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|
/*-*- Mode: C; c-file-style: "linux"; indent-tabs-mode: nil; c-basic-offset: 8 -*-*/
#include <math.h>
#include <stdlib.h>
#include <asoundlib.h>
static float *generate_signal(unsigned n_samples, double amplitude, double frequency) {
float *r;
unsigned i;
if (!(r = malloc(n_samples * sizeof(float))))
return NULL;
for (i = 0; i < n_samples; i++)
r[i] = amplitude * sin(((double) i*frequency*M_PI*2)/(double) n_samples);
return r;
}
static float *generate_silence(unsigned n_samples) {
float *r;
if (!(r = calloc(n_samples, sizeof(float))))
return NULL;
return r;
}
static snd_pcm_t *open_device(const char *name, snd_pcm_stream_t stream, unsigned rate) {
snd_pcm_t *d;
int r;
snd_pcm_hw_params_t *hw;
snd_pcm_uframes_t t;
snd_output_t *output = NULL;
snd_pcm_hw_params_alloca(&hw);
if ((r = snd_pcm_open(&d, name, stream, SND_PCM_NONBLOCK)) < 0) {
fprintf(stderr, "Cannot open audio device %s: %s\n", name, snd_strerror(r));
goto finish;
}
if ((r = snd_pcm_hw_params_any(d, hw)) < 0) {
fprintf(stderr, "Cannot initialize hardware parameters: %s\n", snd_strerror(r));
goto finish;
}
if ((r = snd_pcm_hw_params_set_access(d, hw, SND_PCM_ACCESS_RW_INTERLEAVED)) < 0) {
fprintf(stderr, "Cannot set access type: %s\n", snd_strerror(r));
goto finish;
}
if ((r = snd_pcm_hw_params_set_format(d, hw, SND_PCM_FORMAT_FLOAT_LE)) < 0) {
fprintf(stderr, "Cannot set sample format: %s\n", snd_strerror(r));
goto finish;
}
if ((r = snd_pcm_hw_params_set_rate(d, hw, rate, 0)) < 0) {
fprintf(stderr, "Cannot set sample rate: %s\n", snd_strerror(r));
goto finish;
}
if ((r = snd_pcm_hw_params_set_channels(d, hw, 1)) < 0) {
fprintf(stderr, "Cannot set channel count: %s\n", snd_strerror(r));
goto finish;
}
t = rate;
if ((r = snd_pcm_hw_params_set_buffer_size_near(d, hw, &t)) < 0) {
fprintf(stderr, "Cannot set buffer size: %s\n", snd_strerror(r));
goto finish;
}
if ((r = snd_pcm_hw_params(d, hw)) < 0) {
fprintf(stderr, "Cannot set parameters: %s\n", snd_strerror(r));
goto finish;
}
if ((r = snd_output_stdio_attach(&output, stderr, 0)) < 0) {
fprintf(stderr, "Cannot attach to stderr: %s\n", snd_strerror(r));
goto finish;
}
if ((r = snd_pcm_dump(d, output)) < 0) {
fprintf(stderr, "Cannot dump status: %s\n", snd_strerror(r));
goto finish;
}
snd_output_close(output);
return d;
finish:
if (d)
snd_pcm_close(d);
if (output)
snd_output_close(output);
return NULL;
}
static double compute_level(const float *buffer, float *sum, unsigned n_samples, unsigned iteration) {
unsigned i;
double max = 0.0;
for (i = 0; i < n_samples; i++) {
sum[i] += buffer[i];
if (fabs(sum[i]) > max)
max = fabs(sum[i]);
}
return max / (double) iteration;
}
static int prompt(const char *t) {
char r[64];
fputs(t, stderr);
if (!fgets(r, sizeof(r), stdin))
return 0;
return 1;
}
static double linear_to_dB(double f) {
return 20.0 * log10(f);
}
int main(int argc, char *argv[]) {
int ret = 1;
float *signal = NULL, *silence = NULL, *buffer = NULL, *sum = NULL, *current = NULL;
snd_pcm_t *input = NULL, *output = NULL;
unsigned rate = 44100;
unsigned rindex = 0, windex = 0;
double frequency = 440.0, amplitude = 0.5, noise_level_dB = -80.0, initial_level_max = 0.97, initial_level_min = 0.8, reference_level;
unsigned iteration = 0;
int icount, ocount;
struct pollfd *pollfd;
int e;
unsigned needed_iterations = 0;
int skip = 1;
FILE *log;
int level_count = 0;
if (argc < 3) {
fprintf(stderr, "Need to specify device and output log file.\n");
goto finish;
}
if (!(log = fopen(argv[2], "w"))) {
fprintf(stderr, "Failed to open log file %s: %s\n", argv[2], strerror(errno));
goto finish;
}
if (!(output = open_device(argv[1], SND_PCM_STREAM_PLAYBACK, rate)))
goto finish;
if (!(input = open_device(argv[1], SND_PCM_STREAM_CAPTURE, rate)))
goto finish;
if (!(silence = generate_silence(rate))) {
fprintf(stderr, "Failed to generate silence.\n");
goto finish;
}
