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avfilter/af_aiir: fix phase and group delay calculation

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Properly unwrap phase.
This commit is contained in:
Paul B Mahol 2020-05-20 11:01:56 +02:00
parent 74dfc88b63
commit 86822cfcd9
1 changed files with 45 additions and 17 deletions
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62
libavfilter/af_aiir.c
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@ -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);
snprintf(text, sizeof(text), "%.2f", max_delay);
drawtext(out, 11 * 8 + 2, 22, text, 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 Delay:", 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, 42, text, 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)