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FFmpeg/libavcodec/evrcdec.c
Andreas Rheinhardt a247ac640d avcodec: Constify AVCodecs 
Given that the AVCodec.next pointer has now been removed, most of the
AVCodecs are not modified at all any more and can therefore be made
const (as this patch does); the only exceptions are the very few codecs
for external libraries that have a init_static_data callback.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Signed-off-by: James Almer <jamrial@gmail.com>
2021-04-27 10:43:15 -03:00

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/*
* Enhanced Variable Rate Codec, Service Option 3 decoder
* Copyright (c) 2013 Paul B Mahol
*
* 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
* Enhanced Variable Rate Codec, Service Option 3 decoder
* @author Paul B Mahol
*/
#include "libavutil/mathematics.h"
#include "libavutil/opt.h"
#include "avcodec.h"
#include "internal.h"
#include "get_bits.h"
#include "evrcdata.h"
#include "acelp_vectors.h"
#include "lsp.h"
#define MIN_LSP_SEP (0.05 / (2.0 * M_PI))
#define MIN_DELAY 20
#define MAX_DELAY 120
#define NB_SUBFRAMES 3
#define SUBFRAME_SIZE 54
#define FILTER_ORDER 10
#define ACB_SIZE 128
typedef enum {
RATE_ERRS = -1,
SILENCE,
RATE_QUANT,
RATE_QUARTER,
RATE_HALF,
RATE_FULL,
} evrc_packet_rate;
/**
* EVRC-A unpacked data frame
*/
typedef struct EVRCAFrame {
uint8_t lpc_flag; ///< spectral change indicator
uint16_t lsp[4]; ///< index into LSP codebook
uint8_t pitch_delay; ///< pitch delay for entire frame
uint8_t delay_diff; ///< delay difference for entire frame
uint8_t acb_gain[3]; ///< adaptive codebook gain
uint16_t fcb_shape[3][4]; ///< fixed codebook shape
uint8_t fcb_gain[3]; ///< fixed codebook gain index
uint8_t energy_gain; ///< frame energy gain index
uint8_t tty; ///< tty baud rate bit
} EVRCAFrame;
typedef struct EVRCContext {
AVClass *class;
int postfilter;
GetBitContext gb;
evrc_packet_rate bitrate;
evrc_packet_rate last_valid_bitrate;
EVRCAFrame frame;
float lspf[FILTER_ORDER];
float prev_lspf[FILTER_ORDER];
float synthesis[FILTER_ORDER];
float postfilter_fir[FILTER_ORDER];
float postfilter_iir[FILTER_ORDER];
float postfilter_residual[ACB_SIZE + SUBFRAME_SIZE];
float pitch_delay;
float prev_pitch_delay;
float avg_acb_gain; ///< average adaptive codebook gain
float avg_fcb_gain; ///< average fixed codebook gain
float pitch[ACB_SIZE + FILTER_ORDER + SUBFRAME_SIZE];
float pitch_back[ACB_SIZE];
float interpolation_coeffs[136];
float energy_vector[NB_SUBFRAMES];
float fade_scale;
float last;
uint8_t prev_energy_gain;
uint8_t prev_error_flag;
uint8_t warned_buf_mismatch_bitrate;
} EVRCContext;
/**
* Frame unpacking for RATE_FULL, RATE_HALF and RATE_QUANT
*
* @param e the context
*
* TIA/IS-127 Table 4.21-1
*/
static void unpack_frame(EVRCContext *e)
{
EVRCAFrame *frame = &e->frame;
GetBitContext *gb = &e->gb;
switch (e->bitrate) {
case RATE_FULL:
frame->lpc_flag = get_bits1(gb);
frame->lsp[0] = get_bits(gb, 6);
frame->lsp[1] = get_bits(gb, 6);
frame->lsp[2] = get_bits(gb, 9);
frame->lsp[3] = get_bits(gb, 7);
