.DV quality vs. .MOV (and even .MPG)

Question

The iMovie guys sent me over here with this.
I'm a Windows (and sometimes Linux) guy. But occasionally I have to deal with Macintosh stuff and the process is uniformly confusing. I'm hoping someone can take my (too limited) information and give me some guidance.
I'm part of the A/V team at church. We have two buildings and two computers projecting slides/videos/etc for the worship services. Both computers are Windows. One runs a worship program called MediaShout, the other runs SongShowPlus. Mediashout will display a Quicktime video, SSP will not.
Not that I never get Quicktime MOVs. But usually they are small and I run them through a free Transcoder call Super by eRightSoft and convert them to MPEG-1.
So, of course, this week I got two giant Quicktime files to deal with. One was an 819MB .mov file that was FTPd to me. No problem. It played fine on the MediaShout machine and (after some fiddling with framerates and bitratres) I got an MPG that showed fine in SSP.
The next was more problematic. Our associate pastor's daughter had made an iMovie on her laptop but it wouldn't burn to CD and she didn't know what to do and they wanted it this weekend and she had to go somewhere. So they handed me the laptop.
Did I mention I don't really do Macintoshes?
Anyhow, I thrashed around with it for a while. I discovered that it wouldn't burn to CD because it was > 900MB. But also, it was trying to burn an iMovie project file, which was probably not going to help me. After some more thrashing I found 'Share' and found 'Share Quicktime' and even found 'Full Quality'.
Now it is 1.05GB. Luckily I have a 2GB thumbdrive, though I had to erase a lot of things. More surprising than the size is the suffix. This is a .DV file. Never seen one of those.
So I put the .DV file on the SSP computer, which sure enough does not recognize the file. The computer itself does, however, giving its icon a Quicktime symbol. I drop the DV file on Super and, after a bit, the program generates an MPG. It takes a few trys at some of the Super options before I get rid of the artifacting but, all-in-all, it looks good.
Then I take the original file over to the MediaShout computer. The .DV file is recognized and it appears that all is well. Until I show the video.
At full screen, the video is terrible. This is actually a slide show and what it shows is nasty, pixelated photos. At the default Quicktime screen size it looks quite decent but at full screen it looks horrible.
But ... the MPG made from the same .DV file looks great. How can the information for the high quality pics be in there but Quicktime fail to show it?
Is there some kind of setting in the Quicktime player I need to change to get quality fullscreen?
Is there something I could have done within iMovie that would have relieved these problems?
Is there a way to convert .DV to .MOV to regain the fullscreen quality?
-----Sims-----

Answer 1

illweather--I think I have a solution for you. I think the sound difference is due to dither introduced by some apps, but not by iTunes. Try using Audio Hijack to dither the least significant bits in the iTunes output. Here's the response I posted to another forum:
I solved the mystery. Turns out it's because iTunes (with volume at full, no eq, and no audio processing) truly outputs a raw 16-bit stream, while Logic always outputs a dithered 24-bit stream.
With iTunes, a 16-bit CD gets played back with zeroes in the 8 least significant bits. Logic Pro, however, seems to convert everything to 32-bit float, then dithers to 24-bits, even if all faders are at unity and there's no processing being done. So when you use Logic to play a 16-bit file, you end up with some dither in the 8 bottom bits.
When I compared the digital outputs of iTunes and Logic and concluded they were identical, that was done by recording digitally to a 16-bit DAT machine. The outputs WERE identical to 16-bits, but the full 24-bit output was slightly different.
For whatever reason, some (all ?) 24-bit D/A converters don't seem to sound nearly as good with a truncated 16-bit input. That dither introduced by Logic makes a very noticeable improvement in the sound. I found I could replicate the effect in iTunes by routing output through Audio Hijack and inserting a 24-bit dither plug-in. Then Logic and iTunes sounded virtually identical. Problem solved!
I can't say that I understand why dithering 16-bit audio to 24-bits improves the D/A conversion, though. Typically, dither is used when decreasing wordlength, and it's very clear why using dither in this situation improves resolution. When the original source is 16-bit, though, I don't understand why dithering to 24-bits improves D/A conversion. Very clear from listening that it does, though. Anyone have an explanation ?
Hey, thanks for the advice, and maybe my discovery will be useful to others.