MAXIMUM iPod video output quality.

Question

Because a few have asked me for some specs...
The iPod is designed to play back video files that have square pixels.
DVDs use non-square pixels to fit widescreen images into 720x480 native rez of DVD standard.
When you square the pixels of a 2.35 aspect ratio movie (like "Ep III" for example) you get an image that has a native rez of 720x304(=218,880)pixels, mathmatically speaking, the iPod can play back MPEG-4 at 480x480(=230,400) pixels, cha-ching!
The iPod CAN playback the full VIEWABLE resolution of a widescreen movie. You can "think" of it this way, the black bar pixels are excluded. The iPod does not care how they are arranged as long as the pixel count falls at or below 230,400. The specs of one of my typical files is: MPEG-4 SP 720x304 2-pass VBR 1.4Mbps average bit rate/Stereo 2-pass AAC-LC at 48kHz 160kbps average bit rate. When played back on my PC using the native Nero7 (not iTunes) application that I use for encoding I can also read the subtitle info embedded in the file and I also get chapter marks. You should see the difference between this and the 320x240 H.264 files most everyone else seem to be getting from iTunes purchased files or using some freeware or paid encoders. My files look at least twice as good at less than double the file size, to me that is an accomplishment. Output image quality is most important to me, file size falls where it does Ep III = 1.41Gigs for example.
I have a 60 Gig iPod and am able to carry (approx) 5000 songs AND 45 movies of varying lengths with me when I travel, and the videos are WORTH viewing, they are not just an adequate looking fascimilie of a movie. So if anyone want's to bag on my file size for being bigger than H.264 at 768kbps, too late I beat you to it, again, for me, the image comes first.
I'd love to see what other people are doing.
FJ1

Answer 1

The iPod is designed to play back video files that have square pixels.
DVDs use non-square pixels to fit widescreen images into 720x480 native rez of DVD standard.
I fail to see the relevance of your comment. The DVD (a non-square pixel encoded file container) is made to play on a TV/TV monitor device (which displays non-square pixels). The iPod, like all computer monitors, is a square pixel, non-interlaced device. Most good computer software multimedia applications are intelligent enough to know the difference and display the video information at the correct aspect ratio irrespective of the pixel shape in question.
When you square the pixels of a 2.35 aspect ratio movie (like "Ep III" for example) you get an image that has a native rez of 720x304(=218,880)pixels, mathmatically speaking, the iPod can play back MPEG-4 at 480x480(=230,400) pixels, cha-ching! The iPod CAN playback the full VIEWABLE resolution of a widescreen movie.
While it is true that your file resolution does meet restrictions for both total pixels allowed (218,880 of 230,400) and total number of macro-16 blocks (855 of 900), it is untrue that "The iPod CAN playback the full VIEWABLE resolution of a widescreen movie." What you are actually seeing on the iPod is a "scaled to fit" version of your original data. However, if you plan to view your files on multiple displays (iPod, TV, Computer Monitor), then I whole heartedly endorse with your approach for those devices capable of display at the full resolution.
My files look at least twice as good at less than double the file size, to me that is an accomplishment. Output image quality is most important to me, file size falls where it does Ep III = 1.41Gigs for example.
Believe this statement requires further qualification. Once again, while there is little doubt that your files should look better when displayed on larger display devices (greater resolution quality), the differences become less significant when viewed on the iPod (where greater "per pixel" compression quality becomes more significant when you resolution is scaled to fit the smaller screen).
I have a 60 Gig iPod and am able to carry (approx) 5000 songs AND 45 movies of varying lengths with me when I travel, and the videos are WORTH viewing, they are not just an adequate looking fascimilie of a movie.
"WORTH" is in the eye of the beholder. And since my eyes aren't what they used to be, I have gone the other route. I only have 101 audio files and 391 movies on my 60G iPod which is about 60% full at the current time.
So if anyone want's to bag on my file size for being bigger than H.264 at 768kbps, too late I beat you to it, again, for me, the image comes first.
In these cases one must choose efficiency in terms of time, space, or complexity. I can't fault your choice but merely point out that my priorities are different than yours. At native iPod viewing resolutions I achieve the same quality as you using the H.264 codec at 400 kbps which yields roughly 4MBs/min of source material or approximately 6 hours of program material in the space of your average files.
Hope that answers your E-mail question, Rich.