CBHD Codecs Today: AVS, DRA and Tooling
Starting point
Pressed CBHD discs carried video and audio under Chinese and Western codec labels. Reconstructing or playing ripped material in 2026 depends less on finding a “CBHD player app” and more on whether modern open-source stacks can decode AVS video and DRA audio after the container and DRM layers are stripped. This post inventories what exists today, what is missing, and how those tools map onto the format’s commercial codec list.
AVS video on the open-source side
FFmpeg’s cavs decoder handles AVS1-P2 Jizhun (base) profile. Stefan Gehrer wrote it in 2006-before CBHD’s commercial launch-because AVS itself is older than the disc format. The AVS working group began first-generation work in 2002; AVS Part 2 video became national standard GB/T 20090.2-2006 in February 2006. For software archaeology that timing matters: a CBHD encoding tool may simply have been an AVS encoder feeding a proprietary mux/authoring system, not something branded “CBHD Encoder.”
Support for AVS+ (AVS1-P16, broadcasting profile) was proposed in a 2026 FFmpeg-devel RFC titled along the lines of “avcodec/cavs: bugfixes and AVS1-P16 (AVS+) decoding,” but that work is not yet merged. Encoding uses libxavs, available in FFmpeg builds configured with --enable-libxavs; Chinese CSDN guides document such builds. FFmpeg’s separate avs decoder is for an unrelated game video format and must not be confused with Chinese AVS. The name uAVS appeared as a search target in the research brief; no pass reported usable details.
What commercial CBHD actually put in the bitstream
Official CHDA documentation lists AVS, H.264/AVC, VC-1 and MPEG-2. Player specifications made AVS, MPEG-4 AVC and VC-1 mandatory. Early 2009 discs almost certainly used VC-1 or AVC because AVS content and encoders were not yet available at China Record; AVS and DKAA discs were presented as a “new generation” only at the September 2009 Guangzhou conference. An actual disc could therefore contain a conventional MPEG-2, H.264 or VC-1 stream even though later marketing emphasised AVS.
Technical traits reported for AVS as used on CBHD include compression efficiency comparable to H.264 High Profile with lower computational complexity; licensing about 1 RMB per decoder unit versus multi-dollar MPEG-LA structures; 8×8 integer transforms; quarter-pel motion-vector accuracy; context-adaptive spatial prediction; and its own loop filter. Typical CBHD encodes are described as 1080p at 23.976 or 24 fps, or 1080i at 50 Hz for domestic Chinese TV masters, at average bitrates of 12-18 Mbps under a format maximum video bitrate of 28 Mbps.
DRA audio: silicon IP and one thesis tree
DRA (standardised as SJ/T 11368-2006 and GB/T 22726-2008) was developed by DigiRise / Guangzhou Digital Rise Technology. Expansions of the acronym differ across sources-“Dynamic Resolution Adaptation” versus “Digital Rise Audio” after the developer. It is optional in Blu-ray from version 2.3. Reported capabilities include multi-channel compression using sub-band coding, psychoacoustic masking and MDCT; channel layouts from mono/stereo to 5.1 and 7.1; and bitrates from 64 kbps to 1.5 Mbps.
Commercial decoder IP: Synopsys DesignWare ARC Sound IP (2011, first to support DRA) and Tensilica HiFi Audio DSP library (2012). Open source: a DRA encoder/decoder from Tianyi Geng’s Tsinghua undergraduate thesis, published on GitHub as tianyigeng/DRA-Audio-System. No DRA decoder exists in mainline FFmpeg. For archival workflows that means DRA either goes through the thesis codec or through a conversion step before ordinary desktop players see the soundtrack.
Player-facing audio lists for context
- Official specification: AVS Audio, DRA, Dolby AC-3.
- Shinco CBHD-9100: AVS-Audio, LPCM, DRA, Dolby AC-3; coaxial digital and 5.1 analogue.
- TCL THBD-1008: Dolby Digital, Dolby Digital Plus, Dolby TrueHD, PCM.
CBHD-HiFi (July 2010) used dual-layer capacity for multi-channel LPCM up to 24-bit/192 kHz over secure HDMI. That profile is a separate audio path from DRA compression and matters for identifying special collector editions from China Record Corporation.
Putting decoded streams into players
A decrypted CBHD AVS elementary stream should decode in FFmpeg-based players such as mpv, MPC-HC via LAV Filters, and probably VLC, provided the cavs path is available. Transcoding can use FFmpeg with libxavs when re-encoding is required. DRA still needs the thesis codec or conversion. No research pass found software that decrypts DKAA. International titles protected with AACS follow the AACS route rather than a CBHD-specific PC decryptor.
Standalone player USB paths remain relevant when discussing “home content” without disc authoring: the Shinco CBHD-9100 plays 1080p video files and TS/MP4 from USB with external subtitles; the Shinco HD-3700U plays AVI from USB and network shares. Those routes bypass FSM mastering entirely and are the only documented realistic home-content path on original hardware.
What is still missing
- Mainline FFmpeg DRA decoder.
- Merged AVS+ (AVS1-P16) support in cavs.
- Any public DKAA decryption tool.
- Documented uAVS encoder details usable for reconstruction.
- Confirmed PC application that mounts a pressed CBHD volume end-to-end (filesystem + CETC + DRM + decode).
ChatGPT pass 2 cautions that “there were no PC decoders” has not been proven as a historical absence; PC playback software and a CBHD emulator remain unresolved research targets rather than confirmed non-existence. For practical work today, treat AVS via cavs/libxavs and DRA via the thesis tree as the working open toolchain, and treat DKAA as a hard stop until keys and algorithms surface.
Codec archaeology versus disc archaeology
AVS and DRA outlived CBHD in Chinese broadcasting. AVS was re-engineered as AVS2 and AVS3; together with DRA they were mandated across terrestrial HD, 4K Ultra-HD and 8K state networks. That continuity means codec libraries and silicon IP continued after disc replication ended, but it does not automatically recover CBHD muxers, CETC navigation files or DKAA. Separating the problems helps: decode the elementary streams with tools that already exist; recover containers, navigation and DRM with disc images, firmware dumps and professional verifiers.
When a catalogue title is labelled “1080p AVS, DRA 5.1” in secondary reporting, treat that as a technical profile claim pending MediaInfo or bitstream confirmation. Early launch discs may not match that profile. When a title lists only Western codecs on a player menu screenshot, that is equally consistent with the 2009 encoder gap. Codec tooling today is strong enough to handle AVS Jizhun video once decrypted; audio and DRM remain the thinner layers of the stack.
Quick reference
| Component | Open tooling status |
|---|---|
| AVS1-P2 Jizhun decode | FFmpeg cavs (2006) |
| AVS encode | libxavs via FFmpeg |
| AVS+ | RFC proposed; not merged |
| DRA decode/encode | Thesis GitHub project; not in FFmpeg |
| DRA in silicon IP | Synopsys ARC Sound (2011); Tensilica HiFi (2012) |
| DKAA | No public decryptor found |
| AACS (international CBHD) | Standard AACS research path |
The next posts in this series cover standards numbers and patents, then hardware that actually ran these codecs in living rooms. Codec tooling without a disc image or firmware dump still leaves navigation and protection unresolved; codec tooling with those artefacts turns a sector dump into watchable video.
AVS as a system, not a single FourCC
The AVS organisation describes AVS1 as a full system covering system layer, video, audio, DRM and compliance testing. That breadth affects how researchers hunt tools: filenames may say AVS encoder, AVS muxer or compliance suite rather than CBHD. Part 2 video (GB/T 20090.2-2006) is the elementary stream FFmpeg’s cavs path targets. Broadcasting later moved to AVS+ and then AVS2/AVS3; those later profiles are not automatically present on 2009-2010 CBHD discs. Keeping profile names straight prevents false “unsupported CBHD” reports when the real issue is an AVS+ stream fed to a Jizhun-only decoder.
Licensing economics also explain why Chinese manufacturers preferred AVS on paper: about 1 RMB per decoder versus multi-dollar MPEG-LA stacks. Whether every pressed title actually shipped AVS is a separate empirical question. China Record’s lack of an AVS encoder in April 2009 and the September 2009 “new generation” AVS+DKAA unveiling are contemporaneous evidence that the codec story changed during the format’s short commercial life.
DRA beside Dolby on the same machines
Player marketing lists show DRA and Dolby families coexisting. The Shinco CBHD-9100 advertises DRA and AC-3 together with LPCM; the TCL THBD-1008 leans on Dolby Digital / Digital Plus / TrueHD and PCM in published specs. HDMI bitstream of DRA to Western AV receivers was reported as fragile on the HD-3700U because descriptors did not identify the payload. Desktop preservation therefore cannot assume “if the video decodes, the audio will follow in VLC”-DRA may need an offline conversion pass through the thesis codec before a standard media player sees PCM or AC-3.
Research targets still named but empty
uAVS encoders were on the original search brief; no pass returned usable documentation. Synopsys and Tensilica DRA IP proves silicon-level interest after 2011 but does not yield a Windows DLL for archivists. No pass found DKAA decryption code. AACS on international CBHD titles remains the better-documented protection path solely because AACS LA published a CBHD pre-recorded book (v0.90, 7 October 2008) rather than because those titles are easier to obtain.
Practical lab order: identify whether a given disc is domestic (DKAA) or international (AACS); extract after legal decrypt where applicable; demux; run cavs on AVS; route DRA through tianyigeng/DRA-Audio-System or transcode; archive both elementary streams and a transparent remux. USB playback on the CBHD-9100 remains available for non-DRM test encodes.
Further reading on historic video formats
If you want to learn more about historic video formats, get The History of Physical Video Formats from the Frontier by Stephen Driver on Amazon: