1/*
2 * Assorted DPCM codecs
3 * Copyright (c) 2003 The ffmpeg Project
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/**
23 * @file: dpcm.c
24 * Assorted DPCM (differential pulse code modulation) audio codecs
25 * by Mike Melanson (melanson@pcisys.net)
26 * Xan DPCM decoder by Mario Brito (mbrito@student.dei.uc.pt)
27 * for more information on the specific data formats, visit:
28 *   http://www.pcisys.net/~melanson/codecs/simpleaudio.html
29 * SOL DPCMs implemented by Konstantin Shishkov
30 *
31 * Note about using the Xan DPCM decoder: Xan DPCM is used in AVI files
32 * found in the Wing Commander IV computer game. These AVI files contain
33 * WAVEFORMAT headers which report the audio format as 0x01: raw PCM.
34 * Clearly incorrect. To detect Xan DPCM, you will probably have to
35 * special-case your AVI demuxer to use Xan DPCM if the file uses 'Xxan'
36 * (Xan video) for its video codec. Alternately, such AVI files also contain
37 * the fourcc 'Axan' in the 'auds' chunk of the AVI header.
38 */
39
40#include "libavutil/intreadwrite.h"
41#include "avcodec.h"
42
43typedef struct DPCMContext {
44    int channels;
45    short roq_square_array[256];
46    long sample[2];//for SOL_DPCM
47    const int *sol_table;//for SOL_DPCM
48} DPCMContext;
49
50#define SE_16BIT(x)  if (x & 0x8000) x -= 0x10000;
51
52static const int interplay_delta_table[] = {
53         0,      1,      2,      3,      4,      5,      6,      7,
54         8,      9,     10,     11,     12,     13,     14,     15,
55        16,     17,     18,     19,     20,     21,     22,     23,
56        24,     25,     26,     27,     28,     29,     30,     31,
57        32,     33,     34,     35,     36,     37,     38,     39,
58        40,     41,     42,     43,     47,     51,     56,     61,
59        66,     72,     79,     86,     94,    102,    112,    122,
60       133,    145,    158,    173,    189,    206,    225,    245,
61       267,    292,    318,    348,    379,    414,    452,    493,
62       538,    587,    640,    699,    763,    832,    908,    991,
63      1081,   1180,   1288,   1405,   1534,   1673,   1826,   1993,
64      2175,   2373,   2590,   2826,   3084,   3365,   3672,   4008,
65      4373,   4772,   5208,   5683,   6202,   6767,   7385,   8059,
66      8794,   9597,  10472,  11428,  12471,  13609,  14851,  16206,
67     17685,  19298,  21060,  22981,  25078,  27367,  29864,  32589,
68    -29973, -26728, -23186, -19322, -15105, -10503,  -5481,     -1,
69         1,      1,   5481,  10503,  15105,  19322,  23186,  26728,
70     29973, -32589, -29864, -27367, -25078, -22981, -21060, -19298,
71    -17685, -16206, -14851, -13609, -12471, -11428, -10472,  -9597,
72     -8794,  -8059,  -7385,  -6767,  -6202,  -5683,  -5208,  -4772,
73     -4373,  -4008,  -3672,  -3365,  -3084,  -2826,  -2590,  -2373,
74     -2175,  -1993,  -1826,  -1673,  -1534,  -1405,  -1288,  -1180,
75     -1081,   -991,   -908,   -832,   -763,   -699,   -640,   -587,
76      -538,   -493,   -452,   -414,   -379,   -348,   -318,   -292,
77      -267,   -245,   -225,   -206,   -189,   -173,   -158,   -145,
78      -133,   -122,   -112,   -102,    -94,    -86,    -79,    -72,
79       -66,    -61,    -56,    -51,    -47,    -43,    -42,    -41,
80       -40,    -39,    -38,    -37,    -36,    -35,    -34,    -33,
81       -32,    -31,    -30,    -29,    -28,    -27,    -26,    -25,
82       -24,    -23,    -22,    -21,    -20,    -19,    -18,    -17,
83       -16,    -15,    -14,    -13,    -12,    -11,    -10,     -9,
84        -8,     -7,     -6,     -5,     -4,     -3,     -2,     -1
85
86};
87
88static const int sol_table_old[16] =
89    { 0x0,  0x1,  0x2 , 0x3,  0x6,  0xA,  0xF, 0x15,
90    -0x15, -0xF, -0xA, -0x6, -0x3, -0x2, -0x1, 0x0};
91
92static const int sol_table_new[16] =
93    { 0x0,  0x1,  0x2,  0x3,  0x6,  0xA,  0xF,  0x15,
94      0x0, -0x1, -0x2, -0x3, -0x6, -0xA, -0xF, -0x15};
95
96static const int sol_table_16[128] = {
97    0x000, 0x008, 0x010, 0x020, 0x030, 0x040, 0x050, 0x060, 0x070, 0x080,
98    0x090, 0x0A0, 0x0B0, 0x0C0, 0x0D0, 0x0E0, 0x0F0, 0x100, 0x110, 0x120,
