1/* 2 * ADX ADPCM codecs 3 * Copyright (c) 2001,2003 BERO 4 * 5 * This file is part of Libav. 6 * 7 * Libav 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 * Libav 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 Libav; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 20 */ 21 22#include "libavutil/intreadwrite.h" 23#include "avcodec.h" 24#include "adx.h" 25#include "get_bits.h" 26 27/** 28 * @file 29 * SEGA CRI adx codecs. 30 * 31 * Reference documents: 32 * http://ku-www.ss.titech.ac.jp/~yatsushi/adx.html 33 * adx2wav & wav2adx http://www.geocities.co.jp/Playtown/2004/ 34 */ 35 36static av_cold int adx_decode_init(AVCodecContext *avctx) 37{ 38 ADXContext *c = avctx->priv_data; 39 int ret, header_size; 40 41 if (avctx->extradata_size >= 24) { 42 if ((ret = avpriv_adx_decode_header(avctx, avctx->extradata, 43 avctx->extradata_size, &header_size, 44 c->coeff)) < 0) { 45 av_log(avctx, AV_LOG_ERROR, "error parsing ADX header\n"); 46 return AVERROR_INVALIDDATA; 47 } 48 c->channels = avctx->channels; 49 c->header_parsed = 1; 50 } 51 52 avctx->sample_fmt = AV_SAMPLE_FMT_S16; 53 54 avcodec_get_frame_defaults(&c->frame); 55 avctx->coded_frame = &c->frame; 56 57 return 0; 58} 59 60/** 61 * Decode 32 samples from 18 bytes. 62 * 63 * A 16-bit scalar value is applied to 32 residuals, which then have a 64 * 2nd-order LPC filter applied to it to form the output signal for a single 65 * channel. 66 */ 67static int adx_decode(ADXContext *c, int16_t *out, const uint8_t *in, int ch) 68{ 69 ADXChannelState *prev = &c->prev[ch]; 70 GetBitContext gb; 71 int scale = AV_RB16(in); 72 int i; 73 int s0, s1, s2, d; 74 75 /* check if this is an EOF packet */ 76 if (scale & 0x8000) 77 return -1; 78 79 init_get_bits(&gb, in + 2, (BLOCK_SIZE - 2) * 8); 80 s1 = prev->s1; 81 s2 = prev->s2; 82 for (i = 0; i < BLOCK_SAMPLES; i++) { 83 d = get_sbits(&gb, 4); 84 s0 = ((d << COEFF_BITS) * scale + c->coeff[0] * s1 + c->coeff[1] * s2) >> COEFF_BITS; 85 s2 = s1; 86 s1 = av_clip_int16(s0); 87 *out = s1; 88 out += c->channels; 89 } 90 prev->s1 = s1; 91 prev->s2 = s2; 92 93 return 0; 94} 95 96static int adx_decode_frame(AVCodecContext *avctx, void *data, 97 int *got_frame_ptr, AVPacket *avpkt) 98{ 99 int buf_size = avpkt->size; 100 ADXContext *c = avctx->priv_data; 101 int16_t *samples; 102 const uint8_t *buf = avpkt->data; 103 int num_blocks, ch, ret; 104 105 if (c->eof) { 106 *got_frame_ptr = 0; 107 return buf_size; 108 } 109 110 if (!c->header_parsed && buf_size >= 2 && AV_RB16(buf) == 0x8000) { 111 int header_size; 112 if ((ret = avpriv_adx_decode_header(avctx, buf, buf_size, &header_size, 113 c->coeff)) < 0) { 114 av_log(avctx, AV_LOG_ERROR, "error parsing ADX header\n"); 115 return AVERROR_INVALIDDATA; 116 } 117 c->channels = avctx->channels; 118 c->header_parsed = 1; 119 if (buf_size < header_size) 120 return AVERROR_INVALIDDATA; 121 buf += header_size; 122 buf_size -= header_size; 123 } 124 if (!c->header_parsed) 125 return AVERROR_INVALIDDATA; 126 127 /* calculate number of blocks in the packet */ 128 num_blocks = buf_size / (BLOCK_SIZE * c->channels); 129 130 /* if the packet is not an even multiple of BLOCK_SIZE, check for an EOF 131 packet */ 132 if (!num_blocks || buf_size % (BLOCK_SIZE * avctx->channels)) { 133 if (buf_size >= 4 && (AV_RB16(buf) & 0x8000)) { 134 c->eof = 1; 135 *got_frame_ptr = 0; 136 return avpkt->size; 137 } 138 return AVERROR_INVALIDDATA; 139 } 140 141 /* get output buffer */ 142 c->frame.nb_samples = num_blocks * BLOCK_SAMPLES; 143 if ((ret = avctx->get_buffer(avctx, &c->frame)) < 0) { 144 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); 145 return ret; 146 } 147 samples = (int16_t *)c->frame.data[0]; 148 149 while (num_blocks--) { 150 for (ch = 0; ch < c->channels; ch++) { 151 if (adx_decode(c, samples + ch, buf, ch)) { 152 c->eof = 1; 153 buf = avpkt->data + avpkt->size; 154 break; 155 } 156 buf_size -= BLOCK_SIZE; 157 buf += BLOCK_SIZE; 158 } 159 samples += BLOCK_SAMPLES * c->channels; 160 } 161 162 *got_frame_ptr = 1; 163 *(AVFrame *)data = c->frame; 164 165 return buf - avpkt->data; 166} 167 168static void adx_decode_flush(AVCodecContext *avctx) 169{ 170 ADXContext *c = avctx->priv_data; 171 memset(c->prev, 0, sizeof(c->prev)); 172 c->eof = 0; 173} 174 175AVCodec ff_adpcm_adx_decoder = { 176 .name = "adpcm_adx", 177 .type = AVMEDIA_TYPE_AUDIO, 178 .id = CODEC_ID_ADPCM_ADX, 179 .priv_data_size = sizeof(ADXContext), 180 .init = adx_decode_init, 181 .decode = adx_decode_frame, 182 .flush = adx_decode_flush, 183 .capabilities = CODEC_CAP_DR1, 184 .long_name = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"), 185}; 186