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avfilter/avf_showspectrum: add log scale for frequency plot

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This commit is contained in:
Paul B Mahol 2019-04-28 20:15:17 +02:00
parent 90b21ae5b5
commit ce774e30ff
2 changed files with 200 additions and 65 deletions
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26
doc/filters.texi
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@ -22226,6 +22226,19 @@ logarithmic
Default value is @samp{sqrt}.
@item fscale
Specify frequency scale.
It accepts the following values:
@table @samp
@item lin
linear
@item log
logarithmic
@end table
Default value is @samp{lin}.
@item saturation
Set saturation modifier for displayed colors. Negative values provide
alternative color scheme. @code{0} is no saturation at all.
@ -22398,6 +22411,19 @@ logarithmic
@end table
Default value is @samp{log}.
@item fscale
Specify frequency scale.
It accepts the following values:
@table @samp
@item lin
linear
@item log
logarithmic
@end table
Default value is @samp{lin}.
@item saturation
Set saturation modifier for displayed colors. Negative values provide
alternative color scheme. @code{0} is no saturation at all.

239
libavfilter/avf_showspectrum.c
View File

@ -45,6 +45,7 @@
enum DisplayMode { COMBINED, SEPARATE, NB_MODES };
enum DataMode { D_MAGNITUDE, D_PHASE, NB_DMODES };
enum FrequencyScale { F_LINEAR, F_LOG, NB_FSCALES };
enum DisplayScale { LINEAR, SQRT, CBRT, LOG, FOURTHRT, FIFTHRT, NB_SCALES };
enum ColorMode { CHANNEL, INTENSITY, RAINBOW, MORELAND, NEBULAE, FIRE, FIERY, FRUIT, COOL, MAGMA, GREEN, VIRIDIS, PLASMA, CIVIDIS, TERRAIN, NB_CLMODES };
enum SlideMode { REPLACE, SCROLL, FULLFRAME, RSCROLL, NB_SLIDES };
@ -65,6 +66,7 @@ typedef struct ShowSpectrumContext {
int mode; ///< channel display mode
int color_mode; ///< display color scheme
int scale;
int fscale;
float saturation; ///< color saturation multiplier
float rotation; ///< color rotation
int start, stop; ///< zoom mode
@ -95,6 +97,7 @@ typedef struct ShowSpectrumContext {
int single_pic;
int legend;
int start_x, start_y;
int (*plot_channel)(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs);
} ShowSpectrumContext;
#define OFFSET(x) offsetof(ShowSpectrumContext, x)
@ -134,6 +137,9 @@ static const AVOption showspectrum_options[] = {
{ "log", "logarithmic", 0, AV_OPT_TYPE_CONST, {.i64=LOG}, 0, 0, FLAGS, "scale" },
{ "4thrt","4th root", 0, AV_OPT_TYPE_CONST, {.i64=FOURTHRT}, 0, 0, FLAGS, "scale" },
{ "5thrt","5th root", 0, AV_OPT_TYPE_CONST, {.i64=FIFTHRT}, 0, 0, FLAGS, "scale" },
{ "fscale", "set frequency scale", OFFSET(fscale), AV_OPT_TYPE_INT, {.i64=F_LINEAR}, 0, NB_FSCALES-1, FLAGS, "fscale" },
{ "lin", "linear", 0, AV_OPT_TYPE_CONST, {.i64=F_LINEAR}, 0, 0, FLAGS, "fscale" },
{ "log", "logarithmic", 0, AV_OPT_TYPE_CONST, {.i64=F_LOG}, 0, 0, FLAGS, "fscale" },
{ "saturation", "color saturation multiplier", OFFSET(saturation), AV_OPT_TYPE_FLOAT, {.dbl = 1}, -10, 10, FLAGS },
{ "win_func", "set window function", OFFSET(win_func), AV_OPT_TYPE_INT, {.i64 = WFUNC_HANNING}, 0, NB_WFUNC-1, FLAGS, "win_func" },
{ "rect", "Rectangular", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_RECT}, 0, 0, FLAGS, "win_func" },
@ -623,6 +629,56 @@ static char *get_time(AVFilterContext *ctx, float seconds, int x)
return units;
}
static float log_scale(const float value, const float min, const float max)
{
if (value < min)
return min;
if (value > max)
return max;
{
const float b = logf(max / min) / (max - min);
const float a = max / expf(max * b);
return expf(value * b) * a;
}
}
static float get_log_hz(const int bin, const int num_bins, const float sample_rate)
{
