opus_pvq: merge band encoding and decoding into one function

Most code between the 2 functions was duplicated which made keeping
both in sync difficult.

This also fixes some discovered issues with encoding (incorrect
TF switching buffers) and reduces stack usage (reuse the already
allocated CeltFrame->scratch buffer for the quantized coefficients).

Signed-off-by: Rostislav Pehlivanov <atomnuker@gmail.com>

1 files changed, 112 insertions, 411 deletions

diff --git a/libavcodec/opus_pvq.c b/libavcodec/opus_pvq.c
index d1091677ad..3109e70f17 100644
--- a/libavcodec/opus_pvq.c
+++ b/libavcodec/opus_pvq.c
@@ -412,9 +412,10 @@ static int celt_pvq_search(float *X, int *y, int K, int N)
 }
 
 static uint32_t celt_alg_quant(OpusRangeCoder *rc, float *X, uint32_t N, uint32_t K,
-                               enum CeltSpread spread, uint32_t blocks, float gain)
+                               enum CeltSpread spread, uint32_t blocks, float gain,
+                               void *scratch)
 {
-    int y[176];
+    int *y = scratch;
 
     celt_exp_rotation(X, N, blocks, K, spread, 1);
     gain /= sqrtf(celt_pvq_search(X, y, K, N));
@@ -427,9 +428,10 @@ static uint32_t celt_alg_quant(OpusRangeCoder *rc, float *X, uint32_t N, uint32_
 /** Decode pulse vector and combine the result with the pitch vector to produce
     the final normalised signal in the current band. */
 static uint32_t celt_alg_unquant(OpusRangeCoder *rc, float *X, uint32_t N, uint32_t K,
-                                 enum CeltSpread spread, uint32_t blocks, float gain)
+                                 enum CeltSpread spread, uint32_t blocks, float gain,
+                                 void *scratch)
 {
-    int y[176];
+    int *y = scratch;
 
     gain /= sqrtf(celt_decode_pulses(rc, y, N, K));
     celt_normalize_residual(y, X, N, gain);
@@ -437,354 +439,6 @@ static uint32_t celt_alg_unquant(OpusRangeCoder *rc, float *X, uint32_t N, uint3
     return celt_extract_collapse_mask(y, N, blocks);
 }
 