frame->pitch_delay = get_bits(gb, 7);
frame->delay_diff = get_bits(gb, 5);
frame->acb_gain[0] = get_bits(gb, 3);
frame->fcb_shape[0][0] = get_bits(gb, 8);
frame->fcb_shape[0][1] = get_bits(gb, 8);
frame->fcb_shape[0][2] = get_bits(gb, 8);
frame->fcb_shape[0][3] = get_bits(gb, 11);
frame->fcb_gain[0] = get_bits(gb, 5);
frame->acb_gain[1] = get_bits(gb, 3);
frame->fcb_shape[1][0] = get_bits(gb, 8);
frame->fcb_shape[1][1] = get_bits(gb, 8);
frame->fcb_shape[1][2] = get_bits(gb, 8);
frame->fcb_shape[1][3] = get_bits(gb, 11);
frame->fcb_gain [1] = get_bits(gb, 5);
frame->acb_gain [2] = get_bits(gb, 3);
frame->fcb_shape[2][0] = get_bits(gb, 8);
frame->fcb_shape[2][1] = get_bits(gb, 8);
frame->fcb_shape[2][2] = get_bits(gb, 8);
frame->fcb_shape[2][3] = get_bits(gb, 11);
frame->fcb_gain [2] = get_bits(gb, 5);
frame->tty = get_bits1(gb);
break;
case RATE_HALF:
frame->lsp [0] = get_bits(gb, 7);
frame->lsp [1] = get_bits(gb, 7);
frame->lsp [2] = get_bits(gb, 8);
frame->pitch_delay = get_bits(gb, 7);
frame->acb_gain [0] = get_bits(gb, 3);
frame->fcb_shape[0][0] = get_bits(gb, 10);
frame->fcb_gain [0] = get_bits(gb, 4);
frame->acb_gain [1] = get_bits(gb, 3);
frame->fcb_shape[1][0] = get_bits(gb, 10);
frame->fcb_gain [1] = get_bits(gb, 4);
frame->acb_gain [2] = get_bits(gb, 3);
frame->fcb_shape[2][0] = get_bits(gb, 10);
frame->fcb_gain [2] = get_bits(gb, 4);
break;
case RATE_QUANT:
frame->lsp [0] = get_bits(gb, 4);
frame->lsp [1] = get_bits(gb, 4);
frame->energy_gain = get_bits(gb, 8);
break;
}
}
static evrc_packet_rate buf_size2bitrate(const int buf_size)
{
switch (buf_size) {
case 23: return RATE_FULL;
case 11: return RATE_HALF;
case 6: return RATE_QUARTER;
case 3: return RATE_QUANT;
case 1: return SILENCE;
}
return RATE_ERRS;
}
/**
* Determine the bitrate from the frame size and/or the first byte of the frame.
*
* @param avctx the AV codec context
* @param buf_size length of the buffer
* @param buf the bufffer
*
* @return the bitrate on success,
* RATE_ERRS if the bitrate cannot be satisfactorily determined
*/
static evrc_packet_rate determine_bitrate(AVCodecContext *avctx,
int *buf_size,
const uint8_t **buf)
{
evrc_packet_rate bitrate;
if ((bitrate = buf_size2bitrate(*buf_size)) >= 0) {
if (bitrate > **buf) {
EVRCContext *e = avctx->priv_data;
if (!e->warned_buf_mismatch_bitrate) {
av_log(avctx, AV_LOG_WARNING,
"Claimed bitrate and buffer size mismatch.\n");
e->warned_buf_mismatch_bitrate = 1;
}
bitrate = **buf;
} else if (bitrate < **buf) {
av_log(avctx, AV_LOG_ERROR,
"Buffer is too small for the claimed bitrate.\n");
return RATE_ERRS;
}
(*buf)++;
*buf_size -= 1;
} else if ((bitrate = buf_size2bitrate(*buf_size + 1)) >= 0) {
av_log(avctx, AV_LOG_DEBUG,
"Bitrate byte is missing, guessing the bitrate from packet size.\n");
} else
return RATE_ERRS;
return bitrate;
}
static void warn_insufficient_frame_quality(AVCodecContext *avctx,
const char *message)
{
av_log(avctx, AV_LOG_WARNING, "Frame #%d, %s\n",
avctx->frame_number, message);
}
/**
* Initialize the speech codec according to the specification.
