avcodec/opus: Rename opus.c->opus_celt.c, opus_celt.c->opusdec_celt.c

Since commit 4fc2531fff112836026aad2bdaf128c9d15a72e3 opus.c
contains only the celt stuff shared between decoder and encoder.
meanwhile, opus_celt.c is decoder-only. So the new names
reflect the actual content better than the current ones.

Reviewed-by: Lynne <dev@lynne.ee>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

1 files changed, 586 insertions, 0 deletions

diff --git a/libavcodec/opusdec_celt.c b/libavcodec/opusdec_celt.c
new file mode 100644
index 0000000000..c2904cc9e0
--- /dev/null
+++ b/libavcodec/opusdec_celt.c
@@ -0,0 +1,586 @@
+/*
+ * Copyright (c) 2012 Andrew D'Addesio
+ * Copyright (c) 2013-2014 Mozilla Corporation
+ * Copyright (c) 2016 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
+ */
+
+/**
+ * @file
+ * Opus CELT decoder
+ */
+
+#include <float.h>
+
+#include "opus_celt.h"
+#include "opustab.h"
+#include "opus_pvq.h"
+
+/* Use the 2D z-transform to apply prediction in both the time domain (alpha)
+ * and the frequency domain (beta) */
+static void celt_decode_coarse_energy(CeltFrame *f, OpusRangeCoder *rc)
+{
+    int i, j;
+    float prev[2] = { 0 };
+    float alpha = ff_celt_alpha_coef[f->size];
+    float beta  = ff_celt_beta_coef[f->size];
+    const uint8_t *model = ff_celt_coarse_energy_dist[f->size][0];
+
+    /* intra frame */
+    if (opus_rc_tell(rc) + 3 <= f->framebits && ff_opus_rc_dec_log(rc, 3)) {
+        alpha = 0.0f;
+        beta  = 1.0f - (4915.0f/32768.0f);
+        model = ff_celt_coarse_energy_dist[f->size][1];
+    }
+
+    for (i = 0; i < CELT_MAX_BANDS; i++) {
+        for (j = 0; j < f->channels; j++) {
+            CeltBlock *block = &f->block[j];
+            float value;
+            int available;
+
+            if (i < f->start_band || i >= f->end_band) {
+                block->energy[i] = 0.0;
+                continue;
+            }
+
+            available = f->framebits - opus_rc_tell(rc);
+            if (available >= 15) {
+                /* decode using a Laplace distribution */
+                int k = FFMIN(i, 20) << 1;
+                value = ff_opus_rc_dec_laplace(rc, model[k] << 7, model[k+1] << 6);
+            } else if (available >= 2) {
+                int x = ff_opus_rc_dec_cdf(rc, ff_celt_model_energy_small);
+                value = (x>>1) ^ -(x&1);
+            } else if (available >= 1) {
+                value = -(float)ff_opus_rc_dec_log(rc, 1);
+            } else value = -1;
+
+            block->energy[i] = FFMAX(-9.0f, block->energy[i]) * alpha + prev[j] + value;
+            prev[j] += beta * value;
+        }
+    }
+}
+
+static void celt_decode_fine_energy(CeltFrame *f, OpusRangeCoder *rc)
+{
+    int i;
+    for (i = f->start_band; i < f->end_band; i++) {
+        int j;
+        if (!f->fine_bits[i])
+            continue;
+
+        for (j = 0; j < f->channels; j++) {
+            CeltBlock *block = &f->block[j];
+            int q2;
+            float offset;
+            q2 = ff_opus_rc_get_raw(rc, f->fine_bits[i]);
+            offset = (q2 + 0.5f) * (1 << (14 - f->fine_bits[i])) / 16384.0f - 0.5f;
+            block->energy[i] += offset;
+        }
+    }
+}
+
+static void celt_decode_final_energy(CeltFrame *f, OpusRangeCoder *rc)
+{
+    int priority, i, j;
+    int bits_left = f->framebits - opus_rc_tell(rc);
+
+    for (priority = 0; priority < 2; priority++) {
+        for (i = f->start_band; i < f->end_band && bits_left >= f->channels; i++) {
+            if (f->fine_priority[i] != priority || f->fine_bits[i] >= CELT_MAX_FINE_BITS)
+                continue;
+
+            for (j = 0; j < f->channels; j++) {
+                int q2;
+                float offset;
+                q2 = ff_opus_rc_get_raw(rc, 1);
+                offset = (q2 - 0.5f) * (1 << (14 - f->fine_bits[i] - 1)) / 16384.0f;
+                f->block[j].energy[i] += offset;
+                bits_left--;
+            }
+        }
+    }
+}
+
+static void celt_decode_tf_changes(CeltFrame *f, OpusRangeCoder *rc)
+{
+    int i, diff = 0, tf_select = 0, tf_changed = 0, tf_select_bit;
+    int consumed, bits = f->transient ? 2 : 4;
+
+    consumed = opus_rc_tell(rc);