-uint32_t ff_celt_decode_band(CeltFrame *f, OpusRangeCoder *rc, const int band,
-                             float *X, float *Y, int N, int b, uint32_t blocks,
-                             float *lowband, int duration, float *lowband_out, int level,
-                             float gain, float *lowband_scratch, int fill)
-{
-    int i;
-    const uint8_t *cache;
-    int stereo = !!Y, split = !!Y;
-    int imid = 0, iside = 0;
-    uint32_t N0 = N;
-    int N_B = N / blocks;
-    int N_B0 = N_B;
-    int B0 = blocks;
-    int time_divide = 0;
-    int recombine = 0;
-    int inv = 0;
-    float mid = 0, side = 0;
-    int longblocks = (B0 == 1);
-    uint32_t cm = 0;
-
-    if (N == 1) {
-        /* special case for one sample */
-        float *x = X;
-        for (i = 0; i <= stereo; i++) {
-            int sign = 0;
-            if (f->remaining2 >= 1<<3) {
-                sign           = ff_opus_rc_get_raw(rc, 1);
-                f->remaining2 -= 1 << 3;
-                b             -= 1 << 3;
-            }
-            x[0] = sign ? -1.0f : 1.0f;
-            x = Y;
-        }
-        if (lowband_out)
-            lowband_out[0] = X[0];
-        return 1;
-    }
-
-    if (!stereo && level == 0) {
-        int tf_change = f->tf_change[band];
-        int k;
-        if (tf_change > 0)
-            recombine = tf_change;
-        /* Band recombining to increase frequency resolution */
-
-        if (lowband &&
-            (recombine || ((N_B & 1) == 0 && tf_change < 0) || B0 > 1)) {
-            for (i = 0; i < N; i++)
-                lowband_scratch[i] = lowband[i];
-            lowband = lowband_scratch;
-        }
-
-        for (k = 0; k < recombine; k++) {
-            if (lowband)
-                celt_haar1(lowband, N >> k, 1 << k);
-            fill = ff_celt_bit_interleave[fill & 0xF] | ff_celt_bit_interleave[fill >> 4] << 2;
-        }
-        blocks >>= recombine;
-        N_B <<= recombine;
-
-        /* Increasing the time resolution */
-        while ((N_B & 1) == 0 && tf_change < 0) {
-            if (lowband)
-                celt_haar1(lowband, N_B, blocks);
-            fill |= fill << blocks;
-            blocks <<= 1;
-            N_B >>= 1;
-            time_divide++;
-            tf_change++;
-        }
-        B0 = blocks;
-        N_B0 = N_B;
-
-        /* Reorganize the samples in time order instead of frequency order */
-        if (B0 > 1 && lowband)
-            celt_deinterleave_hadamard(f->scratch, lowband, N_B >> recombine,
-                                       B0 << recombine, longblocks);
-    }
-
-    /* If we need 1.5 more bit than we can produce, split the band in two. */
-    cache = ff_celt_cache_bits +
-            ff_celt_cache_index[(duration + 1) * CELT_MAX_BANDS + band];
-    if (!stereo && duration >= 0 && b > cache[cache[0]] + 12 && N > 2) {
-        N >>= 1;
-        Y = X + N;
-        split = 1;
-        duration -= 1;
-        if (blocks == 1)
-            fill = (fill & 1) | (fill << 1);
-        blocks = (blocks + 1) >> 1;
-    }
-
-    if (split) {
-        int qn;
-        int itheta = 0;
-        int mbits, sbits, delta;
-        int qalloc;
-        int pulse_cap;
-        int offset;
-        int orig_fill;
-        int tell;
-
-        /* Decide on the resolution to give to the split parameter theta */
-        pulse_cap = ff_celt_log_freq_range[band] + duration * 8;
-        offset = (pulse_cap >> 1) - (stereo && N == 2 ? CELT_QTHETA_OFFSET_TWOPHASE :
-                                                          CELT_QTHETA_OFFSET);
-        qn = (stereo && band >= f->intensity_stereo) ? 1 :
-             celt_compute_qn(N, b, offset, pulse_cap, stereo);
-        tell = opus_rc_tell_frac(rc);
-        if (qn != 1) {
-            /* Entropy coding of the angle. We use a uniform pdf for the
-            time split, a step for stereo, and a triangular one for the rest. */
-            if (stereo && N > 2)
-                itheta = ff_opus_rc_dec_uint_step(rc, qn/2);
-            else if (stereo || B0 > 1)
-                itheta = ff_opus_rc_dec_uint(rc, qn+1);
-            else
-                itheta = ff_opus_rc_dec_uint_tri(rc, qn);
-            itheta = itheta * 16384 / qn;
-            /* NOTE: Renormalising X and Y *may* help fixed-point a bit at very high rate.
-            Let's do that at higher complexity */
-        } else if (stereo) {
-            inv = (b > 2 << 3 && f->remaining2 > 2 << 3) ? ff_opus_rc_dec_log(rc, 2) : 0;
-            itheta = 0;
-        }
-        qalloc = opus_rc_tell_frac(rc) - tell;
-        b -= qalloc;
-
-        orig_fill = fill;
-        if (itheta == 0) {
-            imid = 32767;
-            iside = 0;
-            fill = av_mod_uintp2(fill, blocks);
-            delta = -16384;
-        } else if (itheta == 16384) {
-            imid = 0;
-            iside = 32767;
-            fill &= ((1 << blocks) - 1) << blocks;
-            delta = 16384;
-        } else {
-            imid = celt_cos(itheta);
-            iside = celt_cos(16384-itheta);
-            /* This is the mid vs side allocation that minimizes squared error
-            in that band. */
-            delta = ROUND_MUL16((N - 1) << 7, celt_log2tan(iside, imid));
-        }
-
-        mid  = imid  / 32768.0f;
-        side = iside / 32768.0f;
-
-        /* This is a special case for N=2 that only works for stereo and takes
-        advantage of the fact that mid and side are orthogonal to encode
-        the side with just one bit. */
-        if (N == 2 && stereo) {
-            int c;
-            int sign = 0;
-            float tmp;
-            float *x2, *y2;
-            mbits = b;
-            /* Only need one bit for the side */
-            sbits = (itheta != 0 && itheta != 16384) ? 1 << 3 : 0;
-            mbits -= sbits;
-            c = (itheta > 8192);
-            f->remaining2 -= qalloc+sbits;
-
-            x2 = c ? Y : X;
-            y2 = c ? X : Y;
-            if (sbits)
-                sign = ff_opus_rc_get_raw(rc, 1);
-            sign = 1 - 2 * sign;
-            /* We use orig_fill here because we want to fold the side, but if
-            itheta==16384, we'll have cleared the low bits of fill. */
-            cm = ff_celt_decode_band(f, rc, band, x2, NULL, N, mbits, blocks,
-                                     lowband, duration, lowband_out, level, gain,
-                                     lowband_scratch, orig_fill);
-            /* We don't split N=2 bands, so cm is either 1 or 0 (for a fold-collapse),
-            and there's no need to worry about mixing with the other channel. */
-            y2[0] = -sign * x2[1];
-            y2[1] =  sign * x2[0];
-            X[0] *= mid;
-            X[1] *= mid;
-            Y[0] *= side;
-            Y[1] *= side;
-            tmp = X[0];
-            X[0] = tmp - Y[0];
-            Y[0] = tmp + Y[0];
-            tmp = X[1];
