using AAC — so the underlying compression technology is familiar, but the container structure follows the Chinese national standard. It is primarily used in Chinese broadcast, IPTV, and government media contexts rather than general consumer applications.
Adjust the -crf flag in the command. The CRF (Constant Rate Factor) scale for libx264 runs from 0 (lossless) to 51 (worst quality). The default used here is 23, which is a good balance for most content. For higher quality output — for example, when converting broadcast master MOV files — use a lower value like -crf 18. For smaller file sizes where some quality loss is acceptable, use a higher value like -crf 28. The command would look like: ffmpeg -i input.mov -c:v libx264 -c:a aac -crf 18 -b:a 128k output.cavs
Yes. On Linux or macOS you can loop over MOV files in a directory with a shell command like: for f in *.mov; do ffmpeg -i "$f" -c:v libx264 -c:a aac -crf 23 -b:a 128k "${f%.mov}.cavs"; done. On Windows PowerShell you can use: Get-ChildItem *.mov | ForEach-Object { ffmpeg -i $_.FullName -c:v libx264 -c:a aac -crf 23 -b:a 128k ($_.BaseName + '.cavs') }. This is particularly useful for large MOV libraries that exceed the 1GB browser limit of this tool.
Any audio codec other than AAC in the source MOV file will be fully transcoded to AAC at 128k bitrate during the conversion. MOV supports a wide range of audio formats including FLAC, MP3, Opus, and Vorbis, but CAVS only supports AAC. This transcoding step introduces lossy compression regardless of the source quality — if your MOV contains lossless FLAC audio, the output CAVS file will have lossy AAC audio. To preserve as much audio quality as possible, increase the bitrate flag, for example -b:a 256k or -b:a 320k.
Technical Notes
The CAVS format's FFmpeg implementation is significantly more constrained than what its Chinese national standard origins might suggest. In practice, FFmpeg outputs CAVS files using H.264 video (libx264) and AAC audio, making it functionally a specialized container rather than a distinct codec format in the way the standard originally envisioned. Critically, CAVS does not support any of MOV's advanced container features: alpha/transparency channels (common in ProRes 4444 or PNG-coded MOV files used in motion graphics workflows), chapter markers (frequently embedded in Final Cut Pro exports), subtitle streams, or multiple audio tracks. All of these will be silently dropped — FFmpeg will not warn you unless you specifically check the output with ffprobe. File sizes will vary significantly depending on source content: a heavily compressed H.264 MOV at high CRF may produce a similar-sized CAVS output, while a lossless or ProRes MOV source will produce a dramatically smaller CAVS file due to the re-encoding at CRF 23. There are no special faststart or streaming optimization flags available for CAVS, unlike MOV which supports -movflags +faststart for progressive web delivery.