In the past I made several video recordings with my Panasonic camera. Is it possible to improve the sound of those recordings, for example by adding more bass? Which program should I use for that?
What type of camera? A point-and-shoot with HD video capability or an actually HD camcorder?
Most file-based camera audio is low-bit .ac3 (usually 256 bit). Some file-based camcorders like the Sony AX100 record in 1536 bit LPCM.
If you're trying to work with .ac3 256 bit audio in an audio editing program, you really don't have much to work with. It's like trying to work with mp3s. But if that's the only audio you have, you don't have much choice. What I'd highly recommend is getting an audio recording rig. Even if you're only recording with the rig's internal mics, chances of getting higher quality audio are a lot better than relying on the camera's internal mics. The other option is to plug external mics into your video camera. But that's only possible if the camera has a mic in plug - which isn't usually the case with point-and-shoot cams.