+    tf_select_bit = (f->size != 0 && consumed+bits+1 <= f->framebits);
+
+    for (i = f->start_band; i < f->end_band; i++) {
+        if (consumed+bits+tf_select_bit <= f->framebits) {
+            diff ^= ff_opus_rc_dec_log(rc, bits);
+            consumed = opus_rc_tell(rc);
+            tf_changed |= diff;
+        }
+        f->tf_change[i] = diff;
+        bits = f->transient ? 4 : 5;
+    }
+
+    if (tf_select_bit && ff_celt_tf_select[f->size][f->transient][0][tf_changed] !=
+                         ff_celt_tf_select[f->size][f->transient][1][tf_changed])
+        tf_select = ff_opus_rc_dec_log(rc, 1);
+
+    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]];
+    }
+}
+
+static void celt_denormalize(CeltFrame *f, CeltBlock *block, float *data)
+{
+    int i, j;
+
+    for (i = f->start_band; i < f->end_band; i++) {
+        float *dst = data + (ff_celt_freq_bands[i] << f->size);
+        float log_norm = block->energy[i] + ff_celt_mean_energy[i];
+        float norm = exp2f(FFMIN(log_norm, 32.0f));
+
+        for (j = 0; j < ff_celt_freq_range[i] << f->size; j++)
+            dst[j] *= norm;
+    }
+}
+
+static void celt_postfilter_apply_transition(CeltBlock *block, float *data)
+{
+    const int T0 = block->pf_period_old;
+    const int T1 = block->pf_period;
+
+    float g00, g01, g02;
+    float g10, g11, g12;
+
+    float x0, x1, x2, x3, x4;
+
+    int i;
+
+    if (block->pf_gains[0]     == 0.0 &&
+        block->pf_gains_old[0] == 0.0)
+        return;
+
+    g00 = block->pf_gains_old[0];
+    g01 = block->pf_gains_old[1];
+    g02 = block->pf_gains_old[2];
+    g10 = block->pf_gains[0];
+    g11 = block->pf_gains[1];
+    g12 = block->pf_gains[2];
+
+    x1 = data[-T1 + 1];
+    x2 = data[-T1];
+    x3 = data[-T1 - 1];
+    x4 = data[-T1 - 2];
+
+    for (i = 0; i < CELT_OVERLAP; i++) {
+        float w = ff_celt_window2[i];
+        x0 = data[i - T1 + 2];
+
+        data[i] +=  (1.0 - w) * g00 * data[i - T0]                          +
+                    (1.0 - w) * g01 * (data[i - T0 - 1] + data[i - T0 + 1]) +
+                    (1.0 - w) * g02 * (data[i - T0 - 2] + data[i - T0 + 2]) +
+                    w         * g10 * x2                                    +
+                    w         * g11 * (x1 + x3)                             +
+                    w         * g12 * (x0 + x4);
+        x4 = x3;
+        x3 = x2;
+        x2 = x1;
+        x1 = x0;
+    }
+}
+
+static void celt_postfilter(CeltFrame *f, CeltBlock *block)
+{
+    int len = f->blocksize * f->blocks;
+    const int filter_len = len - 2 * CELT_OVERLAP;
+
+    celt_postfilter_apply_transition(block, block->buf + 1024);
+
+    block->pf_period_old = block->pf_period;
+    memcpy(block->pf_gains_old, block->pf_gains, sizeof(block->pf_gains));
+
+    block->pf_period = block->pf_period_new;
+    memcpy(block->pf_gains, block->pf_gains_new, sizeof(block->pf_gains));
+
+    if (len > CELT_OVERLAP) {
+        celt_postfilter_apply_transition(block, block->buf + 1024 + CELT_OVERLAP);
+
+        if (block->pf_gains[0] > FLT_EPSILON && filter_len > 0)
+            f->opusdsp.postfilter(block->buf + 1024 + 2 * CELT_OVERLAP,
+                                  block->pf_period, block->pf_gains,
+                                  filter_len);
+
+        block->pf_period_old = block->pf_period;
+        memcpy(block->pf_gains_old, block->pf_gains, sizeof(block->pf_gains));
+    }
+
+    memmove(block->buf, block->buf + len, (1024 + CELT_OVERLAP / 2) * sizeof(float));
+}
+
+static int parse_postfilter(CeltFrame *f, OpusRangeCoder *rc, int consumed)
+{
+    int i;
+
+    memset(f->block[0].pf_gains_new, 0, sizeof(f->block[0].pf_gains_new));
+    memset(f->block[1].pf_gains_new, 0, sizeof(f->block[1].pf_gains_new));
+
+    if (f->start_band == 0 && consumed + 16 <= f->framebits) {
+        int has_postfilter = ff_opus_rc_dec_log(rc, 1);
+        if (has_postfilter) {
+            float gain;
+            int tapset, octave, period;
+
+            octave = ff_opus_rc_dec_uint(rc, 6);
+            period = (16 << octave) + ff_opus_rc_get_raw(rc, 4 + octave) - 1;
+            gain   = 0.09375f * (ff_opus_rc_get_raw(rc, 3) + 1);
+            tapset = (opus_rc_tell(rc) + 2 <= f->framebits) ?
