Merge branch 'surround'

celt/celt.h

@@ -106,6 +106,14 @@ typedef struct {
 #define CELT_SET_ANALYSIS_REQUEST    10022
 #define CELT_SET_ANALYSIS(x) CELT_SET_ANALYSIS_REQUEST, __celt_check_analysis_ptr(x)
 
+#define OPUS_SET_LFE_REQUEST    10024
+#define OPUS_SET_LFE(x) OPUS_SET_LFE_REQUEST, __opus_check_int(x)
+
+#define OPUS_SET_ENERGY_SAVE_REQUEST    10026
+#define OPUS_SET_ENERGY_SAVE(x) OPUS_SET_ENERGY_SAVE_REQUEST, __opus_check_val16_ptr(x)
+
+#define OPUS_SET_ENERGY_MASK_REQUEST    10028
+#define OPUS_SET_ENERGY_MASK(x) OPUS_SET_ENERGY_MASK_REQUEST, __opus_check_val16_ptr(x)
 
 /* Encoder stuff */
 

celt/celt_encoder.c

@@ -74,6 +74,7 @@ struct OpusCustomEncoder {
    int loss_rate;
    int lsb_depth;
    int variable_duration;
+   int lfe;
 
    /* Everything beyond this point gets cleared on a reset */
 #define ENCODER_RESET_START rng
@@ -108,6 +109,8 @@ struct OpusCustomEncoder {
    opus_val16 overlap_max;
    opus_val16 stereo_saving;
    int intensity;
+   opus_val16 *energy_save;
+   opus_val16 *energy_mask;
 
 #ifdef RESYNTH
    /* +MAX_PERIOD/2 to make space for overlap */
@@ -869,7 +872,7 @@ static int stereo_analysis(const CELTMode *m, const celt_norm *X,
 static opus_val16 dynalloc_analysis(const opus_val16 *bandLogE, const opus_val16 *bandLogE2,
       int nbEBands, int start, int end, int C, int *offsets, int lsb_depth, const opus_int16 *logN,
       int isTransient, int vbr, int constrained_vbr, const opus_int16 *eBands, int LM,
-      int effectiveBytes, opus_int32 *tot_boost_)
+      int effectiveBytes, opus_int32 *tot_boost_, int lfe)
 {
    int i, c;
    opus_int32 tot_boost=0;
@@ -897,7 +900,7 @@ static opus_val16 dynalloc_analysis(const opus_val16 *bandLogE, const opus_val16
          maxDepth = MAX16(maxDepth, bandLogE[c*nbEBands+i]-noise_floor[i]);
    } while (++c<C);
    /* Make sure that dynamic allocation can't make us bust the budget */
-   if (effectiveBytes > 50 && LM>=1)
+   if (effectiveBytes > 50 && LM>=1 && !lfe)
    {
       int last=0;
       c=0;do
@@ -1164,6 +1167,7 @@ int celt_encode_with_ec(CELTEncoder * OPUS_RESTRICT st, const opus_val16 * pcm,
    int secondMdct;
    int signalBandwidth;
    int transient_got_disabled=0;
+   opus_val16 surround_masking=0;
    ALLOC_STACK;
 
    mode = st->mode;
@@ -1327,7 +1331,7 @@ 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
+      enabled = (st->lfe || 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;
@@ -1356,7 +1360,7 @@ int celt_encode_with_ec(CELTEncoder * OPUS_RESTRICT st, const opus_val16 * pcm,
 
    isTransient = 0;
    shortBlocks = 0;
-   if (st->complexity >= 1)
+   if (st->complexity >= 1 && !st->lfe)
    {
       isTransient = transient_analysis(in, N+st->overlap, CC,
             &tf_estimate, &tf_chan);
@@ -1390,7 +1394,43 @@ int celt_encode_with_ec(CELTEncoder * OPUS_RESTRICT st, const opus_val16 * pcm,
       tf_chan = 0;
    compute_band_energies(mode, freq, bandE, effEnd, C, M);
 
+   if (st->lfe)
+   {
+      for (i=2;i<st->end;i++)
+         bandE[i] = IMIN(bandE[i], MULT16_32_Q15(QCONST16(1e-4f,15),bandE[0]));
+   }
    amp2Log2(mode, effEnd, st->end, bandE, bandLogE, C);
+   if (st->energy_save)
+   {
+      opus_val16 offset = shortBlocks?HALF16(SHL16(LM, DB_SHIFT)):0;
+#ifdef FIXED_POINT
+      /* Compensate for the 1/8 gain we apply in the fixed-point downshift to avoid overflows. */
+      offset -= QCONST16(3.0f, DB_SHIFT);
+#endif
+      for(i=0;i<C*nbEBands;i++)
+         st->energy_save[i]=bandLogE[i]-offset;
+      st->energy_save=NULL;
+   }
+   /* This computes how much masking takes place between surround channels */
+   if (st->energy_mask&&!st->lfe)
+   {
+      opus_val32 mask_avg=0;
+      opus_val16 offset = shortBlocks?HALF16(SHL16(LM, DB_SHIFT)):0;
+      for (c=0;c<C;c++)
+      {
+         opus_val16 followE, followMask;
+         followE = followMask = -QCONST16(14.f, DB_SHIFT);
+         for(i=0;i<st->end;i++)
+         {
+            /* We use a simple follower to approximate the masking spreading function. */
+            followE = MAX16(followE-QCONST16(1.f, DB_SHIFT), bandLogE[nbEBands*c+i]-offset);
+            followMask = MAX16(followMask-QCONST16(1.f, DB_SHIFT), st->energy_mask[nbEBands*c+i]);
+            mask_avg += followE-followMask;
+         }
+      }
+      surround_masking = DIV32_16(mask_avg,C*st->end) + QCONST16(.0f, DB_SHIFT);
+      surround_masking = MIN16(MAX16(surround_masking,-QCONST16(1.5f, DB_SHIFT)), 0);
+   }
    /*for (i=0;i<21;i++)
       printf("%f ", bandLogE[i]);
    printf("\n");*/
@@ -1403,7 +1443,7 @@ int celt_encode_with_ec(CELTEncoder * OPUS_RESTRICT st, const opus_val16 * pcm,
 
