Add coarse energy entropy model tuning.

This tunes the entropy model for coarse energy introduced in commit
 c1c40a76.
It uses a constant set of parameters, tuned from about an hour and a
 half of randomly selected test data encoded for each frame size,
 prediction type (inter/intra), and band number.
These will be slightly sub-optimal for different frame sizes, but
 should be better than what we were using.

For inter, this saves an average of 2.8, 5.2, 7.1, and 6.7 bits/frame
 for frame sizes of 120, 240, 480, and 960, respectively.
For intra, this saves an average of 1.5, 3.0, 4.5, and 5.3 bits/frame
 (for the same frame sizes, respectively).

1 files changed, 12 insertions, 3 deletions

diff --git a/tests/laplace-test.c b/tests/laplace-test.c
index 417f4e1..7778667 100644
--- a/tests/laplace-test.c
+++ b/tests/laplace-test.c
@@ -17,6 +17,13 @@
 
 #define DATA_SIZE 40000
 
+int ec_laplace_get_start_freq(int decay)
+{
+   celt_uint32 ft = 32768 - LAPLACE_MINP*(2*LAPLACE_NMIN+1);
+   int fs = (ft*(16384-decay))/(16384+decay);
+   return fs+LAPLACE_MINP;
+}
+
 int main(void)
 {
    int i;
@@ -41,8 +48,9 @@ int main(void)
       decay[i] = rand()%11000+5000;
    }
    for (i=0;i<10000;i++)
-      ec_laplace_encode(&enc, &val[i], decay[i]);      
-      
+      ec_laplace_encode(&enc, &val[i],
+            ec_laplace_get_start_freq(decay[i]), decay[i]);
+
    ec_enc_done(&enc);
 
    ec_byte_readinit(&buf,ec_byte_get_buffer(&buf),ec_byte_bytes(&buf));
@@ -50,7 +58,8 @@ int main(void)
 
    for (i=0;i<10000;i++)
    {
-      int d = ec_laplace_decode(&dec, decay[i]);
+      int d = ec_laplace_decode(&dec,
+            ec_laplace_get_start_freq(decay[i]), decay[i]);
       if (d != val[i])
       {
          fprintf (stderr, "Got %d instead of %d\n", d, val[i]);