-            X[1] = tmp - Y[1];
-            Y[1] = tmp + Y[1];
-        } else {
-            /* "Normal" split code */
-            float *next_lowband2     = NULL;
-            float *next_lowband_out1 = NULL;
-            int next_level = 0;
-            int rebalance;
-
-            /* Give more bits to low-energy MDCTs than they would
-             * otherwise deserve */
-            if (B0 > 1 && !stereo && (itheta & 0x3fff)) {
-                if (itheta > 8192)
-                    /* Rough approximation for pre-echo masking */
-                    delta -= delta >> (4 - duration);
-                else
-                    /* Corresponds to a forward-masking slope of
-                     * 1.5 dB per 10 ms */
-                    delta = FFMIN(0, delta + (N << 3 >> (5 - duration)));
-            }
-            mbits = av_clip((b - delta) / 2, 0, b);
-            sbits = b - mbits;
-            f->remaining2 -= qalloc;
-
-            if (lowband && !stereo)
-                next_lowband2 = lowband + N; /* >32-bit split case */
-
-            /* Only stereo needs to pass on lowband_out.
-             * Otherwise, it's handled at the end */
-            if (stereo)
-                next_lowband_out1 = lowband_out;
-            else
-                next_level = level + 1;
-
-            rebalance = f->remaining2;
-            if (mbits >= sbits) {
-                /* In stereo mode, we do not apply a scaling to the mid
-                 * because we need the normalized mid for folding later */
-                cm = ff_celt_decode_band(f, rc, band, X, NULL, N, mbits, blocks,
-                                         lowband, duration, next_lowband_out1,
-                                         next_level, stereo ? 1.0f : (gain * mid),
-                                         lowband_scratch, fill);
-
-                rebalance = mbits - (rebalance - f->remaining2);
-                if (rebalance > 3 << 3 && itheta != 0)
-                    sbits += rebalance - (3 << 3);
-
-                /* For a stereo split, the high bits of fill are always zero,
-                 * so no folding will be done to the side. */
-                cm |= ff_celt_decode_band(f, rc, band, Y, NULL, N, sbits, blocks,
-                                          next_lowband2, duration, NULL,
-                                          next_level, gain * side, NULL,
-                                          fill >> blocks) << ((B0 >> 1) & (stereo - 1));
-            } else {
-                /* For a stereo split, the high bits of fill are always zero,
-                 * so no folding will be done to the side. */
-                cm = ff_celt_decode_band(f, rc, band, Y, NULL, N, sbits, blocks,
-                                         next_lowband2, duration, NULL,
-                                         next_level, gain * side, NULL,
-                                         fill >> blocks) << ((B0 >> 1) & (stereo - 1));
-
-                rebalance = sbits - (rebalance - f->remaining2);
-                if (rebalance > 3 << 3 && itheta != 16384)
-                    mbits += rebalance - (3 << 3);
-
-                /* In stereo mode, we do not apply a scaling to the mid because
-                 * we need the normalized mid for folding later */
-                cm |= ff_celt_decode_band(f, rc, band, X, NULL, N, mbits, blocks,
-                                          lowband, duration, next_lowband_out1,
-                                          next_level, stereo ? 1.0f : (gain * mid),
-                                          lowband_scratch, fill);
-            }
-        }
-    } else {
-        /* This is the basic no-split case */
-        uint32_t q         = celt_bits2pulses(cache, b);
-        uint32_t curr_bits = celt_pulses2bits(cache, q);
-        f->remaining2 -= curr_bits;
-
-        /* Ensures we can never bust the budget */
-        while (f->remaining2 < 0 && q > 0) {
-            f->remaining2 += curr_bits;
-            curr_bits      = celt_pulses2bits(cache, --q);
-            f->remaining2 -= curr_bits;
-        }
-
-        if (q != 0) {
-            /* Finally do the actual quantization */
-            cm = celt_alg_unquant(rc, X, N, (q < 8) ? q : (8 + (q & 7)) << ((q >> 3) - 1),
-                                  f->spread, blocks, gain);
-        } else {
-            /* If there's no pulse, fill the band anyway */
-            uint32_t cm_mask = (1 << blocks) - 1;
-            fill &= cm_mask;
-            if (fill) {
-                if (!lowband) {
-                    /* Noise */
-                    for (i = 0; i < N; i++)
-                        X[i] = (((int32_t)celt_rng(f)) >> 20);
-                    cm = cm_mask;
-                } else {
-                    /* Folded spectrum */
-                    for (i = 0; i < N; i++) {
-                        /* About 48 dB below the "normal" folding level */
-                        X[i] = lowband[i] + (((celt_rng(f)) & 0x8000) ? 1.0f / 256 : -1.0f / 256);
-                    }
-                    cm = fill;
-                }
-                celt_renormalize_vector(X, N, gain);
-            } else {
-                memset(X, 0, N*sizeof(float));
-            }
-        }
-    }
-
-    /* This code is used by the decoder and by the resynthesis-enabled encoder */
-    if (stereo) {
-        if (N > 2)
-            celt_stereo_merge(X, Y, mid, N);
-        if (inv) {
-            for (i = 0; i < N; i++)
-                Y[i] *= -1;
-        }
-    } else if (level == 0) {
-        int k;
-
-        /* Undo the sample reorganization going from time order to frequency order */
-        if (B0 > 1)
-            celt_interleave_hadamard(f->scratch, X, N_B >> recombine,
-                                     B0 << recombine, longblocks);
-
-        /* Undo time-freq changes that we did earlier */
-        N_B = N_B0;
-        blocks = B0;
-        for (k = 0; k < time_divide; k++) {
-            blocks >>= 1;
-            N_B <<= 1;
-            cm |= cm >> blocks;
-            celt_haar1(X, N_B, blocks);
-        }
-
-        for (k = 0; k < recombine; k++) {
-            cm = ff_celt_bit_deinterleave[cm];
-            celt_haar1(X, N0>>k, 1<<k);
-        }
-        blocks <<= recombine;
-
-        /* Scale output for later folding */
-        if (lowband_out) {
-            float n = sqrtf(N0);
-            for (i = 0; i < N0; i++)
-                lowband_out[i] = n * X[i];
-        }
-        cm = av_mod_uintp2(cm, blocks);
-    }
-
-    return cm;
-}
-
-/* This has to be, AND MUST BE done by the psychoacoustic system, this has a very
- * big impact on the entire quantization and especially huge on transients */
 static int celt_calc_theta(const float *X, const float *Y, int coupling, int N)
 {
     int i;
@@ -823,14 +477,15 @@ static void celt_stereo_ms_decouple(float *X, float *Y, int N)
     }
 }
 
