Thread: Sound Cards With C++

For a portable solution you may want to check out fmod.

The Windows specific APIs you could be interested in are Waveform Audio (samples and articles here) or possibly DirectSound.

>> 2. How will I know the duration of the frequency? <<

The sound data will be returned as a series of samples. If you need the duration of a specific frequency you will need to combine adjacent samples with the same frequency. Remember, there is likely to be some randomness during sound recording so the exact same frequency is unlikely.

Frequency analysis requites some serious mathematics (Fourier transforms).

Actually, you can find code examples or libraries for FFT (Fast Fourier Transform). fmod may even include it, so, you don't have to do the math yourself.

I have a book called Digital Audio Processing, by Doug Coulter. He supplies the source code for a complete audio editor. As I recall, he doesn't discuss how varioius guitar effects work, but if you have an idea what an effect does (distortion, filter, compression, etc.) the book will help you program it.

misplaced,

The PC is great for processing a pre-recorded wave file. But if you want a real-time (live) effect, it could be tricky or unreliable. Windows uses cooperative multitasking, which means you can't count-on having control of the CPU and data bus when you need it. Your data stream can be interrupted.

Normal Windows programs get-around the multitasking problems by using an input buffer, and/or an output buffer. As long as the buffers don't "run dry" or overflow, and as long as the CPU is fast enough, the PC can provide a continuous, but delayed, audio (or video) stream.

It may be possible to get acceptable results (imperceptible delay) with DirextX. Some software/sound cards use low-latency ASIO drivers for real-time audio processing. (I don't know how these work.)