[FFmpeg-cvslog] avfilter/af_aiir: factor out response calculation
Paul B Mahol
git at videolan.org
Fri Nov 22 17:07:23 EET 2019
ffmpeg | branch: master | Paul B Mahol <onemda at gmail.com> | Fri Nov 22 16:04:13 2019 +0100| [e169d3756e921bcad65e64a7c9b3c3892fd8e190] | committer: Paul B Mahol
avfilter/af_aiir: factor out response calculation
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=e169d3756e921bcad65e64a7c9b3c3892fd8e190
---
libavfilter/af_aiir.c | 115 ++++++++++++++++++++++++++++----------------------
1 file changed, 65 insertions(+), 50 deletions(-)
diff --git a/libavfilter/af_aiir.c b/libavfilter/af_aiir.c
index 214aefcde4..d5dc6b8f18 100644
--- a/libavfilter/af_aiir.c
+++ b/libavfilter/af_aiir.c
@@ -737,6 +737,66 @@ static void draw_line(AVFrame *out, int x0, int y0, int x1, int y1, uint32_t col
}
}
+static void get_response(int channel, int format, double w,
+ const double *b, const double *a,
+ int nb_b, int nb_a, double *r, double *i)
+{
+ double realz, realp;
+ double imagz, imagp;
+ double real, imag;
+ double div;
+
+ if (format == 0) {
+ realz = 0., realp = 0.;
+ imagz = 0., imagp = 0.;
+ for (int x = 0; x < nb_a; x++) {
+ realz += cos(-x * w) * a[x];
+ imagz += sin(-x * w) * a[x];
+ }
+
+ for (int x = 0; x < nb_b; x++) {
+ realp += cos(-x * w) * b[x];
+ imagp += sin(-x * w) * b[x];
+ }
+
+ div = realp * realp + imagp * imagp;
+ real = (realz * realp + imagz * imagp) / div;
+ imag = (imagz * realp - imagp * realz) / div;
+ } else {
+ real = 1;
+ imag = 0;
+ for (int x = 0; x < nb_a; x++) {
+ double ore, oim, re, im;
+
+ re = cos(w) - a[2 * x];
+ im = sin(w) - a[2 * x + 1];
+
+ ore = real;
+ oim = imag;
+
+ real = ore * re - oim * im;
+ imag = ore * im + oim * re;
+ }
+
+ for (int x = 0; x < nb_b; x++) {
+ double ore, oim, re, im;
+
+ re = cos(w) - b[2 * x];
+ im = sin(w) - b[2 * x + 1];
+
+ ore = real;
+ oim = imag;
+ div = re * re + im * im;
+
+ real = (ore * re + oim * im) / div;
+ imag = (oim * re - ore * im) / div;
+ }
+ }
+
+ *r = real;
+ *i = imag;
+}
+
static void draw_response(AVFilterContext *ctx, AVFrame *out)
{
AudioIIRContext *s = ctx->priv;
@@ -744,7 +804,7 @@ static void draw_response(AVFilterContext *ctx, AVFrame *out)
float min_delay = FLT_MAX, max_delay = FLT_MIN;
int prev_ymag = -1, prev_yphase = -1, prev_ydelay = -1;
char text[32];
- int ch, i, x;
+ int ch, i;
memset(out->data[0], 0, s->h * out->linesize[0]);
@@ -758,57 +818,12 @@ static void draw_response(AVFilterContext *ctx, AVFrame *out)
for (i = 0; i < s->w; i++) {
const double *b = s->iir[ch].ab[0];
const double *a = s->iir[ch].ab[1];
+ const int nb_b = s->iir[ch].nb_ab[0];
+ const int nb_a = s->iir[ch].nb_ab[1];
double w = i * M_PI / (s->w - 1);
- double realz, realp;
- double imagz, imagp;
- double real, imag, div;
-
- if (s->format == 0) {
- realz = 0., realp = 0.;
- imagz = 0., imagp = 0.;
- for (x = 0; x < s->iir[ch].nb_ab[1]; x++) {
- realz += cos(-x * w) * a[x];
- imagz += sin(-x * w) * a[x];
- }
-
- for (x = 0; x < s->iir[ch].nb_ab[0]; x++) {
- realp += cos(-x * w) * b[x];
- imagp += sin(-x * w) * b[x];
- }
-
- div = realp * realp + imagp * imagp;
- real = (realz * realp + imagz * imagp) / div;
- imag = (imagz * realp - imagp * realz) / div;
- } else {
- real = 1;
- imag = 0;
- for (x = 0; x < s->iir[ch].nb_ab[1]; x++) {
- double ore, oim, re, im;
-
- re = cos(w) - a[2 * x];
- im = sin(w) - a[2 * x + 1];
+ double real, imag;
- ore = real;
- oim = imag;
-
- real = ore * re - oim * im;
- imag = ore * im + oim * re;
- }
-
- for (x = 0; x < s->iir[ch].nb_ab[0]; x++) {
- double ore, oim, re, im;
-
- re = cos(w) - b[2 * x];
- im = sin(w) - b[2 * x + 1];
-
- ore = real;
- oim = imag;
- div = re * re + im * im;
-
- real = (ore * re + oim * im) / div;
- imag = (oim * re - ore * im) / div;
- }
- }
+ get_response(ch, s->format, w, b, a, nb_b, nb_a, &real, &imag);
mag[i] = s->iir[ch].g * hypot(real, imag);
phase[i] = atan2(imag, real);
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