ref: 52f4fa02202cf66929e44e454b548b4532aceea4
parent: 7cacd53ce34313deb5f0cd24dd4f319928e9e5f9
author: robs <robs>
date: Thu Jun 19 03:53:43 EDT 2008
spectrogram effect
--- a/AUTHORS
+++ b/AUTHORS
@@ -9,7 +9,7 @@
Mantainers:
Chris Bagwell cbagwell@users.sourceforge.net
OSS and Sun players, bugfixes, ADPCM support,
- patch collection and maintance.
+ patch collection and maintenance.
Reuben Thomas rrt@sc3d.org
Build system makeover, libsndfile and ffmpeg sound
format support, libao playback, Secret Rabbit Code
@@ -21,7 +21,7 @@
EFFECTS: key, tempo, pad, bass, treble, delay, new reverb, new
flanger, soft-knee companding, speed via resampling, filters
makeover inc. gnuplot & octave plotting, splice, remix, norm,
- contrast, new rate;
+ contrast, new rate, spectrogram;
new effects chain with buffering and any # channels.
OTHERS: open input files via URL, file merge, play
multiple files with mixed format types, play with replay-gain,
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -73,6 +73,7 @@
if (NOT HAVE_LAME_LAME_H)
optional(HAVE_LAME_LAME_H lame.h mp3lame lame_init mp3)
endif (NOT HAVE_LAME_LAME_H)
+optional(HAVE_PNG png.h png png_set_rows spectrogram)
optional(HAVE_SAMPLERATE_H samplerate.h samplerate src_simple rabbit)
optional(HAVE_SNDFILE_H sndfile.h sndfile sf_open sndfile)
optional(HAVE_SNDFILE_H sndfile.h sndfile sf_open fap)
--- a/ChangeLog
+++ b/ChangeLog
@@ -57,6 +57,7 @@
o New `delay' effect; delay one or more channels. (robs)
o New `contrast' enhancement effect [FR 708923]. (robs)
o Rewrite of rate; resample, polyphase, & rabbit now deprecated. (robs)
+ o New `spectrogram' effect; creates a PNG. (robs)
o `synth' can now sweep linearly (as well as logarithmically). (robs)
o Fix synth max. level setting for some output encodings. (robs)
o Fix crash on 64-bit arch. with tempo & key effects. (Sami Liedes)
--- a/README
+++ b/README
@@ -71,9 +71,11 @@
o Band-reject filter
o Bass tone control
o Compress and Expand (compand) the dynamic range of a sample
+ o Contrast enhancement effect
o Chorus effect
o DC-shift audio - useful to get the best volume adjustments
o De-emphasis filter
+ o Delay one or more channels
o Move sound stage of CD audio to in front of you (for headphone
use)
o Add an echo
@@ -91,15 +93,13 @@
o Apply a phaser effect
o Change the key (pitch) of a sound file without affecting its speed
o Repeat audio data
- o Change sampling rates using several different algorithms. A
- 'resample' and 'polyphase' effect use high-grade signal rate
- changes using real signal theory!
+ o Change sampling rate
o Apply a reverb effect
o Reverse the sound samples (to search for Satanic messages ;-)
o Detect periods of silence and start and stop processing based on
it
+ o Create a spectrogram PNG
o Change speed (pitch and tempo together)
- motor on a tape recorder)
o Splice together audio sections
o Display general stats on a sound sample
o Change the tempo an audio file (without affecting pitch)
--- a/configure.ac
+++ b/configure.ac
@@ -414,6 +414,26 @@
AM_CONDITIONAL(HAVE_WAVPACK, test x$using_wavpack = xyes)
AC_SUBST(WAVPACK_LIBS)
+dnl Check for png libraries
+AC_ARG_WITH(png,
+ AC_HELP_STRING([--without-png],
+ [Don't try to use png]))
+using_png=no
+if test "$with_png" != "no"; then
+ using_png=yes
+ AC_CHECK_HEADER(png.h,
+ [AC_CHECK_LIB(png, png_set_rows, PNG_LIBS="$PNG_LIBS -lpng -lz" ,using_png=no)],
+ using_png=no)
+ if test "$with_png" = "yes" -a "$using_png" = "no"; then
+ AC_MSG_FAILURE([cannot find png])
+ fi
+fi
+if test "$using_png" = yes; then
+ AC_DEFINE(HAVE_PNG, 1, [Define to 1 if you have PNG.])
+fi
+AM_CONDITIONAL(HAVE_PNG, test x$using_png = xyes)
+AC_SUBST(PNG_LIBS)
+
dnl Test for libsamplerate.