*
* TIA/IS-127 5.2
*/
static av_cold int evrc_decode_init(AVCodecContext *avctx)
{
EVRCContext *e = avctx->priv_data;
int i, n, idx = 0;
float denom = 2.0 / (2.0 * 8.0 + 1.0);
avctx->channels = 1;
avctx->channel_layout = AV_CH_LAYOUT_MONO;
avctx->sample_fmt = AV_SAMPLE_FMT_FLT;
for (i = 0; i < FILTER_ORDER; i++) {
e->prev_lspf[i] = (i + 1) * 0.048;
e->synthesis[i] = 0.0;
}
for (i = 0; i < ACB_SIZE; i++)
e->pitch[i] = e->pitch_back[i] = 0.0;
e->last_valid_bitrate = RATE_QUANT;
e->prev_pitch_delay = 40.0;
e->fade_scale = 1.0;
e->prev_error_flag = 0;
e->avg_acb_gain = e->avg_fcb_gain = 0.0;
for (i = 0; i < 8; i++) {
float tt = ((float)i - 8.0 / 2.0) / 8.0;
for (n = -8; n <= 8; n++, idx++) {
float arg1 = M_PI * 0.9 * (tt - n);
float arg2 = M_PI * (tt - n);
e->interpolation_coeffs[idx] = 0.9;
if (arg1)
e->interpolation_coeffs[idx] *= (0.54 + 0.46 * cos(arg2 * denom)) *
sin(arg1) / arg1;
}
}
return 0;
}
/**
* Decode the 10 vector quantized line spectral pair frequencies from the LSP
* transmission codes of any bitrate and check for badly received packets.
*
* @param e the context
*
* @return 0 on success, -1 if the packet is badly received
*
* TIA/IS-127 5.2.1, 5.7.1
*/
static int decode_lspf(EVRCContext *e)
{
const float * const *codebooks = evrc_lspq_codebooks[e->bitrate];
int i, j, k = 0;
for (i = 0; i < evrc_lspq_nb_codebooks[e->bitrate]; i++) {
int row_size = evrc_lspq_codebooks_row_sizes[e->bitrate][i];
const float *codebook = codebooks[i];
for (j = 0; j < row_size; j++)
e->lspf[k++] = codebook[e->frame.lsp[i] * row_size + j];
}
// check for monotonic LSPs
for (i = 1; i < FILTER_ORDER; i++)
if (e->lspf[i] <= e->lspf[i - 1])
return -1;
// check for minimum separation of LSPs at the splits
for (i = 0, k = 0; i < evrc_lspq_nb_codebooks[e->bitrate] - 1; i++) {
k += evrc_lspq_codebooks_row_sizes[e->bitrate][i];
if (e->lspf[k] - e->lspf[k - 1] <= MIN_LSP_SEP)
return -1;
}
return 0;
}
/*
* Interpolation of LSP parameters.
*
* TIA/IS-127 5.2.3.1, 5.7.3.2
*/
static void interpolate_lsp(float *ilsp, const float *lsp,
const float *prev, int index)
{
static const float lsp_interpolation_factors[] = { 0.1667, 0.5, 0.8333 };
ff_weighted_vector_sumf(ilsp, prev, lsp,
1.0 - lsp_interpolation_factors[index],
lsp_interpolation_factors[index], FILTER_ORDER);
}
/*
* Reconstruction of the delay contour.
*
* TIA/IS-127 5.2.2.3.2
*/
static void interpolate_delay(float *dst, float current, float prev, int index)
{
static const float d_interpolation_factors[] = { 0, 0.3313, 0.6625, 1, 1 };
dst[0] = (1.0 - d_interpolation_factors[index ]) * prev
+ d_interpolation_factors[index ] * current;
dst[1] = (1.0 - d_interpolation_factors[index + 1]) * prev
+ d_interpolation_factors[index + 1] * current;
dst[2] = (1.0 - d_interpolation_factors[index + 2]) * prev
+ d_interpolation_factors[index + 2] * current;
}
/*
* Convert the quantized, interpolated line spectral frequencies,
* to prediction coefficients.
