What's the easiest way to export a high-quality animation?

Right now I have a 600 frame animation (exported to 720x405 .png files) that I am trying to get exported into high quality video. What is the simplest way to batch convert all of these into one video file?

I have Avidemux, but the files won’t load with Winamp, VLC, or Windows Media player, so I’m assuming there’s a problem with my methodology (also, it’s putting in an green bar on the bottom right, which is not there in the .png files).

Is there a simple step-by-step tutorial for getting from .png to a video?

EDIT: Oh, by the way, my apologies if this is in the wrong place.

EDIT2: Right now I’m putting it into a flash animation frame-by-frame, so it’s not overly crucial, but it’d be very helpful to know a more efficient method.

I use avidemux as well and don’t have any problem. Be sure that you chage the video codec before save to the movie. I have excellent result with MPEG-4 AVC (x264) and Two passes (average bit rate) with 1000 kb/s. Leave the rest of options of the codec unchanged.
-G

I get all the frames, and the video will preview in avidemux, but whenever I open the saved movie, it says that it’s invalid, or it just won’t play anything, depending on which program I use.

Here’s the output file. It says that the export was successful (“File OutputI.mpeg has been successfully saved”), but I can’t view it. There is also a .mpg.idx file, which I’m assuming is metadata, and ergo not necessary (though I’m not 100% sure).

Does the basic animation need to be a certain resolution for it to work smoothly?

Certainly the video produced is badly formed. I cannot help further because the exported movies with the settings I’ve mentioned in the previous post, works for me (linux).
Create a movie based on an image sequence is very easy in any platform. Are you sure that you have the proper codec installed?.
x264.nl/
If everything fails with Avidemux you can work with Virtualdub too.
virtualdub.org/blog/pivot/entry.php?id=34
-G

VirtualDub works with image sequences?

Okay, I’ll try it out.

It works fine, thanks!