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 "avcodec.h" 23#include "adx.h" 24#include "bytestream.h" 25#include "put_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 void adx_encode(ADXContext *c, uint8_t *adx, const int16_t *wav, 37 ADXChannelState *prev, int channels) 38{ 39 PutBitContext pb; 40 int scale; 41 int i, j; 42 int s0, s1, s2, d; 43 int max = 0; 44 int min = 0; 45 int data[BLOCK_SAMPLES]; 46 47 s1 = prev->s1; 48 s2 = prev->s2; 49 for (i = 0, j = 0; j < 32; i += channels, j++) { 50 s0 = wav[i]; 51 d = ((s0 << COEFF_BITS) - c->coeff[0] * s1 - c->coeff[1] * s2) >> COEFF_BITS; 52 data[j] = d; 53 if (max < d) 54 max = d; 55 if (min > d) 56 min = d; 57 s2 = s1; 58 s1 = s0; 59 } 60 prev->s1 = s1; 61 prev->s2 = s2; 62 63 if (max == 0 && min == 0) { 64 memset(adx, 0, BLOCK_SIZE); 65 return; 66 } 67 68 if (max / 7 > -min / 8) 69 scale = max / 7; 70 else 71 scale = -min / 8; 72 73 if (scale == 0) 74 scale = 1; 75 76 AV_WB16(adx, scale); 77 78 init_put_bits(&pb, adx + 2, 16); 79 for (i = 0; i < BLOCK_SAMPLES; i++) 80 put_sbits(&pb, 4, av_clip(data[i] / scale, -8, 7)); 81 flush_put_bits(&pb); 82} 83 84#define HEADER_SIZE 36 85 86static int adx_encode_header(AVCodecContext *avctx, uint8_t *buf, int bufsize) 87{ 88 ADXContext *c = avctx->priv_data; 89 90 if (bufsize < HEADER_SIZE) 91 return AVERROR(EINVAL); 92 93 bytestream_put_be16(&buf, 0x8000); /* header signature */ 94 bytestream_put_be16(&buf, HEADER_SIZE - 4); /* copyright offset */ 95 bytestream_put_byte(&buf, 3); /* encoding */ 96 bytestream_put_byte(&buf, BLOCK_SIZE); /* block size */ 97 bytestream_put_byte(&buf, 4); /* sample size */ 98 bytestream_put_byte(&buf, avctx->channels); /* channels */ 99 bytestream_put_be32(&buf, avctx->sample_rate); /* sample rate */ 100 bytestream_put_be32(&buf, 0); /* total sample count */ 101 bytestream_put_be16(&buf, c->cutoff); /* cutoff frequency */ 102 bytestream_put_byte(&buf, 3); /* version */ 103 bytestream_put_byte(&buf, 0); /* flags */ 104 bytestream_put_be32(&buf, 0); /* unknown */ 105 bytestream_put_be32(&buf, 0); /* loop enabled */ 106 bytestream_put_be16(&buf, 0); /* padding */ 107 bytestream_put_buffer(&buf, "(c)CRI", 6); /* copyright signature */ 108 109 return HEADER_SIZE; 110} 111 112static av_cold int adx_encode_init(AVCodecContext *avctx) 113{ 114 ADXContext *c = avctx->priv_data; 115 116 if (avctx->channels > 2) { 117 av_log(avctx, AV_LOG_ERROR, "Invalid number of channels\n"); 118 return AVERROR(EINVAL); 119 } 120 avctx->frame_size = BLOCK_SAMPLES; 121 122 avctx->coded_frame = avcodec_alloc_frame(); 123 124 /* the cutoff can be adjusted, but this seems to work pretty well */ 125 c->cutoff = 500; 126 ff_adx_calculate_coeffs(c->cutoff, avctx->sample_rate, COEFF_BITS, c->coeff); 127 128 return 0; 129} 130 131static av_cold int adx_encode_close(AVCodecContext *avctx) 132{ 133 av_freep(&avctx->coded_frame); 134 return 0; 135} 136 137static int adx_encode_frame(AVCodecContext *avctx, uint8_t *frame, 138 int buf_size, void *data) 139{ 140 ADXContext *c = avctx->priv_data; 141 const int16_t *samples = data; 142 uint8_t *dst = frame; 143 int ch; 144 145 if (!c->header_parsed) { 146 int hdrsize; 147 if ((hdrsize = adx_encode_header(avctx, dst, buf_size)) < 0) { 148 av_log(avctx, AV_LOG_ERROR, "output buffer is too small\n"); 149 return AVERROR(EINVAL); 150 } 151 dst += hdrsize; 152 buf_size -= hdrsize; 153 c->header_parsed = 1; 154 } 155 if (buf_size < BLOCK_SIZE * avctx->channels) { 156 av_log(avctx, AV_LOG_ERROR, "output buffer is too small\n"); 157 return AVERROR(EINVAL); 158 } 159 160 for (ch = 0; ch < avctx->channels; ch++) { 161 adx_encode(c, dst, samples + ch, &c->prev[ch], avctx->channels); 162 dst += BLOCK_SIZE; 163 } 164 return dst - frame; 165} 166 167AVCodec ff_adpcm_adx_encoder = { 168 .name = "adpcm_adx", 169 .type = AVMEDIA_TYPE_AUDIO, 170 .id = CODEC_ID_ADPCM_ADX, 171 .priv_data_size = sizeof(ADXContext), 172 .init = adx_encode_init, 173 .encode = adx_encode_frame, 174 .close = adx_encode_close, 175 .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16, 176 AV_SAMPLE_FMT_NONE }, 177 .long_name = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"), 178}; 179