Are you talking about doing YouTube kind of videos?
Most video editing applications will take the audio you provide and when you create your final video format, they also compress/convert the audio per settings.
YouTube will do its own compression/conversion to their online format.
I recently did a couple of YouTube videos with music...so when I shot the video, I didn't want to use the sound from the crappy camera mounted mic...so I simultaneously recorded the music into my DAW...which was a CD-quality WAV format.
Then I took that audio, imported it into my video editor (Sony Vegas)...lined up the DAW audio with the existing camera mic audio...deleted the camera mic track, and was left with the WAV audio track and video.
Then I spit out the complete videos in AVI, WMV, and MPEG formats...and compared which sounded and looked the best (for some strange reason, the AVI won out, which I didn't expect....so that's what I uploaded to YouTube.
They in turn applied their own compressions/conversion to my AVI...but with YouTube, it's a streaming format...so even large files will play without waiting for a complete download.
What exactly are you looking to do with your videos/audio?
Oh...if you record the audio into a DAW...make sure the DAW is set to the same SMPTE frame rate as what your video...which is usually 29.97fps here in the USA. Most DAWs that use SMPTE tend to default to 30 fps, which makes better sense for audio since 30 fps devides perfectly into real time (60 secs) which is how music is done. If you do mix the two, there will be a very slight time difference, but for YouTube purposes or the like...I don't think it's much of an issue. It's more of a concern when doing broadcast video where the sync issue will be visible over time...like a bad Kung Fu movie.