shithub: opus

Info  •  Files  •  Log  •  Branches

Don't use too much temporal resolution on hybrid frames at low rate

Otherwise, we risk having "temporal holes" in the HF that anti-collapse
can't always fill in.

--- a/celt/celt_encoder.c

+++ b/celt/celt_encoder.c

@@ -1772,6 +1772,13 @@

       tf_select = tf_analysis(mode, effEnd, isTransient, tf_res, lambda, X, N, LM, &tf_sum, tf_estimate, tf_chan);

       for (i=effEnd;i<end;i++)

          tf_res[i] = tf_res[effEnd-1];

+   } else if (hybrid && effectiveBytes<15)

+   {

+      /* For low bitrate hybrid, we force temporal resolution to 5 ms rather than 2.5 ms. */

+      tf_sum = 0;

+      for (i=0;i<end;i++)

+         tf_res[i] = 0;

+      tf_select=isTransient;

    } else {

       tf_sum = 0;

       for (i=0;i<end;i++)