*
* TIA/IS-127 5.2.3.2, 4.7.2.2
*/
static void decode_predictor_coeffs(const float *ilspf, float *ilpc)
{
double lsp[FILTER_ORDER];
float a[FILTER_ORDER / 2 + 1], b[FILTER_ORDER / 2 + 1];
float a1[FILTER_ORDER / 2] = { 0 };
float a2[FILTER_ORDER / 2] = { 0 };
float b1[FILTER_ORDER / 2] = { 0 };
float b2[FILTER_ORDER / 2] = { 0 };
int i, k;
ff_acelp_lsf2lspd(lsp, ilspf, FILTER_ORDER);
for (k = 0; k <= FILTER_ORDER; k++) {
a[0] = k < 2 ? 0.25 : 0;
b[0] = k < 2 ? k < 1 ? 0.25 : -0.25 : 0;
for (i = 0; i < FILTER_ORDER / 2; i++) {
a[i + 1] = a[i] - 2 * lsp[i * 2 ] * a1[i] + a2[i];
b[i + 1] = b[i] - 2 * lsp[i * 2 + 1] * b1[i] + b2[i];
a2[i] = a1[i];
a1[i] = a[i];
b2[i] = b1[i];
b1[i] = b[i];
}
if (k)
ilpc[k - 1] = 2.0 * (a[FILTER_ORDER / 2] + b[FILTER_ORDER / 2]);
}
}
static void bl_intrp(EVRCContext *e, float *ex, float delay)
{
float *f;
int offset, i, coef_idx;
int16_t t;
offset = lrintf(delay);
t = (offset - delay + 0.5) * 8.0 + 0.5;
if (t == 8) {
t = 0;
offset--;
}
f = ex - offset - 8;
coef_idx = t * (2 * 8 + 1);
ex[0] = 0.0;
for (i = 0; i < 2 * 8 + 1; i++)
ex[0] += e->interpolation_coeffs[coef_idx + i] * f[i];
}
/*
* Adaptive codebook excitation.
*
* TIA/IS-127 5.2.2.3.3, 4.12.5.2
*/
static void acb_excitation(EVRCContext *e, float *excitation, float gain,
const float delay[3], int length)
{
float denom, locdelay, dpr, invl;
int i;
invl = 1.0 / ((float) length);
dpr = length;
/* first at-most extra samples */
denom = (delay[1] - delay[0]) * invl;
for (i = 0; i < dpr; i++) {
locdelay = delay[0] + i * denom;
bl_intrp(e, excitation + i, locdelay);
}
denom = (delay[2] - delay[1]) * invl;
/* interpolation */
for (i = dpr; i < dpr + 10; i++) {
locdelay = delay[1] + (i - dpr) * denom;
bl_intrp(e, excitation + i, locdelay);
}
for (i = 0; i < length; i++)
excitation[i] *= gain;
}
static void decode_8_pulses_35bits(const uint16_t *fixed_index, float *cod)
{
int i, pos1, pos2, offset;
offset = (fixed_index[3] >> 9) & 3;
for (i = 0; i < 3; i++) {
pos1 = ((fixed_index[i] & 0x7f) / 11) * 5 + ((i + offset) % 5);
pos2 = ((fixed_index[i] & 0x7f) % 11) * 5 + ((i + offset) % 5);
cod[pos1] = (fixed_index[i] & 0x80) ? -1.0 : 1.0;
if (pos2 < pos1)
cod[pos2] = -cod[pos1];
else
cod[pos2] += cod[pos1];
}
pos1 = ((fixed_index[3] & 0x7f) / 11) * 5 + ((3 + offset) % 5);
pos2 = ((fixed_index[3] & 0x7f) % 11) * 5 + ((4 + offset) % 5);
cod[pos1] = (fixed_index[3] & 0x100) ? -1.0 : 1.0;
cod[pos2] = (fixed_index[3] & 0x80 ) ? -1.0 : 1.0;
}
static void decode_3_pulses_10bits(uint16_t fixed_index, float *cod)
{
float sign;
int pos;
sign = (fixed_index & 0x200) ? -1.0 : 1.0;
pos = ((fixed_index & 0x7) * 7) + 4;
cod[pos] += sign;
pos = (((fixed_index >> 3) & 0x7) * 7) + 2;
cod[pos] -= sign;
pos = (((fixed_index >> 6) & 0x7) * 7);
cod[pos] += sign;
}
/*
* Reconstruction of ACELP fixed codebook excitation for full and half rate.
*
* TIA/IS-127 5.2.3.7
*/
static void fcb_excitation(EVRCContext *e, const uint16_t *codebook,
float *excitation, float pitch_gain,
int pitch_lag, int subframe_size)
{
int i;
if (e->bitrate == RATE_FULL)
decode_8_pulses_35bits(codebook, excitation);
else
decode_3_pulses_10bits(*codebook, excitation);
pitch_gain = av_clipf(pitch_gain, 0.2, 0.9);
for (i = pitch_lag; i < subframe_size; i++)
excitation[i] += pitch_gain * excitation[i - pitch_lag];
}
/**
* Synthesis of the decoder output signal.
