/*
  * Opus encoder
  * Copyright (c) 2017 Rostislav Pehlivanov <atomnuker@gmail.com>
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 

 #include "opusenc.h"

 #include "opus_pvq.h"

 #include "opusenc_psy.h"

 #include "opustab.h"
 
 #include "libavutil/float_dsp.h"
 #include "libavutil/opt.h"
 #include "internal.h"
 #include "bytestream.h"
 #include "audio_frame_queue.h"
 
 typedef struct OpusEncContext {
     AVClass *av_class;
     OpusEncOptions options;

     OpusPsyContext psyctx;

     AVCodecContext *avctx;
     AudioFrameQueue afq;
     AVFloatDSPContext *dsp;
     MDCT15Context *mdct[CELT_BLOCK_NB];

     CeltPVQ *pvq;

     struct FFBufQueue bufqueue;
 

     uint8_t enc_id[64];
     int enc_id_bits;
 
     OpusPacketInfo packet;

 
     int channels;
 
     CeltFrame *frame;
     OpusRangeCoder *rc;
 
     /* Actual energy the decoder will have */
     float last_quantized_energy[OPUS_MAX_CHANNELS][CELT_MAX_BANDS];
 
     DECLARE_ALIGNED(32, float, scratch)[2048];
 } OpusEncContext;
 
 static void opus_write_extradata(AVCodecContext *avctx)
 {
     uint8_t *bs = avctx->extradata;
 
     bytestream_put_buffer(&bs, "OpusHead", 8);
     bytestream_put_byte  (&bs, 0x1);
     bytestream_put_byte  (&bs, avctx->channels);
     bytestream_put_le16  (&bs, avctx->initial_padding);
     bytestream_put_le32  (&bs, avctx->sample_rate);
     bytestream_put_le16  (&bs, 0x0);
     bytestream_put_byte  (&bs, 0x0); /* Default layout */
 }
 
 static int opus_gen_toc(OpusEncContext *s, uint8_t *toc, int *size, int *fsize_needed)
 {
     int i, tmp = 0x0, extended_toc = 0;
     static const int toc_cfg[][OPUS_MODE_NB][OPUS_BANDWITH_NB] = {
         /*  Silk                    Hybrid                  Celt                    Layer     */
         /*  NB  MB  WB SWB  FB      NB  MB  WB SWB  FB      NB  MB  WB SWB  FB      Bandwidth */
         { {  0,  0,  0,  0,  0 }, {  0,  0,  0,  0,  0 }, { 17,  0, 21, 25, 29 } }, /* 2.5 ms */
         { {  0,  0,  0,  0,  0 }, {  0,  0,  0,  0,  0 }, { 18,  0, 22, 26, 30 } }, /*   5 ms */
         { {  1,  5,  9,  0,  0 }, {  0,  0,  0, 13, 15 }, { 19,  0, 23, 27, 31 } }, /*  10 ms */
         { {  2,  6, 10,  0,  0 }, {  0,  0,  0, 14, 16 }, { 20,  0, 24, 28, 32 } }, /*  20 ms */
         { {  3,  7, 11,  0,  0 }, {  0,  0,  0,  0,  0 }, {  0,  0,  0,  0,  0 } }, /*  40 ms */
         { {  4,  8, 12,  0,  0 }, {  0,  0,  0,  0,  0 }, {  0,  0,  0,  0,  0 } }, /*  60 ms */
     };

     int cfg = toc_cfg[s->packet.framesize][s->packet.mode][s->packet.bandwidth];

     *fsize_needed = 0;
     if (!cfg)
         return 1;

     if (s->packet.frames == 2) {                                       /* 2 packets */

         if (s->frame[0].framebits == s->frame[1].framebits) {          /* same size */
             tmp = 0x1;
         } else {                                                  /* different size */
             tmp = 0x2;
             *fsize_needed = 1;                     /* put frame sizes in the packet */
         }

     } else if (s->packet.frames > 2) {

         tmp = 0x3;
         extended_toc = 1;
     }
     tmp |= (s->channels > 1) << 2;                                /* Stereo or mono */
     tmp |= (cfg - 1)         << 3;                           /* codec configuration */
     *toc++ = tmp;
     if (extended_toc) {

         for (i = 0; i < (s->packet.frames - 1); i++)

             *fsize_needed |= (s->frame[i].framebits != s->frame[i + 1].framebits);

         tmp = (*fsize_needed) << 7;                                /* vbr flag */
         tmp |= (0) << 6;                                       /* padding flag */
         tmp |= s->packet.frames;

