/* Processes the audio segment into discrete frequency bins with an FFT */
static void *fft_segment(void *audio_segment_buffer_orig) {
// create a new copy of the buffer so we don't access the space being used by VLC
uint8_t *audio_segment_buffer = (uint8_t *) malloc(sizeof(audio_segment_buffer_orig));
memcpy(audio_segment_buffer, audio_segment_buffer_orig, sizeof(audio_segment_buffer_orig));
// create and input into an FFT
// an fftw_complex is 2D matrix -- one dimension represents the real components, the other complex.
fftw_complex in[NUM_SAMPLES_PER_FFT];
fftw_complex out[NUM_SAMPLES_PER_FFT];
int win_start_index = 0;
int win_n = 0;
while (win_start_index < NUM_SAMPLES_PER_FFT) {
while (win_n < WINDOW_SAMPLE_SIZE) {
in[win_start_index + win_n][0] = audio_segment_buffer[win_n] * hamming_window(win_n, WINDOW_SAMPLE_SIZE);
win_n++;
}
win_n = 0;
win_start_index += WINDOW_SAMPLE_SIZE / 2;
}
// establish complex component of the input matrix
for (int i = 0; i < NUM_SAMPLES_PER_FFT; i++) {
in[i][1] = 0;
}
fftw_plan plan;
plan = fftw_plan_dft_1d(NUM_SAMPLES_PER_FFT, in, out, FFTW_FORWARD, FFTW_ESTIMATE);
fftw_execute(plan);
double frequency_magnitude_dB[NUM_SAMPLES_PER_FFT];
FILE* fft_out_file = fopen("fft_out.dat", "a");
// test output of frequency data
for (int i = 0; i < NUM_SAMPLES_PER_FFT; i++) {
// calculate the magnitude of the sample, then convert it to a logarithmic scale
// to represent as a decibel
frequency_magnitude_dB[i] = 20 * log10(sqrt(out[i][0] * out[i][0] + out[i][1] * out[i][1]));
fprintf(fft_out_file, "%3d,%f ", i * (SAMPLING_FREQUENCY / NUM_SAMPLES_PER_FFT), frequency_magnitude_dB[i]);
}
fprintf(fft_out_file, "\n");
fclose(fft_out_file);
}
int main(int argc, char *argv[]) {
calculate_sample_count();
node_type_t type = 0;
int port;
int ss;
struct sockaddr_in addr;
data_t d;
int s;
int status = 0;
pthread_t th;
complex double *X = (complex double *)malloc(sizeof(complex double) * SAMPLE);
complex double *Y = (complex double *)malloc(sizeof(complex double) * SAMPLE);
complex short *data = (complex short *)malloc(sizeof(complex short) * N);
sample_t *buf = (sample_t *)malloc(sizeof(sample_t) * SAMPLE);
sample_t *prev_data = (sample_t *)malloc(sizeof(sample_t) * SAMPLE / 2);
char response_send, response_recv;
int m, n;
if (argc == 2) {
type = SERVER;
} else if (argc == 3) {
type = CLIENT;
} else {
fprintf(stderr, "Usage: %s [ip address] <port>", argv[1]);
exit(1);
}
port = atoi(argv[argc - 1]);
ss = socket(PF_INET, SOCK_STREAM, 0);
if (ss == -1) die("socket");
addr.sin_family = AF_INET;
addr.sin_port = htons(port);
d.socket_number = &ss;
d.s = &s;
d.status = &status;
switch (type) {
case SERVER:
addr.sin_addr.s_addr = INADDR_ANY;
if (bind(ss, (struct sockaddr *)&addr, sizeof(addr)) == -1) die("bind");
if (listen(ss, 10) == -1) die("listen");
if (pthread_create(&th, NULL, accept_connection, (void *)&d) != 0) die("pthread_create");
fprintf(stderr, "Waiting...\n");
break;
case CLIENT:
if (inet_aton(argv[1], &addr.sin_addr) == 0) die("inet_aton");
if (connect(ss, (struct sockaddr *)&addr, sizeof(addr)) == -1) die("connect");
s = ss;
status = 1;
fprintf(stderr, "Connected to %s:%d.\n", argv[1], port);
break;
default:
break;
}
memset(prev_data, 0, sizeof(sample_t) * SAMPLE / 2);
while (1) {
m = read_n(0, sizeof(sample_t) * SAMPLE / 2, buf + SAMPLE / 2);
if (m == 0) break;
if (status == 1) {
memcpy(buf, prev_data, sizeof(sample_t) * SAMPLE / 2);
memcpy(prev_data, buf + SAMPLE / 2, sizeof(sample_t) * SAMPLE / 2);
hamming_window(buf, SAMPLE);
sample_to_complex(buf, X, SAMPLE);
fft(X, Y, SAMPLE);
cut_off(data, Y, FREQ_MIN, FREQ_MAX, SAMPLE);
set_response_with_data(&response_send, data, N);
send(s, &response_send, sizeof(char), 0);
switch (response_send) {
case RES_OK:
case RES_OK_TO_SI:
write_n(s, sizeof(complex short) * N, data);
// n = send(s, data, sizeof(complex short) * N, 0);
break;
case RES_SI:
memset(prev_data, 0, sizeof(sample_t) * SAMPLE / 2);
break;
default:
break;
}
// n = recv(s, &response_recv, sizeof(char), 0);
n = read_n(s, sizeof(char), &response_recv);
if (n == -1) die("recv");
if (n == 0) break;
switch (response_recv) {
case RES_OK:
case RES_OK_TO_SI:
n = read_n(s, sizeof(complex short) * N, data);
// n = recv(s, data, sizeof(complex short) * N, 0);
if (n == -1) die("recv");
if (n == 0) break;
re_cut_off(data, Y, FREQ_MIN, FREQ_MAX, SAMPLE);
ifft(Y, X, SAMPLE);
complex_to_sample(X, buf, SAMPLE);
re_hamming_window(buf, SAMPLE);
write_n(1, sizeof(sample_t) * SAMPLE / 2, buf + SAMPLE / 4);
break;
case RES_SI:
break;
default:
break;
}
}
}
pthread_join(th, NULL);
close(ss);
return 0;
}
