1/* 2 * G.729 decoder 3 * Copyright (c) 2008 Vladimir Voroshilov 4 * 5 * This file is part of FFmpeg. 6 * 7 * FFmpeg is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU Lesser General Public 9 * License as published by the Free Software Foundation; either 10 * version 2.1 of the License, or (at your option) any later version. 11 * 12 * FFmpeg is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 * Lesser General Public License for more details. 16 * 17 * You should have received a copy of the GNU Lesser General Public 18 * License along with FFmpeg; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 20 */ 21#include <stdlib.h> 22#include <inttypes.h> 23#include <limits.h> 24#include <stdio.h> 25#include <string.h> 26#include <math.h> 27#include <assert.h> 28 29#include "avcodec.h" 30#include "libavutil/avutil.h" 31#include "get_bits.h" 32 33#include "g729.h" 34#include "lsp.h" 35#include "celp_math.h" 36#include "acelp_filters.h" 37#include "acelp_pitch_delay.h" 38#include "acelp_vectors.h" 39#include "g729data.h" 40 41/** 42 * minimum quantized LSF value (3.2.4) 43 * 0.005 in Q13 44 */ 45#define LSFQ_MIN 40 46 47/** 48 * maximum quantized LSF value (3.2.4) 49 * 3.135 in Q13 50 */ 51#define LSFQ_MAX 25681 52 53/** 54 * minimum LSF distance (3.2.4) 55 * 0.0391 in Q13 56 */ 57#define LSFQ_DIFF_MIN 321 58 59/** 60 * minimum gain pitch value (3.8, Equation 47) 61 * 0.2 in (1.14) 62 */ 63#define SHARP_MIN 3277 64 65/** 66 * maximum gain pitch value (3.8, Equation 47) 67 * (EE) This does not comply with the specification. 68 * Specification says about 0.8, which should be 69 * 13107 in (1.14), but reference C code uses 70 * 13017 (equals to 0.7945) instead of it. 71 */ 72#define SHARP_MAX 13017 73 74typedef struct { 75 uint8_t ac_index_bits[2]; ///< adaptive codebook index for second subframe (size in bits) 76 uint8_t parity_bit; ///< parity bit for pitch delay 77 uint8_t gc_1st_index_bits; ///< gain codebook (first stage) index (size in bits) 78 uint8_t gc_2nd_index_bits; ///< gain codebook (second stage) index (size in bits) 79 uint8_t fc_signs_bits; ///< number of pulses in fixed-codebook vector 80 uint8_t fc_indexes_bits; ///< size (in bits) of fixed-codebook index entry 81} G729FormatDescription; 82 83typedef struct { 84 int pitch_delay_int_prev; ///< integer part of previous subframe's pitch delay (4.1.3) 85 86 /// (2.13) LSP quantizer outputs 87 int16_t past_quantizer_output_buf[MA_NP + 1][10]; 88 int16_t* past_quantizer_outputs[MA_NP + 1]; 89 90 int16_t lsfq[10]; ///< (2.13) quantized LSF coefficients from previous frame 91 int16_t lsp_buf[2][10]; ///< (0.15) LSP coefficients (previous and current frames) (3.2.5) 92 int16_t *lsp[2]; ///< pointers to lsp_buf 93} G729Context; 94 95static const G729FormatDescription format_g729_8k = { 96 .ac_index_bits = {8,5}, 97 .parity_bit = 1, 98 .gc_1st_index_bits = GC_1ST_IDX_BITS_8K, 99 .gc_2nd_index_bits = GC_2ND_IDX_BITS_8K, 100 .fc_signs_bits = 4, 101 .fc_indexes_bits = 13, 102}; 103 104static const G729FormatDescription format_g729d_6k4 = { 105 .ac_index_bits = {8,4}, 106 .parity_bit = 0, 107 .gc_1st_index_bits = GC_1ST_IDX_BITS_6K4, 108 .gc_2nd_index_bits = GC_2ND_IDX_BITS_6K4, 109 .fc_signs_bits = 2, 110 .fc_indexes_bits = 9, 111}; 112 113/** 114 * \brief pseudo random number generator 115 */ 116static inline uint16_t g729_prng(uint16_t value) 117{ 118 return 31821 * value + 13849; 119} 120 121/** 122 * Get parity bit of bit 