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228 lines
7.4 KiB
228 lines
7.4 KiB
/* |
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* G.729 decoder |
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* Copyright (c) 2008 Vladimir Voroshilov |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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#include <stdlib.h> |
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#include <inttypes.h> |
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#include <limits.h> |
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#include <stdio.h> |
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#include <string.h> |
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#include <math.h> |
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#include <assert.h> |
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#include "avcodec.h" |
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#include "libavutil/avutil.h" |
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#include "get_bits.h" |
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#include "g729.h" |
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#include "lsp.h" |
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#include "celp_math.h" |
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#include "acelp_filters.h" |
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#include "acelp_pitch_delay.h" |
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#include "acelp_vectors.h" |
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#include "g729data.h" |
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/** |
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* minimum quantized LSF value (3.2.4) |
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* 0.005 in Q13 |
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*/ |
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#define LSFQ_MIN 40 |
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/** |
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* maximum quantized LSF value (3.2.4) |
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* 3.135 in Q13 |
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*/ |
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#define LSFQ_MAX 25681 |
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/** |
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* minimum LSF distance (3.2.4) |
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* 0.0391 in Q13 |
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*/ |
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#define LSFQ_DIFF_MIN 321 |
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/** |
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* minimum gain pitch value (3.8, Equation 47) |
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* 0.2 in (1.14) |
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*/ |
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#define SHARP_MIN 3277 |
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/** |
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* maximum gain pitch value (3.8, Equation 47) |
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* (EE) This does not comply with the specification. |
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* Specification says about 0.8, which should be |
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* 13107 in (1.14), but reference C code uses |
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* 13017 (equals to 0.7945) instead of it. |
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*/ |
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#define SHARP_MAX 13017 |
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typedef struct { |
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uint8_t ac_index_bits[2]; ///< adaptive codebook index for second subframe (size in bits) |
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uint8_t parity_bit; ///< parity bit for pitch delay |
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uint8_t gc_1st_index_bits; ///< gain codebook (first stage) index (size in bits) |
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uint8_t gc_2nd_index_bits; ///< gain codebook (second stage) index (size in bits) |
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uint8_t fc_signs_bits; ///< number of pulses in fixed-codebook vector |
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uint8_t fc_indexes_bits; ///< size (in bits) of fixed-codebook index entry |
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} G729FormatDescription; |
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static const G729FormatDescription format_g729_8k = { |
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.ac_index_bits = {8,5}, |
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.parity_bit = 1, |
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.gc_1st_index_bits = GC_1ST_IDX_BITS_8K, |
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.gc_2nd_index_bits = GC_2ND_IDX_BITS_8K, |
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.fc_signs_bits = 4, |
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.fc_indexes_bits = 13, |
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}; |
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static const G729FormatDescription format_g729d_6k4 = { |
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.ac_index_bits = {8,4}, |
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.parity_bit = 0, |
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.gc_1st_index_bits = GC_1ST_IDX_BITS_6K4, |
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.gc_2nd_index_bits = GC_2ND_IDX_BITS_6K4, |
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.fc_signs_bits = 2, |
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.fc_indexes_bits = 9, |
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}; |
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/** |
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* \brief pseudo random number generator |
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*/ |
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static inline uint16_t g729_prng(uint16_t value) |
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{ |
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return 31821 * value + 13849; |
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} |
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/** |
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* Get parity bit of bit 2..7 |
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*/ |
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static inline int get_parity(uint8_t value) |
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{ |
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return (0x6996966996696996ULL >> (value >> 2)) & 1; |
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} |
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static av_cold int decoder_init(AVCodecContext * avctx) |
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{ |
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if (avctx->channels != 1) { |
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av_log(avctx, AV_LOG_ERROR, "Only mono sound is supported (requested channels: %d).\n", avctx->channels); |
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return AVERROR_NOFMT; |
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} |
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/* Both 8kbit/s and 6.4kbit/s modes uses two subframes per frame. */ |
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avctx->frame_size = SUBFRAME_SIZE << 1; |
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return 0; |
