Variable framesize improvements

- Properly apply the transient boost by counting all the bits in the cost
- Disable the post-filter for non-20-ms frames that follow a transient (applies
  only to variable framesize)

2 files changed, 26 insertions, 9 deletions

diff --git a/celt/celt_encoder.c b/celt/celt_encoder.c
index d93b15a6..c22100ca 100644
--- a/celt/celt_encoder.c
+++ b/celt/celt_encoder.c
@@ -73,6 +73,7 @@ struct OpusCustomEncoder {
    int constrained_vbr;      /* If zero, VBR can do whatever it likes with the rate */
    int loss_rate;
    int lsb_depth;
+   int variable_duration;
 
    /* Everything beyond this point gets cleared on a reset */
 #define ENCODER_RESET_START rng
@@ -1162,6 +1163,7 @@ int celt_encode_with_ec(CELTEncoder * OPUS_RESTRICT st, const opus_val16 * pcm,
    const opus_int16 *eBands;
    int secondMdct;
    int signalBandwidth;
+   int transient_got_disabled;
    ALLOC_STACK;
 
    mode = st->mode;
@@ -1325,7 +1327,8 @@ int celt_encode_with_ec(CELTEncoder * OPUS_RESTRICT st, const opus_val16 * pcm,
    {
       int enabled;
       int qg;
-      enabled = nbAvailableBytes>12*C && st->start==0 && !silence && !st->disable_pf && st->complexity >= 5;
+      enabled = nbAvailableBytes>12*C && st->start==0 && !silence && !st->disable_pf
+            && st->complexity >= 5 && !(st->consec_transient && LM!=3 && st->variable_duration);
 
       prefilter_tapset = st->tapset_decision;
       pf_on = run_prefilter(st, in, prefilter_mem, CC, N, prefilter_tapset, &pitch_index, &gain1, &qg, enabled, nbAvailableBytes);
@@ -1364,6 +1367,7 @@ int celt_encode_with_ec(CELTEncoder * OPUS_RESTRICT st, const opus_val16 * pcm,
          shortBlocks = M;
    } else {
       isTransient = 0;
+      transient_got_disabled=1;
    }
 
    ALLOC(freq, CC*N, celt_sig); /**< Interleaved signal MDCTs */
@@ -1874,7 +1878,7 @@ int celt_encode_with_ec(CELTEncoder * OPUS_RESTRICT st, const opus_val16 * pcm,
       }
    } while (++c<CC);
 
-   if (isTransient)
+   if (isTransient || transient_got_disabled)
       st->consec_transient++;
    else
       st->consec_transient=0;
@@ -2058,6 +2062,12 @@ int opus_custom_encoder_ctl(CELTEncoder * OPUS_RESTRICT st, int request, ...)
           *value=st->lsb_depth;
       }
       break;
+      case OPUS_SET_EXPERT_FRAME_DURATION_REQUEST:
+      {
+          opus_int32 value = va_arg(ap, opus_int32);
+          st->variable_duration = value;
+      }
+      break;
       case OPUS_RESET_STATE:
       {
          int i;
diff --git a/src/opus_encoder.c b/src/opus_encoder.c
index b0368614..88bf5aff 100644
--- a/src/opus_encoder.c
+++ b/src/opus_encoder.c
@@ -597,11 +597,17 @@ static int transient_viterbi(const float *E, const float *E_1, int N, int frame_
    int states[MAX_DYNAMIC_FRAMESIZE][16];
    float best_cost;
    int best_state;
-
+   float factor;
+   /* Take into account that we damp VBR in the 32 kb/s to 64 kb/s range. */
+   if (rate<80)
+      factor=0;
+   else if (rate>160)
+      factor=1;
+   else
+      factor = (rate-80.f)/80.f;
    /* Makes variable framesize less aggressive at lower bitrates, but I can't
-      find any valid theretical justification for this (other than it seems
+      find any valid theoretical justification for this (other than it seems
       to help) */
-   frame_cost *= 720/rate;
    for (i=0;i<16;i++)
    {
       /* Impossible state */
@@ -610,7 +616,7 @@ static int transient_viterbi(const float *E, const float *E_1, int N, int frame_
    }
    for (i=0;i<4;i++)
    {
-      cost[0][1<<i] = frame_cost + rate*(1<<i)*transient_boost(E, E_1, i, N+1);
+      cost[0][1<<i] = (frame_cost + rate*(1<<i))*(1+factor*transient_boost(E, E_1, i, N+1));
       states[0][1<<i] = i;
    }
    for (i=1;i<N;i++)
@@ -641,7 +647,7 @@ static int transient_viterbi(const float *E, const float *E_1, int N, int frame_
                min_cost = tmp;
             }
          }
-         curr_cost = frame_cost+rate*(1<<j)*transient_boost(E+i, E_1+i, j, N-i+1);
+         curr_cost = (frame_cost + rate*(1<<j))*(1+factor*transient_boost(E+i, E_1+i, j, N-i+1));
          cost[i][1<<j] = min_cost;
          /* If part of the frame is outside the analysis window, only count part of the cost */
          if (N-i < (1<<j))
@@ -760,7 +766,7 @@ int optimize_framesize(const opus_val16 *x, int len, int C, opus_int32 Fs,
    e[i+pos] = e[i+pos-1];
    if (buffering)
       N=IMIN(MAX_DYNAMIC_FRAMESIZE, N+2);
-   bestLM = transient_viterbi(e, e_1, N, (1.f+.5*tonality)*(40*C+40), bitrate/400);
+   bestLM = transient_viterbi(e, e_1, N, (1.f+.5*tonality)*(60*C+40), bitrate/400);
    mem[0] = e[1<<bestLM];
    if (buffering)
    {
@@ -1548,7 +1554,7 @@ opus_int32 opus_encode_native(OpusEncoder *st, const opus_val16 *pcm, int frame_
 #ifndef FIXED_POINT
                 if (st->variable_duration==OPUS_FRAMESIZE_VARIABLE && frame_size != st->Fs/50)
                 {
-                   bonus = (40*st->stream_channels+40)*(st->Fs/frame_size-50);
+                   bonus = (60*st->stream_channels+40)*(st->Fs/frame_size-50);
                    if (analysis_info->valid)
                       bonus = bonus*(1.f+.5*analysis_info->tonality);
                 }
@@ -2159,6 +2165,7 @@ int opus_encoder_ctl(OpusEncoder *st, int request, ...)
         {
             opus_int32 value = va_arg(ap, opus_int32);
             st->variable_duration = value;
+            celt_encoder_ctl(celt_enc, OPUS_SET_EXPERT_FRAME_DURATION(value));
         }
         break;
         case OPUS_GET_EXPERT_FRAME_DURATION_REQUEST: