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.

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?.
If everything fails with Avidemux you can work with Virtualdub too.

VirtualDub works with image sequences?

Okay, I’ll try it out.

It works fine, thanks!