Everywhere on youtube people are adding music over their video's. Some fade out and raise the music to the video's audio back and forth. How do you do this? Is there any freeware programs that can do this easily? Or what program do you recommend? Maybe there is another thread on this, I could not find one?
Jimmy Ruska has short tutorials that can guide. this specifically refers to over dubbing: http://youtube.jimmyr.com/#NukQLpAIess This lists his videos - he uses VirtualDub to extract the audio. Audacity to modify and save the audio and VirtualDub to put it back together again. Also has tips on how to clip files for YouTube.. http://youtube.jimmyr.com/
Do you want to add audio to your flv files? can you say it clearly? I have used a program , I can use it to replace the audio, if your video has no audio, you can add audio to it, hope this is the right thing you want.