JVC - capture

I am wondering if this is the right place to post. I tried to capture DV from my JVC GR-DV3U.But the quality is not really good. I tried to play on computer, and burned to DVD, it looks the movie esp when fast moving, is very poor quality. But If I played directly on my camcord, the quality is very nice.
Is that related with codec?

Thanks,
Jlu

I have a JVC GR-DCVL20E But I cannot get the supplied software to see it. I have connected from the JLP outlet to my PC with an ordinary connector multi-channel cable. What am I doing wrong and is there more recent software available.
Pamal