Project-Piano

A piano controlled by your keyboard made by PyGame

The project is available on Github.

This program has two main part. A GUI that show a piano that allows you to control it using your keyboard. And a phase vocoder that changes the pitch of your input file and maps different pitches to each piano key.

To play you need to install the flowing:

Python 3, Numpy, Scipy, and Pygame

Install

Please console the offical page to install the dependencies.

My recommendation is to instll pip if your python version is older than Python 3.4. Use this link to install pip.

Then we can install all dependencies with pip:

$ python3 -m pip install numpy
$ python3 -m pip install scipy
$ python3 -m pip install pygame

or the following code, if you only has one version of python installed on your computer

$ python -m pip install numpy
$ python -m pip install scipy
$ python -m pip install pygame

Run

The program has two models, a GUI demo model and a main program. To run GUI demo model, simply type following in your commond line in the directory of the program folder

$ python3 piano.py

or

$ python piano.py

For the main function, you need provide a 44100Hz, mono wave file through the commond line, or you can try the two sample included in the project folder. The bowl.wav is the recording of knock a bowl and crash.wav is a recoding of a singal hit of Clash Cymbal. To tun, input the following:

$ python3 piano.py -w bowl.wav
$ python3 piano.py -w crash.wav

or

$ python piano.py -w bowl.wav
$ python piano.py -w crash.wav

Note: if you want to use a whole sound, please understand this may need a long time to process the file and the outcome maybe unsatisfied.

Techniques

The main function of GUI is provided by PyGame, an open-source Python model. However, the process of using it is hard. First, we need to create a pygame object, then draw the basic interface windows and fill the content with pictures of piano keys. I creat the keys using Photoshop, with 93 pixels width and 374 pixels height. Then, for each key, I map a music file to it and assign a keyboard key. Therefore, when the user presses a key, a function will be called inside that key object and output through pygame mixer.

In order to change the pitch of a wav file, the program has a phase vocoder built inside. The operation process is as follows:

1. user input a wav file
2. readWaveFile takes the file and transfers it into a numpy array
3. the audio array have been sent to pitchshift
4. the audio first been stretched, so that its pitch change
5. the audio then been stretched the duration without changing the pitch by re-sample
6. writeWaveFile takes the audio and output to the default folder
7. repeat this process with different factor to get 25 files with different pitch