I am sure as a reader you have either watched Playing Games with Snat, heard about it or have found this link via Google as you are doing your own Lets Play or having problems overlaying audio with footage.
If you are having this problem then carry on reading and if not, why are you here?
The main problem most people have (and the same one I did) is assuming that the audio is recorded as a fix length of time â€“ aka if you recorded 30 minutes of gaming footage and 30 minutes of commentary that it will overlay without any problems. This is not exactly true as I have discovered sampling is what really matters and then secondly making sure audio is recorded without any skips.
With the audio sampling you need to make sure they match. Using my hardware as an example the AVerMedia Game Capture HD records the audio at a typical 48k (most TVs uses this, so good chance your capture device is as well) while I am recording the audio for my commentary at 42.1k â€“ typical CD quality.
When both of these are then put into my editing software (Movie Edit Professional 2013 Plus) they never overlay. The reason for this is mostly due to lost of audio per frame although I will be honest and say I do not understand it too well myself so if anyone knows exactly why then please do post in the comments. If you assume that you are losing a frame a minute then your audio is, every minute about 0.6 second out of sync and this builds up quickly â€“ more so when you are recording for a longer amount of time.
So all this means to start with is when you are recording your commentary or whatever you are doing with overlaying the audio make sure it is recorded at the very same audio sampling rate as the video you are going to overlay it with.
The next issue I had is simply limits on the audio recording that caused skips. When I was recording for Playing Games with Snat: Final Fantasy XIII Part 12 I was doing it with Magix (audio) with a browser open, IM messaging loaded and a anti-virus scanning which caused bits to skip which does make the file length smaller which naturally stops it from overlaying.
In a nut shell make sure all you are doing is recording audio and not stressing your system out and that you are recording everything in the same sampling rate (where possible). Beyond that there is not much more I can say. If you are still having synchronisation problems then post in the comments and I will see what I can do.