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The Unified Video Decoder, previously called "Universal Video Decoder", or UVD in short, is the video decoding unit from ATI Technologies to support hardware decode of H.264 and VC-1 video codec standards, and being a part of ATI Avivo HD 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. 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[1]


OS Support

UVD is supported in Windows (since the launch of the technology) and Linux (since Oct 2008)[2]




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. 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. 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.[3] In addition to handling VLC/CAVLC/CABAC, frequency transform, pixel prediction and inloop deblocking, UVD also contains an advanced video post-processing block. 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.[4] But UVD+ was also being marketed as simply UVD.


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 MPEG2 video streams, and in addition it also supports 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" 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.


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.[5] However, the Radeon HD 2900 series video cards do not include the UVD (though it is able to provide similar 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, either stating the card as featuring ATI Avivo HD or explicitly UVD, which only the former statement of ATI Avivo HD is correct. The exclusion of UVD was also confirmed by AMD officials.[6]

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

Codename Product Name UVD Version
Cypress Radeоn HD 5800 Series UVD 2.2
Juniper Radeоn HD 5700 Series UVD 2.2
RV790 Radeon HD 4890 Series UVD 2[7]
RV770 Radeon HD 4800 Series UVD 2
RV740 Radeon HD 4700 Series UVD 2.2
RV730 Radeon HD 4600 Series UVD 2.2
RV710 Radeon HD 4300/4500 Series UVD 2.2
RV670 Radeon HD 3800 Series UVD+
RV635 Radeon HD 3600 Series UVD+
RV620 Radeon HD 3400 Series UVD+
RV630 Radeon HD 2600 Series UVD
RV610 Radeon HD 2400 Series UVD
RS880 Radeon HD 4200/AMD 785G Chipset UVD 2
Radeon HD 3200/AMD 780G Chipset
Radeon HD 3300 IGP/AMD 790GX Chipset
M98 Mobility Radeon HD 4800 Series UVD 2
M96 Mobility Radeon HD 4600 Series UVD 2
M92 Mobility Radeon HD 4300/4500 Series UVD 2.2
M88 Mobility Radeon HD 3800 Series UVD+
M86 Mobility Radeon HD 3600 Series UVD+
M82 Mobility Radeon HD 3400 Series UVD+
M76 Mobility Radeon HD 2600 Series UVD
M72 Mobility Radeon HD 2400 Series UVD
M71 Mobility Radeon HD 2300 Series UVD
RV550 Unknown


  • Driver version "8.371" 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


  1. ^ AMD's X-Video Bitstream Acceleration
  2. ^ Phoronix
  3. ^ (Chinese)HardSpell review
  4. ^ (Chinese) PC-DVD discussion thread, retrieved August 23, 2008
  5. ^ HKEPC report
  6. ^ DailyTech report
  7. ^

External links


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