Help with quality of exported files

Question

The problem: I'm trying to get a good quality, 34 minute movie onto a DVD with chapter markers separating individual short films. This is supposed to be a compilation of 8 family movies, in addition to an introduction and credits at the end. Four movies are old movies made in iMovie and are .m4v files. Four were made in FCE earlier this year. I linked everything together in a Master Sequence, putting pauses in between each with some livetype text files to introduce each video. The m4v files were imported and placed in the master sequence. The others are nested sequences. I put chapter markers at the beginning of each section. My intention was to export this one master sequence as a quick time movie, then put it into iDVD.
It worked, but the quality was horrible! Everything became grainy, even the movies I had previously created in FCE. This was very disappointing. So I expertimented with a few things, and here’s what I found.
When I exported a quicktime movie, the quality degraded. It became grainy. Also, it changed the aspect ratio and stretches everything horizontally, as if to take a standard size screen and stretch it to a widescreen. It did this even with the original movies I had made in FCE. I don’t like building self contained movies using this mode because the file sizes are too big, so when I export I tend to use quick time conversion. In this case, I was hoping a non-self contained movie would merely point to all the original content and not add compression artifacts (or something like that). It turns out it made it worse.
When I tried to export a quicktime conversion, 640x480 VGA, best quality, H.264, the machine couldn’t do it. It ran for an hour or so and then crashed. Twice. That is for the entire movie. When I export individual clips (3-6 minutes) it works. The quality is good for movies made in FCE, not as good for imported m4v movies made long ago in iMovie, but better than what I get exporting quicktime movie files, either self contained or not. This is surprising to me, because I was expecting the export quick time movie command to produce the best quality. Also, I’m concerned that if I was able to create this, iDVD would not see any chapter markers anyway.
So there is a problem either way. Experimenting has led me to discover several questions/issues which need answering:
Issue #1: Why can’t I get a quick time movie of the same quality as what I see on the canvas, using the quick time movie export command? On a side note, the user's manual says something about a settings pop up menu where you can deselect the "recompress all frames" option. I can't seem to find this, and was thinking maybe that would help.
Issue#2: Why do m4v files which are very high quality in iTunes suddenly become poor quality when imported into a sequence? Seems to be an import problem, because the movies are already grainy when they’re on the canvas. I thought about making XML files and importing them that way, but the original project files in iMovie are gone.
Issue #3: Why do I end up with a stretched picture if I export quick time movies and there are mixed aspect ratio contents in the sequence (the m4v files are widescreen, the others are not)? More important, how to I get FCE to not do this?
Issue #4: When I export movies using quick time movie (not conversion), the grainy movies actually look better when played in VLC. They also look good when opened with FCE. How can I get that kind of quality in quick time, or at least in iDVD? Perhaps that would solve my problem.
Thanks for any help you can provide.
E

Answer 1

Thanks for the response. I’m not fluent with codecs or video compression, so this project quickly became more trouble than I expected.
It turns out the nested sequences are not H.264, the compression field is blank for the nested sequences. I double checked and the other properties are correct. Sorry about that. The other movies, though, (ones built in iMovie for iTunes) are H.264.
These four . m4v movies are in 960x540 and 480 x 272 because of the way they were exported in iMovie (Share -> Export Movie opens a menu with four sizes: Tiny 176 x 144, Mobile 480 x 272, Medium 640 x 360, and Large 960 x 540).
I just imported the final products (what was exported from iMovie) as clips into FCE. Sounds like I should not be doing that. The original media is on my computer, but not the iMovie project files, and for what I’m trying to do it’s just not worth the time to rebuild the movies in FCE.
Bottom Line: Here’s the current status of the project:
All eight of the movies, by themselves, play well in quicktime. I can put all of them on a DVD, and they still play ok. I wanted to string them all together in one sequence, with some transitions in between (creating a “Play All” option on the DVD). That’s why I nested the sequences, and imported the movies made from iMovie, than added chapter markers. Unfortunately, putting these different types of media together and asking the computer to make one sequence is creating a mess. So I’m sticking with Plan B and putting the movies on a DVD without trying to merge them into a single track.
A few follow up questions…
Out of curiosity, when you say “convert everything to QuickTime DV NTSC 720x480 at 29.97fps with 48k audio,” do you mean the original media (all of the bits of video and stills that came from the camera) or the edited sequences I’m currently working with? As a lesson learned, should I be changing properties of clips before importing them to FCE, so the source material has consistent aspect ratios?
The still images, though they are huge, show up with much better quality than the movies (which is expected, and I’m ok with). So I get a product which includes both video and still images, where the images are very sharp and the movie portions are a bit grainy (because they were taken on a small digital camera). If I change the size on the stills, won’t that just bring the still image quality down?
I’m still baffled at why using the export quick time movie command makes a video of lower quality than when using quick time conversion (in other cases as well, not just this project). In every case, I’ve got digital pictures and movies from my digital camera, and some text in FCE or LiveType files on top of that, usually with additional audio tracks.