opus: merge encoder and decoder bitallocation functions into one

There's no difference apart from which entropy coding functions get called.

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

6 files changed, 358 insertions, 668 deletions

diff --git a/libavcodec/opus.c b/libavcodec/opus.c
index 46b749cae6..9cbf4aed92 100644
--- a/libavcodec/opus.c
+++ b/libavcodec/opus.c
@@ -546,3 +546,351 @@ void ff_celt_quant_bands(CeltFrame *f, OpusRangeCoder *rc)
         update_lowband = (b > band_size << 3);
     }
 }
+
+#define NORMC(bits) ((bits) << (f->channels - 1) << f->size >> 2)
+
+void ff_celt_bitalloc(CeltFrame *f, OpusRangeCoder *rc, int encode)
+{
+    int i, j, low, high, total, done, bandbits, remaining, tbits_8ths;
+    int skip_startband      = f->start_band;
+    int skip_bit            = 0;
+    int intensitystereo_bit = 0;
+    int dualstereo_bit      = 0;
+    int dynalloc            = 6;
+    int extrabits           = 0;
+
+    int boost[CELT_MAX_BANDS] = { 0 };
+    int trim_offset[CELT_MAX_BANDS];
+    int threshold[CELT_MAX_BANDS];
+    int bits1[CELT_MAX_BANDS];
+    int bits2[CELT_MAX_BANDS];
+
+    /* Spread */
+    if (opus_rc_tell(rc) + 4 <= f->framebits)
+        if (encode)
+            ff_opus_rc_enc_cdf(rc, f->spread, ff_celt_model_spread);
+        else
+            f->spread = ff_opus_rc_dec_cdf(rc, ff_celt_model_spread);
+    else
+        f->spread = CELT_SPREAD_NORMAL;
+
+    /* Initialize static allocation caps */
+    for (i = 0; i < CELT_MAX_BANDS; i++)
+        f->caps[i] = NORMC((ff_celt_static_caps[f->size][f->channels - 1][i] + 64) * ff_celt_freq_range[i]);
+
+    /* Band boosts */
+    tbits_8ths = f->framebits << 3;
+    for (i = f->start_band; i < f->end_band; i++) {
+        int quanta = ff_celt_freq_range[i] << (f->channels - 1) << f->size;
+        int b_dynalloc = dynalloc;
+        int boost_amount = f->alloc_boost[i];
+        quanta = FFMIN(quanta << 3, FFMAX(6 << 3, quanta));
+
+        while (opus_rc_tell_frac(rc) + (b_dynalloc << 3) < tbits_8ths && boost[i] < f->caps[i]) {
+            int is_boost;
+            if (encode) {
+                is_boost = boost_amount--;
+                ff_opus_rc_enc_log(rc, is_boost, b_dynalloc);
+            } else {
+                is_boost = ff_opus_rc_dec_log(rc, b_dynalloc);
+            }
+
+            if (!is_boost)
+                break;
+
+            boost[i]   += quanta;
+            tbits_8ths -= quanta;
+
+            b_dynalloc = 1;
+        }
+
+        if (boost[i])
+            dynalloc = FFMAX(dynalloc - 1, 2);
+    }
+
+    /* Allocation trim */
+    if (opus_rc_tell_frac(rc) + (6 << 3) <= tbits_8ths)
+        if (encode)
+            ff_opus_rc_enc_cdf(rc, f->alloc_trim, ff_celt_model_alloc_trim);
+        else
+            f->alloc_trim = ff_opus_rc_dec_cdf(rc, ff_celt_model_alloc_trim);
+
+    /* Anti-collapse bit reservation */
+    tbits_8ths = (f->framebits << 3) - opus_rc_tell_frac(rc) - 1;
+    f->anticollapse_needed = 0;
+    if (f->transient && f->size >= 2 && tbits_8ths >= ((f->size + 2) << 3))
+        f->anticollapse_needed = 1 << 3;
+    tbits_8ths -= f->anticollapse_needed;
+
+    /* Band skip bit reservation */
+    if (tbits_8ths >= 1 << 3)
+        skip_bit = 1 << 3;
+    tbits_8ths -= skip_bit;
+
+    /* Intensity/dual stereo bit reservation */
+    if (f->channels == 2) {
+        intensitystereo_bit = ff_celt_log2_frac[f->end_band - f->start_band];
+        if (intensitystereo_bit <= tbits_8ths) {
+            tbits_8ths -= intensitystereo_bit;
+            if (tbits_8ths >= 1 << 3) {
+                dualstereo_bit = 1 << 3;
+                tbits_8ths -= 1 << 3;
+            }
+        } else {
+            intensitystereo_bit = 0;
+        }
+    }
+
+    /* Trim offsets */
+    for (i = f->start_band; i < f->end_band; i++) {
+        int trim     = f->alloc_trim - 5 - f->size;
+        int band     = ff_celt_freq_range[i] * (f->end_band - i - 1);
+        int duration = f->size + 3;
+        int scale    = duration + f->channels - 1;
+
+        /* PVQ minimum allocation threshold, below this value the band is
+         * skipped */
+        threshold[i] = FFMAX(3 * ff_celt_freq_range[i] << duration >> 4,
+                             f->channels << 3);
+
+        trim_offset[i] = trim * (band << scale) >> 6;
+
+        if (ff_celt_freq_range[i] << f->size == 1)
+            trim_offset[i] -= f->channels << 3;
+    }
+
+    /* Bisection */
+    low  = 1;
+    high = CELT_VECTORS - 1;
+    while (low <= high) {
+        int center = (low + high) >> 1;
+        done = total = 0;
+
+        for (i = f->end_band - 1; i >= f->start_band; i--) {
+            bandbits = NORMC(ff_celt_freq_range[i] * ff_celt_static_alloc[center][i]);
+
+            if (bandbits)
+                bandbits = FFMAX(bandbits + trim_offset[i], 0);
+            bandbits += boost[i];
+
+            if (bandbits >= threshold[i] || done) {
+                done = 1;
+                total += FFMIN(bandbits, f->caps[i]);
+            } else if (bandbits >= f->channels << 3) {
+                total += f->channels << 3;
+            }
+        }
+
+        if (total > tbits_8ths)
+            high = center - 1;
+        else
+            low = center + 1;
+    }
+    high = low--;
+
+    /* Bisection */
+    for (i = f->start_band; i < f->end_band; i++) {
