There is a lot of information about HD floating around as broadcasters start to gear up for transmission, but will this high resolution TV standard affect CAD in any way, asks ATI’s Robert Jamieson.
First off, what is HD? High Definition is a term used to say that the television or screen can support a minimum of 720 physical horizontal lines and widescreen. Now, I hear you say even the 1,024x 768 monitor resolution has more lines than this. Yes this is true, but this is the basic requirement to attain the “HD ready” logo, there are actually a number of higher resolution modes that are a lot more useful to us. Manufacturers also have to pay a license fee to EICTA before they can use the logo.
Before the “HD ready” logo a lot of manufactures stated their screens could take a HD input but the high-resolution image was then scaled down to fit into an 800 x 600 display, for example. This would result in an effective 450 lines, which isn’t exactly HD is it? A salesman in a specialist reseller was telling me his complete range was 1080p ready today just because it had this logo – not true. Devices might upscale to fill the screen but native resolution is where the quality is.
So what are the resolutions? The typical standard HD called 720p is 1,280 x 720 pixels. The top standard is 1,920 x 1,080 (1080i and 1080p). The i and the p are Interlaced and progressive scan. Interlaced is where one line is refreshed one cycle and the next line the next cycle. Progressive are refreshed each cycle, and is therefore better quality. A screen at the top resolution is interesting, but why? 1,920 is higher than most standard monitors today and because it’s widescreen you get a nice place to put all those CAD menus on the side.
The other advantage to these high resolution screens is that they need fast refresh rates (8ms or less) so fast motion of a movie is rendered correctly. This is also quite useful for rotation of 3D objects in CAD. You might say that we already have high resolution screens but the quantities of scale of production will help the price and availability to take it out of a specialist area.
Of course all this talk of HD has pushed the camera manufactures and effects people to re-equip. HD cameras are widely available and coming down in price, but creating and editing the HD media results in a lot more information and more detailed model creation because you see everything on the screen. All this work in rendering high quality 3D will bleed off into 3D CAD eventually as well.
How do we connect to one of these screens? DVI-I (Digital Video Interface-integrated) on all current workstation cards should support up to this resolution. DVI-D is the digital only version on some older cards. A physically smaller domestic standard is HDMI (High Definition Multimedia Interface) which can carry audio as well as digital signals. This is becoming popular now but you can get DVI to HDMI converters. HDCP (High-bandwidth Digital Content Protection) is built in to HDMI to protect the copying of the media, but that needs an entire article just to discus the ethics of it.
Hardware video decoding
What is H.264 the new HD hardware video decoder? H.264 is a new video compression scheme that is becoming the worldwide digital video standard for consumer electronics and personal computers etc.
H.264 has already been selected as a key compression scheme (codec) for the next generation of optical disc formats, HD-DVD and Blu-ray disc (sometimes referred to as BD or BD-ROM). H.264 has been adopted by the motion Picture Experts Group (MPEG) to be a key video compression scheme in the MPEG-4 format for digital media exchange. H.264 is sometimes referred to as “MPEG-4 Part 10” (part of the MPEG-4 specification), or as “AVC” (MPEG-4’s Advanced Video Coding). If you are going to want to output high quality 3D walkthroughs etc this is a codec worth looking at in the future to get the maximum resolution and speed.
" HD denotes that the television or screen can support a minimum of 720 physical horizontal lines and widescreen "
ATI’s market brand to do this is called Avivo and Avivo-enabled VPUs and accompanying software work together to permit transcoding of video signals. Transcoding is the process of re-encoding video in a format (or simply at a bit rate) different from its original. Transcoding capability is becoming extremely important at a time when there is an explosion of video-capable devices (PDAs, cell phones, portable game consoles, etc) that have widely-varying capabilities in terms of the formats they support and the amount of storage they take. Now you might say what’s this got to do with CAD? At the first look not a lot but as it’s 4x faster than any current CPU, transcoding it shows what sort of information processing can be done on the GPU or video card. This sort of processing can be applied to other areas and CAD is a graphics-based application!
On sale now
Can you buy anything now? Yes and No. to get the ultra high resolutions of HD you need to spend a lot of money. I often get asked about what is best between CRTs, LCDs and Plasmas. A lot of companies need a large screen in the reception to show what they do to prospect customers etc. My buying experience in high street showrooms is that they feed very low signal or highly encoded with loads of artefacts so you can’t see the real quality the screen can support. CRTs are just too physically big today, plasmas only really support the 720p or resolutions like 1,024 x 768 as a maximum without spending silly money, whereas LCD HD can support 1080i and p just make sure you supply a high quality signal. Some of the top Sharp models look very good.
To sit at your desk with a 32inch screen is unlikely today, but you can already get very high resolution screens in laptops like the HP nw8240, but once this is at reasonable prices and I’m sure the software companies will make use of the extra real-estate!
Robert Jamieson works for workstation graphics specialist, ATI.