    /* Last chance to catch any transient we might have missed in the
       time-domain analysis */
-   if (LM>0 && ec_tell(enc)+3<=total_bits && !isTransient && st->complexity>=5)
+   if (LM>0 && ec_tell(enc)+3<=total_bits && !isTransient && st->complexity>=5 && !st->lfe)
    {
       if (patch_transient_decision(bandLogE, oldBandE, nbEBands, st->end, C))
       {
@@ -1429,7 +1469,7 @@ int celt_encode_with_ec(CELTEncoder * OPUS_RESTRICT st, const opus_val16 * pcm,
 
    ALLOC(tf_res, nbEBands, int);
    /* Disable variable tf resolution for hybrid and at very low bitrate */
-   if (effectiveBytes>=15*C && st->start==0 && st->complexity>=2)
+   if (effectiveBytes>=15*C && st->start==0 && st->complexity>=2 && !st->lfe)
    {
       int lambda;
       if (effectiveBytes<40)
@@ -1455,13 +1495,17 @@ int celt_encode_with_ec(CELTEncoder * OPUS_RESTRICT st, const opus_val16 * pcm,
    quant_coarse_energy(mode, st->start, st->end, effEnd, bandLogE,
          oldBandE, total_bits, error, enc,
          C, LM, nbAvailableBytes, st->force_intra,
-         &st->delayedIntra, st->complexity >= 4, st->loss_rate);
+         &st->delayedIntra, st->complexity >= 4, st->loss_rate, st->lfe);
 
    tf_encode(st->start, st->end, isTransient, tf_res, LM, tf_select, enc);
 
    if (ec_tell(enc)+4<=total_bits)
    {
-      if (shortBlocks || st->complexity < 3 || nbAvailableBytes < 10*C || st->start != 0)
+      if (st->lfe)
+      {
+         st->tapset_decision = 0;
+         st->spread_decision = SPREAD_NORMAL;
+      } else if (shortBlocks || st->complexity < 3 || nbAvailableBytes < 10*C || st->start != 0)
       {
          if (st->complexity == 0)
             st->spread_decision = SPREAD_NONE;
@@ -1494,7 +1538,10 @@ int celt_encode_with_ec(CELTEncoder * OPUS_RESTRICT st, const opus_val16 * pcm,
 
    maxDepth = dynalloc_analysis(bandLogE, bandLogE2, nbEBands, st->start, st->end, C, offsets,
          st->lsb_depth, mode->logN, isTransient, st->vbr, st->constrained_vbr,
-         eBands, LM, effectiveBytes, &tot_boost);
+         eBands, LM, effectiveBytes, &tot_boost, st->lfe);
+   /* For LFE, everything interesting is in the first band */
+   if (st->lfe)
+      offsets[0] = IMIN(8, effectiveBytes/3);
    ALLOC(cap, nbEBands, int);
    init_caps(mode,cap,LM,C);
 
@@ -1560,6 +1607,9 @@ int celt_encode_with_ec(CELTEncoder * OPUS_RESTRICT st, const opus_val16 * pcm,
    alloc_trim = 5;
    if (tell+(6<<BITRES) <= total_bits - total_boost)
    {
+      if (st->lfe)
+         alloc_trim = 5;
+      else
          alloc_trim = alloc_trim_analysis(mode, X, bandLogE,
             st->end, LM, C, N, &st->analysis, &st->stereo_saving, tf_estimate, st->intensity);
       ec_enc_icdf(enc, alloc_trim, trim_icdf, 7);
@@ -1609,7 +1659,7 @@ int celt_encode_with_ec(CELTEncoder * OPUS_RESTRICT st, const opus_val16 * pcm,
         max_frac = DIV32_16(MULT16_16(QCONST16(0.8f, 15), coded_stereo_dof), coded_bins);
         /*printf("%d %d %d ", coded_stereo_dof, coded_bins, tot_boost);*/
         target -= (opus_int32)MIN32(MULT16_32_Q15(max_frac,target),
-                        SHR16(MULT16_16(st->stereo_saving-QCONST16(0.1f,8),(coded_stereo_dof<<BITRES)),8));
+                        SHR32(MULT16_16(st->stereo_saving-QCONST16(0.1f,8),(coded_stereo_dof<<BITRES)),8));
      }
      /* Boost the rate according to dynalloc (minus the dynalloc average for calibration). */
      target += tot_boost-(16<<LM);
@@ -1633,6 +1683,13 @@ int celt_encode_with_ec(CELTEncoder * OPUS_RESTRICT st, const opus_val16 * pcm,
      }
 #endif
 
+     if (st->energy_mask&&!st->lfe)
+     {
+        opus_int32 surround_target = target + SHR32(MULT16_16(surround_masking,coded_bins<<BITRES), DB_SHIFT);
+        /*printf("%f %d %d %d %d %d %d ", surround_masking, coded_bins, st->end, st->intensity, surround_target, target, st->bitrate);*/
+        target = IMAX(target/4, surround_target);
+     }
+
      {
         opus_int32 floor_depth;
         int bins;
@@ -1644,7 +1701,7 @@ int celt_encode_with_ec(CELTEncoder * OPUS_RESTRICT st, const opus_val16 * pcm,
         /*printf("%f %d\n", maxDepth, floor_depth);*/
      }
 