const float max_freq = sample_rate / 2;
const float hz_per_bin = max_freq / num_bins;
const float freq = hz_per_bin * bin;
const float scaled_freq = log_scale(freq + 1, 21, max_freq) - 1;
return num_bins * scaled_freq / max_freq;
}
static float inv_log_scale(const float value, const float min, const float max)
{
if (value < min)
return min;
if (value > max)
return max;
{
const float b = logf(max / min) / (max - min);
const float a = max / expf(max * b);
return logf(value / a) / b;
}
}
static float bin_pos(const int bin, const int num_bins, const float sample_rate)
{
const float max_freq = sample_rate / 2;
const float hz_per_bin = max_freq / num_bins;
const float freq = hz_per_bin * bin;
const float scaled_freq = inv_log_scale(freq + 1, 21, max_freq) - 1;
return num_bins * scaled_freq / max_freq;
}
static int draw_legend(AVFilterContext *ctx, int samples)
{
ShowSpectrumContext *s = ctx->priv;
@ -691,7 +747,8 @@ static int draw_legend(AVFilterContext *ctx, int samples)
}
for (y = 0; y < h; y += 40) {
float range = s->stop ? s->stop - s->start : inlink->sample_rate / 2;
float hertz = s->start + y * range / (float)(1 << (int)ceil(log2(h)));
float bin = s->fscale == F_LINEAR ? y : get_log_hz(y, h, inlink->sample_rate);
float hertz = s->start + bin * range / (float)(1 << (int)ceil(log2(h)));
char *units;
if (hertz == 0)
@ -746,7 +803,8 @@ static int draw_legend(AVFilterContext *ctx, int samples)
}
for (x = 0; x < w - 79; x += 80) {
float range = s->stop ? s->stop - s->start : inlink->sample_rate / 2;
float hertz = s->start + x * range / (float)(1 << (int)ceil(log2(w)));
float bin = s->fscale == F_LINEAR ? x : get_log_hz(x, w, inlink->sample_rate);
float hertz = s->start + bin * range / (float)(1 << (int)ceil(log2(w)));
char *units;
if (hertz == 0)
@ -812,6 +870,110 @@ static int draw_legend(AVFilterContext *ctx, int samples)
return 0;
}
static float get_value(AVFilterContext *ctx, int ch, int y)
{
ShowSpectrumContext *s = ctx->priv;
float *magnitudes = s->magnitudes[ch];
float *phases = s->phases[ch];
float a;
switch (s->data) {
case D_MAGNITUDE:
/* get magnitude */
a = magnitudes[y];
break;
case D_PHASE:
/* get phase */
a = phases[y];
break;
default:
av_assert0(0);
}
/* apply scale */
switch (s->scale) {
case LINEAR:
a = av_clipf(a, 0, 1);
break;
case SQRT:
a = av_clipf(sqrt(a), 0, 1);
break;
case CBRT:
a = av_clipf(cbrt(a), 0, 1);
break;
case FOURTHRT:
a = av_clipf(sqrt(sqrt(a)), 0, 1);
break;
case FIFTHRT:
a = av_clipf(pow(a, 0.20), 0, 1);
break;
case LOG:
a = 1 + log10(av_clipd(a, 1e-6, 1)) / 6; // zero = -120dBFS
break;
default:
av_assert0(0);
}
return a;
}
static int plot_channel_lin(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
{
ShowSpectrumContext *s = ctx->priv;
const int h = s->orientation == VERTICAL ? s->channel_height : s->channel_width;
const int ch = jobnr;
float yf, uf, vf;
int y;
/* decide color range */
color_range(s, ch, &yf, &uf, &vf);
/* draw the channel */
for (y = 0; y < h; y++) {
int row = (s->mode == COMBINED) ? y : ch * h + y;
float *out = &s->color_buffer[ch][3 * row];
float a = get_value(ctx, ch, y);
pick_color(s, yf, uf, vf, a, out);
}
return 0;
}
static int plot_channel_log(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
{
ShowSpectrumContext *s = ctx->priv;
AVFilterLink *inlink = ctx->inputs[0];
const int h = s->orientation == VERTICAL ? s->channel_height : s->channel_width;
const int ch = jobnr;
float y, yf, uf, vf;
int yy = 0;
/* decide color range */
color_range(s, ch, &yf, &uf, &vf);
/* draw the channel */
for (y = 0; y < h && yy < h; yy++) {
float pos0 = bin_pos(yy+0, h, inlink->sample_rate);
float pos1 = bin_pos(yy+1, h, inlink->sample_rate);