AC_ARG_WITH(samplerate,
AC_HELP_STRING([--without-samplerate],
@@ -483,6 +503,7 @@
echo "AMR-NB format..................... $using_amr_nb"
echo "WavPack format.................... $using_wavpack"
echo "LADSPA effects.................... $using_ladspa"
+echo "PNG support....................... $using_png"
echo "Secret Rabbit Code resampling..... $using_samplerate"
echo "pkg-config location............... $pkgconfig_option"
echo
--- a/soxeffect.7
+++ b/soxeffect.7
@@ -1027,6 +1027,110 @@
resampling, in addition to the \fBspeed\fR effect, specify
the \fBrate\fR effect with the desired quality options.
.TP
+\fBspectrogram \fR[options]
+Create a spectrogram of the audio. This effect is optional; type \fBsox
+\-\-help\fR and check the list of supported effects to see if it has
+been included.
+.SP
+The spectrogram is rendered in a Portable Network Graphic (PNG) file,
+and shows time in the X-axis, frequency in the Y-axis, and audio signal
+magnitude in the Z-axis. Z-axis values are represented by the colour
+(or intensity) of the pixels in the X-Y plane.
+.RS
+.IP \fB-x\ \fInum\fR
+X-axis pixels/second, default 100. This controls the width of the
+spectrogram;
+.I num
+can be from 1 (low time resolution) to 5000 (high time resolution). SoX
+may make a slight adjustment to the given number for processing
+quantisation reasons; if so, SoX will report the actual number used
+(viewable when
+.B \-\-verbose
+is in effect).
+.SP
+The maximum width of the spectrogram is 999 pixels; if the audio length
+and the given
+.B \-x
+number are such that this would be exceeded, then the spectrogram (and
+the effects chain) will be truncated. To move the spectrogram to a
+point later in the audio stream, first invoke the
+.B trim
+effect; e.g.
+.EX
+ sox audio.ogg -n trim 1:00 spectrogram
+.EE
+starts the spectrogram at 1 minute through the audio.
+.IP \fB-y\ \fInum\fR
+Y-axis resolution (1 - 4), default 2.
+This controls the height of the spectrogram;
+.I num
+can be from 1 (low frequency resolution) to 4 (high frequency
+resolution). For values greater than 2, the resulting image may be too
+tall to display on the screen; if so, a graphic manipulation package
+(such as
+.BR
+ImageMagick (1))
+can be used to re-size the image.
+.SP
+To increase the frequency resolution without increasing the height of
+the spectrogram, the
+.B rate
+effect may be invoked to reduce the sampling rate of the signal before
+invoking
+.BR spectrogram ;
+e.g.
+.EX
+ sox audio.ogg -r 4k -n rate spectrogram
+.EE
+allows detailed analysis of frequencies up to 2kHz (half the sampling
+rate).
+.IP \fB-z\ \fInum\fR
+Z-axis (colour) range in dB, default 120. This sets the dynamic-range
+of the spectrogram to be \-\fInum\fR\ dBFS to 0\ dBFS.
+.I Num
+may range from 40 to 180. Decreasing dynamic-range, effectively
+increases the `contrast' of the spectrogram display, and vice versa.
+.IP \fB-g\ \fInum\fR
+Apply
+.I num
+dB gain (or attenuation if
+.I num
+is negative) to the audio before displaying it. Appling gain or
+attenuation shifts the the range of the Z-axis and effectively controls
+the `brightness' of the spectrogram display. Note that the audio in the
+SoX effects chain remains unaffected by this option (cf. the
+.B gain
+effect).
+.IP \fB-w\ \fIname\fR
+Window: Hann (default), Hamming, Bartlett, Rectangular, Kaiser. The
+spectrogram is produced using the Discrete Fourier Transform (DFT)
+algorithm. A significant paramater to this algorithm is the choice of
+`window function'. By default, SoX uses the Hann window which has good
+all-round frequency-resolution and dynamic-range properties. For better
+frequency resolution (but lower dynamic-range), select a Hamming window;
+for higher dynamic-range (but poorer frequency-resolution), select a
+Kaiser window. Selecting a window other than Hann will usually require
+a corresponding
+.B \-z
+setting.
+.IP \fB-s\ \fInum\fR
+Display style (1 - 4), default 1. There are 2 colour and 2 monochrome
+styles; select the style that works best with the given audio signal and
+your display or printer.
+.IP \fB-a\fR
+Toggle the presence of the axes lines. This is sometimes useful in
+helping to discern artefacts at the spectrogram edges.
+.IP \fB-t\ \fItext\fR
+Text to display above the spectrogram.
+.IP \fB-c\ \fItext\fR
+Text to display below and to the left of the spectrogram.
+.IP \fB-o\ \fItext\fR
+Name of the spectrogram output PNG file, default `spectrogram.png'.
