This is a dumb question, but is there a way to add audio to video without having to rerender the video? Let's say I just finished this awesome video and already compressed it to the perfect settings, but want to replace the audio with a different track. Is there a way to do this in a lossless manner? Thanks in advance if any replies! :)
You don't mention what tools you have at your disposal but if you have a Mac with Quicktime 7 installed, this is a snap. QT X can't do this.
If you already have sound on your video file, you'll have to delete those tracks. Just open the Movie Properties (cmd-J), select the audio tracks and hit the delete button.
Next you'll need the new sound exported to the exact length of the video. Line it up in your NLE or DAW and export the correct duration for audio only, which shouldn't take long.
Open that audio file with QT7 in another window.
Go to the QT7 window for your audio-less video and select all (cmd-A). Copy that (cmd-c).
Go to the QT7 window with your new audio and, from the Edit menu, select Add to Selection and Scale (all modifiers-V). That should add the video track to your audio ones. Check that sync is good.
Save that as a self-contained movie and you should be set.
Pasting the video to the audio is best as the opposite can give slight audio artifacts if selection length is not sample-accurate. Both files must be of exact same length to the frame for best results. If not, the speed of the video could be changed and that'll throw things out of sync. This can be done on a PC with QT Pro, but that's not free. There are other ways of doing this for sure, but this is the one I use many times a week solidly.
Quicktime seems to be the best at doing simple things like adding audio to video or just joining two videos without rerendering and losing quality.
I have QT10 on a Mac and was trying to add audio to an AVI file. QT said that I didn't have the correct codec so I couldn't open the AVI.
I ended up doing it in After Effects (which read the AVI) and exporting with lossless settings, although this probably does lose some quality I would guess.
Adding audio to video without having to rerender seems like such a simple thing that most programs would have, but doesn't seem like it. Or maybe I'm missing something?