Sorry it’s taken me so long to respond. I’ve been hectic busy.
Generally I wouldn’t recommend recording to the same drive that’s running both the OS and Programs. There’s too much drive access going on to ensure the best throughput.
I’m not sure about the details on all the connectivity on the Sony Vaio you have but you might consider using a Firewire800 drive of at least 7200rpm. I’d strongly recommend against using a USB hard drive.
There’s a few things to consider regarding impact on quality. One is your workflow path with the encoded file. You might consider MJPEG or even PJPEG. It’ll be a large file but it’s be easy on the CPU to encode and will hold up with a post workflow.
If you went the H.264 route (m4v which is mp4), if you use the exact same encoder setting, Wirecast would use less CPU resources but you may want a much higher quality setting than what you’re streaming at. That may have a bigger impact on CPU% than using one of the above iFrame codecs. If the CPU% gets high, you can start to drop frames.
Additionally if you’re going to edit that H.264 recording you’re going to probably take through another round or two of compression depending on your workflow. That’s going to impact final quality.
I know some people who want to push the highest quality will use Wirecast External Display Output and send to an external dedicated recorder.
Wirecast itself can handle streaming and recording but you have to look at your entire workflow to determine what’s best. You may want to do a few short tests to see first hand.