+.RE
+For the ability to perform off-line processing of spectral data, see the
+.B stat
+effect.
+.TP
\fBsplice \fR { \fIposition\fR[\fB,\fIexcess\fR[\fB,\fIleeway\fR]] }Splice together audio sections. This effect provides two things over
simple audio concatenation: a (usually short) cross-fade is applied at
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -231,9 +231,12 @@
remix.c repeat.c resample.c reverb.c reverse.c silence.c skeleff.c \
speed.c splice.c stat.c stretch.c swap.c synth.c tempo.c tremolo.c \
trim.c vol.c
+if HAVE_PNG
+ libsfx_la_SOURCES += spectrogram.c
+endif
libsfx_la_CFLAGS = @SAMPLERATE_CFLAGS@
-libsfx_la_LIBADD = @SAMPLERATE_LIBS@ libsox.la
+libsfx_la_LIBADD = @PNG_LIBS@ @SAMPLERATE_LIBS@ libsox.la
############################################
# libsox - file format and utility library #
--- a/src/effects.h
+++ b/src/effects.h
@@ -64,6 +64,9 @@
EFFECT(reverb)
EFFECT(reverse)
EFFECT(silence)
+#ifdef HAVE_PNG
+ EFFECT(spectrogram)
+#endif
EFFECT(speed)
EFFECT(splice)
EFFECT(stat)
--- a/src/soxconfig.h.cmake
+++ b/src/soxconfig.h.cmake
@@ -19,6 +19,7 @@
#cmakedefine HAVE_MAD_H 1
#cmakedefine HAVE_OGG_VORBIS 1
#cmakedefine HAVE_POPEN 1
+#cmakedefine HAVE_PNG 1
#cmakedefine HAVE_SAMPLERATE_H 1
#cmakedefine HAVE_SNDFILE_1_0_12 1
#cmakedefine HAVE_SNDFILE_H 1
--- /dev/null
+++ b/src/spectrogram.c
@@ -1,0 +1,536 @@
+/* libSoX effect: Spectrogram (c) 2008 robs@users.sourceforge.net
+ *
+ * This library is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or (at
+ * your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifdef NDEBUG /* Enable assert always. */
+#undef NDEBUG /* Must undef above assert.h or other that might include it. */
+#endif
+
+#include "sox_i.h"
+#include "fft4g.h"
+#include "getopt.h"
+#include <assert.h>
+#include <math.h>
+#include <png.h>
+
+#define malloc lsx_malloc
+#define calloc lsx_calloc
+#define realloc lsx_realloc
+#define FROM_SOX SOX_SAMPLE_TO_FLOAT_64BIT
+#define DFT_BASE_SIZE 512
+#define MAX_DFT_SIZE_SHIFT 3
+#define MAX_DFT_SIZE (DFT_BASE_SIZE << MAX_DFT_SIZE_SHIFT)
+#define MAX_COLS 999 /* Also max seconds */
+
+static void apply_hann(double h[], const int num_points)
+{+ int i, m = num_points - 1;
+ for (i = 0; i < num_points; ++i) {+ double x = 2 * M_PI * i / m;
+ h[i] *= .5 - .5 * cos(x);
+ }
+}
+
+static void apply_hamming(double h[], const int num_points)
+{+ int i, m = num_points - 1;
+ for (i = 0; i < num_points; ++i) {+ double x = 2 * M_PI * i / m;
+ h[i] *= .53836 - .46164 * cos(x);
+ }
+}
+
+static void apply_bartlett(double h[], const int num_points)
+{+ int i, m = num_points - 1;
+ for (i = 0; i < num_points; ++i) {+ h[i] *= 2. / m * (m / 2. - fabs(i - m / 2.));
+ }
+}
+
+static double kaiser_beta(double att)
+{+ if (att > 100 ) return .1117 * att - 1.11;
+ if (att > 50 ) return .1102 * (att - 8.7);
+ if (att > 20.96) return .58417 * pow(att -20.96, .4) + .07886 * (att - 20.96);
+ return 0;
+}
+
+static void apply_kaiser(double h[], const int num_points, double beta)
+{+ int i, m = num_points - 1;
+ for (i = 0; i <= m; ++i) {+ double x = 2. * i / m - 1;
+ h[i] *= bessel_I_0(beta * sqrt(1 - x * x)) / bessel_I_0(beta);
+ }
+}
+
