| /* |
| * G.729 decoder |
| * Copyright (c) 2008 Vladimir Voroshilov |
| * |
| * 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 |
| */ |
| #include <stdlib.h> |
| #include <inttypes.h> |
| #include <limits.h> |
| #include <stdio.h> |
| #include <string.h> |
| #include <math.h> |
| #include <assert.h> |
| |
| #include "avcodec.h" |
| #include "libavutil/avutil.h" |
| #include "get_bits.h" |
| |
| #include "lsp.h" |
| #include "celp_math.h" |
| #include "acelp_filters.h" |
| #include "acelp_pitch_delay.h" |
| #include "acelp_vectors.h" |
| #include "g729data.h" |
| |
| /** |
| * minimum quantized LSF value (3.2.4) |
| * 0.005 in Q13 |
| */ |
| #define LSFQ_MIN 40 |
| |
| /** |
| * maximum quantized LSF value (3.2.4) |
| * 3.135 in Q13 |
| */ |
| #define LSFQ_MAX 25681 |
| |
| /** |
| * minimum LSF distance (3.2.4) |
| * 0.0391 in Q13 |
| */ |
| #define LSFQ_DIFF_MIN 321 |
| |
| /** |
| * minimum gain pitch value (3.8, Equation 47) |
| * 0.2 in (1.14) |
| */ |
| #define SHARP_MIN 3277 |
| |
| /** |
| * maximum gain pitch value (3.8, Equation 47) |
| * (EE) This does not comply with the specification. |
| * Specification says about 0.8, which should be |
| * 13107 in (1.14), but reference C code uses |
| * 13017 (equals to 0.7945) instead of it. |
| */ |
| #define SHARP_MAX 13017 |
| |
| /** |
| * subframe size |
| */ |
| #define SUBFRAME_SIZE 40 |
| |
| |
| typedef struct { |
| uint8_t ac_index_bits[2]; ///< adaptive codebook index for second subframe (size in bits) |
| uint8_t parity_bit; ///< parity bit for pitch delay |
| uint8_t gc_1st_index_bits; ///< gain codebook (first stage) index (size in bits) |
| uint8_t gc_2nd_index_bits; ///< gain codebook (second stage) index (size in bits) |
| uint8_t fc_signs_bits; ///< number of pulses in fixed-codebook vector |
| uint8_t fc_indexes_bits; ///< size (in bits) of fixed-codebook index entry |
| } G729FormatDescription; |
| |
| typedef struct { |
| int pitch_delay_int_prev; ///< integer part of previous subframe's pitch delay (4.1.3) |
| |
| /// (2.13) LSP quantizer outputs |
| int16_t past_quantizer_output_buf[MA_NP + 1][10]; |
| int16_t* past_quantizer_outputs[MA_NP + 1]; |
| |
| int16_t lsfq[10]; ///< (2.13) quantized LSF coefficients from previous frame |
| int16_t lsp_buf[2][10]; ///< (0.15) LSP coefficients (previous and current frames) (3.2.5) |
| int16_t *lsp[2]; ///< pointers to lsp_buf |
| } G729Context; |
| |
| static const G729FormatDescription format_g729_8k = { |
| .ac_index_bits = {8,5}, |
| .parity_bit = 1, |
| .gc_1st_index_bits = GC_1ST_IDX_BITS_8K, |
| .gc_2nd_index_bits = GC_2ND_IDX_BITS_8K, |
| .fc_signs_bits = 4, |
| .fc_indexes_bits = 13, |
| }; |
| |
| static const G729FormatDescription format_g729d_6k4 = { |
| .ac_index_bits = {8,4}, |
| .parity_bit = 0, |
| .gc_1st_index_bits = GC_1ST_IDX_BITS_6K4, |
| .gc_2nd_index_bits = GC_2ND_IDX_BITS_6K4, |
| .fc_signs_bits = 2, |
| .fc_indexes_bits = 9, |
| }; |
| |
| /** |
| * \brief pseudo random number generator |
| */ |
| static inline uint16_t g729_prng(uint16_t value) |
| { |
| return 31821 * value + 13849; |
| } |
| |
| /** |
| * Get parity bit of bit 2..7 |
| */ |
| static inline int get_parity(uint8_t value) |
| { |
| return (0x6996966996696996ULL >> (value >> 2)) & 1; |
| } |
| |
| static void lsf_decode(int16_t* lsfq, int16_t* past_quantizer_outputs[MA_NP + 1], |