2..7 123 */ 124static inline int get_parity(uint8_t value) 125{ 126 return (0x6996966996696996ULL >> (value >> 2)) & 1; 127} 128 129static void lsf_decode(int16_t* lsfq, int16_t* past_quantizer_outputs[MA_NP + 1], 130 int16_t ma_predictor, 131 int16_t vq_1st, int16_t vq_2nd_low, int16_t vq_2nd_high) 132{ 133 int i,j; 134 static const uint8_t min_distance[2]={10, 5}; //(2.13) 135 int16_t* quantizer_output = past_quantizer_outputs[MA_NP]; 136 137 for (i = 0; i < 5; i++) { 138 quantizer_output[i] = cb_lsp_1st[vq_1st][i ] + cb_lsp_2nd[vq_2nd_low ][i ]; 139 quantizer_output[i + 5] = cb_lsp_1st[vq_1st][i + 5] + cb_lsp_2nd[vq_2nd_high][i + 5]; 140 } 141 142 for (j = 0; j < 2; j++) { 143 for (i = 1; i < 10; i++) { 144 int diff = (quantizer_output[i - 1] - quantizer_output[i] + min_distance[j]) >> 1; 145 if (diff > 0) { 146 quantizer_output[i - 1] -= diff; 147 quantizer_output[i ] += diff; 148 } 149 } 150 } 151 152 for (i = 0; i < 10; i++) { 153 int sum = quantizer_output[i] * cb_ma_predictor_sum[ma_predictor][i]; 154 for (j = 0; j < MA_NP; j++) 155 sum += past_quantizer_outputs[j][i] * cb_ma_predictor[ma_predictor][j][i]; 156 157 lsfq[i] = sum >> 15; 158 } 159 160 /* Rotate past_quantizer_outputs. */ 161 memmove(past_quantizer_outputs + 1, past_quantizer_outputs, MA_NP * sizeof(int16_t*)); 162 past_quantizer_outputs[0] = quantizer_output; 163 164 ff_acelp_reorder_lsf(lsfq, LSFQ_DIFF_MIN, LSFQ_MIN, LSFQ_MAX, 10); 165} 166 167static av_cold int decoder_init(AVCodecContext * avctx) 168{ 169 G729Context* ctx = avctx->priv_data; 170 int i,k; 171 172 if (avctx->channels != 1) { 173 av_log(avctx, AV_LOG_ERROR, "Only mono sound is supported (requested channels: %d).\n", avctx->channels); 174 return AVERROR(EINVAL); 175 } 176 177 /* Both 8kbit/s and 6.4kbit/s modes uses two subframes per frame. */ 178 avctx->frame_size = SUBFRAME_SIZE << 1; 179 180 for (k = 0; k < MA_NP + 1; k++) { 181 ctx->past_quantizer_outputs[k] = ctx->past_quantizer_output_buf[k]; 182 for (i = 1; i < 11; i++) 183 ctx->past_quantizer_outputs[k][i - 1] = (18717 * i) >> 3; 184 } 185 186 ctx->lsp[0] = ctx->lsp_buf[0]; 187 ctx->lsp[1] = ctx->lsp_buf[1]; 188 memcpy(ctx->lsp[0], lsp_init, 10 * sizeof(int16_t)); 189 190 return 0; 191} 192 193static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, 194 AVPacket *avpkt) 195{ 196 const uint8_t *buf = avpkt->data; 197 int buf_size = avpkt->size; 198 int16_t *out_frame = data; 199 GetBitContext gb; 200 G729FormatDescription format; 201 int frame_erasure = 0; ///< frame erasure detected during decoding 202 int bad_pitch = 0; ///< parity check failed 203 int i; 204 G729Context *ctx = avctx->priv_data; 205 int16_t lp[2][11]; // (3.12) 206 uint8_t ma_predictor; ///< switched MA predictor of LSP quantizer 207 uint8_t quantizer_1st; ///< first stage vector of quantizer 208 uint8_t quantizer_2nd_lo; ///< second stage lower vector of quantizer (size in bits) 209 uint8_t quantizer_2nd_hi; ///< second stage higher vector of quantizer (size in bits) 210 211 int pitch_delay_int; // pitch delay, integer part 212 int pitch_delay_3x; // pitch delay, multiplied by 3 213 214 if (*data_size < SUBFRAME_SIZE << 2) { 215 av_log(avctx, AV_LOG_ERROR, "Error processing packet: output buffer too small\n"); 216 return AVERROR(EIO); 217 } 218 219 if (buf_size == 10) { 220 format = format_g729_8k; 221 av_log(avctx, AV_LOG_DEBUG, "Packet type: %s\n", "G.729 @ 8kbit/s"); 222 } else if (buf_size == 8) { 223 format = format_g729d_6k4; 224 av_log(avctx, AV_LOG_DEBUG, "Packet type: %s\n", "G.729D @ 6.4kbit/s"); 225 } else { 226 av_log(avctx, AV_LOG_ERROR, "Packet size %d is unknown.