+typedef enum {Window_Hann, Window_Hamming, Window_Bartlett, Window_Rectangular, Window_Kaiser} win_type_t;+static enum_item const window_options[] = {+ ENUM_ITEM(Window_,Hann)
+ ENUM_ITEM(Window_,Hamming)
+ ENUM_ITEM(Window_,Bartlett)
+ ENUM_ITEM(Window_,Rectangular)
+ ENUM_ITEM(Window_,Kaiser)
+ {0, 0}};+
+typedef struct {+ int y_size, dft_size, rows, cols, step_size, block_steps, block_num;
+ double buf[MAX_DFT_SIZE];
+ double dft_buf[MAX_DFT_SIZE];
+ double window[MAX_DFT_SIZE];
+ int bit_rev_table[100]; /* For Ooura fft */
+ double sin_cos_table[dft_sc_len(MAX_DFT_SIZE)]; /* ditto */
+ double magnitudes[(MAX_DFT_SIZE >> 1) + 1];
+ float * dBfs;
+ double pixels_per_sec, block_norm, max;
+ int dB_range, gain, style, read, end, end_min, last_end;
+ char const * out_name, * title, * comment;
+ sox_bool no_axes;
+ win_type_t win_type;
+} priv_t;
+
+#define GETOPT_NUMERIC(ch, name, min, max) case ch:{ \+ char * end_ptr; \
+ double d = strtod(optarg, &end_ptr); \
+ if (end_ptr == optarg || d < min || d > max || *end_ptr != '\0') {\+ sox_fail("parameter `%s' must be between %g and %g", #name, (double)min, (double)max); \+ return lsx_usage(effp); \
+ } \
+ p->name = d; \
+ break; \
+}
+
+static int enum_option(int c, enum_item const * items)
+{+ enum_item const * p = find_enum_text(optarg, items);
+ if (p == NULL) {+ unsigned len = 1;
+ char * set = lsx_malloc(len);
+ *set = 0;
+ for (p = items; p->text; ++p) {+ set = lsx_realloc(set, len += 2 + strlen(p->text));
+ strcat(set, ", "); strcat(set, p->text);
+ }
+ sox_fail("-%c: '%s' is not one of: %s.", c, optarg, set + 2);+ free(set);
+ return INT_MAX;
+ }
+ return p->value;
+}
+
+static int getopts(sox_effect_t * effp, int argc, char **argv)
+{+ priv_t * p = (priv_t *)effp->priv;
+ int c, callers_optind = optind, callers_opterr = opterr;
+
+ assert(array_length(p->bit_rev_table) >= (size_t)dft_br_len(MAX_DFT_SIZE));
+
+ --argv, ++argc, optind = 1, opterr = 0; /* re-jig for getopt */
+ p->pixels_per_sec = 100, p->y_size = 2, p->dB_range = 120;/* non-0 defaults */
+ p->style = 1, p->out_name = "spectrogram.png", p->comment = "Created by SoX";
+
+ while ((c = getopt(argc, argv, "+x:y:z:g:s:w:t:c:o:a")) != -1) switch (c) {+ GETOPT_NUMERIC('x', pixels_per_sec, 1 , 5000)+ GETOPT_NUMERIC('y', y_size , 1 , 1 + MAX_DFT_SIZE_SHIFT)+ GETOPT_NUMERIC('z', dB_range , 40 , 180)+ GETOPT_NUMERIC('g', gain ,-100, 100)+ GETOPT_NUMERIC('s', style , 1 , 4)+ case 'w': p->win_type = enum_option(c, window_options); break;
+ case 't': p->title = optarg; break;
+ case 'c': p->comment = optarg; break;
+ case 'o': p->out_name = optarg; break;
+ case 'a': p->no_axes = sox_true; break;
+ default: sox_fail("unknown option `-%c'", optopt); return lsx_usage(effp);+ }
+ p->y_size -= 1, p->style -= 1;
+ argc -= optind, optind = callers_optind, opterr = callers_opterr;
+ return argc || p->win_type == INT_MAX? lsx_usage(effp) : SOX_SUCCESS;
+}
+
+static int make_window(priv_t * p, int end)
+{+ double sum = 0, * w = end < 0? p->window : p->window + end;
+ int i, n = p->dft_size - abs(end);
+
+ if (end) memset(p->window, 0, sizeof(p->window));
+ for (i = 0; i < n; ++i) w[i] = 1;
+ switch (p->win_type) {+ case Window_Hann: apply_hann(w, n); break;
+ case Window_Hamming: apply_hamming(w, n); break;
+ case Window_Bartlett: apply_bartlett(w, n); break;
