1/* 2 * Copyright (c) CMU 1993 Computer Science, Speech Group 3 * Chengxiang Lu and Alex Hauptmann 4 * Copyright (c) 2005 Steve Underwood <steveu at coppice.org> 5 * Copyright (c) 2009 Kenan Gillet 6 * Copyright (c) 2010 Martin Storsjo 7 * 8 * This file is part of Libav. 9 * 10 * Libav is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU Lesser General Public 12 * License as published by the Free Software Foundation; either 13 * version 2.1 of the License, or (at your option) any later version. 14 * 15 * Libav is distributed in the hope that it will be useful, 16 * but WITHOUT ANY WARRANTY; without even the implied warranty of 17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 18 * Lesser General Public License for more details. 19 * 20 * You should have received a copy of the GNU Lesser General Public 21 * License along with Libav; if not, write to the Free Software 22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 23 */ 24 25/** 26 * @file 27 * G.722 ADPCM audio decoder 28 * 29 * This G.722 decoder is a bit-exact implementation of the ITU G.722 30 * specification for all three specified bitrates - 64000bps, 56000bps 31 * and 48000bps. It passes the ITU tests. 32 * 33 * @note For the 56000bps and 48000bps bitrates, the lowest 1 or 2 bits 34 * respectively of each byte are ignored. 35 */ 36 37#include "avcodec.h" 38#include "get_bits.h" 39#include "g722.h" 40#include "libavutil/opt.h" 41 42#define OFFSET(x) offsetof(G722Context, x) 43#define AD AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_DECODING_PARAM 44static const AVOption options[] = { 45 { "bits_per_codeword", "Bits per G722 codeword", OFFSET(bits_per_codeword), AV_OPT_TYPE_FLAGS, { 8 }, 6, 8, AD }, 46 { NULL } 47}; 48 49static const AVClass g722_decoder_class = { 50 .class_name = "g722 decoder", 51 .item_name = av_default_item_name, 52 .option = options, 53 .version = LIBAVUTIL_VERSION_INT, 54}; 55 56static av_cold int g722_decode_init(AVCodecContext * avctx) 57{ 58 G722Context *c = avctx->priv_data; 59 60 if (avctx->channels != 1) { 61 av_log(avctx, AV_LOG_ERROR, "Only mono tracks are allowed.\n"); 62 return AVERROR_INVALIDDATA; 63 } 64 avctx->sample_fmt = AV_SAMPLE_FMT_S16; 65 66 c->band[0].scale_factor = 8; 67 c->band[1].scale_factor = 2; 68 c->prev_samples_pos = 22; 69 70 avcodec_get_frame_defaults(&c->frame); 71 avctx->coded_frame = &c->frame; 72 73 return 0; 74} 75 76static const int16_t low_inv_quant5[32] = { 77 -35, -35, -2919, -2195, -1765, -1458, -1219, -1023, 78 -858, -714, -587, -473, -370, -276, -190, -110, 79 2919, 2195, 1765, 1458, 1219, 1023, 858, 714, 80 587, 473, 370, 276, 190, 110, 35, -35 81}; 82 83static const int16_t *low_inv_quants[3] = { ff_g722_low_inv_quant6, 84 low_inv_quant5, 85 ff_g722_low_inv_quant4 }; 86 87static int g722_decode_frame(AVCodecContext *avctx, void *data, 88 int *got_frame_ptr, AVPacket *avpkt) 89{ 90 G722Context *c = avctx->priv_data; 91 int16_t *out_buf; 92 int j, ret; 93 const int skip = 8 - c->bits_per_codeword; 94 const int16_t *quantizer_table = low_inv_quants[skip]; 95 GetBitContext gb; 96 97 /* get output buffer */ 98 c->frame.nb_samples = avpkt->size * 2; 99 if ((ret = avctx->get_buffer(avctx, &c->frame)) < 0) { 100 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); 101 return ret; 102 } 103 out_buf = (int16_t *)c->frame.data[0]; 104 105 init_get_bits(&gb, avpkt->data, avpkt->size * 8); 106 107 for (j = 0; j < avpkt->size; j++) { 108 int ilow, ihigh, rlow, rhigh, dhigh; 109 int xout1, xout2; 110 111 ihigh = get_bits(&gb, 2); 112 ilow = get_bits(&gb, 6 - skip); 113 skip_bits(&gb, skip); 114 115 rlow = av_clip((c->band[0].scale_factor * quantizer_table[ilow] >> 10) 116 + c->band[0].s_predictor, -16384, 16383); 117 118 ff_g722_update_low_predictor(&c->band[0], ilow >> (2 - skip)); 119 120 dhigh = c->band[1].scale_factor * ff_g722_high_inv_quant[ihigh] >> 10; 121 rhigh = av_clip(dhigh + c->band[1].s_predictor, -16384, 16383); 122 123 ff_g722_update_high_predictor(&c->band[1], dhigh, ihigh); 124 125 c->prev_samples[c->prev_samples_pos++] = rlow + rhigh; 126 c->prev_samples[c->prev_samples_pos++] = rlow - rhigh; 127 ff_g722_apply_qmf(c->prev_samples + c->prev_samples_pos - 24, 128 &xout1, &xout2); 129 *out_buf++ = av_clip_int16(xout1 >> 11); 130 *out_buf++ = av_clip_int16(xout2 >> 11); 131 if (c->prev_samples_pos >= PREV_SAMPLES_BUF_SIZE) { 132 memmove(c->prev_samples, c->prev_samples + c->prev_samples_pos - 22, 133 22 * sizeof(c->prev_samples[0])); 134 c->prev_samples_pos = 22; 135 } 136 } 137 138 *got_frame_ptr = 1; 139 *(AVFrame *)data = c->frame; 140 141 return avpkt->size; 142} 143 144AVCodec ff_adpcm_g722_decoder = { 145 .name = "g722", 146 .type = AVMEDIA_TYPE_AUDIO, 147 .id = CODEC_ID_ADPCM_G722, 148 .priv_data_size = sizeof(G722Context), 149 .init = g722_decode_init, 150 .decode = g722_decode_frame, 151 .capabilities = CODEC_CAP_DR1, 152 .long_name = NULL_IF_CONFIG_SMALL("G.722 ADPCM"), 153 .priv_class = &g722_decoder_class, 154}; 155