-     if (st->constrained_vbr || st->bitrate<64000)
+     if ((!st->energy_mask||st->lfe) && (st->constrained_vbr || st->bitrate<64000))
      {
         opus_val16 rate_factor;
 #ifdef FIXED_POINT
@@ -1751,9 +1808,14 @@ int celt_encode_with_ec(CELTEncoder * OPUS_RESTRICT st, const opus_val16 * pcm,
       signalBandwidth = IMAX(st->analysis.bandwidth, min_bandwidth);
    }
 #endif
+   if (st->lfe)
+      signalBandwidth = 1;
    codedBands = compute_allocation(mode, st->start, st->end, offsets, cap,
          alloc_trim, &st->intensity, &dual_stereo, bits, &balance, pulses,
          fine_quant, fine_priority, C, LM, enc, 1, st->lastCodedBands, signalBandwidth);
+   if (st->lastCodedBands)
+      st->lastCodedBands = IMIN(st->lastCodedBands+1,IMAX(st->lastCodedBands-1,codedBands));
+   else
       st->lastCodedBands = codedBands;
 
    quant_fine_energy(mode, st->start, st->end, oldBandE, error, fine_quant, enc, C);
@@ -2140,6 +2202,24 @@ int opus_custom_encoder_ctl(CELTEncoder * OPUS_RESTRICT st, int request, ...)
          *value=st->rng;
       }
       break;
+      case OPUS_SET_LFE_REQUEST:
+      {
+          opus_int32 value = va_arg(ap, opus_int32);
+          st->lfe = value;
+      }
+      break;
+      case OPUS_SET_ENERGY_SAVE_REQUEST:
+      {
+          opus_val16 *value = va_arg(ap, opus_val16*);
+          st->energy_save=value;
+      }
+      break;
+      case OPUS_SET_ENERGY_MASK_REQUEST:
+      {
+          opus_val16 *value = va_arg(ap, opus_val16*);
+          st->energy_mask = value;
+      }
+      break;
       default:
          goto bad_request;
    }

celt/quant_bands.c

@@ -157,7 +157,7 @@ static int quant_coarse_energy_impl(const CELTMode *m, int start, int end,
       const opus_val16 *eBands, opus_val16 *oldEBands,
       opus_int32 budget, opus_int32 tell,
       const unsigned char *prob_model, opus_val16 *error, ec_enc *enc,
-      int C, int LM, int intra, opus_val16 max_decay)
+      int C, int LM, int intra, opus_val16 max_decay, int lfe)
 {
    int i, c;
    int badness = 0;
@@ -222,6 +222,8 @@ static int quant_coarse_energy_impl(const CELTMode *m, int start, int end,
             if (bits_left < 16)
                qi = IMAX(-1, qi);
          }
+         if (lfe && i>=2)
+            qi = IMIN(qi, 0);
          if (budget-tell >= 15)
          {
             int pi;
@@ -253,13 +255,13 @@ static int quant_coarse_energy_impl(const CELTMode *m, int start, int end,
          prev[c] = prev[c] + SHL32(q,7) - MULT16_16(beta,PSHR32(q,8));
       } while (++c < C);
    }
-   return badness;
+   return lfe ? 0 : badness;
 }
 
 void quant_coarse_energy(const CELTMode *m, int start, int end, int effEnd,
       const opus_val16 *eBands, opus_val16 *oldEBands, opus_uint32 budget,
       opus_val16 *error, ec_enc *enc, int C, int LM, int nbAvailableBytes,
-      int force_intra, opus_val32 *delayedIntra, int two_pass, int loss_rate)
+      int force_intra, opus_val32 *delayedIntra, int two_pass, int loss_rate, int lfe)
 {
    int intra;
    opus_val16 max_decay;
@@ -289,6 +291,8 @@ void quant_coarse_energy(const CELTMode *m, int start, int end, int effEnd,
       max_decay = MIN32(max_decay, .125f*nbAvailableBytes);
 #endif
    }
+   if (lfe)
+      max_decay=3;
    enc_start_state = *enc;
 
    ALLOC(oldEBands_intra, C*m->nbEBands, opus_val16);
@@ -298,7 +302,7 @@ void quant_coarse_energy(const CELTMode *m, int start, int end, int effEnd,
    if (two_pass || intra)
    {
       badness1 = quant_coarse_energy_impl(m, start, end, eBands, oldEBands_intra, budget,
-            tell, e_prob_model[LM][1], error_intra, enc, C, LM, 1, max_decay);
+            tell, e_prob_model[LM][1], error_intra, enc, C, LM, 1, max_decay, lfe);
    }
 
    if (!intra)
@@ -325,7 +329,7 @@ void quant_coarse_energy(const CELTMode *m, int start, int end, int effEnd,
       *enc = enc_start_state;
 
       badness2 = quant_coarse_energy_impl(m, start, end, eBands, oldEBands, budget,
-            tell, e_prob_model[LM][intra], error, enc, C, LM, 0, max_decay);
+            tell, e_prob_model[LM][intra], error, enc, C, LM, 0, max_decay, lfe);
 
       if (two_pass && (badness1 < badness2 || (badness1 == badness2 && ((opus_int32)ec_tell_frac(enc))+intra_bias > tell_intra)))
       {

celt/quant_bands.h

@@ -51,7 +51,7 @@ void quant_coarse_energy(const CELTMode *m, int start, int end, int effEnd,
       const opus_val16 *eBands, opus_val16 *oldEBands, opus_uint32 budget,
       opus_val16 *error, ec_enc *enc, int C, int LM,
       int nbAvailableBytes, int force_intra, opus_val32 *delayedIntra,
-      int two_pass, int loss_rate);
+      int two_pass, int loss_rate, int lfe);
 
 void quant_fine_energy(const CELTMode *m, int start, int end, opus_val16 *oldEBands, opus_val16 *error, int *fine_quant, ec_enc *enc, int C);
 

include/opus_defines.h

@@ -158,6 +158,7 @@ extern "C" {
 #define __opus_check_int(x) (((void)((x) == (opus_int32)0)), (opus_int32)(x))
 #define __opus_check_int_ptr(ptr) ((ptr) + ((ptr) - (opus_int32*)(ptr)))
 #define __opus_check_uint_ptr(ptr) ((ptr) + ((ptr) - (opus_uint32*)(ptr)))
+#define __opus_check_val16_ptr(ptr) ((ptr) + ((ptr) - (opus_val16*)(ptr)))
 /** @endcond */
 