+ case Window_Rectangular: break;
+ default: apply_kaiser(w, n, kaiser_beta(p->dB_range + 10.));
+ }
+ for (i = 0; i < p->dft_size; ++i) sum += p->window[i];
+ for (i = 0; i < p->dft_size; ++i) p->window[i] *= 2 / sum
+ * sqr((double)n / p->dft_size); /* empirical small window adjustment */
+ return sum + .5;
+}
+
+static int start(sox_effect_t * effp)
+{+ priv_t * p = (priv_t *)effp->priv;
+ double actual;
+
+ if (effp->in_signal.channels != 1) {+ sox_fail("only 1 channel is supported");+ return SOX_EOF;
+ }
+ p->end = p->dft_size = DFT_BASE_SIZE << p->y_size;
+ p->rows = (p->dft_size >> 1) + 1;
+ p->step_size = make_window(p, p->last_end = 0);
+ p->block_steps = effp->in_signal.rate / p->pixels_per_sec;
+ p->step_size = p->block_steps / ceil((double)p->block_steps / p->step_size) +.5;
+ p->block_steps = floor((double)p->block_steps / p->step_size +.5);
+ p->block_norm = 1. / p->block_steps;
+ actual = effp->in_signal.rate / p->step_size / p->block_steps;
+ if (actual != p->pixels_per_sec)
+ sox_report("actual pixels/s = %g", actual);+ sox_debug("step_size=%i block_steps=%i", p->step_size, p->block_steps);+ p->max = -p->dB_range;
+ p->read = (p->step_size - p->dft_size) / 2;
+ return SOX_SUCCESS;
+}
+
+static int do_column(sox_effect_t * effp)
+{+ priv_t * p = (priv_t *)effp->priv;
+ int i;
+
+ if (p->cols == MAX_COLS) {+ sox_warn("PNG truncated at %g seconds", (double)MAX_COLS * p->step_size * p->block_steps / effp->in_signal.rate);+ return SOX_EOF;
+ }
+ ++p->cols;
+ p->dBfs = realloc(p->dBfs, p->cols * p->rows * sizeof(*p->dBfs));
+ for (i = 0; i < p->rows; ++i) {+ double dBfs = 10 * log10(p->magnitudes[i] * p->block_norm);
+ p->dBfs[(p->cols - 1) * p->rows + i] = dBfs + p->gain;
+ if (dBfs > p->max)
+ p->max = dBfs;
+ }
+ memset(p->magnitudes, 0, p->rows * sizeof(*p->magnitudes));
+ p->block_num = 0;
+ return SOX_SUCCESS;
+}
+
+static int flow(sox_effect_t * effp,
+ const sox_sample_t * ibuf, sox_sample_t * obuf,
+ sox_size_t * isamp, sox_size_t * osamp)
+{+ priv_t * p = (priv_t *)effp->priv;
+ sox_size_t len = min(*isamp, *osamp), dummy = 0; /* No need to clip count */
+ int i;
+
+ memcpy(obuf, ibuf, len * sizeof(*obuf)); /* Pass on audio unaffected */
+ *isamp = *osamp = len;
+
+ while (sox_true) {+ if (p->read == p->step_size) {+ memmove(p->buf, p->buf + p->step_size,
+ (p->dft_size - p->step_size) * sizeof(*p->buf));
+ p->read = 0;
+ }
+ for (; len && p->read < p->step_size; --len, ++p->read, --p->end)
+ p->buf[p->dft_size - p->step_size + p->read] = FROM_SOX(*ibuf++, dummy);
+ if (p->read != p->step_size)
+ break;
+
+ if ((p->end = max(p->end, p->end_min)) != p->last_end)
+ make_window(p, p->last_end = p->end);
+ for (i = 0; i < p->dft_size; ++i) p->dft_buf[i] = p->buf[i] * p->window[i];
+ rdft(p->dft_size, 1, p->dft_buf, p->bit_rev_table, p->sin_cos_table);
+ p->magnitudes[0] += sqr(p->dft_buf[0]);
+ for (i = 1; i < p->dft_size >> 1; ++i)
+ p->magnitudes[i] += sqr(p->dft_buf[2*i]) + sqr(p->dft_buf[2*i+1]);
+ p->magnitudes[p->dft_size >> 1] += sqr(p->dft_buf[1]);
+
+ if (++p->block_num == p->block_steps && do_column(effp) == SOX_EOF)
+ return SOX_EOF;
+ }
+ return SOX_SUCCESS;
+}
+
+static int drain(sox_effect_t * effp, sox_sample_t * obuf_, sox_size_t * osamp)
