100 lines
3.4 KiB
C++
100 lines
3.4 KiB
C++
/* audioreader.cpp -- reads sequence of overlapping windows
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*
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* 14-Jul-08 RBD
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*/
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#include <assert.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <math.h>
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#include "sautils.h"
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#include "string.h"
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#include <fstream>
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#include "allegro.h"
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#include "audioreader.h"
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#include "scorealign.h"
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using namespace std;
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long Audio_reader::read_window(float *data)
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// reads the next window of samples
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// the first time, fill half the window with zeros and the second half
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// with data from the file
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// after that, shift the window by hop_size and fill the end of the window
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// with hop_size new samples
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// the window is actually constructed in temp_data, then copied to data.
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// That way, the caller can apply a smoothing function to data and we'll
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// still have a copy.
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// the function returns false on the next call when detecting that there
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// is no more samples,
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// data -- the window to be returned
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// temp_data -- since we destroy data by windowing, temp_data saves
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// overlapping samples so we don't have to read them again
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// samples_per_frame -- must be even, note that first window is padded
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// half-full with zeros
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// hop_samples -- additional samples read each time after the first window
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{
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int frames_read; // how many frames did we read?
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int hop = hop_samples;
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if (reading_first_window) {
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hop = samples_per_frame / 2; // first time we read more data
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// zero end of temp_data, which will shift to beginning
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memset(temp_data + hop, 0,
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sizeof(float) * (samples_per_frame - hop));
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reading_first_window = false;
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}
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// before reading in new sounds, shift temp_data by hop_size
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memmove(temp_data, temp_data + hop,
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(samples_per_frame - hop) * sizeof(float));
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frames_read = read(temp_data + samples_per_frame - hop, hop);
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// zero any leftovers (happens at last frame):
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//printf("check fr %i hs %i ws %i ",frames_read,hop_size,window_size);
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memset(temp_data + samples_per_frame - hop + frames_read, 0,
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sizeof(float) * (hop - frames_read));
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assert(samples_per_frame - frames_read >= 0);
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// now copy temp_data to data
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memcpy(data, temp_data, sizeof(float) * samples_per_frame);
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if (frames_read != hop && reading_last_window == false) {
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reading_last_window = true;
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return true;
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} else if (reading_last_window == true) {
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return false;
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} else {
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return true;
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}
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}
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void Audio_reader::calculate_parameters(Scorealign &sa, bool verbose)
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{
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double sample_rate = get_sample_rate();
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long pcm_frames = get_frames();
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// we want to make sure samples_per_frame is even, to keep things
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// consistent we'll change hopsize_samples the same way
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samples_per_frame = (int) (sa.window_size * sample_rate + 0.5);
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if (samples_per_frame % 2 == 1)
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samples_per_frame = samples_per_frame + 1;
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/*=============================================================*/
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hop_samples = (int)(sa.frame_period * sample_rate + 0.5);
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if (hop_samples % 2 == 1)
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hop_samples = hop_samples + 1;
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actual_frame_period = (hop_samples / sample_rate);
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// this is stored back in a field in sa as well as here in the reader
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frame_count= (int) ceil(((float) pcm_frames / hop_samples + 1));
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temp_data = ALLOC(float, samples_per_frame);
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memset(temp_data, 0, samples_per_frame * sizeof(temp_data[0]));
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assert(temp_data);
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}
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