Linux Image Quality Comparison
With the great deal of articles that we publish in regards to NVIDIA and ATI display drivers, it is very evident that at this time NVIDIA has the lead when it comes to the frame-rate performance -- with their Linux drivers performing nearly the same as their Windows ForceWare counterpart. ATI has been struggling to improve the performance of their fglrx drivers, and while they had made strides last year (as noted by our ATI AYiR 2006), they still have a great deal of work ahead of them. However, one of the areas that often is not mentioned in Phoronix articles is the image quality between ATI and NVIDIA's hardware with their respective drivers. In this article today we will be looking at both company's image quality under Linux in video playback and gaming environments.
Before jumping directly to the image quality tests we will briefly explain both ATI's Avivo and NVIDIA's PureVideo. ATI's Avivo was introduced with the Radeon X1000 series as a video platform to enhance the quality and flexibility of video playback. Avivo is able to offload supported video playback to the GPU -- saving on CPU resources. ATI also offers a Windows program called "ATI AVIVO Video Converter", which is transcoder software to convert between various formats when using a Radeon X1000 graphics card.
Launched prior to ATI's Avivo was NVIDIA's PureVideo. NVIDIA PureVideo started with the GeForce 6 series and has continued into the GeForce 7 and 8 series with a PureVideo HD revision. PureVideo Technology offers high-definition video playback with minimal CPU utilization. NVIDIA's PureVideo HD allows GeForce owners to play HD-DVD and Blu-ray movies with PureVideo technology.
When preparing for the ATI Radeon X1000 Linux introduction last year we were very surprised when ATI had told us that they would be supporting Avivo with their initial R500 series 8.24.8 fglrx drivers. Avivo under Linux allows accelerated video playback using the GPU's 3D engine rather than 2D. Any Linux software that uses the X-Video extension can utilize this 3D accelerated playback. This accelerated playback can be extended to non-X1000 graphics cards by enabling TexturedVideo. The proprietary NVIDIA Linux display drivers do not support PureVideo at this time; however, they do support XvMC and X-Video.
For this image quality comparison on the NVIDIA side we have a GeForce 7800GTX 256MB and on the ATI side we have a Radeon X1800XT 256MB. Both of these parts are roughly equivalent with the Windows ForceWare and Catalyst display drivers. The ATI drivers we had used were fglrx 8.32.5 while the NVIDIA version was 1.0-9746. The Linux distribution being used was Fedora Core 6 with X.Org 7.1 and the Linux 2.6.18 kernel. An unfortunate bug that has plagued the fglrx drivers for some time is segmentation faults when attempting to use X-Video on X.Org 6.9 or newer versions with x86_64 Linux. As a result for this article we had used 32-bit Fedora in order to utilize the ATI Radeon AVIVO Video with mplayer 1.0 Release Candidate 1.