---------------------------------------------------------------------------- The Florida SunFlash VideoPix Technical Update or Why won't my VideoPix card descramble HBO? SunFLASH Vol 42 #11 June 1992 ---------------------------------------------------------------------------- This is a brief article about Sun's VideoPix card by members of it's design team -johnj ---------------------------------------------------------------------------- Over the last year since VideoPix FCS'ed to the marketplace, we have been asked some very good questions regarding VideoPix's capabilities and compatibility. In this article we will try and outline some of the basic principles and issues when dealing with the VideoPix card. A New Concept is born --------------------- VideoPix was designed to be Sun's first low cost video solution and to provide an easy answer to our customer request for an clean way to import video images onto the desktop. VideoPix is a multi-standard video capture product which can grab images from any NTSC or PAL source. In using the VFCtool software included with the board, customers can preview, capture, resize, control brightness & contrast, and save the image in any of three different file formats for importing into their favorite application. A Word about Video Standards ---------------------------- There are three basic Television standards in the world. They have existed mostly or in part since the 1940's and they are; NTSC - National Television Systems Committee, PAL - Phase Alternate Line, and SECAM - Sequential Couleur avec Memoire. VideoPix works with the NTSC and PAL standards only. SECAM, which is used in France and the Commonwealth of Independent States (Formerly USSR), was not included in the design because of the added cost to support it. NTSC was established in 1953 as a 525 line, 59.94Hz field rate, 2:1 interlaced, composite color television standard for North America and Japan. PAL is the European composite color standard, it is generally based on a 625 line, 50Hz field rate, 2:1 interlaced scanning rate. There are currently six different PAL standards in the world, all of which VideoPix is compatible with. Black & white television signals are also compatible with VideoPix. Since the black & white video contains no encoded color information, the signal only needs to comply with either EIA RS-170 specification for 525 line scanning (North America & Japan) or the CCIR System 625 line scanning system (Europe & Asia). VideoPix relies on full compliance of these Video standards. Any alterations in these standards by the end users video equipment, can cause compatibility problems for the VideoPix hardware. Non-standard Video ------------------ Non-standard video is a problem for VideoPix. In some cases video equipment manufacturers will design a product which will not follow the industry standards for video scanning or encoding. Many times this will be a cost cutting effort and sometimes it is done to prevent copying the signal. Be aware that not all video equipment automatically follows the NTSC or PAL standards. Non-standard video can take many forms, from a stock traders quotation box to a camera used with a medical imaging system. Technical Questions & Answer ---------------------------- Q: I have a customer that has a stock quotation terminal and wants to capture the quote screen to display on their Sparcstations monitor. Will VideoPix do this? A: Perhaps. Most stock quotation boxes output non-standard video, check with the manufacture of the box to see if they support RS-170A or CCIR video output. If not, the only choice is to find a third party solution that can support non-standard video, or try a different model stock quotation box from a different manufacturer. Q: I have been using a VideoPix with a camcorder in my office for a video conferencing application, but the images don't look that great on my Sun monitor, why is this? Achieving good image quality has always been quite a task in video. The fault is more than likely the conditions you are shooting in, and not with the VideoPix card or camera you are using. Remember: Regardless of how much you spend on video equipment, it will never make up for bad lighting or shooting conditions! Shoot in well lit areas and use incandescent lighting when ever it is possible. Q: I have a video signal that VideoPix won't capture correctly, but a board from another vendor will. Why is this? Some boards can capture non-standard video because they were designed too. VideoPix, in an effort to reduce cost to the customer, follows worldwide video standards of which 98% of the video software available is fully compatible. The other solution, although flexible, is expensive and benefits less than 2% of the video capture marketplace. Q: Can VideoPix support "Slow-Scan" video rates? A: No. Slow Scan is a process in which the video is transmitted slowly over telephone, radio, or other carrier. Slow Scan was created to transmit images over limited bandwidth delivery systems. Unlike compressed video, Slow Scan sends the entire picture data, but over a much longer transmission time. A frame of video which can be displayed in a 1/60th of a second on a normal NTSC monitor would take minutes to send via Slow Scan. Some medical imaging equipment uses a similar scheme for recording their images to external devices. VideoPix operates at 50 or 60 frames per second. Q. Why won't VideoPix correctly digitize images from some VCRs in freeze frame mode? A. In some cases the video the VCR is delivering to VideoPix may not be entirely correct in certain operational modes. Freeze frame, or more correctly, freeze field has been a common feature where this has become a problem. Most video monitors are very forgiving about the signal they accept. Because of this fact, a VCR manufacture may not fully adhere to closely to the video standard in order to reduce product costs and take advantage of the monitors liberal tolerances. VideoPix will correctly synchronize to any legal RS-170 or NTSC signal. Similarly, VideoPix will correctly digitize video that conforms to CCIR or PAL Video specifications. 98% of the video software in the world correctly adheres to the NTSC or PAL standards. VideoPix achieves conformance by using a chipset made by Philips. The digital decoder chipset adheres strictly to all of the published video standards mentioned before. Q. Are there any alternatives/workarounds to these problems ? A. It may be possible to find third party solutions that will work in some cases, but not always. Third party products are available from Parallax, RasterOps, and others. Check the Multimedia portfolio or Sun catalyst catalog for more details. In a case of non-standard video, the customer will need to seek out a third party solution. Be aware that the solution to their problem may not exists as an S-Bus product, most of the non-standard video capture products available are on the PC/AT or VME platform only. With the problem freeze field (frame), Try capturing the frame as it goes by in normal play mode. The other advantage there is that the VCR will be producing a full frame (a full image) of data and not just a field (1/2 an image with lines replicated). The disadvantage to this is that it is awkward to capture exactly the frame desired by hand and it may take several attempts. Another possible fix is to add a frame-store/TBC between the VCR and VideoPix, although this is a very costly solution. The best choice by far is to find a VCR that supplies all the features the customer desires, but doesn't take any short cuts. This too can be expensive and requires the usage of high-end industrial or professional video equipment. For devices that feature RS-232 control. The VCR could be programmed to move the video tape to a point before the image to be digitized. Start the video tape playing and using a known time delay instruct the VideoPix hardware to digitize at the desired moment. This would require the user to write their own application. Q: Will VideoPix work with HDTV, IDTV, or Enhanced NTSC? A: No. VideoPix will only work with NTSC and PAL video. All of the systems mentioned above are still in the testing or research phase around the world and have yet to be acknowledged as standards in most countries. Q: I want to know more about how VideoPix works, and how to get information about the Philips chipset it uses. Where can I get this? A: To find out more about how VideoPix works, order: VideoPix Technical Information Document part# FE297-0/15K For Information about the Philips SAA9051 chipset contact: Philips Components Video Products Linear Division 811 E. Arques Ave Sunnyvale, CA 94088-3409 +1.800.227.1817 Ask for a copy of the Video Data Handbook. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ For information send mail to info-sunflash@sunvice.East.Sun.COM. Subscription requests should be sent to sunflash-request@sunvice.East.Sun.COM. Archives are on solar.nova.edu, paris.cs.miami.edu, uunet.uu.net, src.doc.ic.ac.uk and ftp.adelaide.edu.au All prices, availability, and other statements relating to Sun or third party products are valid in the U.S. only. Please contact your local Sales Representative for details of pricing and product availability in your region. Descriptions of, or references to products or publications within SunFlash does not imply an endorsement of that product or publication by Sun Microsystems. John McLaughlin, SunFlash editor, flash@sunvice.East.Sun.COM. (305) 776-7770.