CAVS to AVI Converter

Convert CAVS to AVI: What This Tutorial Covers

A bare .cavs file is a raw Chinese AVS (AVS1) video bitstream — picture data with no container around it and no audio track inside, which is why most Windows players and editors refuse to open it directly. AVI is the RIFF-based container Microsoft shipped with Video for Windows on November 10, 1992; it wraps a video stream into one self-contained file that legacy Windows tools actually understand. This tutorial walks through wrapping that orphaned AVS stream into a usable AVI — and is honest about the two catches: AVI does not carry AVS1, so the conversion re-encodes the video to MPEG-4, and the AVI comes out silent because the raw stream never had any sound.

How to Convert CAVS to AVI

1. Upload Your CAVS File: Drag and drop your .cavs onto the page or click "+ Add Files" to browse from your computer. You can queue several raw streams and process them with the same settings.
2. Set the Preset: Open Advanced Options. Under "File Compression" leave "Preset" on "Very High (Recommended)" for a near-source result, or switch to "Specific file size" to target an exact size in MB.
3. Set Resolution and Trim (Optional): Use the "Video resolution" presets or "Width x Height" to rescale; under "Show All Options" the "Video Codec" defaults to MPEG-4, the codec AVI files most commonly carry. Use the "Trim" section's "Time Range" to cut to just the segment you need.
4. Convert and Download: Click "Convert" and download your AVI. No sign-up, no watermark.

Walk-through: The AVS1 to MPEG-4 Re-encode

A .cavs stream is coded with AVS1 (China's first-generation Audio Video Standard), and AVI does not carry that codec. So this is not a byte-for-byte rewrap of your existing stream — the converter decodes the AVS1 (AVS1-P2 JiZhun profile) frames and re-encodes them to MPEG-4 ASP, the codec DivX and Xvid made standard in AVI, with MP3 reserved for the audio track. That decode-and-re-encode is one lossy generation, and it is one-way:

• Quality can hold but not improve. Re-encoding AVS1 to MPEG-4 adds a second compression pass on top of whatever the original AVS encoder already applied. No setting recovers detail — keep "Preset" high so the loss stays as invisible as possible.
• Aim for a clean source. Because the output is a fresh encode, a low-bitrate or interlaced broadcast stream shows its artifacts more once re-compressed. Leave the resolution at the source's native size unless you have a reason to rescale.

A few patterns cover most needs:

• If you want near-source quality for editing or archiving, leave "Preset" on "Very High" and keep the native resolution.
• If you need a smaller file for sharing or storage, switch to "Specific file size" or lower the preset.
• If a legacy tool demands a particular codec, open "Show All Options" and switch "Video Codec" — AVI also accepts MPEG-2, H.264, or Xvid — but MPEG-4 is the broadly compatible default for AVI playback.

There is no audio step here because a raw .cavs carries none. In Chinese broadcast and optical-media workflows the picture was encoded as the AVS stream and the sound was carried as its own separate stream, the two muxed together only later into a combined container such as an MP4, MKV, or transport stream. This tool wraps the video alone, so the AVI will be silent — if you need the soundtrack, convert the original container, not the demuxed .cavs.

CAVS Source vs AVI Output at a Glance

Which Container Should a Raw AVS Stream Go Into?

AVI is only one of four wrappers this pipeline can build from a .cavs. The codec listed is the converter's default for that target — each is selectable under "Show All Options".

Common Errors and How to Fix Them

• "The AVI has no sound" — Expected. A raw .cavs is video-only by design, so there is nothing to put on an audio track. The audio for that footage lived in the container the stream was demuxed from; convert that container instead.
• "My player still won't open the .cavs to begin with" — That is the whole reason to wrap it. Ordinary players can't open a bare AVS elementary stream; once it is inside an AVI (or CAVS to MP4) the container gives players and editors something they recognize.
• "The picture looks softer than I expected" — That is the cost of the second encode. Raise "Preset" toward "Very High" and keep the native resolution so the re-encode has the most to work with.
• "The converter rejected my file" — Confirm the upload is a genuine raw AVS stream and not a renamed container or an .avs AviSynth script (a different thing entirely). The AVS decoder expects a real .cavs elementary stream.

