how can I intercept and modify program read/writes?

Question

Say firefox writes to it's own history file, and I'd like to modify what it does when it does it.

How can I do that?

Similarly, say a program sends audio to the speakers/headphones. How could I intercept that signal, process it, and send it back to where it was headed? Certainly the Master Volume does something like that.

Thanks.

Answer 1

If you need to do some stuff with FF only, try to do with add-on API.

As for audio processing, I guess you need to use windows kernel mode.