+                     ff_opus_rc_dec_cdf(rc, ff_celt_model_tapset) : 0;
+
+            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];
+            }
+        }
+
+        consumed = opus_rc_tell(rc);
+    }
+
+    return consumed;
+}
+
+static void process_anticollapse(CeltFrame *f, CeltBlock *block, float *X)
+{
+    int i, j, k;
+
+    for (i = f->start_band; i < f->end_band; i++) {
+        int renormalize = 0;
+        float *xptr;
+        float prev[2];
+        float Ediff, r;
+        float thresh, sqrt_1;
+        int depth;
+
+        /* depth in 1/8 bits */
+        depth = (1 + f->pulses[i]) / (ff_celt_freq_range[i] << f->size);
+        thresh = exp2f(-1.0 - 0.125f * depth);
+        sqrt_1 = 1.0f / sqrtf(ff_celt_freq_range[i] << f->size);
+
+        xptr = X + (ff_celt_freq_bands[i] << f->size);
+
+        prev[0] = block->prev_energy[0][i];
+        prev[1] = block->prev_energy[1][i];
+        if (f->channels == 1) {
+            CeltBlock *block1 = &f->block[1];
+
+            prev[0] = FFMAX(prev[0], block1->prev_energy[0][i]);
+            prev[1] = FFMAX(prev[1], block1->prev_energy[1][i]);
+        }
+        Ediff = block->energy[i] - FFMIN(prev[0], prev[1]);
+        Ediff = FFMAX(0, Ediff);
+
+        /* r needs to be multiplied by 2 or 2*sqrt(2) depending on LM because
+        short blocks don't have the same energy as long */
+        r = exp2f(1 - Ediff);
+        if (f->size == 3)
+            r *= M_SQRT2;
+        r = FFMIN(thresh, r) * sqrt_1;
+        for (k = 0; k < 1 << f->size; k++) {
+            /* Detect collapse */
+            if (!(block->collapse_masks[i] & 1 << k)) {
+                /* Fill with noise */
+                for (j = 0; j < ff_celt_freq_range[i]; j++)
+                    xptr[(j << f->size) + k] = (celt_rng(f) & 0x8000) ? r : -r;
+                renormalize = 1;
+            }
+        }
+
+        /* We just added some energy, so we need to renormalize */
+        if (renormalize)
+            celt_renormalize_vector(xptr, ff_celt_freq_range[i] << f->size, 1.0f);
+    }
+}
+
+int ff_celt_decode_frame(CeltFrame *f, OpusRangeCoder *rc,
+                         float **output, int channels, int frame_size,
+                         int start_band,  int end_band)
+{
+    int i, j, downmix = 0;
+    int consumed;           // bits of entropy consumed thus far for this frame
+    AVTXContext *imdct;
+    av_tx_fn imdct_fn;
+
+    if (channels != 1 && channels != 2) {
+        av_log(f->avctx, AV_LOG_ERROR, "Invalid number of coded channels: %d\n",
+               channels);
+        return AVERROR_INVALIDDATA;
+    }
+    if (start_band < 0 || start_band > end_band || end_band > CELT_MAX_BANDS) {
+        av_log(f->avctx, AV_LOG_ERROR, "Invalid start/end band: %d %d\n",
+               start_band, end_band);
+        return AVERROR_INVALIDDATA;
+    }
+
+    f->silence        = 0;
+    f->transient      = 0;
+    f->anticollapse   = 0;
+    f->flushed        = 0;
+    f->channels       = channels;
+    f->start_band     = start_band;
+    f->end_band       = end_band;
+    f->framebits      = rc->rb.bytes * 8;
+
+    f->size = av_log2(frame_size / CELT_SHORT_BLOCKSIZE);
+    if (f->size > CELT_MAX_LOG_BLOCKS ||
+        frame_size != CELT_SHORT_BLOCKSIZE * (1 << f->size)) {
+        av_log(f->avctx, AV_LOG_ERROR, "Invalid CELT frame size: %d\n",
+               frame_size);
+        return AVERROR_INVALIDDATA;
+    }
+
+    if (!f->output_channels)
+        f->output_channels = channels;
+
