Very interesting, Chineworks - thanks!

It's obvious once you point it out, but as I deal mostly with still images, I always 'focus' on the pixel resolution as the primary factor. Not so with video!

Given this, what would you suggest as a workable Bit Rate for optimal playback on my Touch Pro 2?

And based on what you're saying, there would be no reason to reduce the resolution, in terms of file size, but I imagine there would be in terms of how my device will scale the image for its display. Would switching to 640x480 help, or would it do just as well at the original 1280x720?

Thanks again!

Not having any idea what a Touch Pro 2 is i would be remiss if i made specific recommendations.

I can give you some general concepts. Keep in mind what the physical resolution of the device's screen is. I have a phone with a resolution of 360x240 and a pocket video player with a resolution of 320x240. Assuming i'm going to be watching on those devices, rather than connecting them to a larger display, any frame size larger than those resolutions is not only a complete waste, but actually a drag on system resources that can cause playback to stutter.

Now, keeping in mind that a smaller resolution might be better than larger, also realize that more resolution needs more data and less resolution needs less data. Encoding 1280x720 at 4.5Mbps will end up with more artifacts and quality loss than using 640x480 at the same bitrate. Fewer pixels means that the same bitrate can do a better job with better quality. So for that reason also the lower resolution is a better choice.

Personally, on my pocket player, i generally use 320x240 for 4:3 material and 320x180 for widescreen, and encode at 256Kbps at 14.985fps. The refresh rates of the screen aren't as good as a computer monitor or TV so the lower frame rate doesn't matter. It also means the player only has to do half as much work which often leads to smoother playback than 29.97 would anyway. And, since there are only half as many frames, 256Kbps maintains twice as much quality as encoding at 29.97 would.

256Kbps isn't much. It's considered pretty low ever for web quality these days. On the other hand, the screen i'm watching it on is only 3" so the quality loss isn't noticeable. That bitrate also allows me to store hundreds of hours of video on the 30GB drive. It's sufficiently entertaining so there's no need to waste space on a higher bitrate.

DLCPhoto,

Everything else being equal, a 640x480 video at 1.5Mbs ABR should retain the same relative encoding quality of a 1280x720 video at 4.5Mbs, and will occupy 1/3 the disk space.

Notice I said "relative encoding quality." The resolution of a 640x480 video is only 1/3 that of 1280x720, and that cannot be made up by increasing the bitrate.

A common mistake is as follows:
Does a 640x480 video contain twice as much information as a 320x240 video?
The answer is "No, it contains four times as much information." Any good fifth grade student (and Jeff Foxworthy) can tell you why this is so.