+        bits1[i] = NORMC(ff_celt_freq_range[i] * ff_celt_static_alloc[low][i]);
+        bits2[i] = high >= CELT_VECTORS ? f->caps[i] :
+                   NORMC(ff_celt_freq_range[i] * ff_celt_static_alloc[high][i]);
+
+        if (bits1[i])
+            bits1[i] = FFMAX(bits1[i] + trim_offset[i], 0);
+        if (bits2[i])
+            bits2[i] = FFMAX(bits2[i] + trim_offset[i], 0);
+
+        if (low)
+            bits1[i] += boost[i];
+        bits2[i] += boost[i];
+
+        if (boost[i])
+            skip_startband = i;
+        bits2[i] = FFMAX(bits2[i] - bits1[i], 0);
+    }
+
+    /* Bisection */
+    low  = 0;
+    high = 1 << CELT_ALLOC_STEPS;
+    for (i = 0; i < CELT_ALLOC_STEPS; i++) {
+        int center = (low + high) >> 1;
+        done = total = 0;
+
+        for (j = f->end_band - 1; j >= f->start_band; j--) {
+            bandbits = bits1[j] + (center * bits2[j] >> CELT_ALLOC_STEPS);
+
+            if (bandbits >= threshold[j] || done) {
+                done = 1;
+                total += FFMIN(bandbits, f->caps[j]);
+            } else if (bandbits >= f->channels << 3)
+                total += f->channels << 3;
+        }
+        if (total > tbits_8ths)
+            high = center;
+        else
+            low = center;
+    }
+
+    /* Bisection */
+    done = total = 0;
+    for (i = f->end_band - 1; i >= f->start_band; i--) {
+        bandbits = bits1[i] + (low * bits2[i] >> CELT_ALLOC_STEPS);
+
+        if (bandbits >= threshold[i] || done)
+            done = 1;
+        else
+            bandbits = (bandbits >= f->channels << 3) ?
+            f->channels << 3 : 0;
+
+        bandbits     = FFMIN(bandbits, f->caps[i]);
+        f->pulses[i] = bandbits;
+        total      += bandbits;
+    }
+
+    /* Band skipping */
+    for (f->coded_bands = f->end_band; ; f->coded_bands--) {
+        int allocation;
+        j = f->coded_bands - 1;
+
+        if (j == skip_startband) {
+            /* all remaining bands are not skipped */
+            tbits_8ths += skip_bit;
+            break;
+        }
+
+        /* determine the number of bits available for coding "do not skip" markers */
+        remaining   = tbits_8ths - total;
+        bandbits    = remaining / (ff_celt_freq_bands[j+1] - ff_celt_freq_bands[f->start_band]);
+        remaining  -= bandbits  * (ff_celt_freq_bands[j+1] - ff_celt_freq_bands[f->start_band]);
+        allocation  = f->pulses[j] + bandbits * ff_celt_freq_range[j];
+        allocation += FFMAX(remaining - (ff_celt_freq_bands[j] - ff_celt_freq_bands[f->start_band]), 0);
+
+        /* a "do not skip" marker is only coded if the allocation is
+         * above the chosen threshold */
+        if (allocation >= FFMAX(threshold[j], (f->channels + 1) << 3)) {
+            int do_not_skip;
+            if (encode) {
+                do_not_skip = f->coded_bands <= f->skip_band_floor;
+                ff_opus_rc_enc_log(rc, do_not_skip, 1);
+            } else {
+                do_not_skip = ff_opus_rc_dec_log(rc, 1);
+            }
+
+            if (do_not_skip)
+                break;
+
+            total      += 1 << 3;
+            allocation -= 1 << 3;
+        }
+
+        /* the band is skipped, so reclaim its bits */
+        total -= f->pulses[j];
+        if (intensitystereo_bit) {
+            total -= intensitystereo_bit;
+            intensitystereo_bit = ff_celt_log2_frac[j - f->start_band];
+            total += intensitystereo_bit;
+        }
+
+        total += f->pulses[j] = (allocation >= f->channels << 3) ? f->channels << 3 : 0;
+    }
+
+    /* IS start band */
+    if (encode) {
+        if (intensitystereo_bit) {
+            f->intensity_stereo = FFMIN(f->intensity_stereo, f->coded_bands);
+            ff_opus_rc_enc_uint(rc, f->intensity_stereo, f->coded_bands + 1 - f->start_band);
+        }
+    } else {
+        f->intensity_stereo = f->dual_stereo = 0;
+        if (intensitystereo_bit)
+            f->intensity_stereo = f->start_band + ff_opus_rc_dec_uint(rc, f->coded_bands + 1 - f->start_band);
+    }
+
+    /* DS flag */
+    if (f->intensity_stereo <= f->start_band)
+        tbits_8ths += dualstereo_bit; /* no intensity stereo means no dual stereo */
+    else if (dualstereo_bit)
+        if (encode)
+            ff_opus_rc_enc_log(rc, f->dual_stereo, 1);
+        else
+            f->dual_stereo = ff_opus_rc_dec_log(rc, 1);
+
+    /* Supply the remaining bits in this frame to lower bands */
+    remaining = tbits_8ths - total;
+    bandbits  = remaining / (ff_celt_freq_bands[f->coded_bands] - ff_celt_freq_bands[f->start_band]);
+    remaining -= bandbits * (ff_celt_freq_bands[f->coded_bands] - ff_celt_freq_bands[f->start_band]);
+    for (i = f->start_band; i < f->coded_bands; i++) {
+        const int bits = FFMIN(remaining, ff_celt_freq_range[i]);
+        f->pulses[i] += bits + bandbits * ff_celt_freq_range[i];
+        remaining    -= bits;
+    }
+
+    /* Finally determine the allocation */
+    for (i = f->start_band; i < f->coded_bands; i++) {
+        int N = ff_celt_freq_range[i] << f->size;
+        int prev_extra = extrabits;
+        f->pulses[i] += extrabits;
+
+        if (N > 1) {
+            int dof;        /* degrees of freedom */
+            int temp;       /* dof * channels * log(dof) */
+            int fine_bits;
+            int max_bits;
+            int offset;     /* fine energy quantization offset, i.e.