         *toc++ = tmp;
     }
     *size = 1 + extended_toc;
     return 0;
 }
 
 static void celt_frame_setup_input(OpusEncContext *s, CeltFrame *f)
 {
     int sf, ch;
     AVFrame *cur = NULL;
     const int subframesize = s->avctx->frame_size;

     int subframes = OPUS_BLOCK_SIZE(s->packet.framesize) / subframesize;

 
     cur = ff_bufqueue_get(&s->bufqueue);
 
     for (ch = 0; ch < f->channels; ch++) {
         CeltBlock *b = &f->block[ch];
         const void *input = cur->extended_data[ch];
         size_t bps = av_get_bytes_per_sample(cur->format);
         memcpy(b->overlap, input, bps*cur->nb_samples);
     }
 
     av_frame_free(&cur);
 
     for (sf = 0; sf < subframes; sf++) {
         if (sf != (subframes - 1))
             cur = ff_bufqueue_get(&s->bufqueue);
         else
             cur = ff_bufqueue_peek(&s->bufqueue, 0);
 
         for (ch = 0; ch < f->channels; ch++) {
             CeltBlock *b = &f->block[ch];
             const void *input = cur->extended_data[ch];
             const size_t bps  = av_get_bytes_per_sample(cur->format);
             const size_t left = (subframesize - cur->nb_samples)*bps;
             const size_t len  = FFMIN(subframesize, cur->nb_samples)*bps;
             memcpy(&b->samples[sf*subframesize], input, len);
             memset(&b->samples[cur->nb_samples], 0, left);
         }
 
         /* Last frame isn't popped off and freed yet - we need it for overlap */
         if (sf != (subframes - 1))
             av_frame_free(&cur);
     }
 }
 
 /* Apply the pre emphasis filter */
 static void celt_apply_preemph_filter(OpusEncContext *s, CeltFrame *f)
 {
     int i, sf, ch;
     const int subframesize = s->avctx->frame_size;

     const int subframes = OPUS_BLOCK_SIZE(s->packet.framesize) / subframesize;

 
     /* Filter overlap */
     for (ch = 0; ch < f->channels; ch++) {
         CeltBlock *b = &f->block[ch];
         float m = b->emph_coeff;
         for (i = 0; i < CELT_OVERLAP; i++) {
             float sample = b->overlap[i];
             b->overlap[i] = sample - m;
             m = sample * CELT_EMPH_COEFF;
         }
         b->emph_coeff = m;
     }
 
     /* Filter the samples but do not update the last subframe's coeff - overlap ^^^ */
     for (sf = 0; sf < subframes; sf++) {
         for (ch = 0; ch < f->channels; ch++) {
             CeltBlock *b = &f->block[ch];
             float m = b->emph_coeff;
             for (i = 0; i < subframesize; i++) {
                 float sample = b->samples[sf*subframesize + i];
                 b->samples[sf*subframesize + i] = sample - m;
                 m = sample * CELT_EMPH_COEFF;
             }
             if (sf != (subframes - 1))
                 b->emph_coeff = m;
         }
     }
 }
 
 /* Create the window and do the mdct */
 static void celt_frame_mdct(OpusEncContext *s, CeltFrame *f)
 {

     int i, j, t, ch;

     float *win = s->scratch, *temp = s->scratch + 1920;

 
     if (f->transient) {
         for (ch = 0; ch < f->channels; ch++) {
             CeltBlock *b = &f->block[ch];
             float *src1 = b->overlap;
             for (t = 0; t < f->blocks; t++) {
                 float *src2 = &b->samples[CELT_OVERLAP*t];

                 s->dsp->vector_fmul(win, src1, ff_celt_window, 128);

                 s->dsp->vector_fmul_reverse(&win[CELT_OVERLAP], src2,

                                             ff_celt_window - 8, 128);

                 src1 = src2;
                 s->mdct[0]->mdct(s->mdct[0], b->coeffs + t, win, f->blocks);
             }
         }
     } else {
         int blk_len = OPUS_BLOCK_SIZE(f->size), wlen = OPUS_BLOCK_SIZE(f->size + 1);
         int rwin = blk_len - CELT_OVERLAP, lap_dst = (wlen - blk_len - CELT_OVERLAP) >> 1;

         memset(win, 0, wlen*sizeof(float));

         for (ch = 0; ch < f->channels; ch++) {
             CeltBlock *b = &f->block[ch];
 

             /* Overlap */
             s->dsp->vector_fmul(temp, b->overlap, ff_celt_window, 128);
             memcpy(win + lap_dst, temp, CELT_OVERLAP*sizeof(float));

