From: Pander <pan...@users.sourceforge.net>
references:
https://sourceforge.net/p/sox/mailman/message/33186778/
https://sourceforge.net/p/sox/mailman/message/33175940/
https://sourceforge.net/p/sox/mailman/message/33625255/
Edited-by: Eric Wong <normalper...@yhbt.net>
[ew: removed extraneous whitespace changes,
squashed re_average initialization fix from Pander,
removed unnecessary check before free(3) call
(ref: <5498a2f9.2010...@free.fr>),
converted fft_average to bool]
---
sox.1 | 6 ++++++
src/stat.c | 27 ++++++++++++++++++++++++++-
2 files changed, 32 insertions(+), 1 deletion(-)
diff --git a/sox.1 b/sox.1
index 04ab09b1..d64762af 100644
--- a/sox.1
+++ b/sox.1
@@ -3596,6 +3596,12 @@ audio in SoX's internal buffer.
This is mainly used to help track down endian problems that
sometimes occur in cross-platform versions of SoX.
.SP
+The
+.B \-a
+option
+will output the average input's power spectrum instead of the default
+behavior in which the power spectrum is given for each 4096 point DFT.
+.SP
See also the
.B stats
effect.
diff --git a/src/stat.c b/src/stat.c
index cdea27cc..0ca6c232 100644
--- a/src/stat.c
+++ b/src/stat.c
@@ -34,6 +34,7 @@ typedef struct {
float *re_out;
unsigned long fft_size;
unsigned long fft_offset;
+ sox_bool fft_average;
} priv_t;
@@ -69,6 +70,8 @@ static int sox_stat_getopts(sox_effect_t * effp, int argc,
char **argv)
stat->fft = 1;
else if (!(strcmp(*argv, "-d")))
stat->volume = 2;
+ else if (!(strcmp(*argv, "-a")))
+ stat->fft_average = sox_true;
else {
lsx_fail("Summary effect: unknown option");
return SOX_EOF;
@@ -100,6 +103,7 @@ static int sox_stat_start(sox_effect_t * effp)
stat->bin[i] = 0;
stat->fft_size = 4096;
+ stat->fft_average = sox_false;
stat->re_in = stat->re_out = NULL;
if (stat->fft) {
@@ -134,6 +138,16 @@ static int sox_stat_flow(sox_effect_t * effp, const
sox_sample_t *ibuf, sox_samp
priv_t * stat = (priv_t *) effp->priv;
int done, x, len = min(*isamp, *osamp);
short count = 0;
+ float *re_average = NULL;
+ unsigned samples = 0;
+ float ffa = 0.0;
+ unsigned i;
+
+ if (stat->fft_average) {
+ samples = (stat->fft_size / 2);
+ ffa = effp->in_signal.rate / samples;
+ re_average = lsx_malloc(sizeof(float) * (int)samples);
+ }
if (len) {
if (stat->read == 0) /* 1st sample */
@@ -146,10 +160,20 @@ static int sox_stat_flow(sox_effect_t * effp, const
sox_sample_t *ibuf, sox_samp
if (stat->fft_offset >= stat->fft_size) {
stat->fft_offset = 0;
+ if (stat->fft_average) {
+ lsx_power_spectrum_f((int)samples, stat->re_in, stat->re_out);
+ for (i = 0; i < samples / 2; i++) /* FIXME: should be <= samples
/ 2 */
+ re_average[i] += stat->re_out[i];
+ } else {
print_power_spectrum((unsigned) stat->fft_size,
effp->in_signal.rate, stat->re_in, stat->re_out);
+ }
}
}
+ if (stat->fft_average) {
+ for (i = 0; i < samples / 2; i++) /* FIXME: should be <= samples / 2
*/
+ fprintf(stderr, " %f %f\n", ffa * i, re_average[i] / len);
+ }
}
for (done = 0; done < len; done++) {
@@ -192,6 +216,7 @@ static int sox_stat_flow(sox_effect_t * effp, const
sox_sample_t *ibuf, sox_samp
stat->read += len;
}
+ free(re_average);
*isamp = *osamp = len;
/* Process all samples */
@@ -320,7 +345,7 @@ static int sox_stat_stop(sox_effect_t * effp)
static sox_effect_handler_t sox_stat_effect = {
"stat",
- "[ -s N ] [ -rms ] [-freq] [ -v ] [ -d ]",
+ "[ -s N ] [ -rms ] [-freq] [ -v ] [ -d ] [ -a ]",
SOX_EFF_MCHAN | SOX_EFF_MODIFY,
sox_stat_getopts,
sox_stat_start,
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