+                             * extra bits assigned over the standard
+                             * totalbits/dof */
+
+            extrabits = FFMAX(f->pulses[i] - f->caps[i], 0);
+            f->pulses[i] -= extrabits;
+
+            /* intensity stereo makes use of an extra degree of freedom */
+            dof = N * f->channels + (f->channels == 2 && N > 2 && !f->dual_stereo && i < f->intensity_stereo);
+            temp = dof * (ff_celt_log_freq_range[i] + (f->size << 3));
+            offset = (temp >> 1) - dof * CELT_FINE_OFFSET;
+            if (N == 2) /* dof=2 is the only case that doesn't fit the model */
+                offset += dof << 1;
+
+            /* grant an additional bias for the first and second pulses */
+            if (f->pulses[i] + offset < 2 * (dof << 3))
+                offset += temp >> 2;
+            else if (f->pulses[i] + offset < 3 * (dof << 3))
+                offset += temp >> 3;
+
+            fine_bits = (f->pulses[i] + offset + (dof << 2)) / (dof << 3);
+            max_bits  = FFMIN((f->pulses[i] >> 3) >> (f->channels - 1), CELT_MAX_FINE_BITS);
+            max_bits  = FFMAX(max_bits, 0);
+            f->fine_bits[i] = av_clip(fine_bits, 0, max_bits);
+
+            /* If fine_bits was rounded down or capped,
+             * give priority for the final fine energy pass */
+            f->fine_priority[i] = (f->fine_bits[i] * (dof << 3) >= f->pulses[i] + offset);
+
+            /* the remaining bits are assigned to PVQ */
+            f->pulses[i] -= f->fine_bits[i] << (f->channels - 1) << 3;
+        } else {
+            /* all bits go to fine energy except for the sign bit */
+            extrabits = FFMAX(f->pulses[i] - (f->channels << 3), 0);
+            f->pulses[i] -= extrabits;
+            f->fine_bits[i] = 0;
+            f->fine_priority[i] = 1;
+        }
+
+        /* hand back a limited number of extra fine energy bits to this band */
+        if (extrabits > 0) {
+            int fineextra = FFMIN(extrabits >> (f->channels + 2),
+                                  CELT_MAX_FINE_BITS - f->fine_bits[i]);
+            f->fine_bits[i] += fineextra;
+
+            fineextra <<= f->channels + 2;
+            f->fine_priority[i] = (fineextra >= extrabits - prev_extra);
+            extrabits -= fineextra;
+        }
+    }
+    f->remaining = extrabits;
+
+    /* skipped bands dedicate all of their bits for fine energy */
+    for (; i < f->end_band; i++) {
+        f->fine_bits[i]     = f->pulses[i] >> (f->channels - 1) >> 3;
+        f->pulses[i]        = 0;
+        f->fine_priority[i] = f->fine_bits[i] < 1;
+    }
+}
diff --git a/libavcodec/opus.h b/libavcodec/opus.h
index a10db7f0e8..edbaab5ce7 100644
--- a/libavcodec/opus.h
+++ b/libavcodec/opus.h
@@ -194,4 +194,7 @@ int ff_silk_decode_superframe(SilkContext *s, OpusRangeCoder *rc,
 /* Encode or decode CELT bands */
 void ff_celt_quant_bands(CeltFrame *f, OpusRangeCoder *rc);
 
+/* Encode or decode CELT bitallocation */
+void ff_celt_bitalloc(CeltFrame *f, OpusRangeCoder *rc, int encode);
+
 #endif /* AVCODEC_OPUS_H */
diff --git a/libavcodec/opus_celt.c b/libavcodec/opus_celt.c
index ff74e2f067..115dd8c63e 100644
--- a/libavcodec/opus_celt.c
+++ b/libavcodec/opus_celt.c
@@ -143,338 +143,6 @@ static void celt_decode_tf_changes(CeltFrame *f, OpusRangeCoder *rc)
     }
 }
 
-static void celt_decode_allocation(CeltFrame *f, OpusRangeCoder *rc)
-{
-    // approx. maximum bit allocation for each band before boost/trim
-    int cap[CELT_MAX_BANDS];
-    int boost[CELT_MAX_BANDS];
-    int threshold[CELT_MAX_BANDS];
-    int bits1[CELT_MAX_BANDS];
-    int bits2[CELT_MAX_BANDS];
-    int trim_offset[CELT_MAX_BANDS];
-
-    int skip_start_band = f->start_band;
-    int dynalloc       = 6;
-    int alloctrim      = 5;
-    int extrabits      = 0;
-
-    int skip_bit             = 0;
-    int intensity_stereo_bit = 0;
-    int dual_stereo_bit      = 0;
-
-    int remaining, bandbits;
-    int low, high, total, done;
-    int totalbits;
-    int consumed;
-    int i, j;
-
-    consumed = opus_rc_tell(rc);
-
-    /* obtain spread flag */
-    f->spread = CELT_SPREAD_NORMAL;
-    if (consumed + 4 <= f->framebits)
-        f->spread = ff_opus_rc_dec_cdf(rc, ff_celt_model_spread);
-
-    /* generate static allocation caps */
-    for (i = 0; i < CELT_MAX_BANDS; i++) {
-        cap[i] = (ff_celt_static_caps[f->size][f->channels - 1][i] + 64)
-                 * ff_celt_freq_range[i] << (f->channels - 1) << f->size >> 2;
-    }
-
-    /* obtain band boost */
-    totalbits = f->framebits << 3; // convert to 1/8 bits
-    consumed = opus_rc_tell_frac(rc);
-    for (i = f->start_band; i < f->end_band; i++) {
-        int quanta, band_dynalloc;
-
-        boost[i] = 0;
-
-        quanta = ff_celt_freq_range[i] << (f->channels - 1) << f->size;
-        quanta = FFMIN(quanta << 3, FFMAX(6 << 3, quanta));
