| 1 | /*
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| 2 | * Westwood SNDx codecs
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| 3 | * Copyright (c) 2005 Konstantin Shishkov
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| 4 | *
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| 5 | * This library is free software; you can redistribute it and/or
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| 6 | * modify it under the terms of the GNU Lesser General Public
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| 7 | * License as published by the Free Software Foundation; either
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| 8 | * version 2 of the License, or (at your option) any later version.
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| 9 | *
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| 10 | * This library is distributed in the hope that it will be useful,
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| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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| 13 | * Lesser General Public License for more details.
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| 14 | *
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| 15 | * You should have received a copy of the GNU Lesser General Public
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| 16 | * License along with this library; if not, write to the Free Software
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| 17 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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| 18 | */
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| 19 | #include "avcodec.h"
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| 20 |
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| 21 | /**
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| 22 | * @file ws-snd.c
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| 23 | * Westwood SNDx codecs.
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| 24 | *
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| 25 | * Reference documents about VQA format and its audio codecs
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| 26 | * can be found here:
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| 27 | * http://www.multimedia.cx
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| 28 | */
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| 29 |
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| 30 | typedef struct {
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| 31 | } WSSNDContext;
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| 32 |
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| 33 | static const char ws_adpcm_2bit[] = { -2, -1, 0, 1};
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| 34 | static const char ws_adpcm_4bit[] = {
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| 35 | -9, -8, -6, -5, -4, -3, -2, -1,
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| 36 | 0, 1, 2, 3, 4, 5, 6, 8 };
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| 37 |
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| 38 | #define CLIP8(a) if(a>127)a=127;if(a<-128)a=-128;
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| 39 |
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| 40 | static int ws_snd_decode_init(AVCodecContext * avctx)
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| 41 | {
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| 42 | // WSSNDContext *c = avctx->priv_data;
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| 43 |
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| 44 | return 0;
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| 45 | }
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| 46 |
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| 47 | static int ws_snd_decode_frame(AVCodecContext *avctx,
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| 48 | void *data, int *data_size,
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| 49 | uint8_t *buf, int buf_size)
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| 50 | {
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| 51 | // WSSNDContext *c = avctx->priv_data;
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| 52 |
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| 53 | int in_size, out_size;
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| 54 | int sample = 0;
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| 55 | int i;
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| 56 | short *samples = data;
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| 57 |
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| 58 | if (!buf_size)
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| 59 | return 0;
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| 60 |
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| 61 | out_size = LE_16(&buf[0]);
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| 62 | *data_size = out_size * 2;
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| 63 | in_size = LE_16(&buf[2]);
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| 64 | buf += 4;
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| 65 |
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| 66 | if (in_size == out_size) {
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| 67 | for (i = 0; i < out_size; i++)
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| 68 | *samples++ = (*buf++ - 0x80) << 8;
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| 69 | return buf_size;
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| 70 | }
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| 71 |
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| 72 | while (out_size > 0) {
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| 73 | int code;
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| 74 | uint8_t count;
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| 75 | code = (*buf) >> 6;
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| 76 | count = (*buf) & 0x3F;
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| 77 | buf++;
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| 78 | switch(code) {
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| 79 | case 0: /* ADPCM 2-bit */
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| 80 | for (count++; count > 0; count--) {
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| 81 | code = *buf++;
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| 82 | sample += ws_adpcm_2bit[code & 0x3];
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| 83 | CLIP8(sample);
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| 84 | *samples++ = sample << 8;
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| 85 | sample += ws_adpcm_2bit[(code >> 2) & 0x3];
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| 86 | CLIP8(sample);
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| 87 | *samples++ = sample << 8;
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| 88 | sample += ws_adpcm_2bit[(code >> 4) & 0x3];
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| 89 | CLIP8(sample);
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| 90 | *samples++ = sample << 8;
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| 91 | sample += ws_adpcm_2bit[(code >> 6) & 0x3];
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| 92 | CLIP8(sample);
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| 93 | *samples++ = sample << 8;
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| 94 | out_size -= 4;
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| 95 | }
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| 96 | break;
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| 97 | case 1: /* ADPCM 4-bit */
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| 98 | for (count++; count > 0; count--) {
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| 99 | code = *buf++;
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| 100 | sample += ws_adpcm_4bit[code & 0xF];
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| 101 | CLIP8(sample);
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| 102 | *samples++ = sample << 8;
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| 103 | sample += ws_adpcm_4bit[code >> 4];
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| 104 | CLIP8(sample);
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| 105 | *samples++ = sample << 8;
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| 106 | out_size -= 2;
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| 107 | }
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| 108 | break;
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| 109 | case 2: /* no compression */
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| 110 | if (count & 0x20) { /* big delta */
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| 111 | char t;
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| 112 | t = count;
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| 113 | t <<= 3;
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| 114 | sample += t >> 3;
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| 115 | *samples++ = sample << 8;
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| 116 | out_size--;
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| 117 | } else { /* copy */
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| 118 | for (count++; count > 0; count--) {
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| 119 | *samples++ = (*buf++ - 0x80) << 8;
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| 120 | out_size--;
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| 121 | }
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| 122 | sample = buf[-1] - 0x80;
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| 123 | }
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| 124 | break;
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| 125 | default: /* run */
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| 126 | for(count++; count > 0; count--) {
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| 127 | *samples++ = sample << 8;
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| 128 | out_size--;
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| 129 | }
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| 130 | }
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| 131 | }
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| 132 |
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| 133 | return buf_size;
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| 134 | }
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| 135 |
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| 136 | AVCodec ws_snd1_decoder = {
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| 137 | "ws_snd1",
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| 138 | CODEC_TYPE_AUDIO,
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| 139 | CODEC_ID_WESTWOOD_SND1,
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| 140 | sizeof(WSSNDContext),
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| 141 | ws_snd_decode_init,
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| 142 | NULL,
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| 143 | NULL,
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| 144 | ws_snd_decode_frame,
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| 145 | };
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