CAVS to M4V Converter

CAVS to M4V — and Should You Use M4V or MP4?

A .cavs file is a raw Chinese AVS (AVS1) video bitstream — China's home-grown coding standard, used in domestic digital TV, IPTV, and set-top-box recordings, and almost nothing outside that ecosystem opens it. M4V is Apple's MP4 variant: H.264 video with AAC audio, the format iTunes, QuickTime, Apple TV, and iPhone expect. This converter decodes the orphaned AVS stream and re-encodes the picture into a DRM-free M4V. Pick M4V if the footage is staying inside the Apple ecosystem and you want the iTunes-friendly extension; pick MP4 (CAVS to MP4) if you want one file that plays everywhere — the bytes are essentially identical. One honest catch up front: a raw .cavs carries no audio, so the M4V comes out silent. Files are 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.

M4V vs MP4 — Side-by-side

When to Pick M4V

• The clip is going into an iTunes / Apple TV library and you want the extension Apple's apps expect.
• You're standardising a folder of Apple-ecosystem media and want .m4v to keep it visually consistent.
• You only need H.264 + AAC — which is all M4V carries, and exactly what this conversion produces.
• You're fine with a file that has no broad browser support — M4V is for native Apple players, not the web.

When to Pick MP4

• You want one file that plays anywhere — phones, browsers, smart TVs, editors — not just Apple devices.
• You may later want H.265/HEVC or another codec MP4 can carry but M4V can't.
• You're embedding the video on the web, where .mp4 is the expected, browser-playable extension.
• In that case use CAVS to MP4; for DRM-free clips the M4V and MP4 outputs here are the same H.264 + AAC bytes under a different extension.

How to Convert CAVS to M4V

1. Upload Your CAVS File: Drag and drop your .cavs onto the page or click "+ Add Files" to browse from your device. You can queue several raw streams and convert them with the same settings.
2. Pick a Quality Preset: Open Advanced Options and leave "Preset" on "Very High (Recommended)" to stay close to the source, or switch to "Specific file size" to target an exact size — "Constant Bitrate" and "Variable Bitrate" are there if you need tighter control. Under "Show All Options" the "Video Codec" defaults to H.264 and "Audio Codec" to AAC, the only combination M4V uses.
3. Resize or Trim (Optional): Use "Resolution Percentage" or "Preset Resolutions" to rescale, set an exact "Width x Height", or open "Trim" and switch to "Time Range" to export just the segment you need.
4. Convert and Download: Click "Convert" and download your M4V. No sign-up, no watermark.

For footage you want to keep playable beyond Apple devices, the general Video Converter handles other legacy source formats, and CAVS to WMV targets the Windows ecosystem instead.

Frequently Asked Questions

Is M4V actually different from MP4, or just a renamed file?

For a DRM-free file like the one this tool produces, the difference is mostly the extension. M4V is Apple's MP4 variant — same ISO base media container, carrying H.264 video and AAC audio. The reason Apple uses .m4v is that it can also wrap FairPlay DRM (for iTunes purchases) and signals "this is Apple-ecosystem media" to iTunes and the Apple TV app. Our output has no DRM, so a .m4v here will generally play if you rename it .mp4, and our CAVS to MP4 output is the same H.264 + AAC under the universal extension.

Why does the converted M4V have no sound?

Because a raw .cavs file is an AVS1 video elementary stream — picture only, no audio for the converter to carry. 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, and the M4V therefore comes out silent. It's not a fault in the conversion — there was never any audio in the source. If you have the original container (an MP4, MKV, or transport stream) that holds both the video and its audio, convert that file instead, because the audio lives there, not in the demuxed .cavs.

Will the M4V play in iTunes and on Apple TV?

Yes. The output is H.264 video in an M4V container — exactly the codec and wrapper Apple's apps expect — so it imports into the Apple TV app / iTunes library and plays in QuickTime and on iPhone, iPad, and Apple TV. The only thing it won't have is an audio track, because the source .cavs had none. If you need sound, start from the original container that actually contains the audio.

Will I lose quality converting CAVS to M4V?

Yes, a little, and it's one-way. A .cavs stream is already lossily coded with AVS1, and M4V uses H.264, so the converter decodes the AVS1 frames and re-encodes them to H.264. That second pass discards some data and no setting brings it back. Keep "Preset" on "Very High" and leave the native resolution so the re-encode has the most to work with — you can avoid throwing more away, but you can't add detail in.

Does M4V support H.265/HEVC like MP4 does?

No. M4V is built around H.264/AVC plus AAC — that's the combination Apple's M4V ecosystem expects, and it's what this tool writes. If you specifically want H.265/HEVC (smaller files at similar quality, where your devices support it), convert to CAVS to MP4 instead and pick H.265 there, since MP4 carries codecs M4V doesn't.

Is the AVS1 standard behind CAVS still relevant, or is it obsolete?

AVS1 is dated — it was promulgated as China's GB/T 20090.2-2006 by the AVS Working Group, designed to match H.264's efficiency at lower complexity under a more transparent royalty policy — but it isn't abandoned. The family continued through AVS+ (GY/T 257.1-2012) for HD broadcast and on to AVS2 and AVS3 for UHD. The original .cavs AVS1 streams persist in older Chinese broadcast and set-top-box archives, which is exactly why converting them to an Apple-friendly M4V (or a universal MP4) is the practical way to keep that footage playable.

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

In our testing, re-encoding a short raw .cavs stream to an H.264 M4V at the "Very High" preset produced a clean, Apple-playable file with no audio track — exactly what a silent source should yield. Your file is uploaded over an encrypted connection, decoded and re-encoded into M4V on our servers, and deleted automatically a few hours after conversion — no sign-up, no watermark, never shared or made public. The realistic limit on very large broadcast captures is upload time, not anything on your device.