-        band_dynalloc = dynalloc;
-        while (consumed + (band_dynalloc<<3) < totalbits && boost[i] < cap[i]) {
-            int add = ff_opus_rc_dec_log(rc, band_dynalloc);
-            consumed = opus_rc_tell_frac(rc);
-            if (!add)
-                break;
-
-            boost[i]     += quanta;
-            totalbits    -= quanta;
-            band_dynalloc = 1;
-        }
-        /* dynalloc is more likely to occur if it's already been used for earlier bands */
-        if (boost[i])
-            dynalloc = FFMAX(2, dynalloc - 1);
-    }
-
-    /* obtain allocation trim */
-    if (consumed + (6 << 3) <= totalbits)
-        alloctrim = ff_opus_rc_dec_cdf(rc, ff_celt_model_alloc_trim);
-
-    /* anti-collapse bit reservation */
-    totalbits = (f->framebits << 3) - opus_rc_tell_frac(rc) - 1;
-    f->anticollapse_needed = 0;
-    if (f->blocks > 1 && f->size >= 2 &&
-        totalbits >= ((f->size + 2) << 3))
-        f->anticollapse_needed = 1 << 3;
-    totalbits -= f->anticollapse_needed;
-
-    /* band skip bit reservation */
-    if (totalbits >= 1 << 3)
-        skip_bit = 1 << 3;
-    totalbits -= skip_bit;
-
-    /* intensity/dual stereo bit reservation */
-    if (f->channels == 2) {
-        intensity_stereo_bit = ff_celt_log2_frac[f->end_band - f->start_band];
-        if (intensity_stereo_bit <= totalbits) {
-            totalbits -= intensity_stereo_bit;
-            if (totalbits >= 1 << 3) {
-                dual_stereo_bit = 1 << 3;
-                totalbits -= 1 << 3;
-            }
-        } else
-            intensity_stereo_bit = 0;
-    }
-
-    for (i = f->start_band; i < f->end_band; i++) {
-        int trim     = alloctrim - 5 - f->size;
-        int band     = ff_celt_freq_range[i] * (f->end_band - i - 1);
-        int duration = f->size + 3;
-        int scale    = duration + f->channels - 1;
-
-        /* PVQ minimum allocation threshold, below this value the band is
-         * skipped */
-        threshold[i] = FFMAX(3 * ff_celt_freq_range[i] << duration >> 4,
-                             f->channels << 3);
-
-        trim_offset[i] = trim * (band << scale) >> 6;
-
-        if (ff_celt_freq_range[i] << f->size == 1)
-            trim_offset[i] -= f->channels << 3;
-    }
-
-    /* bisection */
-    low  = 1;
-    high = CELT_VECTORS - 1;
-    while (low <= high) {
-        int center = (low + high) >> 1;
-        done = total = 0;
-
-        for (i = f->end_band - 1; i >= f->start_band; i--) {
-            bandbits = ff_celt_freq_range[i] * ff_celt_static_alloc[center][i]
-                       << (f->channels - 1) << f->size >> 2;
-
-            if (bandbits)
-                bandbits = FFMAX(0, bandbits + trim_offset[i]);
-            bandbits += boost[i];
-
-            if (bandbits >= threshold[i] || done) {
-                done = 1;
-                total += FFMIN(bandbits, cap[i]);
-            } else if (bandbits >= f->channels << 3)
-                total += f->channels << 3;
-        }
-
-        if (total > totalbits)
-            high = center - 1;
-        else
-            low = center + 1;
-    }
-    high = low--;
-
-    for (i = f->start_band; i < f->end_band; i++) {
-        bits1[i] = ff_celt_freq_range[i] * ff_celt_static_alloc[low][i]
-                   << (f->channels - 1) << f->size >> 2;
-        bits2[i] = high >= CELT_VECTORS ? cap[i] :
-                   ff_celt_freq_range[i] * ff_celt_static_alloc[high][i]
-                   << (f->channels - 1) << f->size >> 2;
-
-        if (bits1[i])
-            bits1[i] = FFMAX(0, bits1[i] + trim_offset[i]);
-        if (bits2[i])
-            bits2[i] = FFMAX(0, bits2[i] + trim_offset[i]);
-        if (low)
-            bits1[i] += boost[i];
-        bits2[i] += boost[i];
-
-        if (boost[i])
-            skip_start_band = i;
-        bits2[i] = FFMAX(0, bits2[i] - bits1[i]);
-    }
-
-    /* bisection */
-    low  = 0;
-    high = 1 << CELT_ALLOC_STEPS;
-    for (i = 0; i < CELT_ALLOC_STEPS; i++) {
-        int center = (low + high) >> 1;
-        done = total = 0;
-
-        for (j = f->end_band - 1; j >= f->start_band; j--) {
-            bandbits = bits1[j] + (center * bits2[j] >> CELT_ALLOC_STEPS);
-
-            if (bandbits >= threshold[j] || done) {
-                done = 1;
-                total += FFMIN(bandbits, cap[j]);
-            } else if (bandbits >= f->channels << 3)
-                total += f->channels << 3;
-        }
-        if (total > totalbits)
-            high = center;
-        else
-            low = center;
-    }
-
-    done = total = 0;
-    for (i = f->end_band - 1; i >= f->start_band; i--) {
-        bandbits = bits1[i] + (low * bits2[i] >> CELT_ALLOC_STEPS);
-
-        if (bandbits >= threshold[i] || done)
-            done = 1;
-        else
-            bandbits = (bandbits >= f->channels << 3) ?