 /** @defgroup opus_ctlvalues Pre-defined values for CTL interface

include/opus_multistream.h

@@ -205,6 +205,12 @@ OPUS_EXPORT OPUS_WARN_UNUSED_RESULT opus_int32 opus_multistream_encoder_get_size
       int coupled_streams
 );
 
+OPUS_EXPORT OPUS_WARN_UNUSED_RESULT opus_int32 opus_multistream_surround_encoder_get_size(
+      int channels,
+      int mapping_family
+);
+
+
 /** Allocates and initializes a multistream encoder state.
   * Call opus_multistream_encoder_destroy() to release
   * this object when finished.
@@ -258,6 +264,17 @@ OPUS_EXPORT OPUS_WARN_UNUSED_RESULT OpusMSEncoder *opus_multistream_encoder_crea
       int *error
 ) OPUS_ARG_NONNULL(5);
 
+OPUS_EXPORT OPUS_WARN_UNUSED_RESULT OpusMSEncoder *opus_multistream_surround_encoder_create(
+      opus_int32 Fs,
+      int channels,
+      int mapping_family,
+      int *streams,
+      int *coupled_streams,
+      unsigned char *mapping,
+      int application,
+      int *error
+) OPUS_ARG_NONNULL(5);
+
 /** Initialize a previously allocated multistream encoder state.
   * The memory pointed to by \a st must be at least the size returned by
   * opus_multistream_encoder_get_size().
@@ -316,6 +333,17 @@ OPUS_EXPORT int opus_multistream_encoder_init(
       int application
 ) OPUS_ARG_NONNULL(1) OPUS_ARG_NONNULL(6);
 
+OPUS_EXPORT int opus_multistream_surround_encoder_init(
+      OpusMSEncoder *st,
+      opus_int32 Fs,
+      int channels,
+      int mapping_family,
+      int *streams,
+      int *coupled_streams,
+      unsigned char *mapping,
+      int application
+) OPUS_ARG_NONNULL(1) OPUS_ARG_NONNULL(6);
+
 /** Encodes a multistream Opus frame.
   * @param st <tt>OpusMSEncoder*</tt>: Multistream encoder state.
   * @param[in] pcm <tt>const opus_int16*</tt>: The input signal as interleaved

src/opus_encoder.c

@@ -78,6 +78,7 @@ struct OpusEncoder {
     opus_int32   user_bitrate_bps;
     int          lsb_depth;
     int          encoder_buffer;
+    int          lfe;
 
 #define OPUS_ENCODER_RESET_START stream_channels
     int          stream_channels;
@@ -93,6 +94,7 @@ struct OpusEncoder {
     int          silk_bw_switch;
     /* Sampling rate (at the API level) */
     int          first;
+    int          energy_masking;
     StereoWidthState width_mem;
     opus_val16   delay_buffer[MAX_ENCODER_BUFFER*2];
 #ifndef FIXED_POINT
@@ -1258,6 +1260,11 @@ opus_int32 opus_encode_native(OpusEncoder *st, const opus_val16 *pcm, int frame_
     /* CELT mode doesn't support mediumband, use wideband instead */
     if (st->mode == MODE_CELT_ONLY && st->bandwidth == OPUS_BANDWIDTH_MEDIUMBAND)
         st->bandwidth = OPUS_BANDWIDTH_WIDEBAND;
+    if (st->lfe)
+    {
+       st->bandwidth = OPUS_BANDWIDTH_NARROWBAND;
+       st->mode = MODE_CELT_ONLY;
+    }
 
     /* Can't support higher than wideband for >20 ms frames */
     if (frame_size > st->Fs/50 && (st->mode == MODE_CELT_ONLY || st->bandwidth > OPUS_BANDWIDTH_WIDEBAND))
@@ -1621,7 +1628,7 @@ opus_int32 opus_encode_native(OpusEncoder *st, const opus_val16 *pcm, int frame_
     st->prev_HB_gain = HB_gain;
     if (st->mode != MODE_HYBRID || st->stream_channels==1)
        st->silk_mode.stereoWidth_Q14 = IMIN((1<<14),IMAX(0,st->bitrate_bps-32000));
-    if( st->channels == 2 ) {
+    if( !st->energy_masking && st->channels == 2 ) {
         /* Apply stereo width reduction (at low bitrates) */
         if( st->hybrid_stereo_width_Q14 < (1 << 14) || st->silk_mode.stereoWidth_Q14 < (1 << 14) ) {
             opus_val16 g1, g2;
@@ -2228,6 +2235,26 @@ int opus_encoder_ctl(OpusEncoder *st, int request, ...)
             st->user_forced_mode = value;
         }
         break;
+        case OPUS_SET_LFE_REQUEST:
+        {
+            opus_int32 value = va_arg(ap, opus_int32);
+            st->lfe = value;
+            celt_encoder_ctl(celt_enc, OPUS_SET_LFE(value));
+        }
+        break;
+        case OPUS_SET_ENERGY_SAVE_REQUEST:
+        {
+            opus_val16 *value = va_arg(ap, opus_val16*);
+            celt_encoder_ctl(celt_enc, OPUS_SET_ENERGY_SAVE(value));
+        }
+        break;
+        case OPUS_SET_ENERGY_MASK_REQUEST:
+        {
+            opus_val16 *value = va_arg(ap, opus_val16*);
+            st->energy_masking = (value!=NULL);
+            celt_encoder_ctl(celt_enc, OPUS_SET_ENERGY_MASK(value));
+        }
+        break;
 
         case CELT_GET_MODE_REQUEST:
         {

src/opus_multistream_encoder.c

@@ -38,10 +38,30 @@
 #include "os_support.h"
 #include "analysis.h"
 