*
* param[in] in input signal
* param[in] filter_coeffs LPC coefficients
* param[in/out] memory synthesis filter memory
* param buffer_length amount of data to process
* param[out] samples output samples
*
* TIA/IS-127 5.2.3.15, 5.7.3.4
*/
static void synthesis_filter(const float *in, const float *filter_coeffs,
float *memory, int buffer_length, float *samples)
{
int i, j;
for (i = 0; i < buffer_length; i++) {
samples[i] = in[i];
for (j = FILTER_ORDER - 1; j > 0; j--) {
samples[i] -= filter_coeffs[j] * memory[j];
memory[j] = memory[j - 1];
}
samples[i] -= filter_coeffs[0] * memory[0];
memory[0] = samples[i];
}
}
static void bandwidth_expansion(float *coeff, const float *inbuf, float gamma)
{
double fac = gamma;
int i;
for (i = 0; i < FILTER_ORDER; i++) {
coeff[i] = inbuf[i] * fac;
fac *= gamma;
}
}
static void residual_filter(float *output, const float *input,
const float *coef, float *memory, int length)
{
float sum;
int i, j;
for (i = 0; i < length; i++) {
sum = input[i];
for (j = FILTER_ORDER - 1; j > 0; j--) {
sum += coef[j] * memory[j];
memory[j] = memory[j - 1];
}
sum += coef[0] * memory[0];
memory[0] = input[i];
output[i] = sum;
}
}
/*
* TIA/IS-127 Table 5.9.1-1.
*/
static const struct PfCoeff {
float tilt;
float ltgain;
float p1;
float p2;
} postfilter_coeffs[5] = {
{ 0.0 , 0.0 , 0.0 , 0.0 },
{ 0.0 , 0.0 , 0.57, 0.57 },
{ 0.0 , 0.0 , 0.0 , 0.0 },
{ 0.35, 0.50, 0.50, 0.75 },
{ 0.20, 0.50, 0.57, 0.75 },
};
/*
* Adaptive postfilter.
*
* TIA/IS-127 5.9
*/
static void postfilter(EVRCContext *e, float *in, const float *coeff,
float *out, int idx, const struct PfCoeff *pfc,
int length)
{
float wcoef1[FILTER_ORDER], wcoef2[FILTER_ORDER],
scratch[SUBFRAME_SIZE], temp[SUBFRAME_SIZE],
mem[SUBFRAME_SIZE];
float sum1 = 0.0, sum2 = 0.0, gamma, gain;
float tilt = pfc->tilt;
int i, n, best;
bandwidth_expansion(wcoef1, coeff, pfc->p1);
bandwidth_expansion(wcoef2, coeff, pfc->p2);
/* Tilt compensation filter, TIA/IS-127 5.9.1 */
for (i = 0; i < length - 1; i++)
sum2 += in[i] * in[i + 1];
if (sum2 < 0.0)
tilt = 0.0;
for (i = 0; i < length; i++) {
scratch[i] = in[i] - tilt * e->last;
e->last = in[i];
}
/* Short term residual filter, TIA/IS-127 5.9.2 */
residual_filter(&e->postfilter_residual[ACB_SIZE], scratch, wcoef1, e->postfilter_fir, length);
/* Long term postfilter */
best = idx;
for (i = FFMIN(MIN_DELAY, idx - 3); i <= FFMAX(MAX_DELAY, idx + 3); i++) {
for (n = ACB_SIZE, sum2 = 0; n < ACB_SIZE + length; n++)
sum2 += e->postfilter_residual[n] * e->postfilter_residual[n - i];
if (sum2 > sum1) {
sum1 = sum2;
best = i;
}
}
for (i = ACB_SIZE, sum1 = 0; i < ACB_SIZE + length; i++)
sum1 += e->postfilter_residual[i - best] * e->postfilter_residual[i - best];
for (i = ACB_SIZE, sum2 = 0; i < ACB_SIZE + length; i++)
sum2 += e->postfilter_residual[i] * e->postfilter_residual[i - best];
if (sum2 * sum1 == 0 || e->bitrate == RATE_QUANT) {
memcpy(temp, e->postfilter_residual + ACB_SIZE, length * sizeof(float));