-                       f->channels << 3 : 0;
-
-        bandbits     = FFMIN(bandbits, cap[i]);
-        f->pulses[i] = bandbits;
-        total      += bandbits;
-    }
-
-    /* band skipping */
-    for (f->coded_bands = f->end_band; ; f->coded_bands--) {
-        int allocation;
-        j = f->coded_bands - 1;
-
-        if (j == skip_start_band) {
-            /* all remaining bands are not skipped */
-            totalbits += skip_bit;
-            break;
-        }
-
-        /* determine the number of bits available for coding "do not skip" markers */
-        remaining   = totalbits - total;
-        bandbits    = remaining / (ff_celt_freq_bands[j+1] - ff_celt_freq_bands[f->start_band]);
-        remaining  -= bandbits  * (ff_celt_freq_bands[j+1] - ff_celt_freq_bands[f->start_band]);
-        allocation  = f->pulses[j] + bandbits * ff_celt_freq_range[j]
-                      + FFMAX(0, remaining - (ff_celt_freq_bands[j] - ff_celt_freq_bands[f->start_band]));
-
-        /* a "do not skip" marker is only coded if the allocation is
-           above the chosen threshold */
-        if (allocation >= FFMAX(threshold[j], (f->channels + 1) <<3 )) {
-            if (ff_opus_rc_dec_log(rc, 1))
-                break;
-
-            total      += 1 << 3;
-            allocation -= 1 << 3;
-        }
-
-        /* the band is skipped, so reclaim its bits */
-        total -= f->pulses[j];
-        if (intensity_stereo_bit) {
-            total -= intensity_stereo_bit;
-            intensity_stereo_bit = ff_celt_log2_frac[j - f->start_band];
-            total += intensity_stereo_bit;
-        }
-
-        total += f->pulses[j] = (allocation >= f->channels << 3) ?
-                              f->channels << 3 : 0;
-    }
-
-    /* obtain stereo flags */
-    f->intensity_stereo = 0;
-    f->dual_stereo      = 0;
-    if (intensity_stereo_bit)
-        f->intensity_stereo = f->start_band +
-                          ff_opus_rc_dec_uint(rc, f->coded_bands + 1 - f->start_band);
-    if (f->intensity_stereo <= f->start_band)
-        totalbits += dual_stereo_bit; /* no intensity stereo means no dual stereo */
-    else if (dual_stereo_bit)
-        f->dual_stereo = ff_opus_rc_dec_log(rc, 1);
-
-    /* supply the remaining bits in this frame to lower bands */
-    remaining = totalbits - total;
-    bandbits  = remaining / (ff_celt_freq_bands[f->coded_bands] - ff_celt_freq_bands[f->start_band]);
-    remaining -= bandbits * (ff_celt_freq_bands[f->coded_bands] - ff_celt_freq_bands[f->start_band]);
-    for (i = f->start_band; i < f->coded_bands; i++) {
-        int bits = FFMIN(remaining, ff_celt_freq_range[i]);
-
-        f->pulses[i] += bits + bandbits * ff_celt_freq_range[i];
-        remaining    -= bits;
-    }
-
-    for (i = f->start_band; i < f->coded_bands; i++) {
-        int N = ff_celt_freq_range[i] << f->size;
-        int prev_extra = extrabits;
-        f->pulses[i] += extrabits;
-
-        if (N > 1) {
-            int dof;        // degrees of freedom
-            int temp;       // dof * channels * log(dof)
-            int offset;     // fine energy quantization offset, i.e.
-                            // extra bits assigned over the standard
-                            // totalbits/dof
-            int fine_bits, max_bits;
-
-            extrabits = FFMAX(0, f->pulses[i] - cap[i]);
-            f->pulses[i] -= extrabits;
-
-            /* intensity stereo makes use of an extra degree of freedom */
-            dof = N * f->channels
-                  + (f->channels == 2 && N > 2 && !f->dual_stereo && i < f->intensity_stereo);
-            temp = dof * (ff_celt_log_freq_range[i] + (f->size<<3));
-            offset = (temp >> 1) - dof * CELT_FINE_OFFSET;
-            if (N == 2) /* dof=2 is the only case that doesn't fit the model */
-                offset += dof<<1;
-
-            /* grant an additional bias for the first and second pulses */
-            if (f->pulses[i] + offset < 2 * (dof << 3))
-                offset += temp >> 2;
-            else if (f->pulses[i] + offset < 3 * (dof << 3))
-                offset += temp >> 3;
-
-            fine_bits = (f->pulses[i] + offset + (dof << 2)) / (dof << 3);
-            max_bits  = FFMIN((f->pulses[i]>>3) >> (f->channels - 1),
-                              CELT_MAX_FINE_BITS);
-
-            max_bits  = FFMAX(max_bits, 0);
-
-            f->fine_bits[i] = av_clip(fine_bits, 0, max_bits);
-
-            /* if fine_bits was rounded down or capped,
-               give priority for the final fine energy pass */
-            f->fine_priority[i] = (f->fine_bits[i] * (dof<<3) >= f->pulses[i] + offset);
-
-            /* the remaining bits are assigned to PVQ */
-            f->pulses[i] -= f->fine_bits[i] << (f->channels - 1) << 3;
-        } else {
-            /* all bits go to fine energy except for the sign bit */
-            extrabits = FFMAX(0, f->pulses[i] - (f->channels << 3));
-            f->pulses[i] -= extrabits;
-            f->fine_bits[i] = 0;
-            f->fine_priority[i] = 1;
-        }
-
-        /* hand back a limited number of extra fine energy bits to this band */
-        if (extrabits > 0) {
-            int fineextra = FFMIN(extrabits >> (f->channels + 2),
-                                  CELT_MAX_FINE_BITS - f->fine_bits[i]);
-            f->fine_bits[i] += fineextra;