-uint32_t ff_celt_encode_band(CeltFrame *f, OpusRangeCoder *rc, const int band,
-                             float *X, float *Y, int N, int b, uint32_t blocks,
-                             float *lowband, int duration, float *lowband_out, int level,
-                             float gain, float *lowband_scratch, int fill)
+static av_always_inline uint32_t quant_band_template(CeltFrame *f, OpusRangeCoder *rc, const int band,
+                                                     float *X, float *Y, int N, int b, uint32_t blocks,
+                                                     float *lowband, int duration, float *lowband_out,
+                                                     int level, float gain, float *lowband_scratch,
+                                                     int fill, int quant)
 {
     int i;
     const uint8_t *cache;
-    int stereo = !!Y, split = !!Y;
+    int stereo = !!Y, split = stereo;
     int imid = 0, iside = 0;
     uint32_t N0 = N;
     int N_B = N / blocks;
@@ -844,15 +499,19 @@ uint32_t ff_celt_encode_band(CeltFrame *f, OpusRangeCoder *rc, const int band,
     uint32_t cm = 0;
 
     if (N == 1) {
-        /* special case for one sample - the decoder's output will be +- 1.0f!!! */
         float *x = X;
         for (i = 0; i <= stereo; i++) {
-            if (f->remaining2 >= 1<<3) {
-                ff_opus_rc_put_raw(rc, x[0] < 0, 1);
+            int sign = 0;
+            if (f->remaining2 >= 1 << 3) {
+                if (quant) {
+                    sign = x[0] < 0;
+                    ff_opus_rc_put_raw(rc, sign, 1);
+                } else {
+                    sign = ff_opus_rc_get_raw(rc, 1);
+                }
                 f->remaining2 -= 1 << 3;
-                b             -= 1 << 3;
             }
-            x[0] = 1.0f - 2.0f*(x[0] < 0);
+            x[0] = 1.0f - 2.0f*sign;
             x = Y;
         }
         if (lowband_out)
@@ -875,7 +534,8 @@ uint32_t ff_celt_encode_band(CeltFrame *f, OpusRangeCoder *rc, const int band,
         }
 
