C# WinForms application to display waveforms of playback and recorded sound

Question

I wish to write a C# WinForms application that can play a WAV file. While playing the file, it shows a waveform (similar to an oscilloscope).

At the same time, a user can record sound via the microphone, attempting to follow the original sound played (like a karaoke). The program displays the waveform of the recorded sound real-time, so comparisons can be seen from the waveform display of the original wave file and the recorded one by the user. The comparisons will be done as in the difference in time (the delay) of the original and recorded sound. The waveform displays don't have to be very advanced (there is no need for cut, copy or paste); just being able to see it with a timeline would suffice.

I hope this is clear enough. Please do not hesitate to ask for more clarification if it's not clear. Thank you very much.

Answer 1

You can do what you want with C#, but it isn't going to work like you think. There is effectively no relationship at all between how a recording looks in an oscilloscope-type display and how that recording sounds to a human ear. So, for example, if I showed you two WAV files displayed in an oscilloscope display and told you that one recording was of a tuba playing and the other was of a person speaking a sentence, you would have no idea which was which just from looking at them.

If you want to compare a user's sounds to a pre-recorded WAV, you have to get more sophisticated and do FFT analysis of both and compare the frequency spectra, but even that won't really work for what you're trying to do.

Update: after some thought, I don't think I fully agree with my above statements. What you want to do might sort of work if what you want to do is to use the oscilloscope-type effect to compare the pitch (or frequency) of the WAV and the person's voice. If you tuned the oscilloscope to show a relatively small number of wavelengths at a time (like 20, maybe), the user would be able to quickly see the effect of raising or lowering the pitch of their voice.

I have a small sample C# app that I wrote about 2 years ago that does something kind of like this, only it displays an FFT-produced spectrograph instead of an oscilloscope (the difference is basically that a spectrograph shows frequency-domain information while an oscilloscope shows time-domain information). It's realtime, so you can talk/sing/whatever into a microphone and watch the spectrograph change dynamically.

I can dig this out and post the code here if you like. Or if you want the fun of doing it all yourself, I can post some links to the code resources you'd need.

Answer 2

The NAudio library has plenty of functionality that will (possibly) give you what you need. I've used it in the past for some simple operations, but it is much more powerful than I've had need to use.

Answer 3

@ZombieSheep Naudio is indeed useful, but it has limitations. For example, there is not much control over the waveform display, it cannot be cleared and redrawn again. Besides, if it gets too long its impossible to scroll back to see the waveform in the front part. One more thing is that it only works with playing the sound but does not work with recording the sound. Thank you.