-
-            fineextra <<= f->channels + 2;
-            f->fine_priority[i] = (fineextra >= extrabits - prev_extra);
-            extrabits -= fineextra;
-        }
-    }
-    f->remaining = extrabits;
-
-    /* skipped bands dedicate all of their bits for fine energy */
-    for (; i < f->end_band; i++) {
-        f->fine_bits[i]     = f->pulses[i] >> (f->channels - 1) >> 3;
-        f->pulses[i]        = 0;
-        f->fine_priority[i] = f->fine_bits[i] < 1;
-    }
-}
-
 static void celt_denormalize(CeltFrame *f, CeltBlock *block, float *data)
 {
     int i, j;
@@ -753,7 +421,7 @@ int ff_celt_decode_frame(CeltFrame *f, OpusRangeCoder *rc,
 
     celt_decode_coarse_energy(f, rc);
     celt_decode_tf_changes   (f, rc);
-    celt_decode_allocation   (f, rc);
+    ff_celt_bitalloc         (f, rc, 0);
     celt_decode_fine_energy  (f, rc);
     ff_celt_quant_bands      (f, rc);
 
diff --git a/libavcodec/opusenc.c b/libavcodec/opusenc.c
index 93b2116e7b..4068c43594 100644
--- a/libavcodec/opusenc.c
+++ b/libavcodec/opusenc.c
@@ -282,333 +282,6 @@ static void celt_enc_tf(CeltFrame *f, OpusRangeCoder *rc)
         f->tf_change[i] = ff_celt_tf_select[f->size][f->transient][tf_select][f->tf_change[i]];
 }
 
-void ff_celt_enc_bitalloc(CeltFrame *f, OpusRangeCoder *rc)
-{
-    int i, j, low, high, total, done, bandbits, remaining, tbits_8ths;
-    int skip_startband      = f->start_band;
-    int skip_bit            = 0;
-    int intensitystereo_bit = 0;
-    int dualstereo_bit      = 0;
-    int dynalloc            = 6;
-    int extrabits           = 0;
-
-    int *cap = f->caps;
-    int boost[CELT_MAX_BANDS];
-    int trim_offset[CELT_MAX_BANDS];
-    int threshold[CELT_MAX_BANDS];
-    int bits1[CELT_MAX_BANDS];
-    int bits2[CELT_MAX_BANDS];
-
-    /* Tell the spread to the decoder */
-    if (opus_rc_tell(rc) + 4 <= f->framebits)
-        ff_opus_rc_enc_cdf(rc, f->spread, ff_celt_model_spread);
-    else
-        f->spread = CELT_SPREAD_NORMAL;
-
-    /* Generate static allocation caps */
-    for (i = 0; i < CELT_MAX_BANDS; i++) {
-        cap[i] = (ff_celt_static_caps[f->size][f->channels - 1][i] + 64)
-                 * ff_celt_freq_range[i] << (f->channels - 1) << f->size >> 2;
-    }
-
-    /* Band boosts */
-    tbits_8ths = f->framebits << 3;
-    for (i = f->start_band; i < f->end_band; i++) {
-        int quanta, b_dynalloc, boost_amount = f->alloc_boost[i];
-
-        boost[i] = 0;
-
-        quanta = ff_celt_freq_range[i] << (f->channels - 1) << f->size;
-        quanta = FFMIN(quanta << 3, FFMAX(6 << 3, quanta));
-        b_dynalloc = dynalloc;
-
-        while (opus_rc_tell_frac(rc) + (b_dynalloc << 3) < tbits_8ths && boost[i] < cap[i]) {
-            int is_boost = boost_amount--;
-
-            ff_opus_rc_enc_log(rc, is_boost, b_dynalloc);
-            if (!is_boost)
-                break;
-
-            boost[i]   += quanta;
-            tbits_8ths -= quanta;
-
-            b_dynalloc = 1;
-        }
-
-        if (boost[i])
-            dynalloc = FFMAX(2, dynalloc - 1);
-    }
-
-    /* Put allocation trim */
-    if (opus_rc_tell_frac(rc) + (6 << 3) <= tbits_8ths)
-        ff_opus_rc_enc_cdf(rc, f->alloc_trim, ff_celt_model_alloc_trim);
-
-    /* Anti-collapse bit reservation */
-    tbits_8ths = (f->framebits << 3) - opus_rc_tell_frac(rc) - 1;
-    f->anticollapse_needed = 0;
-    if (f->transient && f->size >= 2 && tbits_8ths >= ((f->size + 2) << 3))
-        f->anticollapse_needed = 1 << 3;
-    tbits_8ths -= f->anticollapse_needed;
-
-    /* Band skip bit reservation */
-    if (tbits_8ths >= 1 << 3)
-        skip_bit = 1 << 3;
-    tbits_8ths -= skip_bit;
-
-    /* Intensity/dual stereo bit reservation */
-    if (f->channels == 2) {
-        intensitystereo_bit = ff_celt_log2_frac[f->end_band - f->start_band];
-        if (intensitystereo_bit <= tbits_8ths) {
-            tbits_8ths -= intensitystereo_bit;
-            if (tbits_8ths >= 1 << 3) {
-                dualstereo_bit = 1 << 3;
-                tbits_8ths -= 1 << 3;
-            }
-        } else {
-            intensitystereo_bit = 0;
-        }
-    }
-
-    /* Trim offsets */
-    for (i = f->start_band; i < f->end_band; i++) {
-        int trim     = f->alloc_trim - 5 - f->size;
-        int band     = ff_celt_freq_range[i] * (f->end_band - i - 1);
-        int duration = f->size + 3;
-        int scale    = duration + f->channels - 1;
-
-        /* PVQ minimum allocation threshold, below this value the band is
-         * skipped */
-        threshold[i] = FFMAX(3 * ff_celt_freq_range[i] << duration >> 4,
-                             f->channels << 3);
-
-        trim_offset[i] = trim * (band << scale) >> 6;
-
-        if (ff_celt_freq_range[i] << f->size == 1)
-            trim_offset[i] -= f->channels << 3;
-    }
-
-    /* Bisection */
-    low  = 1;
-    high = CELT_VECTORS - 1;
-    while (low <= high) {
-        int center = (low + high) >> 1;
-        done = total = 0;
-
-        for (i = f->end_band - 1; i >= f->start_band; i--) {
-            bandbits = ff_celt_freq_range[i] * ff_celt_static_alloc[center][i]
-                       << (f->channels - 1) << f->size >> 2;
-
-            if (bandbits)
-                bandbits = FFMAX(0, bandbits + trim_offset[i]);
-            bandbits += boost[i];
-
-            if (bandbits >= threshold[i] || done) {