+{+ priv_t * p = (priv_t *)effp->priv;
+
+ if (p->cols != MAX_COLS) {+ sox_sample_t * ibuf = calloc(p->dft_size, sizeof(*ibuf));
+ sox_sample_t * obuf = calloc(p->dft_size, sizeof(*obuf));
+ sox_size_t isamp = (p->dft_size - p->step_size) / 2;
+ int left_over = (isamp + p->read) % p->step_size;
+
+ if (left_over >= p->step_size >> 1)
+ isamp += p->step_size - left_over;
+ sox_debug("cols=%i left=%i end=%i", p->cols, p->read, p->end);+ p->end = 0;
+ p->end_min = -p->dft_size;
+ if (flow(effp, ibuf, obuf, &isamp, &isamp) == SOX_SUCCESS && p->block_num) {+ p->block_norm *= (double)p->block_steps / p->block_num;
+ do_column(effp);
+ }
+ sox_debug("flushed cols=%i left=%i end=%i", p->cols, p->read, p->end);+ free(obuf);
+ free(ibuf);
+ }
+ (void)obuf_, *osamp = 0;
+ return SOX_SUCCESS;
+}
+
+#define spectrum_points (1 + 250)
+enum {Background = spectrum_points, Text, Labels, Grid, palette_size};+
+static unsigned colour(double x, int range)
+{+ x = range_limit(x, -range, 0);
+ return (1 + x / range) * (spectrum_points - 1) + .5;
+}
+
+static void make_palette(png_byte * palette, int style)
+{+ int i, j, at;
+ for (i = j = 0; j < spectrum_points; i += 3, ++j) {+ double r, g, b, x = (double)j / (spectrum_points - 1);
+ if (style > 1)
+ palette[i+2] = palette[i+1] = palette[i+0] = style == 2? j : 255 - j;
+ else {+ at = style? (spectrum_points - 1) * 3 - i : i;
+ if (x < .16) r = 0;
+ else if (x < .72) r = .99 * sin((x - .16) / .56 * M_PI / 2);
+ else r = .01 * (x - .72) / .28 + .99;
+ if (x < .52) g = 0;
+ else if (x < .86) g = .99 * .5 * (1 - cos((x - .52) / .34 * M_PI));
+ else g = .01 * (x - .86) / .14 + .99;
+ if (x < .34) b = .5 * sin((x - .00) / .34 * M_PI / 2);
+ else if (x < .63) b = .5 * .5 * (1 + cos((x - .34) / .29 * M_PI));
+ else b = (1 - cos((x - .63) / .37 * M_PI / 2));
+ palette[at + 0] = r * 255 + .5;
+ palette[at + 1] = g * 255 + .5;
+ palette[at + 2] = b * 255 + .5;
+ }
+ }
+ i = spectrum_points * 3;
+ switch (style) {+ case 0: case 2:
+ memcpy(palette + i, "\0\0\0" , 3), i+= 3;
+ memcpy(palette + i, "\377\377\377", 3), i+= 3;
+ memcpy(palette + i, "\277\277\277", 3), i+= 3;
+ memcpy(palette + i, "\177\177\177", 3), i+= 3;
+ return;
+ case 1: memcpy(palette + i, "\335\330\320", 3), i+= 3; break;
+ default: memcpy(palette + i, "\337\337\337", 3), i+= 3;
+ }
+ memcpy(palette + i, "\0\0\0" , 3), i+= 3;
+ memcpy(palette + i, "\077\077\077", 3), i+= 3;
+ memcpy(palette + i, "\077\077\077", 3), i+= 3;
+}
+
+static const Bytef fixed[] =
+ "x\332eT\241\266\2450\fDVV>Y\371$re%2\237\200|2\22YY\211D\"+\337'<y\345\312"
+ "\375\fd\345f\222\224\313\236\235{\270\344L\247a\232\4\246\351\201d\230\222"+ "\304D\364^ \352\362S\"m\347\311\237\237\27\64K\243\2302\265\35\v\371<\363y"
+ "\354_\226g\354\214)e \2458\341\17\20J4\215[z<\271\277\367\0\63\64@\177\330c"
+ "\227\204 Ir.\5$U\200\260\224\326S\17\200=\\k\20QA\334%\342\20*\303P\234\211"
+ "\366\36#\370R\276_\316s-\345\222Dlz\363my*;\217\373\346z\267\343\236\364\246"
+ "\236\365\2419\305p\333\267\23(\207\265\333\233\325Y\342\243\265\357\262\215"
+ "\263t\271$\276\226ea\271.\367&\320\347\202_\234\27\377\345\222\253?\3422\364"
+ "\207y\256\236\229\331\33\f\376\227\266\"\356\253j\366\363\347\334US\34]\371?"