float delta = pos1 - pos0;
float a0, a1;
a0 = get_value(ctx, ch, yy+0);
a1 = get_value(ctx, ch, FFMIN(yy+1, h-1));
for (float j = pos0; j < pos1 && y + j - pos0 < h; j++) {
float row = (s->mode == COMBINED) ? y + j - pos0 : ch * h + y + j - pos0;
float *out = &s->color_buffer[ch][3 * FFMIN(lrintf(row), h-1)];
float lerpfrac = (j - pos0) / delta;
pick_color(s, yf, uf, vf, lerpfrac * a1 + (1.f-lerpfrac) * a0, out);
}
y += delta;
}
return 0;
}
static int config_output(AVFilterLink *outlink)
{
AVFilterContext *ctx = outlink->src;
@ -820,6 +982,12 @@ static int config_output(AVFilterLink *outlink)
int i, fft_bits, h, w;
float overlap;
switch (s->fscale) {
case F_LINEAR: s->plot_channel = plot_channel_lin; break;
case F_LOG: s->plot_channel = plot_channel_log; break;
default: return AVERROR_BUG;
}
s->stop = FFMIN(s->stop, inlink->sample_rate / 2);
if (s->stop && s->stop <= s->start) {
av_log(ctx, AV_LOG_ERROR, "Stop frequency should be greater than start.\n");
@ -1099,68 +1267,6 @@ static void clear_combine_buffer(ShowSpectrumContext *s, int size)
}
}
static int plot_channel(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
{
ShowSpectrumContext *s = ctx->priv;
const int h = s->orientation == VERTICAL ? s->channel_height : s->channel_width;
const int ch = jobnr;
float *magnitudes = s->magnitudes[ch];
float *phases = s->phases[ch];
float yf, uf, vf;
int y;
/* decide color range */
color_range(s, ch, &yf, &uf, &vf);
/* draw the channel */
for (y = 0; y < h; y++) {
int row = (s->mode == COMBINED) ? y : ch * h + y;
float *out = &s->color_buffer[ch][3 * row];
float a;
switch (s->data) {
case D_MAGNITUDE:
/* get magnitude */
a = magnitudes[y];
break;
case D_PHASE:
/* get phase */
a = phases[y];
break;
default:
av_assert0(0);
}
/* apply scale */
switch (s->scale) {
case LINEAR:
a = av_clipf(a, 0, 1);
break;
case SQRT:
a = av_clipf(sqrt(a), 0, 1);
break;
case CBRT:
a = av_clipf(cbrt(a), 0, 1);
break;
case FOURTHRT:
a = av_clipf(sqrt(sqrt(a)), 0, 1);
break;
case FIFTHRT:
a = av_clipf(pow(a, 0.20), 0, 1);
break;
case LOG:
a = 1 + log10(av_clipd(a, 1e-6, 1)) / 6; // zero = -120dBFS
break;
default:
av_assert0(0);
}
pick_color(s, yf, uf, vf, a, out);
}
return 0;
}
static int plot_spectrum_column(AVFilterLink *inlink, AVFrame *insamples)
{
AVFilterContext *ctx = inlink->dst;
@ -1173,7 +1279,7 @@ static int plot_spectrum_column(AVFilterLink *inlink, AVFrame *insamples)
/* initialize buffer for combining to black */
clear_combine_buffer(s, z);
ctx->internal->execute(ctx, plot_channel, NULL, NULL, s->nb_display_channels);
ctx->internal->execute(ctx, s->plot_channel, NULL, NULL, s->nb_display_channels);
for (y = 0; y < z * 3; y++) {
for (x = 0; x < s->nb_display_channels; x++) {
@ -1447,6 +1553,9 @@ static const AVOption showspectrumpic_options[] = {
{ "log", "logarithmic", 0, AV_OPT_TYPE_CONST, {.i64=LOG}, 0, 0, FLAGS, "scale" },
{ "4thrt","4th root", 0, AV_OPT_TYPE_CONST, {.i64=FOURTHRT}, 0, 0, FLAGS, "scale" },
{ "5thrt","5th root", 0, AV_OPT_TYPE_CONST, {.i64=FIFTHRT}, 0, 0, FLAGS, "scale" },
{ "fscale", "set frequency scale", OFFSET(fscale), AV_OPT_TYPE_INT, {.i64=F_LINEAR}, 0, NB_FSCALES-1, FLAGS, "fscale" },
{ "lin", "linear", 0, AV_OPT_TYPE_CONST, {.i64=F_LINEAR}, 0, 0, FLAGS, "fscale" },
{ "log", "logarithmic", 0, AV_OPT_TYPE_CONST, {.i64=F_LOG}, 0, 0, FLAGS, "fscale" },
{ "saturation", "color saturation multiplier", OFFSET(saturation), AV_OPT_TYPE_FLOAT, {.dbl = 1}, -10, 10, FLAGS },
{ "win_func", "set window function", OFFSET(win_func), AV_OPT_TYPE_INT, {.i64 = WFUNC_HANNING}, 0, NB_WFUNC-1, FLAGS, "win_func" },
{ "rect", "Rectangular", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_RECT}, 0, 0, FLAGS, "win_func" },