-                done = 1;
-                total += FFMIN(bandbits, cap[i]);
-            } else if (bandbits >= f->channels << 3)
-                total += f->channels << 3;
-        }
-
-        if (total > tbits_8ths)
-            high = center - 1;
-        else
-            low = center + 1;
-    }
-    high = low--;
-
-    /* Bisection */
-    for (i = f->start_band; i < f->end_band; i++) {
-        bits1[i] = ff_celt_freq_range[i] * ff_celt_static_alloc[low][i]
-                   << (f->channels - 1) << f->size >> 2;
-        bits2[i] = high >= CELT_VECTORS ? cap[i] :
-                   ff_celt_freq_range[i] * ff_celt_static_alloc[high][i]
-                   << (f->channels - 1) << f->size >> 2;
-
-        if (bits1[i])
-            bits1[i] = FFMAX(0, bits1[i] + trim_offset[i]);
-        if (bits2[i])
-            bits2[i] = FFMAX(0, bits2[i] + trim_offset[i]);
-        if (low)
-            bits1[i] += boost[i];
-        bits2[i] += boost[i];
-
-        if (boost[i])
-            skip_startband = i;
-        bits2[i] = FFMAX(0, bits2[i] - bits1[i]);
-    }
-
-    /* Bisection */
-    low  = 0;
-    high = 1 << CELT_ALLOC_STEPS;
-    for (i = 0; i < CELT_ALLOC_STEPS; i++) {
-        int center = (low + high) >> 1;
-        done = total = 0;
-
-        for (j = f->end_band - 1; j >= f->start_band; j--) {
-            bandbits = bits1[j] + (center * bits2[j] >> CELT_ALLOC_STEPS);
-
-            if (bandbits >= threshold[j] || done) {
-                done = 1;
-                total += FFMIN(bandbits, cap[j]);
-            } else if (bandbits >= f->channels << 3)
-                total += f->channels << 3;
-        }
-        if (total > tbits_8ths)
-            high = center;
-        else
-            low = center;
-    }
-
-    /* Bisection */
-    done = total = 0;
-    for (i = f->end_band - 1; i >= f->start_band; i--) {
-        bandbits = bits1[i] + (low * bits2[i] >> CELT_ALLOC_STEPS);
-
-        if (bandbits >= threshold[i] || done)
-            done = 1;
-        else
-            bandbits = (bandbits >= f->channels << 3) ?
-                       f->channels << 3 : 0;
-
-        bandbits     = FFMIN(bandbits, cap[i]);
-        f->pulses[i] = bandbits;
-        total      += bandbits;
-    }
-
-    /* Band skipping */
-    for (f->coded_bands = f->end_band; ; f->coded_bands--) {
-        int allocation;
-        j = f->coded_bands - 1;
-
-        if (j == skip_startband) {
-            /* all remaining bands are not skipped */
-            tbits_8ths += skip_bit;
-            break;
-        }
-
-        /* determine the number of bits available for coding "do not skip" markers */
-        remaining   = tbits_8ths - total;
-        bandbits    = remaining / (ff_celt_freq_bands[j+1] - ff_celt_freq_bands[f->start_band]);
-        remaining  -= bandbits  * (ff_celt_freq_bands[j+1] - ff_celt_freq_bands[f->start_band]);
-        allocation  = f->pulses[j] + bandbits * ff_celt_freq_range[j]
-                      + FFMAX(0, remaining - (ff_celt_freq_bands[j] - ff_celt_freq_bands[f->start_band]));
-
-        /* a "do not skip" marker is only coded if the allocation is
-           above the chosen threshold */
-        if (allocation >= FFMAX(threshold[j], (f->channels + 1) << 3)) {
-            const int do_not_skip = f->coded_bands <= f->skip_band_floor;
-            ff_opus_rc_enc_log(rc, do_not_skip, 1);
-            if (do_not_skip)
-                break;
-
-            total      += 1 << 3;
-            allocation -= 1 << 3;
-        }
-
-        /* the band is skipped, so reclaim its bits */
-        total -= f->pulses[j];
-        if (intensitystereo_bit) {
-            total -= intensitystereo_bit;
-            intensitystereo_bit = ff_celt_log2_frac[j - f->start_band];
-            total += intensitystereo_bit;
-        }
-
-        total += f->pulses[j] = (allocation >= f->channels << 3) ? f->channels << 3 : 0;
-    }
-
-    /* Encode stereo flags */
-    if (intensitystereo_bit) {
-        f->intensity_stereo = FFMIN(f->intensity_stereo, f->coded_bands);
-        ff_opus_rc_enc_uint(rc, f->intensity_stereo, f->coded_bands + 1 - f->start_band);
-    }
-    if (f->intensity_stereo <= f->start_band)
-        tbits_8ths += dualstereo_bit; /* no intensity stereo means no dual stereo */
-    else if (dualstereo_bit)
-        ff_opus_rc_enc_log(rc, f->dual_stereo, 1);
-
-    /* Supply the remaining bits in this frame to lower bands */
-    remaining = tbits_8ths - total;
-    bandbits  = remaining / (ff_celt_freq_bands[f->coded_bands] - ff_celt_freq_bands[f->start_band]);
-    remaining -= bandbits * (ff_celt_freq_bands[f->coded_bands] - ff_celt_freq_bands[f->start_band]);
-    for (i = f->start_band; i < f->coded_bands; i++) {
-        int bits = FFMIN(remaining, ff_celt_freq_range[i]);
-
-        f->pulses[i] += bits + bandbits * ff_celt_freq_range[i];
-        remaining    -= bits;
-    }
-
-    /* Finally determine the allocation */
-    for (i = f->start_band; i < f->coded_bands; i++) {
-        int N = ff_celt_freq_range[i] << f->size;
-        int prev_extra = extrabits;
-        f->pulses[i] += extrabits;
-
-        if (N > 1) {
-            int dof;        // degrees of freedom
-            int temp;       // dof * channels * log(dof)
-            int offset;     // fine energy quantization offset, i.e.