| int16_t ma_predictor, |
| int16_t vq_1st, int16_t vq_2nd_low, int16_t vq_2nd_high) |
| { |
| int i,j; |
| static const uint8_t min_distance[2]={10, 5}; //(2.13) |
| int16_t* quantizer_output = past_quantizer_outputs[MA_NP]; |
| |
| for (i = 0; i < 5; i++) { |
| quantizer_output[i] = cb_lsp_1st[vq_1st][i ] + cb_lsp_2nd[vq_2nd_low ][i ]; |
| quantizer_output[i + 5] = cb_lsp_1st[vq_1st][i + 5] + cb_lsp_2nd[vq_2nd_high][i + 5]; |
| } |
| |
| for (j = 0; j < 2; j++) { |
| for (i = 1; i < 10; i++) { |
| int diff = (quantizer_output[i - 1] - quantizer_output[i] + min_distance[j]) >> 1; |
| if (diff > 0) { |
| quantizer_output[i - 1] -= diff; |
| quantizer_output[i ] += diff; |
| } |
| } |
| } |
| |
| for (i = 0; i < 10; i++) { |
| int sum = quantizer_output[i] * cb_ma_predictor_sum[ma_predictor][i]; |
| for (j = 0; j < MA_NP; j++) |
| sum += past_quantizer_outputs[j][i] * cb_ma_predictor[ma_predictor][j][i]; |
| |
| lsfq[i] = sum >> 15; |
| } |
| |
| /* Rotate past_quantizer_outputs. */ |
| memmove(past_quantizer_outputs + 1, past_quantizer_outputs, MA_NP * sizeof(int16_t*)); |
| past_quantizer_outputs[0] = quantizer_output; |
| |
| ff_acelp_reorder_lsf(lsfq, LSFQ_DIFF_MIN, LSFQ_MIN, LSFQ_MAX, 10); |
| } |
| |
| static av_cold int decoder_init(AVCodecContext * avctx) |
| { |
| G729Context* ctx = avctx->priv_data; |
| int i,k; |
| |
| if (avctx->channels != 1) { |
| av_log(avctx, AV_LOG_ERROR, "Only mono sound is supported (requested channels: %d).\n", avctx->channels); |
| return AVERROR(EINVAL); |
| } |
| |
| /* Both 8kbit/s and 6.4kbit/s modes uses two subframes per frame. */ |
| avctx->frame_size = SUBFRAME_SIZE << 1; |
| |
| for (k = 0; k < MA_NP + 1; k++) { |
| ctx->past_quantizer_outputs[k] = ctx->past_quantizer_output_buf[k]; |
| for (i = 1; i < 11; i++) |
| ctx->past_quantizer_outputs[k][i - 1] = (18717 * i) >> 3; |
| } |
| |
| ctx->lsp[0] = ctx->lsp_buf[0]; |
| ctx->lsp[1] = ctx->lsp_buf[1]; |
| memcpy(ctx->lsp[0], lsp_init, 10 * sizeof(int16_t)); |
| |
| return 0; |
| } |
| |
| static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, |
| AVPacket *avpkt) |
| { |
| const uint8_t *buf = avpkt->data; |
| int buf_size = avpkt->size; |
| int16_t *out_frame = data; |
| GetBitContext gb; |
| G729FormatDescription format; |
| int frame_erasure = 0; ///< frame erasure detected during decoding |
| int bad_pitch = 0; ///< parity check failed |
| int i; |
| G729Context *ctx = avctx->priv_data; |
| int16_t lp[2][11]; // (3.12) |
| uint8_t ma_predictor; ///< switched MA predictor of LSP quantizer |
| uint8_t quantizer_1st; ///< first stage vector of quantizer |
| uint8_t quantizer_2nd_lo; ///< second stage lower vector of quantizer (size in bits) |
| uint8_t quantizer_2nd_hi; ///< second stage higher vector of quantizer (size in bits) |
| |
| int pitch_delay_int; // pitch delay, integer part |
| int pitch_delay_3x; // pitch delay, multiplied by 3 |
| |
| if (*data_size < SUBFRAME_SIZE << 2) { |
| av_log(avctx, AV_LOG_ERROR, "Error processing packet: output buffer too small\n"); |
| return AVERROR(EIO); |
| } |
| |
| if (buf_size == 10) { |
| format = format_g729_8k; |
| av_log(avctx, AV_LOG_DEBUG, "Packet type: %s\n", "G.729 @ 8kbit/s"); |
| } else if (buf_size == 8) { |
| format = format_g729d_6k4; |
| av_log(avctx, AV_LOG_DEBUG, "Packet type: %s\n", "G.729D @ 6.4kbit/s"); |
