I found that is probably because you need to set your encoder to *single pass* otherwise it won't load into the ipod.
I can now confirm that this is one possible option that may work. Ran across my first "would not sync" file today while converting old public domain files. Of the first 6 serial episodes I worked on, number five would not sync to my iPod. So I decided to spend the day running tests. As a result, it appears that the iPod player is not keying on an average data rate, but rather the highest instantaneous data rate found in the file.
My problem file was a 17-minute episode of Undersea Kingdom the first half of which contains "night" battle scenes. As I use 100% high quality, 2-pass, 400 kbps average target VRB for H.264/AAC format, I was more than a little startled when my rather conservative settings would no play on my iPod. Although the average data rate for the file was on the order of only 550 kbps, I noted later in my testing that instantaneous transient video data rate frequently exceeded 700 kbps during some of these "complex" scenes. As a result, I tried varying a number of settings using MPEG StreamClip.
1) 1-Pass vs 2-Pass: It does appear that using a 1-pass encode may allow some files to sync correctly to an iPod. This is likely due to the more conservative 1-pass algorith which "clamps down" on such transients at the expense of quality for these scenes. If this is combined with a "constant data rate" within specs, then you are assured that the resulting file will be iPod compatible. On the other hand, I prefer a file with "constant quality" and will take my chances on having to readjust my VRB target data rate as needed to achieve iPod compatibility. I leave it to the user to adopt his or her own strategy here.
2) Next tried varying the "Quality" setting to see what affect it might have. Turned out that a reduction from 100% to 90% in this particular case reduced my overall average data rate by 25 kbps. Unfortunatle the file produced still would nit sync because the data rate reduction was evenly spread across the file content and my transients were still too much for the player to handle. Further reduction in 5% increments from 90% to 50% produced no additional reduction in data rate.
3) As a last resort, I decided to lower my target VRB data rate by 50 kbps (to 350 kbps) and returned to 100% quality and 2-pass encode settings. This did the trick for my "problem" file. I was able to adjust brightness setting and contrast setting, increase volume, keep the "transients" within specs, and all with little or no visible loss in the overall quality.
Would be interested to learn if anyone having random iPod incompatibility problems can confirm these findings with their own "problem" files. That is to say, would like to know if reducing the data rate, reducing the frame rate (another way to reduce the data rate), and/or switching to a 1-pass/constant data rate mode allows previously "unsyncable" files to suddenly work.
2.0GHZ G5/533MHz G4 DeskTop/400MHz G4 PB Mac OS X (10.4.3)
