Please do the following question in matlab code. The function that needed is located below the question.

PROBLEM2:

"Audio Compression (OR Decomposition of a polyphonic piece of music)"

Here is a simple demo for an interpolation problem using "Discrete Cosine Transform" (a modification from FFT): dct_interpolation_demo.m

Download the following audio_compress demo: audio_compress.m

Run and modify the demo code.

Instead of removing frequencies above 3000 kHz, run a for loop and remove frequencies above "3000/i" kHz and display all the spectrograms, i = 1:10. Are you still able to hear the "Hallelujah" after that?

Choose a piece of music file on your own and complete a task of audio compression following the same code from above.

Note that for this task, I only want you to use "dct" and "idct": Discrete Cosine Transform. This method is very similar to the Discrete Fourier Transform, however it doesn't involve complex numbers.

Remember, you need "clear sound" to turn off the music.

data :

https://drive.google.com/open?id=1ldlHWbDSzo-BFpuOtDWVb4qL-FGc5fJc