Hey

I'm new to this forum and was looking for an answer to my question.

I'm trying to convert MPEGs and WMVs to FLV files (400 bitrates 25 framerates):
The problem is: I sometimes get an awesome result, and sometimes the video is just pixeled like hell and can barely see anything! All the files are changed to 320 width and height is set so we maintain the same ratio. Can anyone help me out with reasons why the quality can be so various? And what might be the possible solutions to this problem??

Thanks in advance,
Marc