Help! Trouble Rendering 16:9 footage in AE, and playing it in Premiere Pro!

Question

I have two issues:
#1. I've spent hours searching for a solution to this dilemma, and I've only managed to come across "similar" problems other people have been having... However, I still cannot fix my problem.
Basically, I've been editing some footage in After Effects.  The source material was filmed in HDV 1080, 30 fps; the source's aspect ratio was 1440 x 1080.  I attempted to render the completely-edited footage in an AVI format with the compression codec: Xvid MPEG-4 Codec (as was suggested by a tutorial video on YouTube) and with an aspect ratio of 1024 x 768.  But, no matter what I do, my rendered video always comes out horizontally "squeezed" when viewed in Windows Media Player, and when uploaded to YouTube/Facebook.  Fortunately, when imported to Premiere Pro, I can interpret the footage properly so it's not squeezed.
Is there anyway I can render footage in After Effects so the widescreen product isn't "squeezed" in WMP/Facebook/YouTube?
#2. Even though the footage can be interpreted properly in Premiere Pro, the playback is jumpy - like, it'll only play 2 seconds smoothly, and then get stuck, jumping to points that are 5-7 seconds apart.  Surprisingly, the original source material does not have this issue in Premiere Pro, despite having a larger aspect ratio and a file size that's more than twice as large.  I thought maybe a small RAM was the problem, but my computer has 3.8 GB of usable space on the RAM when I checked.  Rendering the work area after every little edit I do is getting too tedious, 'cause it takes about a minute to render the 12 second footage - but at least it plays back smoothly... I don't have to do this with the original source, though.  Is there a way around this?  What's causing the jumpy playback in Premiere Pro CS 5.5?
Thanks...

Answer 1

If you want to render for any media player (QT or Windows) you must use a square pixel format that's appropriate to the codec you're using. AE's presets that use square pixels are all legal frame sizes.  If you want to have Premiere or any other NLE playback footage you render in After Effects without having to re-render the previews you must use the same codec you're using for the sequence.
Your frame size from Premiere is NOT square pixels, it's DVC Pro HD with a 1.33 PAR so unless you bring that footage into a square pixel comp (1920 X 1080 for example) or resize it on export using the Adobe Media Encoder (recommended) or by Resizing in the Output Module (not recommended for a bunch of reasons) the output is going to look squeezed in any media player.
Rendering to the Xvid MPEG 4 codec from AE isn't recommended at all because MPEG codecs only give good results when you use multi pass ending (AME will do that), but more importantly MPEG codecs are GOP codecs which make up the data for several virtual frames from a few real (i frames), and they take a tremendous amount of CPU power to decode.
Your best rendering choices are a lossless 10 bit codec (black magic for example) or a lossless like Animation Quicktime if you need alpha channels, or nearly lossless codec like Photo JPEG QT at 95% quality when you're doing further production on the footage including color correction, or to render to the same codec the camera uses. Only the same codec used for your PPro sequence will give you smooth playback in Premiere Pro without rendering previews.
If you told us what codec the camera uses we'd be able to help you figure out the best option for rendering.