if (!(signal = generate_signal(rate, amplitude, frequency))) {
fprintf(stderr, "Failed to generate signal.\n");
goto finish;
}
if (!(buffer = malloc(rate * sizeof(float)))) {
fprintf(stderr, "Failed to allocate buffer.\n");
goto finish;
}
if (!(sum = calloc(rate, sizeof(float)))) {
fprintf(stderr, "Failed to allocate sum buffer.\n");
goto finish;
}
if ((icount = snd_pcm_poll_descriptors_count(input)) <= 0 ||
(ocount = snd_pcm_poll_descriptors_count(output)) <= 0) {
fprintf(stderr, "Failed to determine number of pollfd descriptors.\n");
goto finish;
}
if (!(pollfd = calloc(icount + ocount, sizeof(struct pollfd)))) {
fprintf(stderr, "Failed to allocate pollfd array.\n");
goto finish;
}
if ((e = snd_pcm_prepare(input)) < 0 ||
(e = snd_pcm_prepare(output)) < 0) {
fprintf(stderr, "snd_pcm_prepare() failed: %s\n", snd_strerror(e));
goto finish;
}
if ((e = snd_pcm_start(input)) < 0) {
fprintf(stderr, "snd_pcm_start() failed: %s\n", snd_strerror(e));
goto finish;
}
current = silence;
prompt("Please set your control to the highest volume possible and press return.\n");
fprintf(stderr, "Measuring noise level.\n");
for (;;) {
snd_pcm_sframes_t n;
unsigned short irevents, orevents;
if (snd_pcm_poll_descriptors(input, pollfd, icount) != icount ||
snd_pcm_poll_descriptors(output, pollfd+icount, ocount) != ocount) {
fprintf(stderr, "ALSA changed its mind about number of file descriptors.");
goto finish;
}
if (poll(pollfd, icount+ocount, -1) < 0) {
fprintf(stderr, "poll() failed: %s\n", strerror(errno));
goto finish;
}
if ((e = snd_pcm_poll_descriptors_revents(input, pollfd, icount, &irevents)) < 0 ||
(e = snd_pcm_poll_descriptors_revents(output, pollfd+icount, ocount, &orevents)) < 0) {
fprintf(stderr, "Cannot get revents: %s\n", snd_strerror(e));
goto finish;
}
if (orevents) {
if ((n = snd_pcm_writei(output, current + windex, rate - windex)) < 0) {
if (snd_pcm_recover(output, n, 1) < 0) {
fprintf(stderr, "Cannot write samples: %s\n", snd_strerror(n));
goto finish;
} else
continue;
}
windex += n;
if (windex == rate)
windex = 0;
}
if (irevents) {
if ((n = snd_pcm_readi(input, buffer + rindex, rate - rindex)) < 0) {
if (snd_pcm_recover(input, n, 1) < 0) {
fprintf(stderr, "Cannot read samples: %s\n", snd_strerror(n));
goto finish;
}
if ((e = snd_pcm_start(input)) < 0) {
fprintf(stderr, "snd_pcm_start() failed: %s\n", snd_strerror(e));
goto finish;
}
continue;
}
rindex += n;
if (rindex == rate) {
rindex = 0;
if (skip)
skip = 0;
else {
double level;
iteration++;
level = compute_level(buffer, sum, rate, iteration);
fprintf(stderr, "Iteration %u, level is %g (%g dB).\n", iteration, level, linear_to_dB(level));
if (needed_iterations == 0) {
if (linear_to_dB(level) < noise_level_dB) {
fprintf(stderr, "%u iterations necessary to push noise level below %g dB\n", iteration, noise_level_dB);
needed_iterations = iteration;
current = signal;
windex = 0;
skip = 1;
iteration = 0;
memset(sum, 0, rate * sizeof(float));
fprintf(stderr, "Generating signal.\n");
}
} else {
if (iteration >= needed_iterations) {
if (level_count <= 0) {
if (level < initial_level_min ||
level > initial_level_max) {
fprintf(stderr,
"Volume level measured (%g) was too high or too low.\n"
"Please adjust mixer so that initial level is between %g and %g.\n"
"Test run canceled.\n", level, initial_level_min, initial_level_max);
goto finish;
}
reference_level = level;
}
fprintf(log, "%i\t%g\t%g\t%g\t%g\n",
level_count,
level, linear_to_dB(level),
level/reference_level, linear_to_dB(level/reference_level));
fflush(log);
level_count++;
windex = 0;
skip = 1;
iteration = 0;
memset(sum, 0, rate * sizeof(float));
if (!(prompt("Please reduce volume by one step and press return. Press C-D when finished.\n")))
break;
}
}
}
}
}
}
ret = 0;
finish:
if (input)
snd_pcm_close(input);
if (output)
snd_pcm_close(output);
if (log)
fclose(log);
free(signal);
free(silence);
free(buffer);
free(sum);
return ret;
}
|
