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In Saturday's Digital Foundry "not so high definition" feature, we talked about the technical reasons why some console games don't actually appear to be running at the lowest HD standard: 720p. We revealed that Namco-Bandai's forthcoming Tekken 6 is one of those games, but also stated that the additional graphics processing introduced at the lower resolution, surprisingly, produced a higher overall image quality than the game's in-built HD mode which actually runs in excess of 720p.


Overall, although there's really nothing in it in the heat of gameplay, we'd take the PS3's blur-off 576p 2xMSAA picture as the best IQ option available across both versions, the realisation of which suggests that the whole game would've benefited a lot more with the more traditional arrangement of native 720p and MSAA. Screen-filling bosses aside, there's nothing to suggest that this wouldn't have been possible. It's interesting to note that even when Tekken 6 is running at an HD resolution there is the sense that the game isn't quite all it could've been visually.

Real 3D - as in proper, full-on HDMI 1.4 stereoscopic 3D in the 1280x1470 twin 720p framebuffer configuration - may well be a problem for the Xbox 360. Here's where things get complicated. In terms of the basic capabilities of the Xenos GPU, the resolution should in theory be a walk in the park. Probably the closest version of the 360's graphics architecture on PC is ATI/AMD's R520 (found in the X1x00 cards), capable of a maximum resolution of 2560x1600. Even its predecessor could process 2048x1536, at 75Hz, no less.

However, notable by its absence is 1920x1200, the de facto standard top-end resolution for single-link DVI, and utilised by a large amount of 24" LCDs, and from several of our developer sources, we've learned there's still no support for it in the current revision of the upcoming Kinect dash, nor is there implementation of the HDMI 1.4 720p stereo 3D format when a 3DTV is attached.

At the moment XBOX 360 is supporting 720p (progressive scan) and 1080i (interlaced) resolutions - 720p equates to 1280x720 pixels and 1080i equates to 1920x1080 pixels, however interlacing means that only the odd horizontal lines are refreshed on one cycle and the even lives on the next, which means that the frame buffer is only ever needing to handle 1920x540 pixels per refresh.

There is going to be an increase in cost here as the resultant data of some objects in the command queue may intersect multiple tiles, in which case the geometry will be processed for each tile (note that once it is transformed and setup the pixels that fall outside of the current rendering tile can be clipped and no further processing is required), however with the very large size of the tiles this will, for the most part, reduce the number of commands that span multiple tiles and need to be processed more than once. Bear in mind that going from one FSAA depth to the next one up in the same resolution shouldn't affect Xenos too much in terms of sample processing as the ROP's and bandwidth are designed to operate with 4x FSAA all the time, so there is no extra cost in terms of sub sample read / write / blends, although there is a small cost in the shaders where extra colour samples will need to be calculated for pixels that cover geometry edges. So in terms of supporting FSAA the developers really only need to care about whether they wish to utilise this tiling solution or not when deciding what depth of FSAA to use (with consideration to the depth of the buffers they require as well). ATI have been quoted as suggesting that 720p resolutions with 4x FSAA, which would require three tiles, has about 95% of the performance of 2x FSAA.

Initially there were no digital video outputs such as DVI or HDMI on the Xbox 360; instead, HD-quality output could only be produced over YPBPR component video (used by both the 3 RCA component cable and the Japanese D-terminal cable) and later VGA (via a software update). An HDMI port was introduced to the Xbox 360 by July 2007 with the introduction of the Elite model. All Xbox 360 SKUs currently manufactured feature an HDMI port. A wide array of SDTV and HDTV resolutions are supported by the console hardware;[16] up to 1080p after the October 2006 software upgrade.[17] While most games are rendered natively at 720p, the video from all games can be scaled by the hardware to whatever resolution the user has set in the console's settings; from 480i NTSC and 576i PAL all the way to 1080p HDTV.

During E3 ATI showed a video running on Xenos hardware - the now famous Assassin video. We taped it and put it up here back in May, and ATI now finally released a direct feed 720p version of it. This one is running on ATI X1800 hardware though, but I guess it's worth checking out - it still looks great, and is all in real time of course.

However, MLAA isn't the only solution being worked on by the industry - far from it. Over at NVIDIA, technology developer Timothy Lottes has been working on an alternative to MLAA which is winning widespread acclaim. Lottes' FXAA technique is remarkable in that in its console iteration, it is able to process a 720p framebuffer using around 1ms of GPU time. Bearing in mind that the average console 30FPS game allocates 33.33ms to each frame, this means that anti-aliasing can be implemented without a radical impact on game performance. 350c69d7ab


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