ca6a9f8fef
1) Fix the formula for the 'kth frequency' in getFft method: since the 'fft' array holds n / 2 frequencies ranging from 0 to Fs / 2, the correct formula is k*Fs/n. Also fix the last frequency index in the table. 2) Move the sample code for calculating magnitudes and phases from the fft array from 'onFftDataCapture' to 'getFft', provide a link. 3) Fix the sample code which wasn't taking into account that fft[0] is the real part of FFT at DC, and fft[1] is the real part of FFT at Fs / 2. Improve the sample code by linking the variable names closer to the variable names in the documentation. Bug: 113790190 Test: atest CtsMediaTestCases:VisualizerTest Change-Id: I07cc9cfcda5b8c44aae2742a26173e7a9475120a