Hi all,
Please review the attached patch for outputting the average power spectrum.
For many applications I need to calculate this with additional tools.
This patch will make SoX do it directly.
Regards,
Pander
>From 261b4fb8cc9f8f98e0044e973a81e7a367349339 Mon Sep 17 00:00:00 2001
From: Pander <pan...@users.sourceforge.net>
Date: Mon, 22 Dec 2014 22:45:34 +0100
Subject: [PATCH] Added average power spectrum for stat -freq -a
---
sox.1 | 42 ++++++++++++++++++++++++------------------
src/stat.c | 28 +++++++++++++++++++++++++++-
2 files changed, 51 insertions(+), 19 deletions(-)
diff --git a/sox.1 b/sox.1
index 2c4ca47..30c1c8a 100644
--- a/sox.1
+++ b/sox.1
@@ -8,7 +8,7 @@
..
'\"
'\" Replacement em-dash for nroff (default is too short).
-.ie n .ds m " -
+.ie n .ds m " -
.el .ds m \(em
'\"
'\" Placeholder macro for if longer nroff arrow is needed.
@@ -1204,7 +1204,7 @@ SoX has support for GSM's original 13kbps `Full Rate' audio format.
It is usually CPU-intensive to work with GSM audio.
.RE
.TP
-\
+\
Encoding names can be abbreviated where this would not be ambiguous;
e.g. `unsigned-integer' can be given as `un', but not `u' (ambiguous
with `u-law').
@@ -1306,7 +1306,7 @@ for a list of supported file types.
.if t .sp -.5
.if n .sp -1
.TP
-\
+\
These options specify whether the byte-order of the audio data is,
respectively, `little endian', `big endian', or the opposite to that of
the system on which SoX is being used. Endianness applies only to data
@@ -1489,9 +1489,9 @@ center;
cI cI lI
cB c l.
\ Method Notes
-h Hz \
-k kHz \
-o Octaves \
+h Hz \
+k kHz \
+o Octaves \
q Q-factor See [2]
.TE
.DT
@@ -3301,7 +3301,7 @@ If `-' is given, the spectrogram will be sent to standard output
(stdout).
.RE
.TP
-\
+\
.I Advanced Options:
.br
In order to process a smaller section of audio without affecting other
@@ -3336,7 +3336,7 @@ creates a spectrogram showing all but the first minute of the audio
(the output file, however, receives the entire audio stream).
.RE
.TP
-\
+\
For the ability to perform off-line processing of spectral data, see the
.B stat
effect.
@@ -3412,12 +3412,12 @@ operation. The effect simulates the diagonal cuts and joins the two pieces:
length1 excess
-----------><--->
_________ : : _________________
- \\ : : :\\ `
- \\ : : : \\ `
- \\: : : \\ `
- * : : * - - *
- \\ : : :\\ `
- \\ : : : \\ `
+ \\ : : :\\ `
+ \\ : : : \\ `
+ \\: : : \\ `
+ * : : * - - *
+ \\ : : :\\ `
+ \\ : : : \\ `
_______________\\: : : \\_____`____
: : : :
<---> <----->
@@ -3518,7 +3518,7 @@ as follows:
.TS
center;
lI l l.
-Samples read \fIn\fR\^\(mu\^\fIc\fR \
+Samples read \fIn\fR\^\(mu\^\fIc\fR \
Length (seconds) \fIn\fR\^\(di\^\fIr\fR
Scaled by \ See \-s below.
Maximum amplitude max(\fIx\s-2\dk\u\s0\fR) T{
@@ -3592,6 +3592,12 @@ 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.
@@ -3877,7 +3883,7 @@ Exponential: as `/', but initial phase always zero, and stepped (less
smooth) frequency changes.
.RE
.TP
-\
+\
Not used for noise.
.SP
\fIoff\fR is the bias (DC-offset) of the signal in percent; default=0.
@@ -4070,7 +4076,7 @@ The amount of audio (in seconds) to preserve before the trigger point
and any found quieter/shorter bursts.
.RE
.TP
-\
+\
.I Advanced Options:
.br
These allow fine tuning of the algorithm's internal parameters.
@@ -4109,7 +4115,7 @@ algorithm.
algorithm.
.RE
.TP
-\
+\
See also the
.B silence
effect.
diff --git a/src/stat.c b/src/stat.c
index cdea27c..63d1741 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;
+ int 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 = 1;
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 = 0;
stat->re_in = stat->re_out = NULL;
if (stat->fft) {
@@ -134,6 +138,15 @@ 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;
+ unsigned samples = 0;
+ float ffa = 0.0;
+ unsigned i;
+ if (stat->fft_average == 1) {
+ 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 +159,20 @@ 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 == 1) {
+ 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 == 1) {
+ 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 +215,9 @@ static int sox_stat_flow(sox_effect_t * effp, const sox_sample_t *ibuf, sox_samp
stat->read += len;
}
+ if (re_average) {
+ free(re_average);
+ }
*isamp = *osamp = len;
/* Process all samples */
@@ -320,7 +346,7 @@ 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,
--
2.1.0
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