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Diffstat (limited to 'libavcodec/evrcdec.c')
| -rw-r--r-- | libavcodec/evrcdec.c | 917 |
1 files changed, 917 insertions, 0 deletions
diff --git a/libavcodec/evrcdec.c b/libavcodec/evrcdec.c new file mode 100644 index 0000000000..76914554d4 --- /dev/null +++ b/libavcodec/evrcdec.c @@ -0,0 +1,917 @@ +/* + * 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 "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 { + 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 **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(fabs(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); + + memcpy(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]; + } + + memcpy(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; + + init_get_bits(&e->gb, buf, 8 * buf_size); + 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); + memcpy(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]; + } + + memcpy(e->pitch, e->pitch + subframe_size, ACB_SIZE * sizeof(float)); + + 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; + } + + 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; +} + +AVCodec ff_evrc_decoder = { + .name = "evrc", + .type = AVMEDIA_TYPE_AUDIO, + .id = AV_CODEC_ID_EVRC, + .init = evrc_decode_init, + .decode = evrc_decode_frame, + .capabilities = CODEC_CAP_DR1, + .priv_data_size = sizeof(EVRCContext), + .long_name = NULL_IF_CONFIG_SMALL("EVRC (Enhanced Variable Rate Codec)"), +}; |