How to get the best out of .3GP (720p!)?

[VinylCyril]

Hi everyone!
I'm relatively new to video editing, so let it not surprise you if I don't understand some basics.

Anyway, I got an HTC Desire HD phone recently, and it is able to shoot in 720p — and, given the fact that it has only a basic lens and a 8 MPix camera, it gave good results.
I completely understand that it can't replace a real video camera, but at least now I have something to shoot videos at all times, even if I've brought nothing but my cell phone

Now, I'm not interested in just uploading unedited 3GP's. I want to use this videos in my Sony Vegas 6 projects (yes, Vegas SIX). And that's where things get messy, because the quality keeps worsening.

The source 3GP file has the following properties:

Attributes: 1280x720x24
Format: H.264
Frame rate: 20.000
Field order: None (progressive scan)
Pixel aspect ratio: 1.0000 (Square)

It is 46 seconds long and the file is ~43 MB.

So am I right that it's basically the MPEG-2 H.264 format? What destination format should I choose to preserve good quality and relatively normal size?

I tried rendering as MPEG-2 and ended up with a 24 MB file (even though I chose best quality, it's twice smaller than the original 3GP). Crappy quality, almost webcam-worthy.
YouTube didn't even recognize it was 1280*720 (though it was!) and only allowed 360p and 480p, neither of which looked good.

Then I rendered it as an AVI file with the H.263 codec (don't have H.264 for some reason), best quality. Resulted in a whopping 1 GB file. Quality was good, but 1 GB? Really?

The original file was 43 megabytes. I sense there must be a destination format with the same quality and reasonable bit rate?
After all, if I understand this correctly, 3GP is MPEG-2. It is already encoded with H.264. How do I preserve it?

Thanks in advance for any help!

[sh0nuff]

How did you manage to convert the file for YouTube to see it as HD? There seem to be very few tutorials on the 3gp format and why YouTube won't recognize it as 720p

I have the Desire HD Ace as well, and I had the exact same problem with uploading video

-sh0

[aedipuss]

try identifying the video properties first. mediainfo in text mode, copy and paste the results here.

op - no 3gp can't be mpeg-2 encoded with h264.

[VinylCyril]

OK, I'm still as much a noob as I was initially, but I think I kinda figured this out by just playing with various options. I have the K-Lite codec pack installed, and importing 3GP "as is" into the project and exporting it as XviD with single pass, quantizer = 2 (I've just reinstalled Windows so forgive me if my terminology is wrong; I have no reference as of now) seems to have done the trick. It was uploaded as 720p, and looked almost exactly as the original. I've made the video unlisted so you can view it if you wish, but beware, it's possibly the most dumbestest video out there, and it only features my messy workplace Here it is.
Never thought that XviD had such power