The new Image Viewer uses indexed JPEG decoding with DirectDraw and MMX/SSE instructions to improve the overall performance. It has two levels of image cache - an L2 (lower) level cache stores the relevant portions of the compressed JPEG images (about 5% of the total image size), an L1 level cache stores the decoded images, which are ready to be loaded into the frame buffer. The viewer will try to lock about 75% of the total available physical memory, of which, 50% is used for L1, and 25% for L2. In typical settings, the L1 will hold 40-60 images depending on the current memory usage of the wall machine. The L2 will hold about 200 images when moderate to high level of JPEG quality is used. (The MMS Tuner will reduce "obese" images automatically.) The decoding latency from L2 to L1 is about 50-100ms, again, when moderate to high quality compression is used. In most scenarios, this is negligible. If this does pose a problem to your presentation, you should contact the author for maybe a custom solution. The image viewer also has a much improved cross-fade timing. It used to be that when you say "fade foo bar 100 0 1000" it actually takes 2 seconds to finish, so you have to tweak your script to match the beat of your music. Now, the new viewer enforces a strict timing of fading to an accuracy of about 100ms, so 1000 will be 1 second.
The MMS tuner is a tool for tuning up your mms script file. It walks through your script file and displays the basic information about each image in your script, name, file size, resolution, index, and a description. It checks if the image is a progressive JPEG, which needs to be converted into sequential type of JPEG in order for the index to work. It then checks if the index file is valid. It also checks the file size and recompresses it to reduce the size if necessary. It also tries to estimate the preloading time of your script.
After your starting the program, click "Load MMS" button, and select your script file and click OK. Here is a screen shot:
Checked file will be processed in the tune-up. You can manually override this if you are sure what you are doing. Now, click "Tune-up Now".
It will take a while if you have lots of images in your script. After the tune-up is done, the window looks like:
Notice the reduction is file size and therefore the load time. Your original images will be renamed to foo.jpg.bak in the same directory.
Run the tuner on your script before you run mmshell on it and make sure that all the index files are valid, as shown in the above screen shot.
As just about any software, this new viewer and tuner have bugs and will crash occasionally. If the viewer crashes, report the following: the locations of the screens that crash, the image it's showing or loading. If the tuner reports an error, indicated by a red entry in the list, keep a copy of you script and send that it.
Author: Han Chen Email: chenhan@cs.princeton.edu Copyright 2001