+    for (i = 0; i < f->channels; i++) {
+        memset(f->block[i].coeffs,         0, sizeof(f->block[i].coeffs));
+        memset(f->block[i].collapse_masks, 0, sizeof(f->block[i].collapse_masks));
+    }
+
+    consumed = opus_rc_tell(rc);
+
+    /* obtain silence flag */
+    if (consumed >= f->framebits)
+        f->silence = 1;
+    else if (consumed == 1)
+        f->silence = ff_opus_rc_dec_log(rc, 15);
+
+
+    if (f->silence) {
+        consumed = f->framebits;
+        rc->total_bits += f->framebits - opus_rc_tell(rc);
+    }
+
+    /* obtain post-filter options */
+    consumed = parse_postfilter(f, rc, consumed);
+
+    /* obtain transient flag */
+    if (f->size != 0 && consumed+3 <= f->framebits)
+        f->transient = ff_opus_rc_dec_log(rc, 3);
+
+    f->blocks    = f->transient ? 1 << f->size : 1;
+    f->blocksize = frame_size / f->blocks;
+
+    imdct = f->tx[f->transient ? 0 : f->size];
+    imdct_fn = f->tx_fn[f->transient ? 0 : f->size];
+
+    if (channels == 1) {
+        for (i = 0; i < CELT_MAX_BANDS; i++)
+            f->block[0].energy[i] = FFMAX(f->block[0].energy[i], f->block[1].energy[i]);
+    }
+
+    celt_decode_coarse_energy(f, rc);
+    celt_decode_tf_changes   (f, rc);
+    ff_celt_bitalloc         (f, rc, 0);
+    celt_decode_fine_energy  (f, rc);
+    ff_celt_quant_bands      (f, rc);
+
+    if (f->anticollapse_needed)
+        f->anticollapse = ff_opus_rc_get_raw(rc, 1);
+
+    celt_decode_final_energy(f, rc);
+
+    /* apply anti-collapse processing and denormalization to
+     * each coded channel */
+    for (i = 0; i < f->channels; i++) {
+        CeltBlock *block = &f->block[i];
+
+        if (f->anticollapse)
+            process_anticollapse(f, block, f->block[i].coeffs);
+
+        celt_denormalize(f, block, f->block[i].coeffs);
+    }
+
+    /* stereo -> mono downmix */
+    if (f->output_channels < f->channels) {
+        f->dsp->vector_fmac_scalar(f->block[0].coeffs, f->block[1].coeffs, 1.0, FFALIGN(frame_size, 16));
+        downmix = 1;
+    } else if (f->output_channels > f->channels)
+        memcpy(f->block[1].coeffs, f->block[0].coeffs, frame_size * sizeof(float));
+
+    if (f->silence) {
+        for (i = 0; i < 2; i++) {
+            CeltBlock *block = &f->block[i];
+
+            for (j = 0; j < FF_ARRAY_ELEMS(block->energy); j++)
+                block->energy[j] = CELT_ENERGY_SILENCE;
+        }
+        memset(f->block[0].coeffs, 0, sizeof(f->block[0].coeffs));
+        memset(f->block[1].coeffs, 0, sizeof(f->block[1].coeffs));
+    }
+
+    /* transform and output for each output channel */
+    for (i = 0; i < f->output_channels; i++) {
+        CeltBlock *block = &f->block[i];
+
+        /* iMDCT and overlap-add */
+        for (j = 0; j < f->blocks; j++) {
+            float *dst  = block->buf + 1024 + j * f->blocksize;
+
+            imdct_fn(imdct, dst + CELT_OVERLAP / 2, f->block[i].coeffs + j,
+                     sizeof(float)*f->blocks);
+            f->dsp->vector_fmul_window(dst, dst, dst + CELT_OVERLAP / 2,
+                                       ff_celt_window, CELT_OVERLAP / 2);
+        }
+
+        if (downmix)
+            f->dsp->vector_fmul_scalar(&block->buf[1024], &block->buf[1024], 0.5f, frame_size);
+
+        /* postfilter */
+        celt_postfilter(f, block);
+
+        /* deemphasis */
+        block->emph_coeff = f->opusdsp.deemphasis(output[i],
+                                                  &block->buf[1024 - frame_size],
+                                                  block->emph_coeff, frame_size);