             /* Samples, flat top window */

             memcpy(&win[lap_dst + CELT_OVERLAP], b->samples, rwin*sizeof(float));
 

             /* Samples, windowed */
             s->dsp->vector_fmul_reverse(temp, b->samples + rwin,
                                         ff_celt_window - 8, 128);
             memcpy(win + lap_dst + blk_len, temp, CELT_OVERLAP*sizeof(float));

 
             s->mdct[f->size]->mdct(s->mdct[f->size], b->coeffs, win, 1);
         }
     }
 
     for (ch = 0; ch < f->channels; ch++) {
         CeltBlock *block = &f->block[ch];
         for (i = 0; i < CELT_MAX_BANDS; i++) {
             float ener = 0.0f;

             int band_offset = ff_celt_freq_bands[i] << f->size;
             int band_size   = ff_celt_freq_range[i] << f->size;
             float *coeffs   = &block->coeffs[band_offset];

             for (j = 0; j < band_size; j++)
                 ener += coeffs[j]*coeffs[j];

 
             block->lin_energy[i] = sqrtf(ener) + FLT_EPSILON;
             ener = 1.0f/block->lin_energy[i];
 

             for (j = 0; j < band_size; j++)
                 coeffs[j] *= ener;

 
             block->energy[i] = log2f(block->lin_energy[i]) - ff_celt_mean_energy[i];
 
             /* CELT_ENERGY_SILENCE is what the decoder uses and its not -infinity */
             block->energy[i] = FFMAX(block->energy[i], CELT_ENERGY_SILENCE);
         }
     }
 }
 

 static void celt_enc_tf(OpusRangeCoder *rc, CeltFrame *f)

 {
     int i, tf_select = 0, diff = 0, tf_changed = 0, tf_select_needed;
     int bits = f->transient ? 2 : 4;
 
     tf_select_needed = ((f->size && (opus_rc_tell(rc) + bits + 1) <= f->framebits));
 
     for (i = f->start_band; i < f->end_band; i++) {
         if ((opus_rc_tell(rc) + bits + tf_select_needed) <= f->framebits) {
             const int tbit = (diff ^ 1) == f->tf_change[i];
             ff_opus_rc_enc_log(rc, tbit, bits);
             diff ^= tbit;
             tf_changed |= diff;
         }
         bits = f->transient ? 4 : 5;
     }
 
     if (tf_select_needed && ff_celt_tf_select[f->size][f->transient][0][tf_changed] !=
                             ff_celt_tf_select[f->size][f->transient][1][tf_changed]) {
         ff_opus_rc_enc_log(rc, f->tf_select, 1);
         tf_select = f->tf_select;
     }
 
     for (i = f->start_band; i < f->end_band; i++)
         f->tf_change[i] = ff_celt_tf_select[f->size][f->transient][tf_select][f->tf_change[i]];
 }
 

 void ff_celt_enc_bitalloc(OpusRangeCoder *rc, CeltFrame *f)

 {
     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;
     int i, txval, octave = f->pf_octave, period = f->pf_period, tapset = f->pf_tapset;
 
     ff_opus_rc_enc_log(rc, f->pfilter, 1);
     if (!f->pfilter)
         return;
 
     /* Octave */
     txval = FFMIN(octave, 6);
     ff_opus_rc_enc_uint(rc, txval, 6);
     octave = txval;
     /* Period */
     txval = av_clip(period - (16 << octave) + 1, 0, (1 << (4 + octave)) - 1);
     ff_opus_rc_put_raw(rc, period, 4 + octave);
     period = txval + (16 << octave) - 1;
     /* Gain */
     txval = FFMIN(((int)(gain / 0.09375f)) - 1, 7);
     ff_opus_rc_put_raw(rc, txval, 3);
     gain   = 0.09375f * (txval + 1);
     /* Tapset */
     if ((opus_rc_tell(rc) + 2) <= f->framebits)
         ff_opus_rc_enc_cdf(rc, tapset, ff_celt_model_tapset);
     else
         tapset = 0;
     /* Finally create the coeffs */
     for (i = 0; i < 2; i++) {
         CeltBlock *block = &f->block[i];
 
         block->pf_period_new = FFMAX(period, CELT_POSTFILTER_MINPERIOD);
         block->pf_gains_new[0] = gain * ff_celt_postfilter_taps[tapset][0];
         block->pf_gains_new[1] = gain * ff_celt_postfilter_taps[tapset][1];
         block->pf_gains_new[2] = gain * ff_celt_postfilter_taps[tapset][2];
     }
 }
 

 static void exp_quant_coarse(OpusRangeCoder *rc, CeltFrame *f,
                              float last_energy[][CELT_MAX_BANDS], int intra)

