Unified Video Decoder

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 AVIVO HD technology.

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 AVIVO HD for hardware decoding videos, along with the Advanced Video Processor (AVP). The UVD, as stated by ATI, handles decoding of H.264/AVC, and VC-1 video codecs almost entirely in hardware. 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 and dual-stream decoding support, which would make picture-in-picture possible.

Unlike video acceleration blocks in previous generation GPUs, UVD offloads almost the entire video-decoder process for VC-1 and H.264, requiring minimal host (CPU) attention. For example, neither ATI Radeon R520 series' AVIVO nor NVidia Geforce 7 series' PureVideo assist front-end bitstream/entropy decompression in VC-1 and H.264 - the host CPU performs this work. [zh icon [http://www.hardspell.com/pic/2007/4/30/9e955066-558b-490c-8d06-5cf935f72a79.jpgHardSpell review] ] 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.

In terms of functionality, UVD is similar to the 2nd-generation of PureVideo HD, which Nvidia introduced with its GeForce 8500/8600 series family. But unlike UVD, PureVideo 2 does not assist VLC bitstream decoding for VC-1. Benchmarks have demonstrated UVD to cause less CPU utilization than PureVideo 2 in both Blu-ray and HD DVD playback when VC-1 is the codec used, while both cause similar amounts of utilization when decoding content compressed with H.264 Fact|date=November 2007.

UVD+ is present on the Radeon HD 3000 series products, with the major difference over UVD is the support of HDCP on higher resolution video streams. [zh icon [http://www.pcdvd.com.tw/printthread.php?t=780017 PC-DVD discussion thread] , retrieved August 23, 2008]

UVD 2

The UVD saw a refresh with the release of the Radeon HD 4800 series products. The UVD 2 features full bitstream decoding of H.264/MPEG-4 AVC and VC-1 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.

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 current date, no information about the release of related products. Some suggested the RV550 products were for OEMs, while some speculated the product as being cancelled.

Most of the Radeon HD 2000 series video cards implement the UVD for hardware decoding of 1080p high definition contents. [ [http://www.hkepc.com/bbs/itnews.php?tid=751990 HKEPC report] ] 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 AVIVO HD or explicitly UVD, which only the former statement of AVIVO HD is correct. The exclusion of UVD was also confirmed by AMD officials. [ [http://dailytech.com/Whoops+ATI+Radeon+HD+2900+XT+Lacks+UVD/article7447.htm DailyTech report] ]

The 780G IGP motherboards include UVD+. While the Radeon HD 4800 series implements the UVD2.

UVD enabled GPUs

Note:
*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.

ee also

*ATI Technologies
*Advanced Micro Devices
*Radeon R700
*Radeon R600
*Radeon R520
*AVIVO
*NVIDIA PureVideo

References

External links

* [http://www.hardwaresecrets.com/article/448/6 Presentation slides comparison between CPU decode, AVIVO HD and PureVideo HD and Decode comparision of VC-1 and H.264 video]