Mp4 rendering problem and mp4 vs wmv file sizes

[Justinec101]

So I was messing with different rendering settings today trying to get some better quality for video tours I do. I started off by testing some footage shot with an HMC150 at 720p 30fps. I rendered two files, one a wmv file, the other an mp4 file. Both of them youtubes standard res (640x360). The mp4 was 4000kbps and looked better and was much smaller (the wmv was 52mb and the mp4 was 35). I thought I had found my solution. Then I went to try it on an actual tour. These are shot with a canon gl2. I rendered a wmv and an mp4 and the mp4 was rediculously big, even at 2000kbps, under that and the quality became worse than the wmv. So why am I getting such substantially different results?

Also, after doing many tests, I started getting the message "The system is low on memory. You may be able to reduce memory usage by closing other applications". I get this every time I attempt to render an mp4 file, even though I output about 20 of them earlier today. I restarted my computer but that didn't help. . . .

*Edit, adding some info - 4121kbps, 360x240, 3 minutes 55 seconds, 115mb. Those are the specs of the mp4 I output. Does that seem excessively big for an mp4 file with those specs? The wmv that says it's 2206kbps is 32mb. I deleted the 2000kbps mp4 I made (and obviously can't render another one now) but it was still about 60mbs.

 

[Justinec101]

Ok, I'm retarded. I wasn't comparing the bitrates properly. That is, I wasn't changing the bitrate when I rendered the wmv. The bitrate automatically adjusts depending on the size of the file when you're outputting with wmvs, but requires an entry for mp4. So I was outputting small resolutions with big bitrates and wondering why the filesizes were so big >.<

However, my mainconcept avc/aac still won't work, although I can still get mp4s using SonyAVC.