\n", buf_size); 227 return AVERROR_INVALIDDATA; 228 } 229 230 for (i=0; i < buf_size; i++) 231 frame_erasure |= buf[i]; 232 frame_erasure = !frame_erasure; 233 234 init_get_bits(&gb, buf, buf_size); 235 236 ma_predictor = get_bits(&gb, 1); 237 quantizer_1st = get_bits(&gb, VQ_1ST_BITS); 238 quantizer_2nd_lo = get_bits(&gb, VQ_2ND_BITS); 239 quantizer_2nd_hi = get_bits(&gb, VQ_2ND_BITS); 240 241 lsf_decode(ctx->lsfq, ctx->past_quantizer_outputs, 242 ma_predictor, 243 quantizer_1st, quantizer_2nd_lo, quantizer_2nd_hi); 244 245 ff_acelp_lsf2lsp(ctx->lsp[1], ctx->lsfq, 10); 246 247 ff_acelp_lp_decode(&lp[0][0], &lp[1][0], ctx->lsp[1], ctx->lsp[0], 10); 248 249 FFSWAP(int16_t*, ctx->lsp[1], ctx->lsp[0]); 250 251 for (i = 0; i < 2; i++) { 252 uint8_t ac_index; ///< adaptive codebook index 253 uint8_t pulses_signs; ///< fixed-codebook vector pulse signs 254 int fc_indexes; ///< fixed-codebook indexes 255 uint8_t gc_1st_index; ///< gain codebook (first stage) index 256 uint8_t gc_2nd_index; ///< gain codebook (second stage) index 257 258 ac_index = get_bits(&gb, format.ac_index_bits[i]); 259 if(!i && format.parity_bit) 260 bad_pitch = get_parity(ac_index) == get_bits1(&gb); 261 fc_indexes = get_bits(&gb, format.fc_indexes_bits); 262 pulses_signs = get_bits(&gb, format.fc_signs_bits); 263 gc_1st_index = get_bits(&gb, format.gc_1st_index_bits); 264 gc_2nd_index = get_bits(&gb, format.gc_2nd_index_bits); 265 266 if(!i) { 267 if (bad_pitch) 268 pitch_delay_3x = 3 * ctx->pitch_delay_int_prev; 269 else 270 pitch_delay_3x = ff_acelp_decode_8bit_to_1st_delay3(ac_index); 271 } else { 272 int pitch_delay_min = av_clip(ctx->pitch_delay_int_prev - 5, 273 PITCH_DELAY_MIN, PITCH_DELAY_MAX - 9); 274 275 if(packet_type == FORMAT_G729D_6K4) 276 pitch_delay_3x = ff_acelp_decode_4bit_to_2nd_delay3(ac_index, pitch_delay_min); 277 else 278 pitch_delay_3x = ff_acelp_decode_5_6_bit_to_2nd_delay3(ac_index, pitch_delay_min); 279 } 280 281 /* Round pitch delay to nearest (used everywhere except ff_acelp_interpolate). */ 282 pitch_delay_int = (pitch_delay_3x + 1) / 3; 283 284 ff_acelp_weighted_vector_sum(fc + pitch_delay_int, 285 fc + pitch_delay_int, 286 fc, 1 << 14, 287 av_clip(ctx->gain_pitch, SHARP_MIN, SHARP_MAX), 288 0, 14, 289 SUBFRAME_SIZE - pitch_delay_int); 290 291 if (frame_erasure) { 292 ctx->gain_pitch = (29491 * ctx->gain_pitch) >> 15; // 0.90 (0.15) 293 ctx->gain_code = ( 2007 * ctx->gain_code ) >> 11; // 0.98 (0.11) 294 295 gain_corr_factor = 0; 296 } else { 297 ctx->gain_pitch = cb_gain_1st_8k[gc_1st_index][0] + 298 cb_gain_2nd_8k[gc_2nd_index][0]; 299 gain_corr_factor = cb_gain_1st_8k[gc_1st_index][1] + 300 cb_gain_2nd_8k[gc_2nd_index][1]; 301 302 ff_acelp_weighted_vector_sum(ctx->exc + i * SUBFRAME_SIZE, 303 ctx->exc + i * SUBFRAME_SIZE, fc, 304 (!voicing && frame_erasure) ? 0 : ctx->gain_pitch, 305 ( voicing && frame_erasure) ? 0 : ctx->gain_code, 306 1 << 13, 14, SUBFRAME_SIZE); 307 308 ctx->pitch_delay_int_prev = pitch_delay_int; 309 } 310 311 *data_size = SUBFRAME_SIZE << 2; 312 return buf_size; 313} 314 315AVCodec g729_decoder = 316{ 317 "g729", 318 AVMEDIA_TYPE_AUDIO, 319 CODEC_ID_G729, 320 sizeof(G729Context), 321 decoder_init, 322 NULL, 323 NULL, 324 decode_frame, 325 .long_name = NULL_IF_CONFIG_SMALL("G.729"), 326}; 327