         for (k = 0; k < recombine; k++) {
-            celt_haar1(X, N >> k, 1 << k);
+            if (quant || lowband)
+                celt_haar1(quant ? X : lowband, N >> k, 1 << k);
             fill = ff_celt_bit_interleave[fill & 0xF] | ff_celt_bit_interleave[fill >> 4] << 2;
         }
         blocks >>= recombine;
@@ -883,7 +543,8 @@ uint32_t ff_celt_encode_band(CeltFrame *f, OpusRangeCoder *rc, const int band,
 
         /* Increasing the time resolution */
         while ((N_B & 1) == 0 && tf_change < 0) {
-            celt_haar1(X, N_B, blocks);
+            if (quant || lowband)
+                celt_haar1(quant ? X : lowband, N_B, blocks);
             fill |= fill << blocks;
             blocks <<= 1;
             N_B >>= 1;
@@ -894,9 +555,10 @@ uint32_t ff_celt_encode_band(CeltFrame *f, OpusRangeCoder *rc, const int band,
         N_B0 = N_B;
 
         /* Reorganize the samples in time order instead of frequency order */
-        if (B0 > 1)
-            celt_deinterleave_hadamard(f->scratch, X, N_B >> recombine,
-                                       B0 << recombine, longblocks);
+        if (B0 > 1 && (quant || lowband))
+            celt_deinterleave_hadamard(f->scratch, quant ? X : lowband,
+                                       N_B >> recombine, B0 << recombine,
+                                       longblocks);
     }
 
     /* If we need 1.5 more bit than we can produce, split the band in two. */
@@ -914,7 +576,7 @@ uint32_t ff_celt_encode_band(CeltFrame *f, OpusRangeCoder *rc, const int band,
 
