Convert CAVS to DVR — Free Online Tool
Convert CAVS (Chinese Audio Video Standard) files to DVR format using H.264 video and AAC audio encoding — ideal for archiving or repurposing Chinese broadcast content into a format compatible with digital video recorder systems. Both formats share H.264/AAC as their default codec stack, making this a straightforward re-encode optimized for surveillance and broadcast capture workflows.
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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 use a proprietary Chinese national standard video codec (AVS/AVS+), but when processed through this tool, the video stream is decoded and re-encoded using the widely supported H.264 (libx264) codec, and the audio is encoded as AAC at 128k bitrate. The output is wrapped in a DVR container, which is the proprietary format used by digital video recorders to store broadcast and surveillance footage. Because CAVS and DVR share no native codec compatibility, full re-encoding of both streams is required — there is no lossless remux path here. Quality is controlled by the CRF 23 value, which represents a balanced midpoint between file size and visual fidelity on the H.264 scale.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg binary — the open-source multimedia processing engine that handles all decoding, encoding, and container muxing for this CAVS-to-DVR conversion. |
-i input.cavs
|
Specifies the input file in CAVS format, which contains AVS-codec video and audio encoded to the Chinese national broadcast standard. |
-c:v libx264
|
Sets the video encoder to libx264, re-encoding the AVS-standard CAVS video stream into H.264, which is the primary video codec supported by the DVR output container. |
-c:a aac
|
Sets the audio encoder to AAC, re-encoding the audio stream from the CAVS source into AAC format as expected by the DVR container's default audio codec. |
-crf 23
|
Sets the Constant Rate Factor for H.264 encoding to 23, the x264 default, which balances output file size and visual quality — appropriate for archiving broadcast-origin CAVS content into DVR storage without excessive bitrate. |
-b:a 128k
|
Sets the AAC audio bitrate to 128 kilobits per second, the standard quality level for stereo broadcast audio that keeps DVR file sizes manageable while maintaining clear dialogue and ambient sound. |
output.dvr
|
Specifies the output filename with the .dvr extension, instructing FFmpeg to wrap the encoded H.264 video and AAC audio into the DVR container format used by digital video recorder systems. |
Common Use Cases
- Archiving Chinese broadcast recordings originally captured in CAVS format into a DVR-compatible format for playback on standalone digital video recorder hardware
- Integrating CAVS-encoded television content from Chinese broadcasters into a surveillance or broadcast capture system that ingests DVR files
- Converting CAVS footage from Chinese set-top boxes or IPTV streams into DVR format for long-term storage on NVR or DVR appliances
- Preparing Chinese national standard video content for use in security operations centers that use DVR-based playback infrastructure
- Repurposing CAVS broadcast clips into DVR format for compatibility with video management software designed for recorded television and CCTV footage
- Transcoding bulk CAVS archives from Chinese media libraries into DVR format to standardize a mixed-format video storage system
Frequently Asked Questions
Yes, some quality loss is inevitable because this conversion requires a full decode-and-re-encode of both the video and audio streams — there is no lossless copy path between CAVS and DVR. The default CRF 23 setting for H.264 is generally considered visually transparent for most content, meaning artifacts are minimal at typical viewing distances. If your source CAVS file was already heavily compressed, re-encoding compounds that loss, so using a lower CRF (e.g., 18) will better preserve detail at the cost of a larger output file.
DVR is a proprietary container format primarily designed for device-level recording rather than rich metadata storage, so most embedded metadata from the CAVS source — such as title tags, language labels, or broadcast timestamps — will not be preserved in the output. If metadata retention is important for your workflow, consider whether an intermediate format like MP4 or MKV might be more appropriate before final delivery to a DVR system.
DVR is not a single unified standard — different DVR manufacturers (Hikvision, Dahua, etc.) use their own proprietary DVR container variants with different internal structures. The output from this tool uses H.264 video and AAC audio wrapped in a generic DVR container, which may or may not be directly playable on all DVR hardware. You may need to verify compatibility with your specific DVR device or use the manufacturer's own conversion utility for final device compatibility.
CAVS files use the AVS (Audio Video coding Standard) video codec, which is a Chinese national standard codec entirely distinct from H.264. DVR containers expect H.264 or MJPEG video streams, so the AVS-encoded video must be fully decoded and re-encoded into H.264 — there is no way to copy the CAVS video stream directly into a DVR container without transcoding.
The CRF value in the command controls the quality-to-size tradeoff for H.264 encoding. Lower CRF values produce higher quality and larger files (CRF 18 is near-visually lossless), while higher values produce smaller files with more compression (CRF 28–35 for storage-constrained DVR archives). To change it, replace '-crf 23' in the command with your desired value, for example: 'ffmpeg -i input.cavs -c:v libx264 -c:a aac -crf 18 -b:a 128k output.dvr'.
Yes, on Linux or macOS you can use a shell loop: 'for f in *.cavs; do ffmpeg -i "$f" -c:v libx264 -c:a aac -crf 23 -b:a 128k "${f%.cavs}.dvr"; done'. On Windows Command Prompt, use: 'for %f in (*.cavs) do ffmpeg -i "%f" -c:v libx264 -c:a aac -crf 23 -b:a 128k "%~nf.dvr"'. The browser-based tool processes one file at a time, so the local FFmpeg command is the recommended approach for bulk conversion of large CAVS archives.
Technical Notes
CAVS (Chinese Audio Video Standard, also known as AVS1-P2) is a codec standard developed by China's Audio Video coding Standard Workgroup as a royalty-reduced alternative to H.264. Because CAVS uses its own entropy coding and motion compensation algorithms, it shares no stream-level compatibility with H.264 — full transcode is mandatory. The output DVR container uses H.264 (libx264) at CRF 23, which is the x264 encoder's default and produces output with an average quality comparable to H.264 encodes at roughly 2–4 Mbps for standard-definition content, though bitrate varies significantly by scene complexity. AAC audio at 128k is the default for both containers and requires no format change, though the audio is still re-encoded in this pipeline rather than stream-copied. Neither CAVS nor DVR support subtitles, transparency, chapters, or multiple audio tracks, so no feature-related data is silently dropped during this conversion. MJPEG is also a valid video codec option in the DVR container if frame-accurate editing compatibility is a priority over compression efficiency, but it is not used here since H.264 offers far better compression for broadcast-origin content.