When This Doesn't Work — and What to Use Instead

AVI is the right target when a legacy Windows editor or pipeline specifically needs that container — getting Chinese-broadcast-era AVS test or archive streams into older VirtualDub, Premiere, or Movie Maker workflows is the classic case. For almost everything else, AVI is dated: it lacks the broad device and streaming support of modern containers. If you just want the clip to play and stay efficient, CAVS to MP4 is the modern wrap — MP4 plays natively almost everywhere and is the better default for sharing or upload. If you want a web-friendly open container instead, CAVS to WebM re-encodes to VP9. And if your real goal was the soundtrack rather than the picture, a bare .cavs cannot help — see CAVS to FLAC for why a raw AVS stream produces a silent audio file and where your audio actually lives.

Frequently Asked Questions

Is converting CAVS to AVI a lossless rewrap or a re-encode?

A re-encode. A .cavs stream is coded with AVS1, and AVI does not carry that codec — by default this tool puts MPEG-4 video in the AVI, so the converter decodes the AVS1 frames and re-encodes them to MPEG-4, which is one lossy generation. There is no setting that drops the original AVS1 stream byte-for-byte into an AVI. If you only need the clip to play rather than to live in an AVI specifically, CAVS to MP4 is the more compatible wrap.

Why doesn't the converted AVI have any audio?

Because a raw .cavs file is an AVS1 video elementary stream — it carries no audio for the converter to copy or transcode. In Chinese AVS workflows the sound was encoded as a separate stream and muxed in only when the final container was built, so the bare .cavs on its own is mute. The AVI therefore comes out silent. If you have the original container (an MP4, MKV, or transport stream) that holds both the video and its audio, convert that file instead.

What is a .cavs file, and why won't it open in my player?

It is a raw Chinese AVS video bitstream — the picture half of AVS1, China's first-generation Audio Video Standard, standardized as GB/T 20090.2 and adopted as a national standard in February 2006 by the AVS Workgroup (founded June 2002). A plain .cavs is an elementary stream handled by FFmpeg's cavsvideo raw demuxer: coded video frames with no container, no audio, and no timing index. Most players expect a container (AVI, MP4, MKV) rather than a loose stream, so they refuse to open a .cavs directly. Wrapping it into AVI gives them the container they need.

Which video codec does the AVI output use?

MPEG-4 ASP, with MP3 reserved for the audio track (though there is no audio to write from a raw .cavs). AVI is most strongly associated with MPEG-4 video — the codec DivX and Xvid popularized — so this converter defaults to it. Under "Show All Options" you can switch "Video Codec" to other formats AVI accepts, including MPEG-2, H.264, or Xvid, but MPEG-4 is the broadly compatible default for AVI playback on legacy Windows tools.

Is .cavs the same as a .avs AviSynth script?

No, and they are easy to confuse. A .cavs file is a raw AVS1 video bitstream — actual coded picture data from the Chinese AVS standard. A .avs file is an AviSynth script: a small text file of frameserving instructions, not video itself. This converter expects the video bitstream. If you uploaded an AviSynth script by mistake, there is no AVS1 picture inside it to wrap into AVI.

Is AVS1 the same thing as AVS2 or AVS3?

No — they are three generations of the same Chinese standards family, and a .cavs file is the first one. AVS1 was promulgated as national standard GB/T 20090.2-2006 in February 2006 by the AVS Workgroup, which was established in June 2002. AVS2 followed as a Chinese national standard on December 30, 2016 and was later adopted as IEEE 1857.4-2018, and AVS3 is the current generation, added to DVB's media-delivery toolbox in 2022. This page's decoder handles the AVS1 elementary stream that the .cavs extension denotes; the later generations use different bitstream syntax and normally arrive inside a real container rather than as a loose stream.

What resolution and frame rate does the AVI keep?

By default the output keeps the source stream's picture size — "Video resolution" is set to "Keep original" unless you change it. If you need a different size, use "Preset Resolutions" for a standard target such as 720p or 1080p, or "Width x Height" for an exact figure; "Width (Keep aspect ratio)" and "Height (Keep aspect ratio)" scale one dimension and derive the other. Rescaling is a resample on top of the re-encode, so leave it alone unless you have a reason. A bare .cavs carries no container-level timing metadata, so if the resulting AVI reports an unexpected duration or frame rate, that is the raw stream's missing timing information rather than a fault in the encode.

How are my files handled, and how long are they kept?

In our testing, wrapping a short raw .cavs stream into AVI at the "Very High" preset produced a clean MPEG-4 file with no audio track, exactly as expected from a silent source. Your file is uploaded over an encrypted connection, decoded and re-encoded into AVI on our servers, and deleted automatically a few hours after conversion — no sign-up, no watermark, never shared or made public.