 {
     int i, ch;
     float alpha, beta, prev[2] = { 0, 0 };

     const uint8_t *pmod = ff_celt_coarse_energy_dist[f->size][intra];

 
     /* Inter is really just differential coding */
     if (opus_rc_tell(rc) + 3 <= f->framebits)

         ff_opus_rc_enc_log(rc, intra, 3);

     else

         intra = 0;

     if (intra) {

         alpha = 0.0f;

         beta  = 1.0f - (4915.0f/32768.0f);

     } else {
         alpha = ff_celt_alpha_coef[f->size];

         beta  = ff_celt_beta_coef[f->size];

     }
 
     for (i = f->start_band; i < f->end_band; i++) {
         for (ch = 0; ch < f->channels; ch++) {
             CeltBlock *block = &f->block[ch];
             const int left = f->framebits - opus_rc_tell(rc);

             const float last = FFMAX(-9.0f, last_energy[ch][i]);

             float diff = block->energy[i] - prev[ch] - last*alpha;
             int q_en = lrintf(diff);
             if (left >= 15) {
                 ff_opus_rc_enc_laplace(rc, &q_en, pmod[i << 1] << 7, pmod[(i << 1) + 1] << 6);
             } else if (left >= 2) {
                 q_en = av_clip(q_en, -1, 1);

                 ff_opus_rc_enc_cdf(rc, 2*q_en + 3*(q_en < 0), ff_celt_model_energy_small);

             } else if (left >= 1) {
                 q_en = av_clip(q_en, -1, 0);
                 ff_opus_rc_enc_log(rc, (q_en & 1), 1);
             } else q_en = -1;
 
             block->error_energy[i] = q_en - diff;
             prev[ch] += beta * q_en;
         }
     }
 }
 

 static void celt_quant_coarse(OpusRangeCoder *rc, CeltFrame *f,
                               float last_energy[][CELT_MAX_BANDS])
 {
     uint32_t inter, intra;
     OPUS_RC_CHECKPOINT_SPAWN(rc);
 
     exp_quant_coarse(rc, f, last_energy, 1);
     intra = OPUS_RC_CHECKPOINT_BITS(rc);
 
     OPUS_RC_CHECKPOINT_ROLLBACK(rc);
 
     exp_quant_coarse(rc, f, last_energy, 0);
     inter = OPUS_RC_CHECKPOINT_BITS(rc);
 
     if (inter > intra) { /* Unlikely */
         OPUS_RC_CHECKPOINT_ROLLBACK(rc);
         exp_quant_coarse(rc, f, last_energy, 1);
     }
 }
 

 static void celt_quant_fine(OpusRangeCoder *rc, CeltFrame *f)

 {
     int i, ch;
     for (i = f->start_band; i < f->end_band; i++) {
         if (!f->fine_bits[i])
             continue;
         for (ch = 0; ch < f->channels; ch++) {
             CeltBlock *block = &f->block[ch];
             int quant, lim = (1 << f->fine_bits[i]);
             float offset, diff = 0.5f - block->error_energy[i];
             quant = av_clip(floor(diff*lim), 0, lim - 1);
             ff_opus_rc_put_raw(rc, quant, f->fine_bits[i]);
             offset = 0.5f - ((quant + 0.5f) * (1 << (14 - f->fine_bits[i])) / 16384.0f);
             block->error_energy[i] -= offset;
         }
     }
 }
 
 static void celt_quant_final(OpusEncContext *s, OpusRangeCoder *rc, CeltFrame *f)
 {
     int i, ch, priority;
     for (priority = 0; priority < 2; priority++) {
         for (i = f->start_band; i < f->end_band && (f->framebits - opus_rc_tell(rc)) >= f->channels; i++) {
             if (f->fine_priority[i] != priority || f->fine_bits[i] >= CELT_MAX_FINE_BITS)
                 continue;
             for (ch = 0; ch < f->channels; ch++) {
                 CeltBlock *block = &f->block[ch];
                 const float err = block->error_energy[i];
                 const float offset = 0.5f * (1 << (14 - f->fine_bits[i] - 1)) / 16384.0f;
                 const int sign = FFABS(err + offset) < FFABS(err - offset);
                 ff_opus_rc_put_raw(rc, sign, 1);
                 block->error_energy[i] -= offset*(1 - 2*sign);
             }
         }
     }
 }
 

 static void celt_quant_bands(OpusRangeCoder *rc, CeltFrame *f)