} else {
gamma = sum2 / sum1;
if (gamma < 0.5)
memcpy(temp, e->postfilter_residual + ACB_SIZE, length * sizeof(float));
else {
gamma = FFMIN(gamma, 1.0);
for (i = 0; i < length; i++) {
temp[i] = e->postfilter_residual[ACB_SIZE + i] + gamma *
pfc->ltgain * e->postfilter_residual[ACB_SIZE + i - best];
}
}
}
memcpy(scratch, temp, length * sizeof(float));
memcpy(mem, e->postfilter_iir, FILTER_ORDER * sizeof(float));
synthesis_filter(scratch, wcoef2, mem, length, scratch);
/* Gain computation, TIA/IS-127 5.9.4-2 */
for (i = 0, sum1 = 0, sum2 = 0; i < length; i++) {
sum1 += in[i] * in[i];
sum2 += scratch[i] * scratch[i];
}
gain = sum2 ? sqrt(sum1 / sum2) : 1.0;
for (i = 0; i < length; i++)
temp[i] *= gain;
/* Short term postfilter */
synthesis_filter(temp, wcoef2, e->postfilter_iir, length, out);
memmove(e->postfilter_residual,
e->postfilter_residual + length, ACB_SIZE * sizeof(float));
}
static void frame_erasure(EVRCContext *e, float *samples)
{
float ilspf[FILTER_ORDER], ilpc[FILTER_ORDER], idelay[NB_SUBFRAMES],
tmp[SUBFRAME_SIZE + 6], f;
int i, j;
for (i = 0; i < FILTER_ORDER; i++) {
if (e->bitrate != RATE_QUANT)
e->lspf[i] = e->prev_lspf[i] * 0.875 + 0.125 * (i + 1) * 0.048;
else
e->lspf[i] = e->prev_lspf[i];
}
if (e->prev_error_flag)
e->avg_acb_gain *= 0.75;
if (e->bitrate == RATE_FULL)
memcpy(e->pitch_back, e->pitch, ACB_SIZE * sizeof(float));
if (e->last_valid_bitrate == RATE_QUANT)
e->bitrate = RATE_QUANT;
else
e->bitrate = RATE_FULL;
if (e->bitrate == RATE_FULL || e->bitrate == RATE_HALF) {
e->pitch_delay = e->prev_pitch_delay;
} else {
float sum = 0;
idelay[0] = idelay[1] = idelay[2] = MIN_DELAY;
for (i = 0; i < NB_SUBFRAMES; i++)
sum += evrc_energy_quant[e->prev_energy_gain][i];
sum /= (float) NB_SUBFRAMES;
sum = pow(10, sum);
for (i = 0; i < NB_SUBFRAMES; i++)
e->energy_vector[i] = sum;
}
if (fabs(e->pitch_delay - e->prev_pitch_delay) > 15)
e->prev_pitch_delay = e->pitch_delay;
for (i = 0; i < NB_SUBFRAMES; i++) {
int subframe_size = subframe_sizes[i];
int pitch_lag;
interpolate_lsp(ilspf, e->lspf, e->prev_lspf, i);
if (e->bitrate != RATE_QUANT) {
if (e->avg_acb_gain < 0.3) {
idelay[0] = estimation_delay[i];
idelay[1] = estimation_delay[i + 1];
idelay[2] = estimation_delay[i + 2];
} else {
interpolate_delay(idelay, e->pitch_delay, e->prev_pitch_delay, i);
}
}
pitch_lag = lrintf((idelay[1] + idelay[0]) / 2.0);
decode_predictor_coeffs(ilspf, ilpc);
if (e->bitrate != RATE_QUANT) {
acb_excitation(e, e->pitch + ACB_SIZE,
e->avg_acb_gain, idelay, subframe_size);
for (j = 0; j < subframe_size; j++)
e->pitch[ACB_SIZE + j] *= e->fade_scale;
e->fade_scale = FFMAX(e->fade_scale - 0.05, 0.0);
} else {
for (j = 0; j < subframe_size; j++)
e->pitch[ACB_SIZE + j] = e->energy_vector[i];
}
memmove(e->pitch, e->pitch + subframe_size, ACB_SIZE * sizeof(float));
if (e->bitrate != RATE_QUANT && e->avg_acb_gain < 0.4) {
f = 0.1 * e->avg_fcb_gain;
for (j = 0; j < subframe_size; j++)
e->pitch[ACB_SIZE + j] += f;