+typedef struct {
+   int nb_streams;
+   int nb_coupled_streams;
+   unsigned char mapping[8];
+} VorbisLayout;
+
+/* Index is nb_channel-1*/
+static const VorbisLayout vorbis_mappings[8] = {
+      {1, 0, {0}},                      /* 1: mono */
+      {1, 1, {0, 1}},                   /* 2: stereo */
+      {2, 1, {0, 2, 1}},                /* 3: 1-d surround */
+      {2, 2, {0, 1, 2, 3}},             /* 4: quadraphonic surround */
+      {3, 2, {0, 4, 1, 2, 3}},          /* 5: 5-channel surround */
+      {4, 2, {0, 4, 1, 2, 3, 5}},       /* 6: 5.1 surround */
+      {4, 3, {0, 4, 1, 2, 3, 5, 6}},    /* 7: 6.1 surround */
+      {5, 3, {0, 6, 1, 2, 3, 4, 5, 7}}, /* 8: 7.1 surround */
+};
+
 struct OpusMSEncoder {
    TonalityAnalysisState analysis;
    ChannelLayout layout;
+   int lfe_stream;
    int variable_duration;
+   int surround;
    opus_int32 bitrate_bps;
    opus_val32 subframe_mem[3];
    /* Encoder states go here */
@@ -81,16 +101,50 @@ opus_int32 opus_multistream_encoder_get_size(int nb_streams, int nb_coupled_stre
         + (nb_streams-nb_coupled_streams) * align(mono_size);
 }
 
+opus_int32 opus_multistream_surround_encoder_get_size(int channels, int mapping_family)
+{
+   int nb_streams;
+   int nb_coupled_streams;
+   opus_int32 size;
+
+   if (mapping_family==0)
+   {
+      if (channels==1)
+      {
+         nb_streams=1;
+         nb_coupled_streams=0;
+      } else if (channels==2)
+      {
+         nb_streams=1;
+         nb_coupled_streams=1;
+      } else
+         return 0;
+   } else if (mapping_family==1 && channels<=8 && channels>=1)
+   {
+      nb_streams=vorbis_mappings[channels-1].nb_streams;
+      nb_coupled_streams=vorbis_mappings[channels-1].nb_coupled_streams;
+   } else if (mapping_family==255)
+   {
+      nb_streams=channels;
+      nb_coupled_streams=0;
+   } else
+      return 0;
+   size = opus_multistream_encoder_get_size(nb_streams, nb_coupled_streams);
+   if (channels>2)
+      size += align(opus_encoder_get_size(2));
+   return size;
+}
 
 
-int opus_multistream_encoder_init(
+static int opus_multistream_encoder_init_impl(
       OpusMSEncoder *st,
       opus_int32 Fs,
       int channels,
       int streams,
       int coupled_streams,
       const unsigned char *mapping,
-      int application
+      int application,
+      int surround
 )
 {
    int coupled_size;
@@ -107,7 +161,8 @@ int opus_multistream_encoder_init(
    st->layout.nb_coupled_streams = coupled_streams;
    st->subframe_mem[0]=st->subframe_mem[1]=st->subframe_mem[2]=0;
    OPUS_CLEAR(&st->analysis,1);
-
+   if (!surround)
+      st->lfe_stream = -1;
    st->bitrate_bps = OPUS_AUTO;
    st->variable_duration = OPUS_FRAMESIZE_ARG;
    for (i=0;i<st->layout.nb_channels;i++)
@@ -122,14 +177,88 @@ int opus_multistream_encoder_init(
    {
       ret = opus_encoder_init((OpusEncoder*)ptr, Fs, 2, application);
       if(ret!=OPUS_OK)return ret;
+      if (i==st->lfe_stream)
+         opus_encoder_ctl((OpusEncoder*)ptr, OPUS_SET_LFE(1));
       ptr += align(coupled_size);
    }
    for (;i<st->layout.nb_streams;i++)
    {
       ret = opus_encoder_init((OpusEncoder*)ptr, Fs, 1, application);
+      if (i==st->lfe_stream)
+         opus_encoder_ctl((OpusEncoder*)ptr, OPUS_SET_LFE(1));
       if(ret!=OPUS_OK)return ret;
       ptr += align(mono_size);
    }
+   if (surround && st->layout.nb_channels>2)
+   {
+      OpusEncoder *downmix_enc;
+      downmix_enc = (OpusEncoder*)ptr;
+      ret = opus_encoder_init(downmix_enc, Fs, 2, OPUS_APPLICATION_AUDIO);
+      if(ret!=OPUS_OK)return ret;
+   }
+   st->surround = surround;
+   return OPUS_OK;
+}
+
+int opus_multistream_encoder_init(
+      OpusMSEncoder *st,
+      opus_int32 Fs,
+      int channels,
+      int streams,
+      int coupled_streams,
+      const unsigned char *mapping,
+      int application
+)
+{
+   return opus_multistream_encoder_init_impl(st, Fs, channels, streams, coupled_streams, mapping, application, 0);
+}
+
+int opus_multistream_surround_encoder_init(
+      OpusMSEncoder *st,
+      opus_int32 Fs,
+      int channels,
+      int mapping_family,
+      int *streams,
+      int *coupled_streams,
+      unsigned char *mapping,
+      int application
+)
+{
+   st->lfe_stream = -1;
+   if (mapping_family==0)
+   {
+      if (channels==1)
+      {
+         *streams=1;
+         *coupled_streams=0;
+         mapping[0]=0;
+      } else if (channels==2)
+      {
+         *streams=1;
+         *coupled_streams=1;
+         mapping[0]=0;
+         mapping[1]=1;
+      } else
+         return OPUS_UNIMPLEMENTED;
+   } else if (mapping_family==1 && channels<=8 && channels>=1)
+   {
+      int i;
+      *streams=vorbis_mappings[channels-1].nb_streams;
+      *coupled_streams=vorbis_mappings[channels-1].nb_coupled_streams;
+      for (i=0;i<channels;i++)
+         mapping[i] = vorbis_mappings[channels-1].mapping[i];
+      if (channels>=6)
+         st->lfe_stream = *streams-1;
+   } else if (mapping_family==255)
+   {
+      int i;
+      *streams=channels;
+      *coupled_streams=0;
+      for(i=0;i<channels;i++)
+         mapping[i] = i;
+   } else
+      return OPUS_UNIMPLEMENTED;
+   opus_multistream_encoder_init_impl(st, Fs, channels, *streams, *coupled_streams, mapping, application, 1);
    return OPUS_OK;
 }
 