 {
     float lowband_scratch[8 * 22];
     float norm[2 * 8 * 100];
 
     int totalbits = (f->framebits << 3) - f->anticollapse_needed;
 
     int update_lowband = 1;
     int lowband_offset = 0;
 
     int i, j;
 
     for (i = f->start_band; i < f->end_band; i++) {

         uint32_t cm[2] = { (1 << f->blocks) - 1, (1 << f->blocks) - 1 };

         int band_offset = ff_celt_freq_bands[i] << f->size;
         int band_size   = ff_celt_freq_range[i] << f->size;
         float *X = f->block[0].coeffs + band_offset;
         float *Y = (f->channels == 2) ? f->block[1].coeffs + band_offset : NULL;
 
         int consumed = opus_rc_tell_frac(rc);
         float *norm2 = norm + 8 * 100;
         int effective_lowband = -1;

         int b = 0;

 
         /* Compute how many bits we want to allocate to this band */
         if (i != f->start_band)
             f->remaining -= consumed;
         f->remaining2 = totalbits - consumed - 1;
         if (i <= f->coded_bands - 1) {
             int curr_balance = f->remaining / FFMIN(3, f->coded_bands-i);
             b = av_clip_uintp2(FFMIN(f->remaining2 + 1, f->pulses[i] + curr_balance), 14);

         }

 
         if (ff_celt_freq_bands[i] - ff_celt_freq_range[i] >= ff_celt_freq_bands[f->start_band] &&
             (update_lowband || lowband_offset == 0))
             lowband_offset = i;
 
         /* Get a conservative estimate of the collapse_mask's for the bands we're
         going to be folding from. */
         if (lowband_offset != 0 && (f->spread != CELT_SPREAD_AGGRESSIVE ||
                                     f->blocks > 1 || f->tf_change[i] < 0)) {
             int foldstart, foldend;
 
             /* This ensures we never repeat spectral content within one band */
             effective_lowband = FFMAX(ff_celt_freq_bands[f->start_band],
                                       ff_celt_freq_bands[lowband_offset] - ff_celt_freq_range[i]);
             foldstart = lowband_offset;
             while (ff_celt_freq_bands[--foldstart] > effective_lowband);
             foldend = lowband_offset - 1;
             while (ff_celt_freq_bands[++foldend] < effective_lowband + ff_celt_freq_range[i]);
 
             cm[0] = cm[1] = 0;
             for (j = foldstart; j < foldend; j++) {
                 cm[0] |= f->block[0].collapse_masks[j];
                 cm[1] |= f->block[f->channels - 1].collapse_masks[j];
             }

         }

 
         if (f->dual_stereo && i == f->intensity_stereo) {
             /* Switch off dual stereo to do intensity */
             f->dual_stereo = 0;
             for (j = ff_celt_freq_bands[f->start_band] << f->size; j < band_offset; j++)
                 norm[j] = (norm[j] + norm2[j]) / 2;
         }
 
         if (f->dual_stereo) {

             cm[0] = f->pvq->encode_band(f->pvq, f, rc, i, X, NULL, band_size, b / 2, f->blocks,

                                         effective_lowband != -1 ? norm + (effective_lowband << f->size) : NULL, f->size,
                                         norm + band_offset, 0, 1.0f, lowband_scratch, cm[0]);
 

             cm[1] = f->pvq->encode_band(f->pvq, f, rc, i, Y, NULL, band_size, b / 2, f->blocks,

                                         effective_lowband != -1 ? norm2 + (effective_lowband << f->size) : NULL, f->size,
                                         norm2 + band_offset, 0, 1.0f, lowband_scratch, cm[1]);
         } else {

             cm[0] = f->pvq->encode_band(f->pvq, f, rc, i, X, Y, band_size, b, f->blocks,

                                         effective_lowband != -1 ? norm + (effective_lowband << f->size) : NULL, f->size,

                                         norm + band_offset, 0, 1.0f, lowband_scratch, cm[0] | cm[1]);

             cm[1] = cm[0];
         }
 
         f->block[0].collapse_masks[i]               = (uint8_t)cm[0];
         f->block[f->channels - 1].collapse_masks[i] = (uint8_t)cm[1];
         f->remaining += f->pulses[i] + consumed;
 
         /* Update the folding position only as long as we have 1 bit/sample depth */
         update_lowband = (b > band_size << 3);
     }
 }
 

 static void celt_encode_frame(OpusEncContext *s, OpusRangeCoder *rc,
                               CeltFrame *f, int index)

