/* * 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_INT, {.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, }; 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 = CODEC_CAP_DR1, .priv_data_size = sizeof(EVRCContext), .priv_class = &evrcdec_class, };