+ "\255\371\336\372z\265v\34\226\247\32\324\217\334\337\317U4\16\316{N\370\31"+ "\365\357iL\231y\33y\264\211D7\337\4\244\261\220D\346\1\261\357\355>\3\342"
+ "\223\363\0\303\277\f[\214A,p\34`\255\355\364\37\372\224\342\277\f\207\255\36"
+ "_V\7\34\241^\316W\257\177\b\242\300\34\f\276\33?/9_\331f\346\36\25Y)\2301"
+ "\257\2414|\35\365\237\3424k\3\244\3\242\261\6\b\275>z$\370\215:\270\363w\36/"
+ "\265kF\v\20o6\242\301\364\336\27\325\257\321\364fs\231\215G\32=\257\305Di"
+ "\304^\177\304R\364Q=\225\373\33\320\375\375\372\200\337\37\374}\334\337\20"
+ "\364\310(]\304\267b\177\326Yrj\312\277\373\233\37\340";
+static unsigned char * font;
+#define font_x 5
+#define font_y 12
+#define font_X (font_x + 1)
+
+#define pixel(x,y) pixels[(y) * cols + (x)]
+#define print_at(x,y,c,t) print_at_(pixels,cols,x,y,c,t,0)
+#define print_up(x,y,c,t) print_at_(pixels,cols,x,y,c,t,1)
+
+static void print_at_(png_byte * pixels, int cols, int x, int y, int c, char const * text, int orientation)
+{+ for (;*text; ++text) {+ int pos = (*text - ' ') * font_y;
+ int i, j;
+ for (i = 0; i < font_y; ++i) {+ unsigned line = font[pos++];
+ for (j = 0; j < font_x; ++j, line <<= 1)
+ if (line & 0x80) switch (orientation) {+ case 0: pixel(x + j, y - i) = c; break;
+ case 1: pixel(x + i, y + j) = c; break;
+ }
+ }
+ switch (orientation) {+ case 0: x += font_X; break;
+ case 1: y += font_X; break;
+ }
+ }
+}
+
+static int axis(double to, int max_steps, int * limit, char * * prefix)
+{+ double scale = 1, step = 1;
+ int i, prefix_num = 0;
+ if (max_steps) {+ double try, log_10 = HUGE_VAL, min_step = (to *= 10) / max_steps;
+ for (i = 5; i; i >>= 1) if ((try = ceil(log10(min_step * i))) <= log_10)
+ step = pow(10., log_10 = try) / i, log_10 -= i > 1;
+ prefix_num = floor(log_10 / 3);
+ scale = pow(10., -3. * prefix_num);
+ }
+ *prefix = "pnum-kMGTPE" + prefix_num + (prefix_num? 4 : 11);
+ *limit = to * scale + .5;
+ return step * scale + .5;
+}
+
+#define below 48
+#define left 58
+#define between 37
+#define spectrum_width 14
+#define right 35
+
+static int stop(sox_effect_t * effp)
+{+ priv_t * p = (priv_t *) effp->priv;
+ FILE * file = fopen(p->out_name, "w");
+ uLong font_len = 96 * font_y;
+ int rows = below + p->rows + 30 + 20 * !!p->title;
+ int cols = left + p->cols + between + spectrum_width + right;
+ sox_bool do_frame = !p->no_axes;
+ png_byte * pixels = malloc(cols * rows * sizeof(*pixels));
+ png_bytepp png_rows = malloc(rows * sizeof(*png_rows));
+ png_structp png = png_create_write_struct(PNG_LIBPNG_VER_STRING, 0, 0,0);
+ png_infop png_info = png_create_info_struct(png);
+ png_byte palette[palette_size * 3];
+ int i, j, step, limit, tick_len = 2 + do_frame;
+ char text[200], * prefix;
+
+ if (!file) {+ sox_fail("failed to create `%s' :(", p->out_name);+ png_destroy_write_struct(&png, &png_info);
+ free(png_rows);
+ free(pixels);
+ free(p->dBfs);
+ return SOX_EOF;
+ }
+ sox_debug("signal-max=%g", p->max);+ font = malloc(font_len);
+ assert(uncompress(font, &font_len, fixed, sizeof(fixed)-1) == Z_OK);
+ make_palette(palette, p->style);
+ memset(pixels, Background, cols * rows * sizeof(*pixels));
+ png_init_io(png, file);
+ png_set_PLTE(png, png_info, (png_colorp)palette, palette_size);
+ png_set_IHDR(png, png_info, (size_t)cols, (size_t)rows, 8,
+ PNG_COLOR_TYPE_PALETTE, PNG_INTERLACE_NONE,
+ PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
+ for (j = 0; j < rows; ++j)
+ png_rows[rows - 1 - j] = (png_bytep)(pixels + j * cols);
+
+ if (p->title && (i = (int)strlen(p->title) * font_X) < cols + 1) /* Title */
