af_hrtf: initialize coefficient arrays

Sometimes, --af=hrtf produces heavy artifacts or silence. It's possible
that this commit fixes these issues. My theory is that usually, the
uninitialized coefficients quickly converge to sane values as more audio
is filtered, which would explain why there are often artifacts on init,
with normal playback after that. It's also possible that sometimes, the
uninitialized values were NaN or inf, so that the artifacts (or silence)
would never go away.

Fix this by initializing the coefficients to 0. I'm not sure if this is
correct, but certainly better than before.

See issue #1104.

1 files changed, 25 insertions, 0 deletions

diff --git a/audio/filter/af_hrtf.c b/audio/filter/af_hrtf.c
index 9ffda62448..4fb382aff4 100644
--- a/audio/filter/af_hrtf.c
+++ b/audio/filter/af_hrtf.c
@@ -284,6 +284,27 @@ static inline void update_ch(af_hrtf_t *s, short *in, const int k)
     s->ba_r[k] = in[4] + in[1] + in[3];
 }
 
+static void clear_coeff(af_hrtf_t *s, float *c)
+{
+    memset(c, 0, s->dlbuflen * sizeof(float));
+}
+
+static void reset(af_hrtf_t *s)
+{
+    clear_coeff(s, s->lf);
+    clear_coeff(s, s->rf);
+    clear_coeff(s, s->lr);
+    clear_coeff(s, s->rr);
+    clear_coeff(s, s->cf);
+    clear_coeff(s, s->cr);
+    clear_coeff(s, s->ba_l);
+    clear_coeff(s, s->ba_r);
+    clear_coeff(s, s->fwrbuf_l);
+    clear_coeff(s, s->fwrbuf_r);
+    clear_coeff(s, s->fwrbuf_lr);
+    clear_coeff(s, s->fwrbuf_rr);
+}
+
 /* Initialization and runtime control */
 static int control(struct af_instance *af, int cmd, void* arg)
 {
@@ -292,6 +313,7 @@ static int control(struct af_instance *af, int cmd, void* arg)
 
     switch(cmd) {
     case AF_CONTROL_REINIT:
+        reset(s);
         af->data->rate = 48000;
         mp_audio_set_channels_old(af->data, ((struct mp_audio*)arg)->nch);
         if(af->data->nch == 2) {
@@ -309,6 +331,9 @@ static int control(struct af_instance *af, int cmd, void* arg)
         mp_audio_set_num_channels(af->data, 2);
         s->print_flag = 1;
         return test_output_res;
+    case AF_CONTROL_RESET:
+        reset(s);
+        return AF_OK;
     }
 
     return AF_UNKNOWN;