iir->biquads[current_biquad].a0 = 1.0;
iir->biquads[current_biquad].a1 = a[2] / a[4];
iir->biquads[current_biquad].a2 = a[0] / a[4];
- iir->biquads[current_biquad].b0 = b[4] / a[4] * (current_biquad ? 1.0 : iir->g);
- iir->biquads[current_biquad].b1 = b[2] / a[4] * (current_biquad ? 1.0 : iir->g);
- iir->biquads[current_biquad].b2 = b[0] / a[4] * (current_biquad ? 1.0 : iir->g);
+ iir->biquads[current_biquad].b0 = (b[4] / a[4]) * (current_biquad ? 1.0 : iir->g);
+ iir->biquads[current_biquad].b1 = (b[2] / a[4]) * (current_biquad ? 1.0 : iir->g);
+ iir->biquads[current_biquad].b2 = (b[0] / a[4]) * (current_biquad ? 1.0 : iir->g);
av_log(ctx, AV_LOG_VERBOSE, "a=%f %f %f:b=%f %f %f\n",
iir->biquads[current_biquad].a0,
}
}
+static void check_stability(AVFilterContext *ctx, int channels)
+{
+ AudioIIRContext *s = ctx->priv;
+ int ch;
+
+ for (ch = 0; ch < channels; ch++) {
+ IIRChannel *iir = &s->iir[ch];
+
+ for (int n = 0; n < iir->nb_ab[0]; n++) {
+ double pr = hypot(iir->ab[0][2*n], iir->ab[0][2*n+1]);
+
+ if (pr >= 1.) {
+ av_log(ctx, AV_LOG_WARNING, "pole %d at channel %d is unstable\n", n, ch);
+ break;
+ }
+ }
+ }
+}
+
static void drawtext(AVFrame *pic, int x, int y, const char *txt, uint32_t color)
{
const uint8_t *font;
} else if (s->format == 3) {
convert_pd2zp(ctx, inlink->channels);
}
+ if (s->format > 0) {
+ check_stability(ctx, inlink->channels);
+ }
av_frame_free(&s->video);
if (s->response) {