At 10:35 AM -0500 1/4/05, John Shutt wrote: >Which brings me to the nut of my question: Have there been any studies on >the relative quality of transcoder chips in various consumer devices such as >Cable STBs, OTA STBs, and Consumer displays? Is Sony's chip better than >Panasonic's, or do they both purchase off the shelf solutions from a third >party? We know there are performance differences among ATSC demod chips, >are there similar performance differences with transcoding chips? I have not seen any studies, and for that matter I am not certain who the major chip foundries are, other than ATI. Part of the problem is that there are different functions that may be integrated into a single chip, or spread out among several chips. These functions may include: Video scaling (inter-format conversion) De-interlacing Generation of on screen graphics (OSG) Composituion of multiple sources (OSG, main video, and PIP) And in some cases support for a portion of the MPEG decoding functionality. The scaling functions are fairly straight forward; it is now fairly inexpensive to provide high quality scaling with plenty of taps to get good results, even when the scaling factors are small. It is the de-interlacing functions that seem to vary the most. The trend seems to be in the direction of fairly sophisticated chips that use block based processing for motion compensated predictions. Earlier designs generally relied on multi-field averaging (spatio/temporal filtering). Last night I discovered something interesting about my new Samsung RPTV. As i noted in an earlier post, the set uses some form of block based motion compensated prediction for deinterlacing. I don't have the tools to make precise measurements, but it appears that this processing is introducing a delay of at least 3 frames, and possibly even more; the good news is that the set appears to have a built in audio delay to keep sound and picture in sync. Last night we were watching the Sugar Bowl on the big screen; unfortunately we had to watch in SD as the local ABC station WCJB-DT is still not operational. Meanwhile my wife was surfing the web in the bedroom; the 27" analog TV was tuned to the Sugar Bowl as well. When i walked into the bedroom I heard a distinct echo. The sound from the big screen was obviously delayed relative to the analog set that had no delay. So there appears to be no direct answer to your question. The results you see on the screen will be impacted by the performance of the de-interlacer (assumes 480i/1080i source) and the video scaling engine. > >How long before a high end video manufacturer comes out with a stand alone >transcoder for true videophiles? (To be connected to the display with >outrageously over-gauged Monster Cable so the video signal can 'breathe.') > >Just staying curious, An interesting question. I believe that such devices already exist. First stop Faroudja, which is now a subsidiary of Genesis Microchip, one of the largest foundries of video scaling/deinterlacing chips in the world. Here is a link for a .pdf file describing the Genesis FLI2300 Digital Video Format Converter chip that is used in many TVs and graphics cards for computers. The stuff about pixel by pixel motion compensated prediction is intersting. Then check this link: http://www.faroudja.com/prod_dvp-1000.phtml Here's the spiel: DVP-1000 Digital Cinema Source Processor The DVP-1000 is offered as an option for installations that require adjustable output resolutions. Up to eight "Profiles" can be stored and easily recalled from the On-Screen Menu or via RS232 for easy operation and system integration. Each profile includes all setup and image parameters. HDTV Cross conversion is also added so HDTV sources can be optimized at the display's native resolution. Digital projectors and plasmas offer the highest image quality when the DVI input is used. Faroudja's DVP-1000 digital video processor takes standard analog video and converts it to high-resolution digital video. The digital information is sent to the display as a pure digital DVI signal at the display's native resolution. The result is an extremely clear image with sharper depth and detail, free of motion and video processing artifacts. Patented technology such as 3:2 Pull-Down with bad edit detection, DCDi, Cross-color suppression and TrueLife non-linear enhancement combine to create superb results from any display technology: plasma DLP, LCD DILA and CRT. * Selectable output rates * HDTV cross-conversion * Analog sources converted to digital DVI * Digital DVI and analog RGBHV/YPrPb outputs * HDTV transcoding from YPrPb to RGBHV * Auto-detection of HDTV or 480P on the Component inputs * Aspect ratio control and image shift adjustments * Internal test pattern generator * HDTV/computer pass-through * Compact Single rack space size * Infrared and RS232 control The list price appears to be $5,995; street prices seem to be in the range of $3300 - $3500. Quite a bargain, given that Faroudja line doubling products selling for upwards of $16,000 in the early '90s were a staple of upscale home theater installations. A <$20 Genesis chip now outperforms those early Faroudja products. Regards Craig ---------------------------------------------------------------------- You can UNSUBSCRIBE from the OpenDTV list in two ways: - Using the UNSUBSCRIBE command in your user configuration settings at FreeLists.org - By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word unsubscribe in the subject line.