OPALPCD.DOC This program takes an image file from a Photo CD ® disc and either displays it on an Amiga ® computer. It will display on an OpalVision ® screen and can be saved as an IFF24 file on the command line. PhotoCD is a format where negatives and slides are scanned at resolutions up to 3072x2048 and storing up to 100 of these on a compact disc. It costs approximately US $1.50 to $2.00 per image with a ten image minimum, and gives the user access to scans on a $35 000 scanner. This version is still not complete. Resolutions above Base ( -4 and -5 opts) are not rung out yet due to decompression and memory size problems. Overviews are not implimented either. This was originally written by Hadmut Danisch for a ppm file converter. That source only file has been modified and (partially) debugged to work with IFF24 and OpalVision. There are two versions. Opalpcd requires a 68020 and 68881 and up accel- erator or an A3000 or an A4000 and is optimized for these and will crash if run on a vanilla 500, etc. For those less fortunate there is a version, opalpcd.68000 for standard machines. This uses the IEEE library in Workbench 1.3 and up. Other requirements are opal.library in libs: and an OpalVision card for viewing. Also, at least 3 meg of FAST RAM are needed, and one meg of chip RAM for Base resolution. Of course, a CD-ROM drive is required and CDROM-FS by Canadian Prototype Replicas. To use, type "OpalPcd [options] pcdfile [iff24file]" and return. It must be run from CLI or shell, but can be tied into a directory utility or other program. Options are the items starting with a "-" that denote size and operation. Just typing opalpcd will list these for you. There are five sizes from 1 to 5, with 3 being the base at 768 X512. This is the largest currently usable and is suitable for most Amiga applications. The next one down (-2) is 368X256 and works well with lo-res noninterlaced and loads faster(6 vs 25 sec on 68030/882). Due to floating point manipulations the conversion is slow. Data is NOT in a straight RGB format, but is in a Luma Chroma Chroma format, somewhat like HSV I think. The pcdfile must be typed except when using the slideshow mode. Look in CD0:PHOTO_CD/IMAGES for these. They are large files, 3-6 Meg. Iff24file is the filename with path for a resulting 24 bit IFF file in the same resolution as the PCD file, and omitting this will cause display only. Slideshow mode is a new mode with -p for presentation (s is already taken for sharpening). This workes with base and base/4 resolution. In the latter pictures will load and change every 20-30 sec and about 7 on the latter on an accelerated machine. To stop hold the left mouse button, and instead of changing again it will exit. It will also exit when it goes beyond the last file. The image files are numbered like frames of an animation, IMG00XX.PCD where XX is 01 for the first, 30 for the thirtyith, etc. A disk can hold a hundred or so. Due to this standard the path is fixed at CD0:PHOTO_CD/IMAGES. If your drive is NOT CD0:, try "assign CD0: CD_DRIVE" where CD_DRIVE is the name of your CD ROM device. To view an image taken with the camera tilted sideways for better vertical capture, use the -l or -r option to right the image. Newly added is the -b option to place the image as a backdrop to Amiga when exiting. This is not in the 68000 version yet. TO DO: Finish debugging resolution 4, which may work now with at least 10 meg of fast ram. Allow cropping of images, from command line at least. Use hard disk to cache some data to reduce memory requirements. test and impliment resolution 5. load directly to OpalPaint if even possible. convert overview to thumbnail and allow storage of a copy on hard drive. Whatever else I feel like adding. This program is a purely experimental venture and is being released as a service to Amiga users to gain exposure to the PhotoCD format and develop understanding therof. It may be reproduced and distributed inkeeping with Hadmut's original condition that no profit be made from this. I think a few companies may frown upon this as a commercial product too. No warranties are expressed or implied whatsover and the user assumes all responsibility arising out of use thereof, including but not limited to, loss of data, damage to hardware, infringement of patents or copyrights, or even the decline of Western Civilization. No money is expected for this program, and the user may alter this and complete debugging as long as it is not for commercial gain. It is hoped the Amiga community benefits from this program. Trademark and product recognition to Commodore Amiga, Centaur Development (OpalVision), and Eastman Kodak (Photo-CD). It has been tested with a PhotoCD processed by KodaLux, and example images from a Tempera PhotoCD access program. In over 100 images, all have successfully loaded.