} else if (e->bitrate == RATE_QUANT) {
for (j = 0; j < subframe_size; j++)
e->pitch[ACB_SIZE + j] = e->energy_vector[i];
}
synthesis_filter(e->pitch + ACB_SIZE, ilpc,
e->synthesis, subframe_size, tmp);
postfilter(e, tmp, ilpc, samples, pitch_lag,
&postfilter_coeffs[e->bitrate], subframe_size);
samples += subframe_size;
}
}
static int evrc_decode_frame(AVCodecContext *avctx, void *data,
int *got_frame_ptr, AVPacket *avpkt)
{
const uint8_t *buf = avpkt->data;
AVFrame *frame = data;
EVRCContext *e = avctx->priv_data;
int buf_size = avpkt->size;
float ilspf[FILTER_ORDER], ilpc[FILTER_ORDER], idelay[NB_SUBFRAMES];
float *samples;
int i, j, ret, error_flag = 0;
frame->nb_samples = 160;
if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
return ret;
samples = (float *)frame->data[0];
if ((e->bitrate = determine_bitrate(avctx, &buf_size, &buf)) == RATE_ERRS) {
warn_insufficient_frame_quality(avctx, "bitrate cannot be determined.");
goto erasure;
}
if (e->bitrate <= SILENCE || e->bitrate == RATE_QUARTER)
goto erasure;
if (e->bitrate == RATE_QUANT && e->last_valid_bitrate == RATE_FULL
&& !e->prev_error_flag)
goto erasure;
if ((ret = init_get_bits8(&e->gb, buf, buf_size)) < 0)
return ret;
memset(&e->frame, 0, sizeof(EVRCAFrame));
unpack_frame(e);
if (e->bitrate != RATE_QUANT) {
uint8_t *p = (uint8_t *) &e->frame;
for (i = 0; i < sizeof(EVRCAFrame); i++) {
if (p[i])
break;
}
if (i == sizeof(EVRCAFrame))
goto erasure;
} else if (e->frame.lsp[0] == 0xf &&
e->frame.lsp[1] == 0xf &&
e->frame.energy_gain == 0xff) {
goto erasure;
}
if (decode_lspf(e) < 0)
goto erasure;
if (e->bitrate == RATE_FULL || e->bitrate == RATE_HALF) {
/* Pitch delay parameter checking as per TIA/IS-127 5.1.5.1 */
if (e->frame.pitch_delay > MAX_DELAY - MIN_DELAY)
goto erasure;
e->pitch_delay = e->frame.pitch_delay + MIN_DELAY;
/* Delay diff parameter checking as per TIA/IS-127 5.1.5.2 */
if (e->frame.delay_diff) {
int p = e->pitch_delay - e->frame.delay_diff + 16;
if (p < MIN_DELAY || p > MAX_DELAY)
goto erasure;
}
/* Delay contour reconstruction as per TIA/IS-127 5.2.2.2 */
if (e->frame.delay_diff &&
e->bitrate == RATE_FULL && e->prev_error_flag) {
float delay;
memcpy(e->pitch, e->pitch_back, ACB_SIZE * sizeof(float));
delay = e->prev_pitch_delay;
e->prev_pitch_delay = delay - e->frame.delay_diff + 16.0;
if (fabs(e->pitch_delay - delay) > 15)
delay = e->pitch_delay;
for (i = 0; i < NB_SUBFRAMES; i++) {
int subframe_size = subframe_sizes[i];
interpolate_delay(idelay, delay, e->prev_pitch_delay, i);
acb_excitation(e, e->pitch + ACB_SIZE, e->avg_acb_gain, idelay, subframe_size);
memmove(e->pitch, e->pitch + subframe_size, ACB_SIZE * sizeof(float));
}
}
/* Smoothing of the decoded delay as per TIA/IS-127 5.2.2.5 */
if (fabs(e->pitch_delay - e->prev_pitch_delay) > 15)
e->prev_pitch_delay = e->pitch_delay;
e->avg_acb_gain = e->avg_fcb_gain = 0.0;
} else {
idelay[0] = idelay[1] = idelay[2] = MIN_DELAY;
