Actually SplitCam has been able to do 720 for some time. Yes may not be full HD IE 1080 but 720 is still HD. If you need something that works with the audio and the SplitCam virtual mic does not work. Getting Virtual Audio Cable will always work. Since its a highly configurable audio program. For myself this is what I use to record audio along with SplitCam at 720.
For those reading Ace Player HD will also work. Its a free program and adaption of the popular VLC. Basically as the authors put it is VLC with many added features to it. One is going above and beyond what VLC can do.
I only left a message here because even with the original date of the request SplitCam could do 720 (HD) recording and you could always use its integrated SplitCam virtual audio or another like Virtual Audio Cable. So yes I know this reply is very late considering the date posted. Just misinformation or lack of, bugs me.
IE 'No, you can't use this application to record videos and audio in HD.' SplitCam even at the reply date of April 28, 2015 could do 720 HD. And Virtual Audio Cable can record and do just about anything. A snip from the website 'All transfers are made digitally, providing NO sound quality loss (a bitperfect streaming).' So SplitCam along with it would work as a 720 HD recording. And personally I have found nothing that Virtual Audio Cable could not capture in full detail. If you can get a device hooked up to a PC and working, Virtual Audio Cable WILL capture the audio for it.