Used VirtualDub to join two DV-avi files, but lost quality, any advice?

[videoconverter11]

Hi, I recently had two DV-avi files and I wanted to join them together. I first used Avidemux, but it said it couldn't load the files. I then used VirtualDub, which joined them in about 30 minutes. I made sure to use the direct stream copy function. However, afterwards, I looked at the final video information and noticed that it had a bit rate less then both of the original videos. My question is:

I used type-1 for Avidemux, should I re-record in type 2? Would it finally accept?

Also, why is virtualdub creating a combined file with a bit rate that is slightly less than both? Am I losing quality? thanks!

[Baldrick]

DV has a constant bitrate. What does it say under video codec with mediainfo / mediainfoxp ?