+ print_at((cols - i) / 2, rows - font_y, Text, p->title);
+ if ((int)strlen(p->comment) * font_X < cols + 1) /* Footer comment */
+ print_at(1, font_y, Text, p->comment);
+
+ /* Spectrogram */
+ for (j = 0; j < p->rows; ++j) {+ for (i = 0; i < p->cols; ++i)
+ pixel(left + i, below + j) = colour(p->dBfs[i*p->rows + j], p->dB_range);
+ if (do_frame) /* Frame verticals */
+ pixel(left - 1, below + j) = pixel(left + p->cols,below + j) = Grid;
+ }
+ if (do_frame) for (i = -1; i <= p->cols; ++i) /* Frame horizontals */
+ pixel(left + i, below - 1) = pixel(left + i, below + p->rows) = Grid;
+
+ /* X-axis */
+ step = axis((double)p->cols * p->step_size * p->block_steps / effp->in_signal.rate, p->cols / (font_X * 9 / 2), &limit, &prefix);
+ sprintf(text, "Time (%.1ss)", prefix); /* Axis label */
+ print_at(left + (p->cols - font_X * (int)strlen(text)) / 2, 24, Text, text);
+ for (i = 0; i <= limit; i += step) {+ int y, x = limit? (double)i / limit * p->cols + .5 : 0;
+ for (y = 0; y < tick_len; ++y) /* Ticks */
+ pixel(left - 1 + x, below - 1 - y) = pixel(left - 1 + x, below + p->rows + y) = Grid;
+ if (step == 5 && (i%10))
+ continue;
+ sprintf(text, "%g", .1 * i); /* Tick labels */
+ x = left + x - 3 * strlen(text);
+ print_at(x, below - 6, Labels, text);
+ print_at(x, below + p->rows + 14, Labels, text);
+ }
+
+ /* Y-axis */
+ step = axis(effp->in_signal.rate / 2, (p->rows - 1) / ((font_y * 3 + 1) >> 1), &limit, &prefix);
+ sprintf(text, "Frequency (%.1sHz)", prefix); /* Axis label */
+ print_up(10, below + (p->rows - font_X * (int)strlen(text)) / 2, Text, text);
+ for (i = 0; i <= limit; i += step) {+ int x, y = limit? (double)i / limit * (p->rows - 1) + .5 : 0;
+ for (x = 0; x < tick_len; ++x) /* Ticks */
+ pixel(left - 1 - x, below + y) = pixel(left + p->cols + x, below + y) = Grid;
+ if (step == 5 && (i%10))
+ continue;
+ sprintf(text, i?"%5g":" DC", .1 * i); /* Tick labels */
+ print_at(left - 4 - font_X * 5, below + y + 5, Labels, text);
+ sprintf(text, i?"%g":"DC", .1 * i);
+ print_at(left + p->cols + 6, below + y + 5, Labels, text);
+ }
+
+ /* Z-axis */
+ print_at(cols - right - 2 - font_X, below - 13, Text, "dBFS");/* Axis label */
+ for (j = 0; j < p->rows; ++j) { /* Spectrum */+ png_byte b = colour(p->dB_range * (j / (p->rows - 1.) - 1), p->dB_range);
+ for (i = 0; i < spectrum_width; ++i)
+ pixel(cols - right - 1 - i, below + j) = b;
+ }
+ for (i = 0; i <= p->dB_range; i += 10) { /* (Tick) labels */+ int y = (double)i / p->dB_range * (p->rows - 1) + .5;
+ sprintf(text, "%+i", i - p->gain - p->dB_range);
+ print_at(cols - right + 1, below + y + 5, Labels, text);
+ }
+
+ free(font);
+ png_set_rows(png, png_info, png_rows);
+ png_write_png(png, png_info, PNG_TRANSFORM_IDENTITY, NULL);
+ png_destroy_write_struct(&png, &png_info);
+ free(png_rows);
+ free(pixels);
+ fclose(file);
+ free(p->dBfs);
+ return SOX_SUCCESS;
+}
+
+sox_effect_handler_t const * sox_spectrogram_effect_fn(void)
+{+ static sox_effect_handler_t handler = {+ "spectrogram", "[options]\n"
+ " -x num X-axis pixels/second, default 100\n"
+ " -y num Y-axis resolution (1 - 4), default 2\n"
+ " -z num Z-axis (colour) range in dB, default 120\n"
+ " -g num Apply num dB gain; to shift Z-axis\n"
+ " -w name Window: Hann (default), Hamming, Bartlett, Rectangular, Kaiser\n"
+ " -s num Display style (1 - 4), default 1\n"
+ " -a Toggle the presence of the axes' lines\n"
+ " -t text Title text\n"
+ " -c text Comment text\n"
+ " -o text Name of the spectrogram output file, default `spectrogram.png'\n",
+ 0, getopts, start, flow, drain, stop, NULL, sizeof(priv_t)};
+ return &handler;
+}