3 * Copyright (c) 2003 The ffmpeg Project.
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.
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.
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
22 * Assorted DPCM (differential pulse code modulation) audio codecs
23 * by Mike Melanson (melanson@pcisys.net)
24 * Xan DPCM decoder by Mario Brito (mbrito@student.dei.uc.pt)
25 * for more information on the specific data formats, visit:
26 * http://www.pcisys.net/~melanson/codecs/simpleaudio.html
28 * Note about using the Xan DPCM decoder: Xan DPCM is used in AVI files
29 * found in the Wing Commander IV computer game. These AVI files contain
30 * WAVEFORMAT headers which report the audio format as 0x01: raw PCM.
31 * Clearly incorrect. To detect Xan DPCM, you will probably have to
32 * special-case your AVI demuxer to use Xan DPCM if the file uses 'Xxan'
33 * (Xan video) for its video codec. Alternately, such AVI files also contain
34 * the fourcc 'Axan' in the 'auds' chunk of the AVI header.
39 typedef struct DPCMContext {
41 short roq_square_array[256];
45 #define SATURATE_S16(x) if (x < -32768) x = -32768; \
46 else if (x > 32767) x = 32767;
47 #define SE_16BIT(x) if (x & 0x8000) x -= 0x10000;
48 #define LE_16(x) ((((uint8_t*)(x))[1] << 8) | ((uint8_t*)(x))[0])
49 #define LE_32(x) ((((uint8_t*)(x))[3] << 24) | \
50 (((uint8_t*)(x))[2] << 16) | \
51 (((uint8_t*)(x))[1] << 8) | \
54 static int interplay_delta_table[] = {
55 0, 1, 2, 3, 4, 5, 6, 7,
56 8, 9, 10, 11, 12, 13, 14, 15,
57 16, 17, 18, 19, 20, 21, 22, 23,
58 24, 25, 26, 27, 28, 29, 30, 31,
59 32, 33, 34, 35, 36, 37, 38, 39,
60 40, 41, 42, 43, 47, 51, 56, 61,
61 66, 72, 79, 86, 94, 102, 112, 122,
62 133, 145, 158, 173, 189, 206, 225, 245,
63 267, 292, 318, 348, 379, 414, 452, 493,
64 538, 587, 640, 699, 763, 832, 908, 991,
65 1081, 1180, 1288, 1405, 1534, 1673, 1826, 1993,
66 2175, 2373, 2590, 2826, 3084, 3365, 3672, 4008,
67 4373, 4772, 5208, 5683, 6202, 6767, 7385, 8059,
68 8794, 9597, 10472, 11428, 12471, 13609, 14851, 16206,
69 17685, 19298, 21060, 22981, 25078, 27367, 29864, 32589,
70 -29973, -26728, -23186, -19322, -15105, -10503, -5481, -1,
71 1, 1, 5481, 10503, 15105, 19322, 23186, 26728,
72 29973, -32589, -29864, -27367, -25078, -22981, -21060, -19298,
73 -17685, -16206, -14851, -13609, -12471, -11428, -10472, -9597,
74 -8794, -8059, -7385, -6767, -6202, -5683, -5208, -4772,
75 -4373, -4008, -3672, -3365, -3084, -2826, -2590, -2373,
76 -2175, -1993, -1826, -1673, -1534, -1405, -1288, -1180,
77 -1081, -991, -908, -832, -763, -699, -640, -587,
78 -538, -493, -452, -414, -379, -348, -318, -292,
79 -267, -245, -225, -206, -189, -173, -158, -145,
80 -133, -122, -112, -102, -94, -86, -79, -72,
81 -66, -61, -56, -51, -47, -43, -42, -41,
82 -40, -39, -38, -37, -36, -35, -34, -33,
83 -32, -31, -30, -29, -28, -27, -26, -25,
84 -24, -23, -22, -21, -20, -19, -18, -17,
85 -16, -15, -14, -13, -12, -11, -10, -9,
86 -8, -7, -6, -5, -4, -3, -2, -1
90 static int dpcm_decode_init(AVCodecContext *avctx)
92 DPCMContext *s = avctx->priv_data;
96 s->channels = avctx->channels;
98 switch(avctx->codec->id) {
100 case CODEC_ID_ROQ_DPCM:
101 /* initialize square table */
102 for (i = 0; i < 128; i++) {
104 s->roq_square_array[i] = square;
105 s->roq_square_array[i + 128] = -square;
116 static int dpcm_decode_frame(AVCodecContext *avctx,
117 void *data, int *data_size,
118 uint8_t *buf, int buf_size)
120 DPCMContext *s = avctx->priv_data;
124 int channel_number = 0;
125 short *output_samples = data;
131 switch(avctx->codec->id) {
133 case CODEC_ID_ROQ_DPCM:
134 if (s->channels == 1)
135 predictor[0] = LE_16(&buf[6]);
137 predictor[0] = buf[7] << 8;
138 predictor[1] = buf[6] << 8;
140 SE_16BIT(predictor[0]);
141 SE_16BIT(predictor[1]);
143 /* decode the samples */
144 for (in = 8, out = 0; in < buf_size; in++, out++) {
145 predictor[channel_number] += s->roq_square_array[buf[in]];
146 SATURATE_S16(predictor[channel_number]);
147 output_samples[out] = predictor[channel_number];
150 channel_number ^= s->channels - 1;
154 case CODEC_ID_INTERPLAY_DPCM:
156 sequence_number = LE_16(&buf[in]);
157 in += 6; /* skip over the stream mask and stream length */
158 if (sequence_number == 1) {
159 predictor[0] = LE_16(&buf[in]);
161 SE_16BIT(predictor[0])
162 if (s->channels == 2) {
163 predictor[1] = LE_16(&buf[in]);
164 SE_16BIT(predictor[1])
168 for (i = 0; i < s->channels; i++)
169 predictor[i] = s->last_delta[i];
172 while (in < buf_size) {
173 predictor[channel_number] += interplay_delta_table[buf[in++]];
174 SATURATE_S16(predictor[channel_number]);
175 output_samples[out++] = predictor[channel_number];
178 channel_number ^= s->channels - 1;
181 /* save predictors for next round */
182 for (i = 0; i < s->channels; i++)
183 s->last_delta[i] = predictor[i];
187 case CODEC_ID_XAN_DPCM:
189 shift[0] = shift[1] = 4;
190 predictor[0] = LE_16(&buf[in]);
192 SE_16BIT(predictor[0]);
193 if (s->channels == 2) {
194 predictor[1] = LE_16(&buf[in]);
196 SE_16BIT(predictor[1]);
199 while (in < buf_size) {
201 diff = (byte & 0xFC) << 8;
202 if ((byte & 0x03) == 3)
203 shift[channel_number]++;
205 shift[channel_number] -= (2 * (byte & 3));
206 /* saturate the shifter to a lower limit of 0 */
207 if (shift[channel_number] < 0)
208 shift[channel_number] = 0;
210 diff >>= shift[channel_number];
211 predictor[channel_number] += diff;
213 SATURATE_S16(predictor[channel_number]);
214 output_samples[out++] = predictor[channel_number];
217 channel_number ^= s->channels - 1;
222 *data_size = out * sizeof(short);
226 AVCodec roq_dpcm_decoder = {
237 AVCodec interplay_dpcm_decoder = {
240 CODEC_ID_INTERPLAY_DPCM,
248 AVCodec xan_dpcm_decoder = {