CAVS to WebM Converter

CAVS to WebM Converter

CAVS is the video stream of China's first-generation Audio Video Standard (AVS1) — a national broadcast codec that almost no Western player, phone, or browser can decode. WebM is the open web container built around VP9 and Opus, which plays natively in every current desktop browser. Converting .cavs to .webm re-encodes a stranded broadcast clip into something you can embed in a web page or watch in any modern browser, no plugin or set-top box required.

CAVS (AVS1) Format at a Glance

WebM Format at a Glance

How to Convert CAVS to WebM

1. Upload Your CAVS File: Drag and drop the .cavs file onto the page or click "+ Add Files". You can queue several clips at once; the same settings apply to every file.
2. Set the Quality Preset: Under Advanced Options the output defaults to the VP9 video codec with Opus audio. Leave Preset on Very High (Recommended) for the cleanest re-encode, or pick File Compression options like Specific file size, Constant Bitrate, or Variable Bitrate to cap the output.
3. Adjust Resolution or Trim (Optional): Use a Video resolution preset or Keep original to control pixel dimensions, and set a Time Range under Trim to export only part of the clip.
4. Convert and Download: Click "Convert" and download the .webm file. No sign-up, no watermark.

Frequently Asked Questions

What is a CAVS file, and can this tool actually open it?

CAVS is the video part of China's first-generation Audio Video Standard (AVS1), promulgated as national standard GB/T 20090.2 in February 2006 by the AVS Working Group, which was founded in June 2002. It was created to give Chinese digital television and IPTV a home-grown codec roughly twice as efficient as MPEG-2 at equal quality. Because almost no mainstream player ships an AVS1 decoder, .cavs files are hard to open in the West — but xconvert decodes them server-side through FFmpeg's libavcodec, so you can convert without installing anything.

Which codecs does the WebM output use?

By default this converter encodes WebM with the VP9 video codec and Opus audio, which is the modern, widely supported pairing for web playback. WebM is a profile of the Matroska container and also supports the older VP8 and Vorbis codecs as well as AV1; you can switch the video and audio codecs under Advanced Options if you need VP8 for a legacy decoder.

Will the conversion lose quality?

Some, yes — this is a re-encode, not a remux. CAVS (AVS1) and WebM's VP9 are incompatible codecs, so the AVS1 stream is fully decoded and then re-compressed into VP9, which is a generational, lossy step. Keeping Preset on Very High minimizes added artifacts, but the WebM can only ever be as sharp as the source: CAVS is a standard-definition broadcast format that was already compressed hard for transmission, so the result will look like good SD, not HD.

Why convert to WebM instead of MP4?

WebM is royalty-free and ideal when you are embedding video in a web page with HTML5 <video>, since VP9 and Opus carry no licensing fees and play natively in current desktop browsers. MP4 (H.264) is the safer pick when the clip needs to play on phones, smart TVs, and older hardware players, which more reliably ship H.264 decoders. If broad device playback matters more than open licensing, use CAVS to MP4 instead.

Does WebM keep the audio from my CAVS broadcast stream?

Yes. Unlike a still-image or GIF export, WebM is a full video container, so any soundtrack on the CAVS stream is re-encoded to Opus and kept in sync. If you would rather store the clip in a more flexible multi-track container, CAVS to MKV writes Matroska directly.

In your testing, what does a converted CAVS clip look like?

In our testing, a standard-definition CAVS broadcast clip converted to VP9 WebM at the Very High preset produced a clean, browser-playable file that matched the source's coded frame size and frame rate, with no visible added blocking beyond what the SD source already carried. Interlaced source frames captured during fast motion can still show faint combing; picking a more static segment or letting the encoder deinterlace reduces it.

My .cavs file is rejected — what now?

A handful of Chinese karaoke and DVD tools reuse the .cavs extension loosely, so not every file with that name is genuine AVS1 video; if the stream is not real AVS1 the decoder can refuse it. In that case, re-export from the original software to a standard format first, then convert. For shrinking an oversized WebM after conversion, run it through the Video Compressor.

What happens to my CAVS file after I convert it?

Your file is uploaded over an encrypted connection, processed on our servers, and deleted automatically a few hours after conversion — no sign-up, no watermark, never shared or made public.