@@ -170,6 +299,43 @@ OpusMSEncoder *opus_multistream_encoder_create(
    return st;
 }
 
+OpusMSEncoder *opus_multistream_surround_encoder_create(
+      opus_int32 Fs,
+      int channels,
+      int mapping_family,
+      int *streams,
+      int *coupled_streams,
+      unsigned char *mapping,
+      int application,
+      int *error
+)
+{
+   int ret;
+   OpusMSEncoder *st;
+   if ((channels>255) || (channels<1))
+   {
+      if (error)
+         *error = OPUS_BAD_ARG;
+      return NULL;
+   }
+   st = (OpusMSEncoder *)opus_alloc(opus_multistream_surround_encoder_get_size(channels, mapping_family));
+   if (st==NULL)
+   {
+      if (error)
+         *error = OPUS_ALLOC_FAIL;
+      return NULL;
+   }
+   ret = opus_multistream_surround_encoder_init(st, Fs, channels, mapping_family, streams, coupled_streams, mapping, application);
+   if (ret != OPUS_OK)
+   {
+      opus_free(st);
+      st = NULL;
+   }
+   if (error)
+      *error = ret;
+   return st;
+}
+
 typedef void (*opus_copy_channel_in_func)(
   opus_val16 *dst,
   int dst_stride,
@@ -179,6 +345,81 @@ typedef void (*opus_copy_channel_in_func)(
   int frame_size
 );
 
+typedef void (*opus_surround_downmix_funct)(
+  opus_val16 *dst,
+  const void *src,
+  int channels,
+  int frame_size
+);
+
+static void surround_rate_allocation(
+      OpusMSEncoder *st,
+      opus_int32 *rate,
+      int frame_size
+      )
+{
+   int i;
+   opus_int32 channel_rate;
+   opus_int32 Fs;
+   char *ptr;
+   int stream_offset;
+   int lfe_offset;
+   int coupled_ratio; /* Q8 */
+   int lfe_ratio;     /* Q8 */
+
+   ptr = (char*)st + align(sizeof(OpusMSEncoder));
+   opus_encoder_ctl((OpusEncoder*)ptr, OPUS_GET_SAMPLE_RATE(&Fs));
+
+   /* We start by giving each stream (coupled or uncoupled) the same bitrate.
+      This models the main saving of coupled channels over uncoupled. */
+   stream_offset = 20000;
+   /* The LFE stream is an exception to the above and gets fewer bits. */
+   lfe_offset = 3500;
+   /* Coupled streams get twice the mono rate after the first 20 kb/s. */
+   coupled_ratio = 512;
+   /* Should depend on the bitrate, for now we assume LFE gets 1/8 the bits of mono */
+   lfe_ratio = 32;
+
+   /* Compute bitrate allocation between streams */
+   if (st->bitrate_bps==OPUS_AUTO)
+   {
+      channel_rate = Fs+60*Fs/frame_size;
+   } else if (st->bitrate_bps==OPUS_BITRATE_MAX)
+   {
+      channel_rate = 300000;
+   } else {
+      int nb_lfe;
+      int nb_uncoupled;
+      int nb_coupled;
+      int total;
+      nb_lfe = (st->lfe_stream!=-1);
+      nb_coupled = st->layout.nb_coupled_streams;
+      nb_uncoupled = st->layout.nb_streams-nb_coupled-nb_lfe;
+      total = (nb_uncoupled<<8)         /* mono */
+            + coupled_ratio*nb_coupled /* stereo */
+            + nb_lfe*lfe_ratio;
+      channel_rate = 256*(st->bitrate_bps-lfe_offset*nb_lfe-stream_offset*(nb_coupled+nb_uncoupled))/total;
+   }
+#ifndef FIXED_POINT
+   if (st->variable_duration==OPUS_FRAMESIZE_VARIABLE && frame_size != Fs/50)
+   {
+      opus_int32 bonus;
+      bonus = 60*(Fs/frame_size-50);
+      channel_rate += bonus;
+   }
+#endif
+
+   for (i=0;i<st->layout.nb_streams;i++)
+   {
+      if (i<st->layout.nb_coupled_streams)
+         rate[i] = stream_offset+(channel_rate*coupled_ratio>>8);
+      else if (i!=st->lfe_stream)
+         rate[i] = stream_offset+channel_rate;
+      else
+         rate[i] = lfe_offset+(channel_rate*lfe_ratio>>8);
+   }
+}
+
 /* Max size in case the encoder decides to return three frames */
 #define MS_FRAME_TMP (3*1275+7)
 static int opus_multistream_encode_native
@@ -189,7 +430,8 @@ static int opus_multistream_encode_native
     int frame_size,
     unsigned char *data,
     opus_int32 max_data_bytes,
-    int lsb_depth
+    int lsb_depth,
+    opus_surround_downmix_funct surround_downmix
 #ifndef FIXED_POINT
     , downmix_func downmix
     , const void *pcm_analysis
@@ -205,12 +447,12 @@ static int opus_multistream_encode_native
    VARDECL(opus_val16, buf);
    unsigned char tmp_data[MS_FRAME_TMP];
    OpusRepacketizer rp;
-   int orig_frame_size;
-   int coded_channels;
-   opus_int32 channel_rate;
    opus_int32 complexity;
    AnalysisInfo analysis_info;
    const CELTMode *celt_mode;
+   opus_int32 bitrates[256];
+   opus_val16 bandLogE[42];
+   opus_val16 bandLogE_mono[21];
    ALLOC_STACK;
 