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} |
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static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, |
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AVPacket *avpkt) |
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{ |
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const uint8_t *buf = avpkt->data; |
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int buf_size = avpkt->size; |
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int16_t *out_frame = data; |
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GetBitContext gb; |
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G729FormatDescription format; |
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int frame_erasure = 0; ///< frame erasure detected during decoding |
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int bad_pitch = 0; ///< parity check failed |
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int i; |
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uint8_t ma_predictor; ///< switched MA predictor of LSP quantizer |
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uint8_t quantizer_1st; ///< first stage vector of quantizer |
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uint8_t quantizer_2nd_lo; ///< second stage lower vector of quantizer (size in bits) |
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uint8_t quantizer_2nd_hi; ///< second stage higher vector of quantizer (size in bits) |
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if (*data_size < SUBFRAME_SIZE << 2) { |
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av_log(avctx, AV_LOG_ERROR, "Error processing packet: output buffer too small\n"); |
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return AVERROR(EIO); |
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} |
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if (buf_size == 10) { |
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format = format_g729_8k; |
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av_log(avctx, AV_LOG_DEBUG, "Packet type: %s\n", "G.729 @ 8kbit/s"); |
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} else if (buf_size == 8) { |
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format = format_g729d_6k4; |
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av_log(avctx, AV_LOG_DEBUG, "Packet type: %s\n", "G.729D @ 6.4kbit/s"); |
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} else { |
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av_log(avctx, AV_LOG_ERROR, "Packet size %d is unknown.\n", buf_size); |
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return (AVERROR_NOFMT); |
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} |
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for (i=0; i < buf_size; i++) |
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frame_erasure |= buf[i]; |
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frame_erasure = !frame_erasure; |
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init_get_bits(&gb, buf, buf_size); |
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ma_predictor = get_bits(&gb, 1); |
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quantizer_1st = get_bits(&gb, VQ_1ST_BITS); |
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quantizer_2nd_lo = get_bits(&gb, VQ_2ND_BITS); |
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quantizer_2nd_hi = get_bits(&gb, VQ_2ND_BITS); |
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for (i = 0; i < 2; i++) { |
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uint8_t ac_index; ///< adaptive codebook index |
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uint8_t pulses_signs; ///< fixed-codebook vector pulse signs |
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int fc_indexes; ///< fixed-codebook indexes |
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uint8_t gc_1st_index; ///< gain codebook (first stage) index |
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uint8_t gc_2nd_index; ///< gain codebook (second stage) index |
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ac_index = get_bits(&gb, format.ac_index_bits[i]); |
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if(!i && format.parity_bit) |
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bad_pitch = get_parity(ac_index) == get_bits1(&gb); |
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fc_indexes = get_bits(&gb, format.fc_indexes_bits); |
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pulses_signs = get_bits(&gb, format.fc_signs_bits); |
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gc_1st_index = get_bits(&gb, format.gc_1st_index_bits); |
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gc_2nd_index = get_bits(&gb, format.gc_2nd_index_bits); |
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ff_acelp_weighted_vector_sum(fc + pitch_delay_int[i], |
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fc + pitch_delay_int[i], |
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fc, 1 << 14, |
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av_clip(ctx->gain_pitch, SHARP_MIN, SHARP_MAX), |
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0, 14, |
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SUBFRAME_SIZE - pitch_delay_int[i]); |
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if (frame_erasure) { |
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ctx->gain_pitch = (29491 * ctx->gain_pitch) >> 15; // 0.90 (0.15) |
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ctx->gain_code = ( 2007 * ctx->gain_code ) >> 11; // 0.98 (0.11) |
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gain_corr_factor = 0; |
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} else { |
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ctx->gain_pitch = cb_gain_1st_8k[gc_1st_index][0] + |
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cb_gain_2nd_8k[gc_2nd_index][0]; |
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gain_corr_factor = cb_gain_1st_8k[gc_1st_index][1] + |
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cb_gain_2nd_8k[gc_2nd_index][1]; |
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ff_acelp_weighted_vector_sum(ctx->exc + i * SUBFRAME_SIZE, |
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ctx->exc + i * SUBFRAME_SIZE, fc, |
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(!voicing && frame_erasure) ? 0 : ctx->gain_pitch, |
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( voicing && frame_erasure) ? 0 : ctx->gain_code, |
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1 << 13, 14, SUBFRAME_SIZE); |
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} |
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*data_size = SUBFRAME_SIZE << 2; |
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return buf_size; |
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} |
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AVCodec g729_decoder = |
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{ |
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"g729", |
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CODEC_TYPE_AUDIO, |
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CODEC_ID_G729, |
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sizeof(G729Context), |
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decoder_init, |
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NULL, |
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NULL, |
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decode_frame, |
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.long_name = NULL_IF_CONFIG_SMALL("G.729"), |
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};
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