| } else { |
| av_log(avctx, AV_LOG_ERROR, "Packet size %d is unknown.\n", buf_size); |
| return AVERROR_INVALIDDATA; |
| } |
| |
| for (i=0; i < buf_size; i++) |
| frame_erasure |= buf[i]; |
| frame_erasure = !frame_erasure; |
| |
| init_get_bits(&gb, buf, buf_size); |
| |
| ma_predictor = get_bits(&gb, 1); |
| quantizer_1st = get_bits(&gb, VQ_1ST_BITS); |
| quantizer_2nd_lo = get_bits(&gb, VQ_2ND_BITS); |
| quantizer_2nd_hi = get_bits(&gb, VQ_2ND_BITS); |
| |
| lsf_decode(ctx->lsfq, ctx->past_quantizer_outputs, |
| ma_predictor, |
| quantizer_1st, quantizer_2nd_lo, quantizer_2nd_hi); |
| |
| ff_acelp_lsf2lsp(ctx->lsp[1], ctx->lsfq, 10); |
| |
| ff_acelp_lp_decode(&lp[0][0], &lp[1][0], ctx->lsp[1], ctx->lsp[0], 10); |
| |
| FFSWAP(int16_t*, ctx->lsp[1], ctx->lsp[0]); |
| |
| for (i = 0; i < 2; i++) { |
| uint8_t ac_index; ///< adaptive codebook index |
| uint8_t pulses_signs; ///< fixed-codebook vector pulse signs |
| int fc_indexes; ///< fixed-codebook indexes |
| uint8_t gc_1st_index; ///< gain codebook (first stage) index |
| uint8_t gc_2nd_index; ///< gain codebook (second stage) index |
| |
| ac_index = get_bits(&gb, format.ac_index_bits[i]); |
| if(!i && format.parity_bit) |
| bad_pitch = get_parity(ac_index) == get_bits1(&gb); |
| fc_indexes = get_bits(&gb, format.fc_indexes_bits); |
| pulses_signs = get_bits(&gb, format.fc_signs_bits); |
| gc_1st_index = get_bits(&gb, format.gc_1st_index_bits); |
| gc_2nd_index = get_bits(&gb, format.gc_2nd_index_bits); |
| |
| if(!i) { |
| if (bad_pitch) |
| pitch_delay_3x = 3 * ctx->pitch_delay_int_prev; |
| else |
| pitch_delay_3x = ff_acelp_decode_8bit_to_1st_delay3(ac_index); |
| } else { |
| int pitch_delay_min = av_clip(ctx->pitch_delay_int_prev - 5, |
| PITCH_DELAY_MIN, PITCH_DELAY_MAX - 9); |
| |
| if(packet_type == FORMAT_G729D_6K4) |
| pitch_delay_3x = ff_acelp_decode_4bit_to_2nd_delay3(ac_index, pitch_delay_min); |
| else |
| pitch_delay_3x = ff_acelp_decode_5_6_bit_to_2nd_delay3(ac_index, pitch_delay_min); |
| } |
| |
| /* Round pitch delay to nearest (used everywhere except ff_acelp_interpolate). */ |
| pitch_delay_int = (pitch_delay_3x + 1) / 3; |
| |
| ff_acelp_weighted_vector_sum(fc + pitch_delay_int, |
| fc + pitch_delay_int, |
| fc, 1 << 14, |
| av_clip(ctx->gain_pitch, SHARP_MIN, SHARP_MAX), |
| 0, 14, |
| SUBFRAME_SIZE - pitch_delay_int); |
| |
| if (frame_erasure) { |
| ctx->gain_pitch = (29491 * ctx->gain_pitch) >> 15; // 0.90 (0.15) |
| ctx->gain_code = ( 2007 * ctx->gain_code ) >> 11; // 0.98 (0.11) |
| |
| gain_corr_factor = 0; |
| } else { |
| ctx->gain_pitch = cb_gain_1st_8k[gc_1st_index][0] + |
| cb_gain_2nd_8k[gc_2nd_index][0]; |
| gain_corr_factor = cb_gain_1st_8k[gc_1st_index][1] + |
| cb_gain_2nd_8k[gc_2nd_index][1]; |
| |
| ff_acelp_weighted_vector_sum(ctx->exc + i * SUBFRAME_SIZE, |
| ctx->exc + i * SUBFRAME_SIZE, fc, |
| (!voicing && frame_erasure) ? 0 : ctx->gain_pitch, |
| ( voicing && frame_erasure) ? 0 : ctx->gain_code, |
| 1 << 13, 14, SUBFRAME_SIZE); |
| |
| ctx->pitch_delay_int_prev = pitch_delay_int; |
| } |
| |
| *data_size = SUBFRAME_SIZE << 2; |
| return buf_size; |
| } |
| |
| AVCodec ff_g729_decoder = |
| { |
| "g729", |
| AVMEDIA_TYPE_AUDIO, |
| CODEC_ID_G729, |
| sizeof(G729Context), |
| decoder_init, |
| NULL, |
| NULL, |
| decode_frame, |
| .long_name = NULL_IF_CONFIG_SMALL("G.729"), |
| }; |
