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Testing GeForce 8600 with HD playback
The newest recent mid-range graphics cards from AMD-ATI and NVIDIA have an extended and new video processing unit that can decode all the Blu-Ray and HD-DVD glory. We figured it was a good time to put some of the newer graphics cards to the test. We picked up a Toshiba HD-DVD player, seated it into a test system and started designing a couple of tests. As you might know, HD DVD is a new high definition video disc standard that delivers up to six times the image quality of standard DVD movies. HD DVD (and Blu-ray) is a major advancement over video discs in the same way that HDTV deliver superior image detail over standard TV.
Two items in today's test are important. Keep them in mind at all times:
HD AccelerationThe more your graphics card can decode the better, as it'll lower the overall used CPU cycles of your PC. We'll measure with the two most popular codecs used on both Blu-Ray and HD-DVD movies. VC1 without a doubt is the most used format, and secondly, the hefty, but oh so sweet H.264 format. We'll fire off a couple of movies and allow the graphics cards to decode the content; meanwhile like a vicious minx we'll be monitoring and recording the CPU load of the test PC.
HD Quality
Not only can the graphics card help offloading the CPU, it can also improve (enhance) image quality; as it should. So besides checking out performance of AMD's Avivo HD and NVIDIA's PureVideo HD video engines, we want to see how they effect the image quality, e.g. post-process and enhance the image quality of the movie.
To do this, we will utilize the popular HQV-HD test (www.hqv.com) developed by Silicon Optix.
Decoding VC-1 and H.264
To decode the content we need to learn how the content (movie) is written as data on the media (HD-DVD/Blu-Ray disc). The data on your HD-DVD or Blu-ray disc is written on there in a specific format. Pretty much we see two major codecs for both Blu-Ray and HD-DVD namely H.264 and VC-1.
VC-1 is ruler of the majority of releases ... 80% of all released are being released in the VC-1 format. Both Avivo HD and PureVideo HD provide hardware acceleration for decoding the compression routines used on both Blu-ray and HD DVD movies: H.264, VC-1, and MPEG-2 (TS,TP). NVIDIA however only partly handles VC-1, we'll explain later.
MPEG stands for Motion Pictures Encoding Group.
MPEG is divided into 4 layers. MPEG Layer 1, MPEG Layer 2, MPEG Layer 3, MPEG Layer 4.
MPEG Layer 1 is a video and audio format which is capped at 640x480 resolutions, MPEG layer 1 was a very early codec, and was primarily used for Video CDs (VCDs). VCDs never caught on in North America and Europe. however in Asia ( China, Japan, Korea), VCD replaced VHS. A lot of old videos are encoded in Mpeg 1, some are ripped straight from VCDs.
MPEG Layer 2 this is the most widely used video codec, It's primarily used for digital Cable and Satellite Broadcasts. It's also used in DVD. Mpeg Layer 2 has no restrictions on resolution nor bitrate, which is why SONY used it on BLU-RAY for their launch titles. MPEG Layer 2 is better at compression than layer 1, but still pretty large in size compared to MPEG layer 4.
MPEG Layer 3 this is the most famous codec used on the planet. MPEG Layer 3 is better known as MP3. This is the infamous music codec that started out as under ground but evolved to a massively mainstream audience, thanks to napster and Apple's I-pod (hey who doesn't own one right?).
MPEG Layer 4 actually has been around for a while. Divx, Xvid, VC1, AVC, AAC, H.264 are all MPEG 4. AVC and VC1 are being seen as as the next-generation codecs. AVC by Sony, VC1 by Microsoft.VC-1
VC-1 is a video codec based on Windows Media Video Version 9. Both HD DVD and Blu-ray Disc have adopted
VC-1 as a codec, meaning all video playback devices will be capable of decoding and playing video-content compressed using VC-1. VC-1 minimizes the complexity of decoding high-definition content through improved intermediate stage processing and more robust transforms. VC-1 decodes HD video twice as fast as H.264, while offering two to three times better compression than MPEG-2.H.264
H.264 is also known as MPEG-4 AVC (Advanced Video Coding), is a video compression standard that offers significantly greater compression than its predecessors while retaining exceptionally good image quality.The intent of the H.264/AVC project was to create a standard capable of providing good video quality at substantially lower bit rates (e.g., half or less) than previous standards (e.g., relative to MPEG-2, H.263, or MPEG-4 Part 2), without increasing the complexity of design so much that it would be impractical (or excessively expensive) to implement.
Both HD DVD and Blu-ray Disc support both formats, yet have adopted VC-1 as a mandatory video standard.
PureVideo HD
The in April released GeForce 8600 and 8500 products will have a newly revised video engine that will help you to decode all that Blu-ray and HD-DVD madness. This engine and respective software is labeled Purevideo HD.
The video engine provides HD video playback up to resolutions of 1080p. G84 and G86 support hardware accelerated decoding of H.264 video as well. The cards also feature advanced post-processing video algorithms. Supported algorithms include spatial-temporal de-interlacing, inverse 2:2, 3:2 pull-down and 4-tap horizontal and 5-tap vertical video scaling.
PureVideo HD is is a video engine built into the GPU (this is dedicated core logic) and thus is dedicated GPU-based video processing hardware, software drivers and software-based players that accelerate decoding and enhance image quality of high definition video in the following formats: H.264, VC-1 and MPEG-2 HD.
In my opinion two key factors are a big advantage. First off to allow offloading the CPU by allowing the GPU to take over a huge sum of the workload. HDTV decoding through a VC-1 file, for example, can be very demanding for a CPU. These media files can peak to 20 Mbit/sec easily as HDTV streams offer high-resolution playback in 1280x720p or even 1920x1080p without framedrops and image quality loss. Secondly image quality enhancements like deblocking.
The engine got revised. The previous engine was already rather good. It did get a little better though as the new engine offloads another chunk of what the CPU normally does namely it now handles Bitstream processing (format of the data found in some stream of bits used in a digital communication or storage application) and a function called inverse transform as well. Unfortunately .. the biggest format being used right now is VC-1 and NVIDIA does not fully handle it's bitstream decoding. It does optimize the VC-1 stream though as our tests will show.
To be able to use PureVideo HD you'll need a GeForce 8600 or 8500, PureVideo software or highly recommended the latest PowerDVD.