     if (split) {
         int qn;
-        int itheta = celt_calc_theta(X, Y, stereo, N);
+        int itheta = quant ? celt_calc_theta(X, Y, stereo, N) : 0;
         int mbits, sbits, delta;
         int qalloc;
         int pulse_cap;
@@ -929,43 +591,53 @@ uint32_t ff_celt_encode_band(CeltFrame *f, OpusRangeCoder *rc, const int band,
         qn = (stereo && band >= f->intensity_stereo) ? 1 :
              celt_compute_qn(N, b, offset, pulse_cap, stereo);
         tell = opus_rc_tell_frac(rc);
-
         if (qn != 1) {
-
-            itheta = (itheta*qn + 8192) >> 14;
-
+            if (quant)
+                itheta = (itheta*qn + 8192) >> 14;
             /* Entropy coding of the angle. We use a uniform pdf for the
              * time split, a step for stereo, and a triangular one for the rest. */
-            if (stereo && N > 2)
-                ff_opus_rc_enc_uint_step(rc, itheta, qn / 2);
-            else if (stereo || B0 > 1)
-                ff_opus_rc_enc_uint(rc, itheta, qn + 1);
-            else
-                ff_opus_rc_enc_uint_tri(rc, itheta, qn);
-            itheta = itheta * 16384 / qn;
-
-            if (stereo) {
-                if (itheta == 0)
-                    celt_stereo_is_decouple(X, Y, f->block[0].lin_energy[band],
-                                            f->block[1].lin_energy[band], N);
+            if (quant) {
+                if (stereo && N > 2)
+                    ff_opus_rc_enc_uint_step(rc, itheta, qn / 2);
+                else if (stereo || B0 > 1)
+                    ff_opus_rc_enc_uint(rc, itheta, qn + 1);
+                else
+                    ff_opus_rc_enc_uint_tri(rc, itheta, qn);
+                itheta = itheta * 16384 / qn;
+                if (stereo) {
+                    if (itheta == 0)
+                        celt_stereo_is_decouple(X, Y, f->block[0].lin_energy[band],
+                                                f->block[1].lin_energy[band], N);
+                    else
+                        celt_stereo_ms_decouple(X, Y, N);
+                }
+            } else {
+                if (stereo && N > 2)
+                    itheta = ff_opus_rc_dec_uint_step(rc, qn / 2);
+                else if (stereo || B0 > 1)
+                    itheta = ff_opus_rc_dec_uint(rc, qn+1);
                 else
-                    celt_stereo_ms_decouple(X, Y, N);
+                    itheta = ff_opus_rc_dec_uint_tri(rc, qn);
+                itheta = itheta * 16384 / qn;
             }
         } else if (stereo) {
-             inv = itheta > 8192;
-             if (inv) {
-                for (i = 0; i < N; i++)
-                   Y[i] *= -1;
-             }
-             celt_stereo_is_decouple(X, Y, f->block[0].lin_energy[band],
-                                     f->block[1].lin_energy[band], N);
-
-            if (b > 2 << 3 && f->remaining2 > 2 << 3) {
-                ff_opus_rc_enc_log(rc, inv, 2);
+            if (quant) {
+                inv = itheta > 8192;
+                 if (inv) {
+                    for (i = 0; i < N; i++)
+                       Y[i] *= -1;
+                 }
+                 celt_stereo_is_decouple(X, Y, f->block[0].lin_energy[band],
+                                         f->block[1].lin_energy[band], N);
+
+                if (b > 2 << 3 && f->remaining2 > 2 << 3) {
+                    ff_opus_rc_enc_log(rc, inv, 2);
+                } else {
+                    inv = 0;
+                }
             } else {
-                inv = 0;
+                inv = (b > 2 << 3 && f->remaining2 > 2 << 3) ? ff_opus_rc_dec_log(rc, 2) : 0;
             }
-
             itheta = 0;
         }
         qalloc = opus_rc_tell_frac(rc) - tell;
@@ -1011,13 +683,17 @@ uint32_t ff_celt_encode_band(CeltFrame *f, OpusRangeCoder *rc, const int band,
             x2 = c ? Y : X;
             y2 = c ? X : Y;
             if (sbits) {
-                sign = x2[0]*y2[1] - x2[1]*y2[0] < 0;
-                ff_opus_rc_put_raw(rc, sign, 1);
+                if (quant) {
+                    sign = x2[0]*y2[1] - x2[1]*y2[0] < 0;
+                    ff_opus_rc_put_raw(rc, sign, 1);
+                } else {
+                    sign = ff_opus_rc_get_raw(rc, 1);
+                }
             }
             sign = 1 - 2 * sign;
             /* We use orig_fill here because we want to fold the side, but if
             itheta==16384, we'll have cleared the low bits of fill. */
-            cm = ff_celt_encode_band(f, rc, band, x2, NULL, N, mbits, blocks,
+            cm = ff_celt_decode_band(f, rc, band, x2, NULL, N, mbits, blocks,
                                      lowband, duration, lowband_out, level, gain,
                                      lowband_scratch, orig_fill);
             /* We don't split N=2 bands, so cm is either 1 or 0 (for a fold-collapse),
@@ -1070,10 +746,10 @@ uint32_t ff_celt_encode_band(CeltFrame *f, OpusRangeCoder *rc, const int band,
             if (mbits >= sbits) {
                 /* In stereo mode, we do not apply a scaling to the mid
                  * because we need the normalized mid for folding later */
-                cm = ff_celt_encode_band(f, rc, band, X, NULL, N, mbits, blocks,
+                cm = quant_band_template(f, rc, band, X, NULL, N, mbits, blocks,
                                          lowband, duration, next_lowband_out1,
                                          next_level, stereo ? 1.0f : (gain * mid),
-                                         lowband_scratch, fill);
+                                         lowband_scratch, fill, quant);
 
                 rebalance = mbits - (rebalance - f->remaining2);
                 if (rebalance > 3 << 3 && itheta != 0)
@@ -1081,17 +757,17 @@ uint32_t ff_celt_encode_band(CeltFrame *f, OpusRangeCoder *rc, const int band,
 