+    }
+
+    if (channels == 1)
+        memcpy(f->block[1].energy, f->block[0].energy, sizeof(f->block[0].energy));
+
+    for (i = 0; i < 2; i++ ) {
+        CeltBlock *block = &f->block[i];
+
+        if (!f->transient) {
+            memcpy(block->prev_energy[1], block->prev_energy[0], sizeof(block->prev_energy[0]));
+            memcpy(block->prev_energy[0], block->energy,         sizeof(block->prev_energy[0]));
+        } else {
+            for (j = 0; j < CELT_MAX_BANDS; j++)
+                block->prev_energy[0][j] = FFMIN(block->prev_energy[0][j], block->energy[j]);
+        }
+
+        for (j = 0; j < f->start_band; j++) {
+            block->prev_energy[0][j] = CELT_ENERGY_SILENCE;
+            block->energy[j]         = 0.0;
+        }
+        for (j = f->end_band; j < CELT_MAX_BANDS; j++) {
+            block->prev_energy[0][j] = CELT_ENERGY_SILENCE;
+            block->energy[j]         = 0.0;
+        }
+    }
+
+    f->seed = rc->range;
+
+    return 0;
+}
+
+void ff_celt_flush(CeltFrame *f)
+{
+    int i, j;
+
+    if (f->flushed)
+        return;
+
+    for (i = 0; i < 2; i++) {
+        CeltBlock *block = &f->block[i];
+
+        for (j = 0; j < CELT_MAX_BANDS; j++)
+            block->prev_energy[0][j] = block->prev_energy[1][j] = CELT_ENERGY_SILENCE;
+
+        memset(block->energy, 0, sizeof(block->energy));
+        memset(block->buf,    0, sizeof(block->buf));
+
+        memset(block->pf_gains,     0, sizeof(block->pf_gains));
+        memset(block->pf_gains_old, 0, sizeof(block->pf_gains_old));
+        memset(block->pf_gains_new, 0, sizeof(block->pf_gains_new));
+
+        /* libopus uses CELT_EMPH_COEFF on init, but 0 is better since there's
+         * a lesser discontinuity when seeking.
+         * The deemphasis functions differ from libopus in that they require
+         * an initial state divided by the coefficient. */
+        block->emph_coeff = 0.0f / CELT_EMPH_COEFF;
+    }
+    f->seed = 0;
+
+    f->flushed = 1;
+}
+
+void ff_celt_free(CeltFrame **f)
+{
+    CeltFrame *frm = *f;
+    int i;
+
+    if (!frm)
+        return;
+
+    for (i = 0; i < FF_ARRAY_ELEMS(frm->tx); i++)
+        av_tx_uninit(&frm->tx[i]);
+
+    ff_celt_pvq_uninit(&frm->pvq);
+
+    av_freep(&frm->dsp);
+    av_freep(f);
+}
+
+int ff_celt_init(AVCodecContext *avctx, CeltFrame **f, int output_channels,
+                 int apply_phase_inv)
+{
+    CeltFrame *frm;
+    int i, ret;
+
+    if (output_channels != 1 && output_channels != 2) {
+        av_log(avctx, AV_LOG_ERROR, "Invalid number of output channels: %d\n",
+               output_channels);
+        return AVERROR(EINVAL);
+    }
+
+    frm = av_mallocz(sizeof(*frm));
+    if (!frm)
+        return AVERROR(ENOMEM);
+
+    frm->avctx           = avctx;
+    frm->output_channels = output_channels;
+    frm->apply_phase_inv = apply_phase_inv;
+
+    for (i = 0; i < FF_ARRAY_ELEMS(frm->tx); i++) {
+        const float scale = -1.0f/32768;
+        if ((ret = av_tx_init(&frm->tx[i], &frm->tx_fn[i], AV_TX_FLOAT_MDCT, 1, 15 << (i + 3), &scale, 0)) < 0)
+            goto fail;
+    }
+
+    if ((ret = ff_celt_pvq_init(&frm->pvq, 0)) < 0)
+        goto fail;
+
+    frm->dsp = avpriv_float_dsp_alloc(avctx->flags & AV_CODEC_FLAG_BITEXACT);
+    if (!frm->dsp) {
+        ret = AVERROR(ENOMEM);
+        goto fail;
+    }
+
+    ff_opus_dsp_init(&frm->opusdsp);
+    ff_celt_flush(frm);
+
+    *f = frm;
+
+    return 0;
+fail:
+    ff_celt_free(&frm);
+    return ret;
+}