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 FFmpeg. 9 * 10 * FFmpeg 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 * FFmpeg 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 FFmpeg; 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 "libavutil/channel_layout.h" 38#include "libavutil/opt.h" 39#include "avcodec.h" 40#include "get_bits.h" 41#include "g722.h" 42#include "internal.h" 43 44#define OFFSET(x) offsetof(G722Context, x) 45#define AD AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_DECODING_PARAM 46static const AVOption options[] = { 47 { "bits_per_codeword", "Bits per G722 codeword", OFFSET(bits_per_codeword), AV_OPT_TYPE_INT, { .i64 = 8 }, 6, 8, AD }, 48 { NULL } 49}; 50 51static const AVClass g722_decoder_class = { 52 .class_name = "g722 decoder", 53 .item_name = av_default_item_name, 54 .option = options, 55 .version = LIBAVUTIL_VERSION_INT, 56}; 57 58static av_cold int g722_decode_init(AVCodecContext * avctx) 59{ 60 G722Context *c = avctx->priv_data; 61 62 avctx->channels = 1; 63 avctx->channel_layout = AV_CH_LAYOUT_MONO; 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 return 0; 71} 72 73static const int16_t low_inv_quant5[32] = { 74 -35, -35, -2919, -2195, -1765, -1458, -1219, -1023, 75 -858, -714, -587, -473, -370, -276, -190, -110, 76 2919, 2195, 1765, 1458, 1219, 1023, 858, 714, 77 587, 473, 370, 276, 190, 110, 35, -35 78}; 79 80static const int16_t *low_inv_quants[3] = { ff_g722_low_inv_quant6, 81 low_inv_quant5, 82 ff_g722_low_inv_quant4 }; 83 84static int g722_decode_frame(AVCodecContext *avctx, void *data, 85 int *got_frame_ptr, AVPacket *avpkt) 86{ 87 G722Context *c = avctx->priv_data; 88 AVFrame *frame = data; 89 int16_t *out_buf; 90 int j, ret; 91 const int skip = 8 - c->bits_per_codeword; 92 const int16_t *quantizer_table = low_inv_quants[skip]; 93 GetBitContext gb; 94 95 /* get output buffer */ 96 frame->nb_samples = avpkt->size * 2; 97 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) 98 return ret; 99 out_buf = (int16_t *)frame->data[0]; 100 101 init_get_bits(&gb, avpkt->data, avpkt->size * 8); 102 103 for (j = 0; j < avpkt->size; j++) { 104 int ilow, ihigh, rlow, rhigh, dhigh; 105 int xout1, xout2; 106 107 ihigh = get_bits(&gb, 2); 108 ilow = get_bits(&gb, 6 - skip); 109 skip_bits(&gb, skip); 110 111 rlow = av_clip((c->band[0].scale_factor * quantizer_table[ilow] >> 10) 112 + c->band[0].s_predictor, -16384, 16383); 113 114 ff_g722_update_low_predictor(&c->band[0], ilow >> (2 - skip)); 115 116 dhigh = c->band[1].scale_factor * ff_g722_high_inv_quant[ihigh] >> 10; 117 rhigh = av_clip(dhigh + c->band[1].s_predictor, -16384, 16383); 118 119 ff_g722_update_high_predictor(&c->band[1], dhigh, ihigh); 120 121 c->prev_samples[c->prev_samples_pos++] = rlow + rhigh; 122 c->prev_samples[c->prev_samples_pos++] = rlow - rhigh; 123 ff_g722_apply_qmf(c->prev_samples + c->prev_samples_pos - 24, 124 &xout1, &xout2); 125 *out_buf++ = av_clip_int16(xout1 >> 11); 126 *out_buf++ = av_clip_int16(xout2 >> 11); 127 if (c->prev_samples_pos >= PREV_SAMPLES_BUF_SIZE) { 128 memmove(c->prev_samples, c->prev_samples + c->prev_samples_pos - 22, 129 22 * sizeof(c->prev_samples[0])); 130 c->prev_samples_pos = 22; 131 } 132 } 133 134 *got_frame_ptr = 1; 135 136 return avpkt->size; 137} 138 139AVCodec ff_adpcm_g722_decoder = { 140 .name = "g722", 141 .long_name = NULL_IF_CONFIG_SMALL("G.722 ADPCM"), 142 .type = AVMEDIA_TYPE_AUDIO, 143 .id = AV_CODEC_ID_ADPCM_G722, 144 .priv_data_size = sizeof(G722Context), 145 .init = g722_decode_init, 146 .decode = g722_decode_frame, 147 .capabilities = CODEC_CAP_DR1, 148 .priv_class = &g722_decoder_class, 149}; 150