                 /* For a stereo split, the high bits of fill are always zero,
                  * so no folding will be done to the side. */
-                cm |= ff_celt_encode_band(f, rc, band, Y, NULL, N, sbits, blocks,
+                cm |= quant_band_template(f, rc, band, Y, NULL, N, sbits, blocks,
                                           next_lowband2, duration, NULL,
                                           next_level, gain * side, NULL,
-                                          fill >> blocks) << ((B0 >> 1) & (stereo - 1));
+                                          fill >> blocks, quant) << ((B0 >> 1) & (stereo - 1));
             } else {
                 /* For a stereo split, the high bits of fill are always zero,
                  * so no folding will be done to the side. */
-                cm = ff_celt_encode_band(f, rc, band, Y, NULL, N, sbits, blocks,
+                cm = quant_band_template(f, rc, band, Y, NULL, N, sbits, blocks,
                                          next_lowband2, duration, NULL,
                                          next_level, gain * side, NULL,
-                                         fill >> blocks) << ((B0 >> 1) & (stereo - 1));
+                                         fill >> blocks, quant) << ((B0 >> 1) & (stereo - 1));
 
                 rebalance = sbits - (rebalance - f->remaining2);
                 if (rebalance > 3 << 3 && itheta != 16384)
@@ -1099,10 +775,10 @@ uint32_t ff_celt_encode_band(CeltFrame *f, OpusRangeCoder *rc, const int band,
 
                 /* In stereo mode, we do not apply a scaling to the mid because
                  * we need the normalized mid for folding later */
-                cm |= ff_celt_encode_band(f, rc, band, X, NULL, N, mbits, blocks,
+                cm |= quant_band_template(f, rc, band, X, NULL, N, mbits, blocks,
                                           lowband, duration, next_lowband_out1,
                                           next_level, stereo ? 1.0f : (gain * mid),
-                                          lowband_scratch, fill);
+                                          lowband_scratch, fill, quant);
             }
         }
     } else {
@@ -1119,9 +795,14 @@ uint32_t ff_celt_encode_band(CeltFrame *f, OpusRangeCoder *rc, const int band,
         }
 
         if (q != 0) {
-            /* Finally do the actual quantization */
-            cm = celt_alg_quant(rc, X, N, (q < 8) ? q : (8 + (q & 7)) << ((q >> 3) - 1),
-                                f->spread, blocks, gain);
+            /* Finally do the actual (de)quantization */
+            if (quant) {
+                cm = celt_alg_quant(rc, X, N, (q < 8) ? q : (8 + (q & 7)) << ((q >> 3) - 1),
+                                    f->spread, blocks, gain, f->scratch);
+            } else {
+                cm = celt_alg_unquant(rc, X, N, (q < 8) ? q : (8 + (q & 7)) << ((q >> 3) - 1),
+                                      f->spread, blocks, gain, f->scratch);
+            }
         } else {
             /* If there's no pulse, fill the band anyway */
             uint32_t cm_mask = (1 << blocks) - 1;
@@ -1191,6 +872,26 @@ uint32_t ff_celt_encode_band(CeltFrame *f, OpusRangeCoder *rc, const int band,
     return cm;
 }
 
+uint32_t ff_celt_decode_band(CeltFrame *f, OpusRangeCoder *rc, const int band,
+                             float *X, float *Y, int N, int b, uint32_t blocks,
+                             float *lowband, int duration, float *lowband_out,
+                             int level, float gain, float *lowband_scratch,
+                             int fill)
+{
+    return quant_band_template(f, rc, band, X, Y, N, b, blocks, lowband, duration,
+                               lowband_out, level, gain, lowband_scratch, fill, 0);
+}
+
+uint32_t ff_celt_encode_band(CeltFrame *f, OpusRangeCoder *rc, const int band,
+                             float *X, float *Y, int N, int b, uint32_t blocks,
+                             float *lowband, int duration, float *lowband_out,
+                             int level, float gain, float *lowband_scratch,
+                             int fill)
+{
+    return quant_band_template(f, rc, band, X, Y, N, b, blocks, lowband, duration,
+                               lowband_out, level, gain, lowband_scratch, fill, 1);
+}
+
 float ff_celt_quant_band_cost(CeltFrame *f, OpusRangeCoder *rc, int band, float *bits,
                               float lambda)
 {