/* Decode frame energy vectors as per TIA/IS-127 5.7.2 */
for (i = 0; i < NB_SUBFRAMES; i++)
e->energy_vector[i] = pow(10, evrc_energy_quant[e->frame.energy_gain][i]);
e->prev_energy_gain = e->frame.energy_gain;
}
for (i = 0; i < NB_SUBFRAMES; i++) {
float tmp[SUBFRAME_SIZE + 6] = { 0 };
int subframe_size = subframe_sizes[i];
int pitch_lag;
interpolate_lsp(ilspf, e->lspf, e->prev_lspf, i);
if (e->bitrate != RATE_QUANT)
interpolate_delay(idelay, e->pitch_delay, e->prev_pitch_delay, i);
pitch_lag = lrintf((idelay[1] + idelay[0]) / 2.0);
decode_predictor_coeffs(ilspf, ilpc);
/* Bandwidth expansion as per TIA/IS-127 5.2.3.3 */
if (e->frame.lpc_flag && e->prev_error_flag)
bandwidth_expansion(ilpc, ilpc, 0.75);
if (e->bitrate != RATE_QUANT) {
float acb_sum, f;
f = exp((e->bitrate == RATE_HALF ? 0.5 : 0.25)
* (e->frame.fcb_gain[i] + 1));
acb_sum = pitch_gain_vq[e->frame.acb_gain[i]];
e->avg_acb_gain += acb_sum / NB_SUBFRAMES;
e->avg_fcb_gain += f / NB_SUBFRAMES;
acb_excitation(e, e->pitch + ACB_SIZE,
acb_sum, idelay, subframe_size);
fcb_excitation(e, e->frame.fcb_shape[i], tmp,
acb_sum, pitch_lag, subframe_size);
/* Total excitation generation as per TIA/IS-127 5.2.3.9 */
for (j = 0; j < subframe_size; j++)
e->pitch[ACB_SIZE + j] += f * tmp[j];
e->fade_scale = FFMIN(e->fade_scale + 0.2, 1.0);
} else {
for (j = 0; j < subframe_size; j++)
e->pitch[ACB_SIZE + j] = e->energy_vector[i];
}
memmove(e->pitch, e->pitch + subframe_size, ACB_SIZE * sizeof(float));
synthesis_filter(e->pitch + ACB_SIZE, ilpc,
e->synthesis, subframe_size,
e->postfilter ? tmp : samples);
if (e->postfilter)
postfilter(e, tmp, ilpc, samples, pitch_lag,
&postfilter_coeffs[e->bitrate], subframe_size);
samples += subframe_size;
}
if (error_flag) {
erasure:
error_flag = 1;
av_log(avctx, AV_LOG_WARNING, "frame erasure\n");
frame_erasure(e, samples);
}
memcpy(e->prev_lspf, e->lspf, sizeof(e->prev_lspf));
e->prev_error_flag = error_flag;
e->last_valid_bitrate = e->bitrate;
if (e->bitrate != RATE_QUANT)
e->prev_pitch_delay = e->pitch_delay;
samples = (float *)frame->data[0];
for (i = 0; i < 160; i++)
samples[i] /= 32768;
*got_frame_ptr = 1;
return avpkt->size;
}
#define OFFSET(x) offsetof(EVRCContext, x)
#define AD AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_DECODING_PARAM
static const AVOption options[] = {
{ "postfilter", "enable postfilter", OFFSET(postfilter), AV_OPT_TYPE_BOOL, {.i64 = 1}, 0, 1, AD },
{ NULL }
};
static const AVClass evrcdec_class = {
.class_name = "evrc",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
const AVCodec ff_evrc_decoder = {
.name = "evrc",
.long_name = NULL_IF_CONFIG_SMALL("EVRC (Enhanced Variable Rate Codec)"),
.type = AVMEDIA_TYPE_AUDIO,
.id = AV_CODEC_ID_EVRC,
.init = evrc_decode_init,
.decode = evrc_decode_frame,
.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_CHANNEL_CONF,
.priv_data_size = sizeof(EVRCContext),
.priv_class = &evrcdec_class,
};
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