-                            // extra bits assigned over the standard
-                            // totalbits/dof
-            int fine_bits, max_bits;
-
-            extrabits = FFMAX(0, f->pulses[i] - cap[i]);
-            f->pulses[i] -= extrabits;
-
-            /* intensity stereo makes use of an extra degree of freedom */
-            dof = N * f->channels + (f->channels == 2 && N > 2 && !f->dual_stereo && i < f->intensity_stereo);
-            temp = dof * (ff_celt_log_freq_range[i] + (f->size << 3));
-            offset = (temp >> 1) - dof * CELT_FINE_OFFSET;
-            if (N == 2) /* dof=2 is the only case that doesn't fit the model */
-                offset += dof << 1;
-
-            /* grant an additional bias for the first and second pulses */
-            if (f->pulses[i] + offset < 2 * (dof << 3))
-                offset += temp >> 2;
-            else if (f->pulses[i] + offset < 3 * (dof << 3))
-                offset += temp >> 3;
-
-            fine_bits = (f->pulses[i] + offset + (dof << 2)) / (dof << 3);
-            max_bits  = FFMIN((f->pulses[i] >> 3) >> (f->channels - 1), CELT_MAX_FINE_BITS);
-
-            max_bits  = FFMAX(max_bits, 0);
-
-            f->fine_bits[i] = av_clip(fine_bits, 0, max_bits);
-
-            /* if fine_bits was rounded down or capped,
-               give priority for the final fine energy pass */
-            f->fine_priority[i] = (f->fine_bits[i] * (dof << 3) >= f->pulses[i] + offset);
-
-            /* the remaining bits are assigned to PVQ */
-            f->pulses[i] -= f->fine_bits[i] << (f->channels - 1) << 3;
-        } else {
-            /* all bits go to fine energy except for the sign bit */
-            extrabits = FFMAX(0, f->pulses[i] - (f->channels << 3));
-            f->pulses[i] -= extrabits;
-            f->fine_bits[i] = 0;
-            f->fine_priority[i] = 1;
-        }
-
-        /* hand back a limited number of extra fine energy bits to this band */
-        if (extrabits > 0) {
-            int fineextra = FFMIN(extrabits >> (f->channels + 2),
-                                  CELT_MAX_FINE_BITS - f->fine_bits[i]);
-            f->fine_bits[i] += fineextra;
-
-            fineextra <<= f->channels + 2;
-            f->fine_priority[i] = (fineextra >= extrabits - prev_extra);
-            extrabits -= fineextra;
-        }
-    }
-    f->remaining = extrabits;
-
-    /* skipped bands dedicate all of their bits for fine energy */
-    for (; i < f->end_band; i++) {
-        f->fine_bits[i]     = f->pulses[i] >> (f->channels - 1) >> 3;
-        f->pulses[i]        = 0;
-        f->fine_priority[i] = f->fine_bits[i] < 1;
-    }
-}
-
 static void celt_enc_quant_pfilter(OpusRangeCoder *rc, CeltFrame *f)
 {
     float gain = f->pf_gain;
@@ -794,11 +467,11 @@ static void celt_encode_frame(OpusEncContext *s, OpusRangeCoder *rc,
         ff_opus_rc_enc_log(rc, f->transient, 3);
 
     /* Main encoding */
-    celt_quant_coarse   (f, rc, s->last_quantized_energy);
-    celt_enc_tf         (f, rc);
-    ff_celt_enc_bitalloc(f, rc);
-    celt_quant_fine     (f, rc);
-    ff_celt_quant_bands (f, rc);
+    celt_quant_coarse  (f, rc, s->last_quantized_energy);
+    celt_enc_tf        (f, rc);
+    ff_celt_bitalloc   (f, rc, 1);
+    celt_quant_fine    (f, rc);
+    ff_celt_quant_bands(f, rc);
 
     /* Anticollapse bit */
     if (f->anticollapse_needed)
diff --git a/libavcodec/opusenc.h b/libavcodec/opusenc.h
index 56e4af67e3..b9162ebec6 100644
--- a/libavcodec/opusenc.h
+++ b/libavcodec/opusenc.h
@@ -51,6 +51,4 @@ typedef struct OpusPacketInfo {
     int frames;
 } OpusPacketInfo;
 
-void ff_celt_enc_bitalloc(CeltFrame *f, OpusRangeCoder *rc);
-
 #endif /* AVCODEC_OPUSENC_H */
diff --git a/libavcodec/opusenc_psy.c b/libavcodec/opusenc_psy.c
index 5393c9d7de..50890c65d6 100644
--- a/libavcodec/opusenc_psy.c
+++ b/libavcodec/opusenc_psy.c
@@ -366,7 +366,7 @@ static int bands_dist(OpusPsyContext *s, CeltFrame *f, float *total_dist)
     OpusRangeCoder dump;
 
     ff_opus_rc_enc_init(&dump);
-    ff_celt_enc_bitalloc(f, &dump);
+    ff_celt_bitalloc(f, &dump, 1);
 
     for (i = 0; i < CELT_MAX_BANDS; i++) {
         float bits = 0.0f;