[Brian Klein] “I was seeing blocky artifacts on slanty lines from the footage in the video”
It’s hard to tell what you’re actually seeing but if it’s what I think it is, using deinterlace blur in Compressor 2 might help. If what you’re seeing is on slanty lines you really should look at deinterlacing and other edge releated processing filters (blurring edges for example). It really depends on what you mean by artifact. It may depend on adjacent colors and luminance levels.
[Brian Klein] “I have actually re-installed an old copy of Cleaner 5.1.2”
I don’t remember 5.1.2 specifically (I started with 4 though) but 6 and 6.5 do very good adaptive deinterlacing.
[Brian Klein] “I did try Compressor, but got similar results as Squeeze.”
I actually think Compressor can do better deinterlacing than Squeeze.
[Brian Klein] “I don’t believe the poor results were from deinterlacing issues.”
[Brian Klein] “I was seeing blocky artifacts on slanty lines from the footage in the video.. not the combing issues you get with interlaced footage”
Again I can’t tell by your description but there are many ways and algorithms to deinterlacing and each have plusses and minuses depending on the content but you can get nasty things that go beyond combing.
Some, not I, have complained about compatibility issues with Cleaner’s MPEG1 encoding.
Good? The result should look good and the file should work as intended in the target application. MPEG1 has its issues. Different compression apps have processing filters to help, many sware by Compression Master (some sware at it though). Don’t underestimate the impact deinterlacing algorithms have. There’s no single way to do it and even a “best” way may be relative to the content in a given piece.
If you have several apps (Squeeze, Cleaner Compressor, you seem to have) then try them with common settings but take advantage of their unique processing and deinterlace filters to see which will give you the best results. You can just target the area(s) your seeing the “issues” with and you’ll have a good idea which can do what. Squeeze has the least flexible deinterlacing if that’s the issue (and it may be).