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authorPaul B Mahol <onemda@gmail.com>2020-05-20 11:01:56 +0200
committerPaul B Mahol <onemda@gmail.com>2020-05-20 12:08:32 +0200
commit86822cfcd99e38c6a787ebc6141967df4ff80eb5 (patch)
tree18842bf89f9766bc245ecb66b485a74448278c2b
parent74dfc88b638f0c3768aee090054bb2fc41e8ae04 (diff)
downloadffmpeg-86822cfcd99e38c6a787ebc6141967df4ff80eb5.tar.gz
avfilter/af_aiir: fix phase and group delay calculation
Properly unwrap phase.
-rw-r--r--libavfilter/af_aiir.c60
1 files changed, 44 insertions, 16 deletions
diff --git a/libavfilter/af_aiir.c b/libavfilter/af_aiir.c
index c56ed0f3a0..187cbb6fd7 100644
--- a/libavfilter/af_aiir.c
+++ b/libavfilter/af_aiir.c
@@ -819,11 +819,11 @@ static void get_response(int channel, int format, double w,
*i = imag;
}
-static void draw_response(AVFilterContext *ctx, AVFrame *out)
+static void draw_response(AVFilterContext *ctx, AVFrame *out, int sample_rate)
{
AudioIIRContext *s = ctx->priv;
- float *mag, *phase, *delay, min = FLT_MAX, max = FLT_MIN;
- float min_delay = FLT_MAX, max_delay = FLT_MIN;
+ double *mag, *phase, *temp, *delay, min = DBL_MAX, max = -DBL_MAX;
+ double min_delay, max_delay, min_phase, max_phase;
int prev_ymag = -1, prev_yphase = -1, prev_ydelay = -1;
char text[32];
int ch, i;
@@ -831,9 +831,10 @@ static void draw_response(AVFilterContext *ctx, AVFrame *out)
memset(out->data[0], 0, s->h * out->linesize[0]);
phase = av_malloc_array(s->w, sizeof(*phase));
+ temp = av_malloc_array(s->w, sizeof(*temp));
mag = av_malloc_array(s->w, sizeof(*mag));
delay = av_malloc_array(s->w, sizeof(*delay));
- if (!mag || !phase || !delay)
+ if (!mag || !phase || !delay || !temp)
goto end;
ch = av_clip(s->ir_channel, 0, s->channels - 1);
@@ -849,16 +850,34 @@ static void draw_response(AVFilterContext *ctx, AVFrame *out)
mag[i] = s->iir[ch].g * hypot(real, imag);
phase[i] = atan2(imag, real);
- min = fminf(min, mag[i]);
- max = fmaxf(max, mag[i]);
+ min = fmin(min, mag[i]);
+ max = fmax(max, mag[i]);
}
+ temp[0] = 0.;
for (i = 0; i < s->w - 1; i++) {
- float dw = M_PI / (s->w - 1);
+ double d = phase[i] - phase[i + 1];
+ temp[i + 1] = ceil(fabs(d) / (2. * M_PI)) * 2. * M_PI * ((d > M_PI) - (d < -M_PI));
+ }
- delay[i] = -(phase[i + 1] - phase[i]) / dw;
- min_delay = fminf(min_delay, delay[i]);
- max_delay = fmaxf(max_delay, delay[i]);
+ min_phase = phase[0];
+ max_phase = phase[0];
+ for (i = 1; i < s->w; i++) {
+ temp[i] += temp[i - 1];
+ phase[i] += temp[i];
+ min_phase = fmin(min_phase, phase[i]);
+ max_phase = fmax(max_phase, phase[i]);
+ }
+
+ delay[0] = 0.;
+ min_delay = 0.;
+ max_delay = 0.;
+ for (i = 0; i < s->w - 1; i++) {
+ double div = s->w / (double)sample_rate;
+
+ delay[i + 1] = -(phase[i] - phase[i + 1]) / div;
+ min_delay = fmin(min_delay, delay[i + 1]);
+ max_delay = fmax(max_delay, delay[i + 1]);
}
delay[i] = delay[i - 1];
@@ -866,7 +885,7 @@ static void draw_response(AVFilterContext *ctx, AVFrame *out)
for (i = 0; i < s->w; i++) {
int ymag = mag[i] / max * (s->h - 1);
int ydelay = (delay[i] - min_delay) / (max_delay - min_delay) * (s->h - 1);
- int yphase = (0.5 * (1. + phase[i] / M_PI)) * (s->h - 1);
+ int yphase = (phase[i] - min_phase) / (max_phase - min_phase) * (s->h - 1);
ymag = s->h - 1 - av_clip(ymag, 0, s->h - 1);
yphase = s->h - 1 - av_clip(yphase, 0, s->h - 1);
@@ -897,17 +916,26 @@ static void draw_response(AVFilterContext *ctx, AVFrame *out)
snprintf(text, sizeof(text), "%.2f", min);
drawtext(out, 15 * 8 + 2, 12, text, 0xDDDDDDDD);
- drawtext(out, 2, 22, "Max Delay:", 0xDDDDDDDD);
+ drawtext(out, 2, 22, "Max Phase:", 0xDDDDDDDD);
+ snprintf(text, sizeof(text), "%.2f", max_phase);
+ drawtext(out, 15 * 8 + 2, 22, text, 0xDDDDDDDD);
+
+ drawtext(out, 2, 32, "Min Phase:", 0xDDDDDDDD);
+ snprintf(text, sizeof(text), "%.2f", min_phase);
+ drawtext(out, 15 * 8 + 2, 32, text, 0xDDDDDDDD);
+
+ drawtext(out, 2, 42, "Max Delay:", 0xDDDDDDDD);
snprintf(text, sizeof(text), "%.2f", max_delay);
- drawtext(out, 11 * 8 + 2, 22, text, 0xDDDDDDDD);
+ drawtext(out, 11 * 8 + 2, 42, text, 0xDDDDDDDD);
- drawtext(out, 2, 32, "Min Delay:", 0xDDDDDDDD);
+ drawtext(out, 2, 52, "Min Delay:", 0xDDDDDDDD);
snprintf(text, sizeof(text), "%.2f", min_delay);
- drawtext(out, 11 * 8 + 2, 32, text, 0xDDDDDDDD);
+ drawtext(out, 11 * 8 + 2, 52, text, 0xDDDDDDDD);
}
end:
av_free(delay);
+ av_free(temp);
av_free(phase);
av_free(mag);
}
@@ -951,7 +979,7 @@ static int config_output(AVFilterLink *outlink)
if (!s->video)
return AVERROR(ENOMEM);
- draw_response(ctx, s->video);
+ draw_response(ctx, s->video, inlink->sample_rate);
}
if (s->format == 0)