 {
     int i, ch;
 

     ff_opus_rc_enc_init(rc);
 
     ff_opus_psy_celt_frame_init(&s->psyctx, f, index);
 

     celt_frame_setup_input(s, f);

 
     if (f->silence) {
         if (f->framebits >= 16)
             ff_opus_rc_enc_log(rc, 1, 15); /* Silence (if using explicit singalling) */
         for (ch = 0; ch < s->channels; ch++)
             memset(s->last_quantized_energy[ch], 0.0f, sizeof(float)*CELT_MAX_BANDS);
         return;
     }
 
     /* Filters */

     celt_apply_preemph_filter(s, f);
     if (f->pfilter) {

         ff_opus_rc_enc_log(rc, 0, 15);
         celt_enc_quant_pfilter(rc, f);

     }

 
     /* Transform */

     celt_frame_mdct(s, f);
 

     /* Need to handle transient/non-transient switches at any point during analysis */
     while (ff_opus_psy_celt_frame_process(&s->psyctx, f, index))
         celt_frame_mdct(s, f);

     ff_opus_rc_enc_init(rc);

     /* Silence */
     ff_opus_rc_enc_log(rc, 0, 15);
 
     /* Pitch filter */
     if (!f->start_band && opus_rc_tell(rc) + 16 <= f->framebits)
         celt_enc_quant_pfilter(rc, f);

     /* Transient flag */

     if (f->size && opus_rc_tell(rc) + 3 <= f->framebits)
         ff_opus_rc_enc_log(rc, f->transient, 3);
 

     /* Main encoding */

     celt_quant_coarse(rc, f, s->last_quantized_energy);

     celt_enc_tf      (rc, f);
     ff_celt_enc_bitalloc(rc, f);
     celt_quant_fine  (rc, f);
     celt_quant_bands (rc, f);

     /* Anticollapse bit */

     if (f->anticollapse_needed)
         ff_opus_rc_put_raw(rc, f->anticollapse, 1);
 

     /* Final per-band energy adjustments from leftover bits */

     celt_quant_final(s, rc, f);
 
     for (ch = 0; ch < f->channels; ch++) {
         CeltBlock *block = &f->block[ch];
         for (i = 0; i < CELT_MAX_BANDS; i++)
             s->last_quantized_energy[ch][i] = block->energy[i] + block->error_energy[i];
     }
 }
 

 static inline int write_opuslacing(uint8_t *dst, int v)

 {

     dst[0] = FFMIN(v - FFALIGN(v - 255, 4), v);
     dst[1] = v - dst[0] >> 2;
     return 1 + (v >= 252);

 }
 
 static void opus_packet_assembler(OpusEncContext *s, AVPacket *avpkt)
 {
     int i, offset, fsize_needed;
 
     /* Write toc */
     opus_gen_toc(s, avpkt->data, &offset, &fsize_needed);
 

     /* Frame sizes if needed */
     if (fsize_needed) {
         for (i = 0; i < s->packet.frames - 1; i++) {
             offset += write_opuslacing(avpkt->data + offset,
                                        s->frame[i].framebits >> 3);
         }
     }
 
     /* Packets */
     for (i = 0; i < s->packet.frames; i++) {
         ff_opus_rc_enc_end(&s->rc[i], avpkt->data + offset,
                            s->frame[i].framebits >> 3);

         offset += s->frame[i].framebits >> 3;
     }
 
     avpkt->size = offset;
 }
 
 /* Used as overlap for the first frame and padding for the last encoded packet */
 static AVFrame *spawn_empty_frame(OpusEncContext *s)
 {
     int i;
     AVFrame *f = av_frame_alloc();
     if (!f)
         return NULL;
     f->format         = s->avctx->sample_fmt;
     f->nb_samples     = s->avctx->frame_size;
     f->channel_layout = s->avctx->channel_layout;
     if (av_frame_get_buffer(f, 4)) {
         av_frame_free(&f);
         return NULL;
     }
     for (i = 0; i < s->channels; i++) {
         size_t bps = av_get_bytes_per_sample(f->format);
         memset(f->extended_data[i], 0, bps*f->nb_samples);
     }
     return f;
 }
 
 static int opus_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
                              const AVFrame *frame, int *got_packet_ptr)
 {
     OpusEncContext *s = avctx->priv_data;

     int i, ret, frame_size, alloc_size = 0;

 
     if (frame) { /* Add new frame to queue */
         if ((ret = ff_af_queue_add(&s->afq, frame)) < 0)
             return ret;
         ff_bufqueue_add(avctx, &s->bufqueue, av_frame_clone(frame));
     } else {

         ff_opus_psy_signal_eof(&s->psyctx);

         if (!s->afq.remaining_samples)
             return 0; /* We've been flushed and there's nothing left to encode */
     }
 