    ptr = (char*)st + align(sizeof(OpusMSEncoder));
@@ -223,7 +465,6 @@ static int opus_multistream_encode_native
       RESTORE_STACK;
       return OPUS_BAD_ARG;
    }
-   orig_frame_size = IMIN(frame_size,Fs/50);
 #ifndef FIXED_POINT
    analysis_info.valid = 0;
    if (complexity >= 7 && Fs==48000)
@@ -255,6 +496,36 @@ static int opus_multistream_encode_native
    coupled_size = opus_encoder_get_size(2);
    mono_size = opus_encoder_get_size(1);
 
+   if (st->surround && st->layout.nb_channels>2)
+   {
+      int i;
+      unsigned char dummy[512];
+      /* Temporary kludge -- remove */
+      OpusEncoder *downmix_enc;
+
+      ptr = (char*)st + align(sizeof(OpusMSEncoder));
+      for (s=0;s<st->layout.nb_streams;s++)
+      {
+         if (s < st->layout.nb_coupled_streams)
+            ptr += align(coupled_size);
+         else
+            ptr += align(mono_size);
+      }
+      downmix_enc = (OpusEncoder*)ptr;
+      surround_downmix(buf, pcm, st->layout.nb_channels, frame_size);
+      opus_encoder_ctl(downmix_enc, OPUS_SET_ENERGY_SAVE(bandLogE));
+      opus_encoder_ctl(downmix_enc, OPUS_SET_BANDWIDTH(OPUS_BANDWIDTH_FULLBAND));
+      opus_encoder_ctl(downmix_enc, OPUS_SET_FORCE_MODE(MODE_CELT_ONLY));
+      opus_encoder_ctl(downmix_enc, OPUS_SET_FORCE_CHANNELS(2));
+      opus_encode_native(downmix_enc, buf, frame_size, dummy, 512, lsb_depth
+#ifndef FIXED_POINT
+            , &analysis_info
+#endif
+            );
+      for(i=0;i<21;i++)
+         bandLogE_mono[i] = MAX16(bandLogE[i], bandLogE[21+i]);
+   }
+
    if (max_data_bytes < 4*st->layout.nb_streams-1)
    {
       RESTORE_STACK;
@@ -262,24 +533,8 @@ static int opus_multistream_encode_native
    }
 
    /* Compute bitrate allocation between streams (this could be a lot better) */
-   coded_channels = st->layout.nb_streams + st->layout.nb_coupled_streams;
+   surround_rate_allocation(st, bitrates, frame_size);
-   if (st->bitrate_bps==OPUS_AUTO)
+
-   {
-      channel_rate = Fs+60*Fs/orig_frame_size;
-   } else if (st->bitrate_bps==OPUS_BITRATE_MAX)
-   {
-      channel_rate = 300000;
-   } else {
-      channel_rate = st->bitrate_bps/coded_channels;
-   }
-#ifndef FIXED_POINT
-   if (st->variable_duration==OPUS_FRAMESIZE_VARIABLE && frame_size != Fs/50)
-   {
-      opus_int32 bonus;
-      bonus = 60*(Fs/frame_size-50);
-      channel_rate += bonus;
-   }
-#endif
    ptr = (char*)st + align(sizeof(OpusMSEncoder));
    for (s=0;s<st->layout.nb_streams;s++)
    {
@@ -289,7 +544,14 @@ static int opus_multistream_encode_native
          ptr += align(coupled_size);
       else
          ptr += align(mono_size);
-      opus_encoder_ctl(enc, OPUS_SET_BITRATE(channel_rate * (s < st->layout.nb_coupled_streams ? 2 : 1)));
+      opus_encoder_ctl(enc, OPUS_SET_BITRATE(bitrates[s]));
+      if (st->surround)
+      {
+         opus_encoder_ctl(enc, OPUS_SET_FORCE_MODE(MODE_CELT_ONLY));
+         opus_encoder_ctl(enc, OPUS_SET_BANDWIDTH(OPUS_BANDWIDTH_FULLBAND));
+         if (s < st->layout.nb_coupled_streams)
+            opus_encoder_ctl(enc, OPUS_SET_FORCE_CHANNELS(2));
+      }
    }
 
