1/* 2 * Westwood SNDx codecs 3 * Copyright (c) 2005 Konstantin Shishkov 4 * 5 * This file is part of FFmpeg. 6 * 7 * FFmpeg 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 * FFmpeg 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 FFmpeg; 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 25/** 26 * @file 27 * Westwood SNDx codecs. 28 * 29 * Reference documents about VQA format and its audio codecs 30 * can be found here: 31 * http://www.multimedia.cx 32 */ 33 34static const char ws_adpcm_2bit[] = { -2, -1, 0, 1}; 35static const char ws_adpcm_4bit[] = { 36 -9, -8, -6, -5, -4, -3, -2, -1, 37 0, 1, 2, 3, 4, 5, 6, 8 }; 38 39#define CLIP8(a) if(a>127)a=127;if(a<-128)a=-128; 40 41static av_cold int ws_snd_decode_init(AVCodecContext * avctx) 42{ 43// WSSNDContext *c = avctx->priv_data; 44 45 avctx->sample_fmt = SAMPLE_FMT_S16; 46 return 0; 47} 48 49static int ws_snd_decode_frame(AVCodecContext *avctx, 50 void *data, int *data_size, 51 AVPacket *avpkt) 52{ 53 const uint8_t *buf = avpkt->data; 54 int buf_size = avpkt->size; 55// WSSNDContext *c = avctx->priv_data; 56 57 int in_size, out_size; 58 int sample = 0; 59 int i; 60 short *samples = data; 61 62 if (!buf_size) 63 return 0; 64 65 out_size = AV_RL16(&buf[0]); 66 *data_size = out_size * 2; 67 in_size = AV_RL16(&buf[2]); 68 buf += 4; 69 70 if (out_size > *data_size) { 71 av_log(avctx, AV_LOG_ERROR, "Frame is too large to fit in buffer\n"); 72 return -1; 73 } 74 if (in_size > buf_size) { 75 av_log(avctx, AV_LOG_ERROR, "Frame data is larger than input buffer\n"); 76 return -1; 77 } 78 if (in_size == out_size) { 79 for (i = 0; i < out_size; i++) 80 *samples++ = (*buf++ - 0x80) << 8; 81 return buf_size; 82 } 83 84 while (out_size > 0) { 85 int code; 86 uint8_t count; 87 code = (*buf) >> 6; 88 count = (*buf) & 0x3F; 89 buf++; 90 switch(code) { 91 case 0: /* ADPCM 2-bit */ 92 for (count++; count > 0; count--) { 93 code = *buf++; 94 sample += ws_adpcm_2bit[code & 0x3]; 95 CLIP8(sample); 96 *samples++ = sample << 8; 97 sample += ws_adpcm_2bit[(code >> 2) & 0x3]; 98 CLIP8(sample); 99 *samples++ = sample << 8; 100 sample += ws_adpcm_2bit[(code >> 4) & 0x3]; 101 CLIP8(sample); 102 *samples++ = sample << 8; 103 sample += ws_adpcm_2bit[(code >> 6) & 0x3]; 104 CLIP8(sample); 105 *samples++ = sample << 8; 106 out_size -= 4; 107 } 108 break; 109 case 1: /* ADPCM 4-bit */ 110 for (count++; count > 0; count--) { 111 code = *buf++; 112 sample += ws_adpcm_4bit[code & 0xF]; 113 CLIP8(sample); 114 *samples++ = sample << 8; 115 sample += ws_adpcm_4bit[code >> 4]; 116 CLIP8(sample); 117 *samples++ = sample << 8; 118 out_size -= 2; 119 } 120 break; 121 case 2: /* no compression */ 122 if (count & 0x20) { /* big delta */ 123 char t; 124 t = count; 125 t <<= 3; 126 sample += t >> 3; 127 *samples++ = sample << 8; 128 out_size--; 129 } else { /* copy */ 130 for (count++; count > 0; count--) { 131 *samples++ = (*buf++ - 0x80) << 8; 132 out_size--; 133 } 134 sample = buf[-1] - 0x80; 135 } 136 break; 137 default: /* run */ 138 for(count++; count > 0; count--) { 139 *samples++ = sample << 8; 140 out_size--; 141 } 142 } 143 } 144 145 return buf_size; 146} 147 148AVCodec ws_snd1_decoder = { 149 "ws_snd1", 150 AVMEDIA_TYPE_AUDIO, 151 CODEC_ID_WESTWOOD_SND1, 152 0, 153 ws_snd_decode_init, 154 NULL, 155 NULL, 156 ws_snd_decode_frame, 157 .long_name = NULL_IF_CONFIG_SMALL("Westwood Audio (SND1)"), 158}; 159