The iPod Touch has one of the best screens for a mobile device on the market today.
- 3.5-inch (diagonal) widescreen Multi-Touch display
- 480-by-320-pixel resolution at 163 pixels per inch
It is just so sweet.
Beautiful as it is, native video resolutions and configurations sometimes need proper conversion to maximize the file efficiency and viewing quality. That is, getting the best possible quality for the least possible file size. Because lets face it, the iPod Touch's low disk space is on of its major let-downs. Its hard to keep a lot of stuff on one cool device.
Anyway. Lets start.
Take note of the resolution - 480 x 320 pixels - this is very important. When you are converting video files for viewing on the iPod Touch, ensure that the resolution of the resulting video is less than the iPod's. Higher resolutions will most likely still be playable, but you wont notice too much of a difference since the device wont be able to display the additional pixels anyway - it'll just fit everything in its 480 x 320 screen. No use cramming up 720 pixels of video on 480 pixel screen right? Sometimes, it can actually be worse if the resolution is too high as it takes more processing power (generates more heat, shortens battery life) to play. But then again, if you choose a resolution that is too low, you are not maximizing the device's full potential.
To maximize file size efficiency, determine the original resolution of the video. I do this by opening the file in Media Player Classic and pressing Shift + F10 then going to the Details Tab. You can use other means if you want to, this is just the easiest for me.
Remember our device's resolution - 480 (width) x 320 (height). If the height and width of the original video is smaller than 480 x 320, no need to make adjustments on the resolution. This is the case for most regular videos downloaded from YouTube or other online video services. Same is true for simple video cameras or video captured from phones.
But the example above (720 x 540) needs to be scaled down. Again, the height and the width of the video needs to be less than or equal to the iPod's resolution. We need to scale the video to a resolution closest to 480 x 320.
But do not just directly convert to 480 x 320. When scaling down, the proportion of the width to the height needs to be retained. Depending on the original resolution, it can create an undesirable stretching effect if you just directly convert to 480 x 320.
To properly scale down, just divide the height and width of the video by the same number so that the width is less than or equal to 480 and the height is less than or equal to 320.
Divide the height and width by 2.
720 / 2 = 360. This is the width
540 / 2 = 270. This is the height.
Resulting resolution will be 360 x 270. Although this will save a lot of disk space, you will not be able to maximize the iPod's screen.
Lets use 1.5
720 / 1.5 = 480
540 / 1.5 = 360
Though the width (480) will fit perfectly on the iPod's screen, the height (360) is too tall. It will work, but this will not get us the best file size to quality efficiency.
Lets use 1.7
720 / 1.7 = approx 424
540 / 1.7 = approx 318
Resolution 424 x 318 would be our ideal choice. Its not too tall nor too wide for the iPod's screen. But it still uses up the iPod's screen to its full potential based on the original file's resolution.
Depending on your original resolution, you will sometimes have black bars on the sides or on the top and bottom. This is normal as we don't want to undesirably stretch the video as shown above. If you are really saving up on disk space, yo can scale down to much lower than 480 x 320 but you will be compromising the quality.
Other factors to consider are audio/video bitrate and frame rate. Higher bitrate of course, means better sound quality. Normal audio bitrate is 192 kbps (near CD quality sound). Lower the bitrate if you want to save more disk space (this works for songs too). Up to 128 kbps is considered acceptable. I prefer to leave the frame rate as it is because I noticed that bitrate and resolution affects the file size more.
You'd have to play with the settings of your video converter and DVD ripper in order for you to get the your desired results. Ill try to post software and methods I use to put videos on my iPod.
Hope this helps.