SOFTWARE
Video playback quality is almost entirely dependent on having good software. Clever and innovative software can play back high quality video and sound, while poorly designed software can be unusable for any number of reasons.

At first, creating a video playback program might seem straightforward. One need only take a series of still images stored in memory and display them in sequence to produce a moving image. And indeed, this is exactly what some photo album programs do to offer a so-called "movie playback" feature.

Such a simplistic approach, however, has a fatal flaw. Video footage stored uncompressed in this manner is unusably large. Even at 160 x 160 low resolution and a minimum 10 frames per second, 16-bit color video eats up memory at a staggering half-megabyte per second. At this rate, even an otherwise empty eight-megabyte handheld could only hold a scarce 15 seconds of footage, completely unacceptable for almost any purpose.

To achieve a usable video solution, the images must be significantly compressed. Natural video is incredibly difficult to compress, and doing so on a handheld is doubly so. Standard video compression algorithms like MPEG are simply too CPU-intensive to use on PalmOS handhelds, requiring processors roughly ten times faster than currently available to play back at full speed.

Any video algorithm needs to create a delicate balance between 1) file size, 2) playback speed, and 3) image quality. More clever software can give you a better overall combination, but even still, the results will reflect trade-off made between these three factors; you can't simply improve one factor without affecting the other two. That would be like trying to find a car that had the lowest price, highest fuel efficiency, and most powerful engine all at the same time. For instance, it's possible to get perfect image quality with a simplistic uncompressed approach, but this comes at a horrible cost in file size. And while MPEG might give good image quality and small file sizes, running at only one frame per second on a Palm would really be more of a slideshow than moving video.

The best software tends to simplify moving images to make them easier to compress. Simple methods include color reduction, lowering the resolution, or masking out regions of the screen that aren't moving. More complex programs like TealMovie also use smarter algorithms to subtly simplify the images in ways the eye often won't notice. Using such techniques, TealMovie achieves roughly a 25-fold reduction in file size, maintaining excellent image quality and storing more than six minutes of footage in the memory of an 8-Meg Palm; much more if stored an external storage card.

Better yet, TealMovie also offers support for sound on all but the original PalmPilot and Palm III models, a feature virtually unheard-of on the PalmOS platform.

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