I am new to the world of video editing having got my first ever camcorder in November.

I've been messing around in Sony Vegas 9 Pro but have stumbled across a couple of issues.

The first is when I try and speed up / slow down a clip (CTRL + stretch the clip on the timeline) Vegas will crash when I try and preview it. Any ideas why it might do this?

My other issue is with rendering. My AVCHD files are recorded in 1080i and I have the project setup to match this in Vegas. I am rendering my videos in WMV format (needs to be in this format for streaming purposes) but when I render Vegas tells me its in progressive mode. Is there an interlaced setting with this codec? If the original clips are interlaced would this have an effect on the output quality?

Any help / advice would be great.