    ptr = (char*)st + align(sizeof(OpusMSEncoder));
@@ -313,11 +575,17 @@ static int opus_multistream_encode_native
          (*copy_channel_in)(buf+1, 2,
             pcm, st->layout.nb_channels, right, frame_size);
          ptr += align(coupled_size);
+         /* FIXME: This isn't correct for the coupled center channels in
+            6.1 surround configuration */
+         if (st->surround)
+            opus_encoder_ctl(enc, OPUS_SET_ENERGY_MASK(bandLogE));
       } else {
          int chan = get_mono_channel(&st->layout, s, -1);
          (*copy_channel_in)(buf, 1,
             pcm, st->layout.nb_channels, chan, frame_size);
          ptr += align(mono_size);
+         if (st->surround)
+            opus_encoder_ctl(enc, OPUS_SET_ENERGY_MASK(bandLogE_mono));
       }
       /* number of bytes left (+Toc) */
       curr_max = max_data_bytes - tot_size;
@@ -367,6 +635,85 @@ static void opus_copy_channel_in_float(
       dst[i*dst_stride] = float_src[i*src_stride+src_channel];
 #endif
 }
+
+static void channel_pos(int channels, int pos[8])
+{
+   /* Position in the mix: 0 don't mix, 1: left, 2: center, 3:right */
+   if (channels==4)
+   {
+      pos[0]=1;
+      pos[1]=3;
+      pos[2]=1;
+      pos[3]=3;
+   } else if (channels==3||channels==5||channels==6)
+   {
+      pos[0]=1;
+      pos[1]=2;
+      pos[2]=3;
+      pos[3]=1;
+      pos[4]=3;
+      pos[5]=0;
+   } else if (channels==7)
+   {
+      pos[0]=1;
+      pos[1]=2;
+      pos[2]=3;
+      pos[3]=1;
+      pos[4]=3;
+      pos[5]=2;
+      pos[6]=0;
+   } else if (channels==8)
+   {
+      pos[0]=1;
+      pos[1]=2;
+      pos[2]=3;
+      pos[3]=1;
+      pos[4]=3;
+      pos[5]=1;
+      pos[6]=3;
+      pos[7]=0;
+   }
+}
+
+static void opus_surround_downmix_float(
+  opus_val16 *dst,
+  const void *src,
+  int channels,
+  int frame_size
+)
+{
+   const float *float_src;
+   opus_int32 i;
+   int pos[8] = {0};
+   int c;
+   float_src = (const float *)src;
+
+   channel_pos(channels, pos);
+   for (i=0;i<2*frame_size;i++)
+      dst[i]=0;
+
+   for (c=0;c<channels;c++)
+   {
+      if (pos[c]==1||pos[c]==2)
+      {
+         for (i=0;i<frame_size;i++)
+#if defined(FIXED_POINT)
+            dst[2*i] += SHR16(FLOAT2INT16(float_src[i*channels+c]),3);
+#else
+            dst[2*i] += float_src[i*channels+c];
+#endif
+      }
+      if (pos[c]==2||pos[c]==3)
+      {
+         for (i=0;i<frame_size;i++)
+#if defined(FIXED_POINT)
+            dst[2*i+1] += SHR16(FLOAT2INT16(float_src[i*channels+c]),3);
+#else
+            dst[2*i+1] += float_src[i*channels+c];
+#endif
+      }
+   }
+}
 #endif
 
 static void opus_copy_channel_in_short(
@@ -389,6 +736,47 @@ static void opus_copy_channel_in_short(
 #endif
 }
 
+static void opus_surround_downmix_short(
+  opus_val16 *dst,
+  const void *src,
+  int channels,
+  int frame_size
+)
+{
+   const opus_int16 *short_src;
+   opus_int32 i;
+   int pos[8] = {0};
+   int c;
+   short_src = (const opus_int16 *)src;
+
+   channel_pos(channels, pos);
+   for (i=0;i<2*frame_size;i++)
+      dst[i]=0;
+
+   for (c=0;c<channels;c++)
+   {
+      if (pos[c]==1||pos[c]==2)
+      {
+         for (i=0;i<frame_size;i++)
+#if defined(FIXED_POINT)
+            dst[2*i] += SHR16(short_src[i*channels+c],3);
+#else
+            dst[2*i] += (1/32768.f)*short_src[i*channels+c];
+#endif
+      }
+      if (pos[c]==2||pos[c]==3)
+      {
+         for (i=0;i<frame_size;i++)
+#if defined(FIXED_POINT)
+            dst[2*i+1] += SHR16(short_src[i*channels+c],3);
+#else
+            dst[2*i+1] += (1/32768.f)*short_src[i*channels+c];
+#endif
+      }
+   }
+}
+
+
 #ifdef FIXED_POINT
 int opus_multistream_encode(
     OpusMSEncoder *st,
@@ -399,7 +787,7 @@ int opus_multistream_encode(
 )
 {
    return opus_multistream_encode_native(st, opus_copy_channel_in_short,
-      pcm, frame_size, data, max_data_bytes, 16);
+      pcm, frame_size, data, max_data_bytes, 16, opus_surround_downmix_float);
 }
 
 #ifndef DISABLE_FLOAT_API
@@ -412,7 +800,7 @@ int opus_multistream_encode_float(
 )
 {
    return opus_multistream_encode_native(st, opus_copy_channel_in_float,
-      pcm, frame_size, data, max_data_bytes, 16);
+      pcm, frame_size, data, max_data_bytes, 16, opus_surround_downmix_short);
 }
 #endif
 
@@ -429,7 +817,7 @@ int opus_multistream_encode_float
 {
    int channels = st->layout.nb_streams + st->layout.nb_coupled_streams;
    return opus_multistream_encode_native(st, opus_copy_channel_in_float,
-      pcm, frame_size, data, max_data_bytes, 24, downmix_float, pcm+channels*st->analysis.analysis_offset);
+      pcm, frame_size, data, max_data_bytes, 24, opus_surround_downmix_float, downmix_float, pcm+channels*st->analysis.analysis_offset);
 }
 
 int opus_multistream_encode(
@@ -442,7 +830,7 @@ int opus_multistream_encode(
 {
    int channels = st->layout.nb_streams + st->layout.nb_coupled_streams;
    return opus_multistream_encode_native(st, opus_copy_channel_in_short,
-      pcm, frame_size, data, max_data_bytes, 16, downmix_int, pcm+channels*st->analysis.analysis_offset);
+      pcm, frame_size, data, max_data_bytes, 16, opus_surround_downmix_short, downmix_int, pcm+channels*st->analysis.analysis_offset);
 }
 #endif