Unified Video Decoder

The Unified Video Decoder (UVD), previously called Universal Video Decoder is the video decoding unit from AMD to support hardware decode of H.264 and VC-1 video codec standards, and being a part of ATI Avivo HD technology.

OS Support

• Windows – supported since the launch of the technology. UVD currently only supports DXVA (DirectX Video Acceleration) API specification for the Microsoft Windows and Xbox 360 platforms to allow video decoding to be hardware accelerated, thus the media player software also has to support DXVA to be able to utilize UVD hardware acceleration.
• Linux – since Oct 2008.^[1] XvBA (X-Video Bitstream Acceleration) API as designed by AMD for its Radeon GPU is a future extension of the X video extension (Xv) for the X Window System on Linux and UNIX operating-systems that will enable UVD hardware acceleration on those platforms as well.^[2]
• Linux – since 2013^[3] open source UVD support through the VDPAU API, based on the existing VDPAU Gallium3D state tracker in Mesa 3D.

Features

UVD/UVD+

The UVD is based on an ATI Xilleon video processor, incorporated into the same die of the GPU and part of the ATI Avivo HD for hardware decoding videos, along with the Advanced Video Processor (AVP). UVD, as stated by AMD, handles decoding of H.264/AVC, and VC-1 video codecs entirely in hardware. However, video post-processing is passed to Pixel shaders and OpenCL Kernels. MPEG-2 decoding is not performed within UVD, but in the shader processors. The decoder meets the performance and profile requirements of Blu-ray and HD DVD, decoding H.264 bitstreams up to a bitrate of 40 Mbit/s. It has context-adaptive binary arithmetic coding (CABAC) support for H.264/AVC.

Unlike video acceleration blocks in previous generation GPUs, which demanded considerable host-CPU involvement, UVD offloads the entire video-decoder process for VC-1 and H.264 except for video post-processing, which is offloaded to the shaders. MPEG-2 decode is also supported, but the bitstream/entropy decode is not performed for MPEG-2 video in hardware. Previously, neither ATI Radeon R520 series' ATI Avivo nor NVidia Geforce 7 series' PureVideo assisted front-end bitstream/entropy decompression in VC-1 and H.264 - the host CPU performed this work.^[4] UVD handles VLC/CAVLC/CABAC, frequency transform, pixel prediction and inloop deblocking, but passes the post processing to the shaders.^[5] Post-processing includes denoising, de-interlacing, and scaling/resizing. AMD has also stated that the UVD component being incorporated into the GPU core only occupies 4.7 mm² in area on 65 nm fabrication process node.

A variation on UVD, called UVD+, was introduced with the Radeon HD 3000 series. UVD+ support HDCP for higher resolution video streams.^[6] But UVD+ was also being marketed as simply UVD.

UVD 2

The UVD saw a refresh with the release of the Radeon HD 4000 series products. The UVD 2 features full bitstream decoding of H.264/MPEG-4 AVC, VC-1, as well as iDCT level acceleration of MPEG2 video streams. Performance improvements allow dual video stream decoding and Picture-in-Picture mode. This makes UVD2 full BD-Live compliant.

UVD 2.2

The UVD 2.2 features a re-designed local memory interface and enhances the compatibility with MPEG2/H.264/VC-1 videos. However, it was marketed under the same alias as "UVD 2 Enhanced" as the "special core-logic, available in RV770 and RV730 series of GPUs, for hardware decoding of MPEG2, H.264 and VC-1 video with dual-stream decoding". The nature of UVD 2.2 being an incremental update to the UVD 2 can be accounted for this move.

UVD 3

UVD3 adds support for bitstream MPEG2 decoding, DivX and Xvid via MPEG-4 Part 2 decoding and Blu-ray 3D via MVC.^[7] along with 120 Hz stereo 3D support,^[8] and is optimized to utilise less CPU processing power.

Availability

Originally, ATI planned to implement the UVD in its RV550 series GPU aimed at mainstream market, with two different specifications in which one features HDMI and video out support another featuring DVI as well as video-out support, and production was in December 2006, revealed by the slides. However, as of the current date, no information is available about the release of related products. Some suggested the RV550 products were for OEMs, while some speculated the product was cancelled.

Most of the Radeon HD 2000 series video cards implement the UVD for hardware decoding of 1080p high definition contents.^[9] However, the Radeon HD 2900 series video cards do not include the UVD (though it is able to provide partial functionality through the use of its shaders), which was incorrectly stated to be present on the product pages and package boxes of the add-in partners' products before the launch of the Radeon HD 2900 XT,^{[citation needed]} either stating the card as featuring ATI Avivo HD or explicitly UVD,^{[citation needed]} which only the former statement of ATI Avivo HD is correct. The exclusion of UVD was also confirmed by AMD officials.^[10]

UVD2 is implemented in the Radeon RV7x0 and R7x0 series GPUs. This also includes the RS7x0 series used for the AMD 700 chipset series IGP motherboards.

UVD enabled GPUs

Notes:

• NB1: Dual-GPU variants with 2 of the latter GPUs.
• NB2: Driver version 8.371 or later must be used if the GPU is "Mobility Radeon HD 2300" for enabling UVD functions for H.264 videos, or system may crash.

See also

• X-Video Bitstream Acceleration (XvBA) - AMD's future hardware acceleration API for Linux/UNIX operating-system.
• OpenVideo Decode (OVD) – an new open cross-platform video acceleration API from AMD.^[15]
• Video Acceleration API (VA API) - an alternative video acceleration API to XvBA for Linux/UNIX operating-system that supports XvBA as a backend.
• ATI Avivo
• DirectX Video Acceleration (DxVA) - Microsoft's hardware acceleration API for Microsoft Windows based operating-system.
• Nvidia PureVideo - the bit-stream technology from NVIDIA used in their graphics chips to accelerate video decoding.
• VDPAU (Video Decode and Presentation API for Unix) from NVIDIA
• Comparison of AMD graphics processing units

References

External links

• ATI Avivo(TM) HD Technology Brief, July 2008
• Presentation slides comparison between CPU decode, ATI Avivo HD and PureVideo HD and Decode comparison of VC-1 and H.264 video
• AMD Media Codecs—optional download