     /* Run the psychoacoustic system */

     if (ff_opus_psy_process(&s->psyctx, &s->packet))

         return 0;
 

     frame_size = OPUS_BLOCK_SIZE(s->packet.framesize);

 
     if (!frame) {
         /* This can go negative, that's not a problem, we only pad if positive */

         int pad_empty = s->packet.frames*(frame_size/s->avctx->frame_size) - s->bufqueue.available + 1;

         /* Pad with empty 2.5 ms frames to whatever framesize was decided,
          * this should only happen at the very last flush frame. The frames
          * allocated here will be freed (because they have no other references)
          * after they get used by celt_frame_setup_input() */
         for (i = 0; i < pad_empty; i++) {
             AVFrame *empty = spawn_empty_frame(s);
             if (!empty)
                 return AVERROR(ENOMEM);
             ff_bufqueue_add(avctx, &s->bufqueue, empty);
         }
     }
 

     for (i = 0; i < s->packet.frames; i++) {
         celt_encode_frame(s, &s->rc[i], &s->frame[i], i);

         alloc_size += s->frame[i].framebits >> 3;
     }
 
     /* Worst case toc + the frame lengths if needed */

     alloc_size += 2 + s->packet.frames*2;

 
     if ((ret = ff_alloc_packet2(avctx, avpkt, alloc_size, 0)) < 0)
         return ret;
 
     /* Assemble packet */
     opus_packet_assembler(s, avpkt);
 

     /* Update the psychoacoustic system */
     ff_opus_psy_postencode_update(&s->psyctx, s->frame, s->rc);
 

     /* Remove samples from queue and skip if needed */

     ff_af_queue_remove(&s->afq, s->packet.frames*frame_size, &avpkt->pts, &avpkt->duration);
     if (s->packet.frames*frame_size > avpkt->duration) {

         uint8_t *side = av_packet_new_side_data(avpkt, AV_PKT_DATA_SKIP_SAMPLES, 10);
         if (!side)
             return AVERROR(ENOMEM);

         AV_WL32(&side[4], s->packet.frames*frame_size - avpkt->duration + 120);

     }
 
     *got_packet_ptr = 1;
 
     return 0;
 }
 
 static av_cold int opus_encode_end(AVCodecContext *avctx)
 {
     int i;
     OpusEncContext *s = avctx->priv_data;
 
     for (i = 0; i < CELT_BLOCK_NB; i++)
         ff_mdct15_uninit(&s->mdct[i]);
 

     ff_celt_pvq_uninit(&s->pvq);

     av_freep(&s->dsp);
     av_freep(&s->frame);
     av_freep(&s->rc);
     ff_af_queue_close(&s->afq);

     ff_opus_psy_end(&s->psyctx);

     ff_bufqueue_discard_all(&s->bufqueue);
     av_freep(&avctx->extradata);
 
     return 0;
 }
 
 static av_cold int opus_encode_init(AVCodecContext *avctx)
 {

     int i, ch, ret, max_frames;

     OpusEncContext *s = avctx->priv_data;
 
     s->avctx = avctx;
     s->channels = avctx->channels;
 
     /* Opus allows us to change the framesize on each packet (and each packet may
      * have multiple frames in it) but we can't change the codec's frame size on
      * runtime, so fix it to the lowest possible number of samples and use a queue
      * to accumulate AVFrames until we have enough to encode whatever the encoder
      * decides is the best */
     avctx->frame_size = 120;
     /* Initial padding will change if SILK is ever supported */
     avctx->initial_padding = 120;
 
     if (!avctx->bit_rate) {
         int coupled = ff_opus_default_coupled_streams[s->channels - 1];
         avctx->bit_rate = coupled*(96000) + (s->channels - coupled*2)*(48000);
     } else if (avctx->bit_rate < 6000 || avctx->bit_rate > 255000 * s->channels) {
         int64_t clipped_rate = av_clip(avctx->bit_rate, 6000, 255000 * s->channels);

         av_log(avctx, AV_LOG_ERROR, "Unsupported bitrate %"PRId64" kbps, clipping to %"PRId64" kbps\n",

                avctx->bit_rate/1000, clipped_rate/1000);
         avctx->bit_rate = clipped_rate;
     }
 
     /* Extradata */
     avctx->extradata_size = 19;
     avctx->extradata = av_malloc(avctx->extradata_size + AV_INPUT_BUFFER_PADDING_SIZE);
     if (!avctx->extradata)
         return AVERROR(ENOMEM);
     opus_write_extradata(avctx);
 
     ff_af_queue_init(avctx, &s->afq);
 

     if ((ret = ff_celt_pvq_init(&s->pvq)) < 0)
         return ret;
 

     if (!(s->dsp = avpriv_float_dsp_alloc(avctx->flags & AV_CODEC_FLAG_BITEXACT)))
         return AVERROR(ENOMEM);
 
     /* I have no idea why a base scaling factor of 68 works, could be the twiddles */
     for (i = 0; i < CELT_BLOCK_NB; i++)
         if ((ret = ff_mdct15_init(&s->mdct[i], 0, i + 3, 68 << (CELT_BLOCK_NB - 1 - i))))
             return AVERROR(ENOMEM);
 
     /* Zero out previous energy (matters for inter first frame) */
     for (ch = 0; ch < s->channels; ch++)

         memset(s->last_quantized_energy[ch], 0.0f, sizeof(float)*CELT_MAX_BANDS);

 
     /* Allocate an empty frame to use as overlap for the first frame of audio */
     ff_bufqueue_add(avctx, &s->bufqueue, spawn_empty_frame(s));
     if (!ff_bufqueue_peek(&s->bufqueue, 0))
         return AVERROR(ENOMEM);
 

     if ((ret = ff_opus_psy_init(&s->psyctx, s->avctx, &s->bufqueue, &s->options)))
         return ret;
 
     /* Frame structs and range coder buffers */
     max_frames = ceilf(FFMIN(s->options.max_delay_ms, 120.0f)/2.5f);
     s->frame = av_malloc(max_frames*sizeof(CeltFrame));
     if (!s->frame)
         return AVERROR(ENOMEM);
     s->rc = av_malloc(max_frames*sizeof(OpusRangeCoder));
     if (!s->rc)
         return AVERROR(ENOMEM);
 
     for (i = 0; i < max_frames; i++) {
         s->frame[i].dsp = s->dsp;
         s->frame[i].avctx = s->avctx;
         s->frame[i].seed = 0;
         s->frame[i].pvq = s->pvq;
         s->frame[i].block[0].emph_coeff = s->frame[i].block[1].emph_coeff = 0.0f;
     }
 

     return 0;
 }
 
 #define OPUSENC_FLAGS AV_OPT_FLAG_ENCODING_PARAM | AV_OPT_FLAG_AUDIO_PARAM
 static const AVOption opusenc_options[] = {

     { "opus_delay", "Maximum delay in milliseconds", offsetof(OpusEncContext, options.max_delay_ms), AV_OPT_TYPE_FLOAT, { .dbl = OPUS_MAX_LOOKAHEAD }, 2.5f, OPUS_MAX_LOOKAHEAD, OPUSENC_FLAGS, "max_delay_ms" },

     { NULL },
 };
 
 static const AVClass opusenc_class = {
     .class_name = "Opus encoder",
     .item_name  = av_default_item_name,
     .option     = opusenc_options,
     .version    = LIBAVUTIL_VERSION_INT,
 };
 
 static const AVCodecDefault opusenc_defaults[] = {
     { "b", "0" },
     { "compression_level", "10" },
     { NULL },
 };
 
 AVCodec ff_opus_encoder = {
     .name           = "opus",
     .long_name      = NULL_IF_CONFIG_SMALL("Opus"),
     .type           = AVMEDIA_TYPE_AUDIO,
     .id             = AV_CODEC_ID_OPUS,
     .defaults       = opusenc_defaults,
     .priv_class     = &opusenc_class,
     .priv_data_size = sizeof(OpusEncContext),
     .init           = opus_encode_init,
     .encode2        = opus_encode_frame,
     .close          = opus_encode_end,
     .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
     .capabilities   = AV_CODEC_CAP_EXPERIMENTAL | AV_CODEC_CAP_SMALL_LAST_FRAME | AV_CODEC_CAP_DELAY,
     .supported_samplerates = (const int []){ 48000, 0 },
     .channel_layouts = (const uint64_t []){ AV_CH_LAYOUT_MONO,
                                             AV_CH_LAYOUT_STEREO, 0 },
     .sample_fmts    = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_FLTP,
                                                      AV_SAMPLE_FMT_NONE },
 };