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chromium / chromium / third_party / ffmpeg / 3ef8be2bfc89672060a2a2f2b8926b3decb08172 / . / libavcodec / dpcm.c
blob: bd3ad7fd0f2943164a7639d710a26a65d6214053 [file] [log] [blame]
Mike Melanson3ef8be22003-09-02 04:32:02[diff] [blame^]1/*
2 * Assorted DPCM codecs
3 * Copyright (c) 2003 The ffmpeg Project.
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
9 *
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
14 *
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 */
19
20/**
21 * @file: dpcm.c
22 * Assorted DPCM (differential pulse code modulation) audio codecs
23 * by Mike Melanson ([email protected])
24 * for more information on the specific data formats, visit:
25 * http://www.pcisys.net/~melanson/codecs/simpleaudio.html
26 */
27
28#include "avcodec.h"
29
30typedef struct DPCMContext {
31 int channels;
32 short roq_square_array[256];
33 int last_delta[2];
34} DPCMContext;
35
36#define SATURATE_S16(x) if (x < -32768) x = -32768; \
37 else if (x > 32767) x = 32767;
38#define SE_16BIT(x) if (x & 0x8000) x -= 0x10000;
39#define LE_16(x) ((((uint8_t*)(x))[1] << 8) | ((uint8_t*)(x))[0])
40#define LE_32(x) ((((uint8_t*)(x))[3] << 24) | \
41 (((uint8_t*)(x))[2] << 16) | \
42 (((uint8_t*)(x))[1] << 8) | \
43 ((uint8_t*)(x))[0])
44
45static int interplay_delta_table[] = {
46 0, 1, 2, 3, 4, 5, 6, 7,
47 8, 9, 10, 11, 12, 13, 14, 15,
48 16, 17, 18, 19, 20, 21, 22, 23,
49 24, 25, 26, 27, 28, 29, 30, 31,
50 32, 33, 34, 35, 36, 37, 38, 39,
51 40, 41, 42, 43, 47, 51, 56, 61,
52 66, 72, 79, 86, 94, 102, 112, 122,
53 133, 145, 158, 173, 189, 206, 225, 245,
54 267, 292, 318, 348, 379, 414, 452, 493,
55 538, 587, 640, 699, 763, 832, 908, 991,
56 1081, 1180, 1288, 1405, 1534, 1673, 1826, 1993,
57 2175, 2373, 2590, 2826, 3084, 3365, 3672, 4008,
58 4373, 4772, 5208, 5683, 6202, 6767, 7385, 8059,
59 8794, 9597, 10472, 11428, 12471, 13609, 14851, 16206,
60 17685, 19298, 21060, 22981, 25078, 27367, 29864, 32589,
61 -29973, -26728, -23186, -19322, -15105, -10503, -5481, -1,
62 1, 1, 5481, 10503, 15105, 19322, 23186, 26728,
63 29973, -32589, -29864, -27367, -25078, -22981, -21060, -19298,
64 -17685, -16206, -14851, -13609, -12471, -11428, -10472, -9597,
65 -8794, -8059, -7385, -6767, -6202, -5683, -5208, -4772,
66 -4373, -4008, -3672, -3365, -3084, -2826, -2590, -2373,
67 -2175, -1993, -1826, -1673, -1534, -1405, -1288, -1180,
68 -1081, -991, -908, -832, -763, -699, -640, -587,
69 -538, -493, -452, -414, -379, -348, -318, -292,
70 -267, -245, -225, -206, -189, -173, -158, -145,
71 -133, -122, -112, -102, -94, -86, -79, -72,
72 -66, -61, -56, -51, -47, -43, -42, -41,
73 -40, -39, -38, -37, -36, -35, -34, -33,
74 -32, -31, -30, -29, -28, -27, -26, -25,
75 -24, -23, -22, -21, -20, -19, -18, -17,
76 -16, -15, -14, -13, -12, -11, -10, -9,
77 -8, -7, -6, -5, -4, -3, -2, -1
78
79};
80
81static int dpcm_decode_init(AVCodecContext *avctx)
82{
83 DPCMContext *s = avctx->priv_data;
84 int i;
85 short square;
86
87 s->channels = avctx->channels;
88
89 switch(avctx->codec->id) {
90
91 case CODEC_ID_ROQ_DPCM:
92 /* initialize square table */
93 for (i = 0; i < 128; i++) {
94 square = i * i;
95 s->roq_square_array[i] = square;
96 s->roq_square_array[i + 128] = -square;
97 }
98 break;
99
100 default:
101 break;
102 }
103
104 return 0;
105}
106
107static int dpcm_decode_frame(AVCodecContext *avctx,
108 void *data, int *data_size,
109 uint8_t *buf, int buf_size)
110{
111 DPCMContext *s = avctx->priv_data;
112 int in, out = 0;
113 int i;
114 int predictor[2];
115 int channel_number = 0;
116 short *output_samples = data;
117 int sequence_number;
118
119 switch(avctx->codec->id) {
120
121 case CODEC_ID_ROQ_DPCM:
122 if (s->channels == 1)
123 predictor[0] = LE_16(&buf[6]);
124 else {
125 predictor[0] = buf[7] << 8;
126 predictor[1] = buf[6] << 8;
127 }
128 SE_16BIT(predictor[0]);
129 SE_16BIT(predictor[1]);
130
131 /* decode the samples */
132 for (in = 8, out = 0; in < buf_size; in++, out++) {
133 predictor[channel_number] += s->roq_square_array[buf[in]];
134 SATURATE_S16(predictor[channel_number]);
135 output_samples[out] = predictor[channel_number];
136
137 /* toggle channel */
138 channel_number ^= s->channels - 1;
139 }
140 break;
141
142 case CODEC_ID_INTERPLAY_DPCM:
143 in = 0;
144 sequence_number = LE_16(&buf[in]);
145 in += 6; /* skip over the stream mask and stream length */
146 if (sequence_number == 1) {
147 predictor[0] = LE_16(&buf[in]);
148 in += 2;
149 SE_16BIT(predictor[0])
150 if (s->channels == 2) {
151 predictor[1] = LE_16(&buf[in]);
152 SE_16BIT(predictor[1])
153 in += 2;
154 }
155 } else {
156 for (i = 0; i < s->channels; i++)
157 predictor[i] = s->last_delta[i];
158 }
159
160 while (in < buf_size) {
161 predictor[channel_number] += interplay_delta_table[buf[in++]];
162 SATURATE_S16(predictor[channel_number]);
163 output_samples[out++] = predictor[channel_number];
164
165 /* toggle channel */
166 channel_number ^= s->channels - 1;
167 }
168
169 /* save predictors for next round */
170 for (i = 0; i < s->channels; i++)
171 s->last_delta[i] = predictor[i];
172
173 break;
174 }
175
176 *data_size = out * sizeof(short);
177 return buf_size;
178}
179
180AVCodec roq_dpcm_decoder = {
181 "roq_dpcm",
182 CODEC_TYPE_AUDIO,
183 CODEC_ID_ROQ_DPCM,
184 sizeof(DPCMContext),
185 dpcm_decode_init,
186 NULL,
187 NULL,
188 dpcm_decode_frame,
189};
190
191AVCodec interplay_dpcm_decoder = {
192 "interplay_dpcm",
193 CODEC_TYPE_AUDIO,
194 CODEC_ID_INTERPLAY_DPCM,
195 sizeof(DPCMContext),
196 dpcm_decode_init,
197 NULL,
198 NULL,
199 dpcm_decode_frame,
200};