DRED: quantize r and p0 parameters with 8 bits

Only code non-degenerate symbols, which makes the encoder faster

3 files changed, 11 insertions, 10 deletions

diff --git a/silk/dred_config.h b/silk/dred_config.h
index 06ff397b..5e3e74a3 100644
--- a/silk/dred_config.h
+++ b/silk/dred_config.h
@@ -32,7 +32,7 @@
 #define DRED_EXTENSION_ID 126
 
 /* Remove these two completely once DRED gets an extension number assigned. */
-#define DRED_EXPERIMENTAL_VERSION 6
+#define DRED_EXPERIMENTAL_VERSION 7
 #define DRED_EXPERIMENTAL_BYTES 2
 
 
diff --git a/silk/dred_decoder.c b/silk/dred_decoder.c
index 658d340f..68ba8559 100644
--- a/silk/dred_decoder.c
+++ b/silk/dred_decoder.c
@@ -43,20 +43,21 @@ static int sign_extend(int x, int b) {
   return (x ^ m) - m;
 }
 
-static void dred_decode_latents(ec_dec *dec, float *x, const opus_uint16 *scale, const opus_uint16 *r, const opus_uint16 *p0, int dim) {
+static void dred_decode_latents(ec_dec *dec, float *x, const opus_uint16 *scale, const opus_uint8 *r, const opus_uint8 *p0, int dim) {
     int i;
     for (i=0;i<dim;i++) {
         int q;
-        q = ec_laplace_decode_p0(dec, p0[i], r[i]);
+        if (r[i] == 0 || p0[i] == 255) q = 0;
+        else q = ec_laplace_decode_p0(dec, p0[i]<<7, r[i]<<7);
         x[i] = q*256.f/(scale[i] == 0 ? 1 : scale[i]);
     }
 }
 
 int dred_ec_decode(OpusDRED *dec, const opus_uint8 *bytes, int num_bytes, int min_feature_frames)
 {
-  const opus_uint16 *p0              = DRED_rdovae_get_p0_pointer();
+  const opus_uint8 *p0              = DRED_rdovae_get_p0_pointer();
   const opus_uint16 *quant_scales    = DRED_rdovae_get_quant_scales_pointer();
-  const opus_uint16 *r               = DRED_rdovae_get_r_pointer();
+  const opus_uint8 *r               = DRED_rdovae_get_r_pointer();
   ec_dec ec;
   int q_level;
   int i;
diff --git a/silk/dred_encoder.c b/silk/dred_encoder.c
index 6b585416..3f842af0 100644
--- a/silk/dred_encoder.c
+++ b/silk/dred_encoder.c
@@ -217,7 +217,7 @@ void dred_compute_latents(DREDEnc *enc, const float *pcm, int frame_size, int ex
     }
 }
 
-static void dred_encode_latents(ec_enc *enc, const float *x, const opus_uint16 *scale, const opus_uint16 *dzone, const opus_uint16 *r, const opus_uint16 *p0, int dim) {
+static void dred_encode_latents(ec_enc *enc, const float *x, const opus_uint16 *scale, const opus_uint16 *dzone, const opus_uint8 *r, const opus_uint8 *p0, int dim) {
     int i;
     int q[IMAX(DRED_LATENT_DIM,DRED_STATE_DIM)];
     float xq[IMAX(DRED_LATENT_DIM,DRED_STATE_DIM)];
@@ -238,16 +238,16 @@ static void dred_encode_latents(ec_enc *enc, const float *x, const opus_uint16 *
     }
     for (i=0;i<dim;i++) {
         /* Make the impossible actually impossible. */
-        if (r[i] == 0 || p0[i] >= 32767) q[i] = 0;
-        ec_laplace_encode_p0(enc, q[i], p0[i], r[i]);
+        if (r[i] == 0 || p0[i] == 255) q[i] = 0;
+        else ec_laplace_encode_p0(enc, q[i], p0[i]<<7, r[i]<<7);
     }
 }
 
 int dred_encode_silk_frame(const DREDEnc *enc, unsigned char *buf, int max_chunks, int max_bytes) {
     const opus_uint16 *dead_zone       = DRED_rdovae_get_dead_zone_pointer();
-    const opus_uint16 *p0              = DRED_rdovae_get_p0_pointer();
+    const opus_uint8 *p0              = DRED_rdovae_get_p0_pointer();
     const opus_uint16 *quant_scales    = DRED_rdovae_get_quant_scales_pointer();
-    const opus_uint16 *r               = DRED_rdovae_get_r_pointer();
+    const opus_uint8 *r               = DRED_rdovae_get_r_pointer();
     ec_enc ec_encoder;
 
     int q_level;