lpc: Add a function for calculating reflection coefficients from samples

Signed-off-by: Martin Storsjö <martin@martin.st>

1 files changed, 12 insertions, 0 deletions

diff --git a/libavcodec/lpc.c b/libavcodec/lpc.c
index 126dbc1266..2093e7e802 100644
--- a/libavcodec/lpc.c
+++ b/libavcodec/lpc.c
@@ -148,6 +148,18 @@ static int estimate_best_order(double *ref, int min_order, int max_order)
     return est;
 }
 
+int ff_lpc_calc_ref_coefs(LPCContext *s,
+                          const int32_t *samples, int order, double *ref)
+{
+    double autoc[MAX_LPC_ORDER + 1];
+
+    s->lpc_apply_welch_window(samples, s->blocksize, s->windowed_samples);
+    s->lpc_compute_autocorr(s->windowed_samples, s->blocksize, order, autoc);
+    compute_ref_coefs(autoc, order, ref, NULL);
+
+    return order;
+}
+
 /**
  * Calculate LPC coefficients for multiple orders
  *