99    0x130, 0x140, 0x150, 0x160, 0x170, 0x180, 0x190, 0x1A0, 0x1B0, 0x1C0,
100    0x1D0, 0x1E0, 0x1F0, 0x200, 0x208, 0x210, 0x218, 0x220, 0x228, 0x230,
101    0x238, 0x240, 0x248, 0x250, 0x258, 0x260, 0x268, 0x270, 0x278, 0x280,
102    0x288, 0x290, 0x298, 0x2A0, 0x2A8, 0x2B0, 0x2B8, 0x2C0, 0x2C8, 0x2D0,
103    0x2D8, 0x2E0, 0x2E8, 0x2F0, 0x2F8, 0x300, 0x308, 0x310, 0x318, 0x320,
104    0x328, 0x330, 0x338, 0x340, 0x348, 0x350, 0x358, 0x360, 0x368, 0x370,
105    0x378, 0x380, 0x388, 0x390, 0x398, 0x3A0, 0x3A8, 0x3B0, 0x3B8, 0x3C0,
106    0x3C8, 0x3D0, 0x3D8, 0x3E0, 0x3E8, 0x3F0, 0x3F8, 0x400, 0x440, 0x480,
107    0x4C0, 0x500, 0x540, 0x580, 0x5C0, 0x600, 0x640, 0x680, 0x6C0, 0x700,
108    0x740, 0x780, 0x7C0, 0x800, 0x900, 0xA00, 0xB00, 0xC00, 0xD00, 0xE00,
109    0xF00, 0x1000, 0x1400, 0x1800, 0x1C00, 0x2000, 0x3000, 0x4000
110};
111
112
113
114static av_cold int dpcm_decode_init(AVCodecContext *avctx)
115{
116    DPCMContext *s = avctx->priv_data;
117    int i;
118    short square;
119
120    s->channels = avctx->channels;
121    s->sample[0] = s->sample[1] = 0;
122
123    switch(avctx->codec->id) {
124
125    case CODEC_ID_ROQ_DPCM:
126        /* initialize square table */
127        for (i = 0; i < 128; i++) {
128            square = i * i;
129            s->roq_square_array[i] = square;
130            s->roq_square_array[i + 128] = -square;
131        }
132        break;
133
134
135    case CODEC_ID_SOL_DPCM:
136        switch(avctx->codec_tag){
137        case 1:
138            s->sol_table=sol_table_old;
139            s->sample[0] = s->sample[1] = 0x80;
140            break;
141        case 2:
142            s->sol_table=sol_table_new;
143            s->sample[0] = s->sample[1] = 0x80;
144            break;
145        case 3:
146            s->sol_table=sol_table_16;
147            break;
148        default:
149            av_log(avctx, AV_LOG_ERROR, "Unknown SOL subcodec\n");
150            return -1;
151        }
152        break;
153
154    default:
155        break;
156    }
157
158    avctx->sample_fmt = SAMPLE_FMT_S16;
159    return 0;
160}
161
162static int dpcm_decode_frame(AVCodecContext *avctx,
163                             void *data, int *data_size,
164                             AVPacket *avpkt)
165{
166    const uint8_t *buf = avpkt->data;
167    int buf_size = avpkt->size;
168    DPCMContext *s = avctx->priv_data;
169    int in, out = 0;
170    int predictor[2];
171    int channel_number = 0;
172    short *output_samples = data;
173    int shift[2];
174    unsigned char byte;
175    short diff;
176
177    if (!buf_size)
178        return 0;
179
180    // almost every DPCM variant expands one byte of data into two
181    if(*data_size/2 < buf_size)
182        return -1;
183
184    switch(avctx->codec->id) {
185
186    case CODEC_ID_ROQ_DPCM:
187        if (s->channels == 1)
188            predictor[0] = AV_RL16(&buf[6]);
189        else {
190            predictor[0] = buf[7] << 8;
191            predictor[1] = buf[6] << 8;
192        }
193        SE_16BIT(predictor[0]);
194        SE_16BIT(predictor[1]);
195
196        /* decode the samples */
197        for (in = 8, out = 0; in < buf_size; in++, out++) {
198            predictor[channel_number] += s->roq_square_array[buf[in]];
199            predictor[channel_number] = av_clip_int16(predictor[channel_number]);
200            output_samples[out] = predictor[channel_number];
201
202            /* toggle channel */
203            channel_number ^= s->channels - 1;
204        }
205        break;
206
207    case CODEC_ID_INTERPLAY_DPCM:
208        in = 6;  /* skip over the stream mask and stream length */
209        predictor[0] = AV_RL16(&buf[in]);
210        in += 2;
211        SE_16BIT(predictor[0])
212        output_samples[out++] = predictor[0];
213        if (s->channels == 2) {
214            predictor[1] = AV_RL16(&buf[in]);
215            in += 2;
216            SE_16BIT(predictor[1])
217            output_samples[out++] = predictor[1];
218        }
219
220        while (in < buf_size) {
221            predictor[channel_number] += interplay_delta_table[buf[in++]];
222            predictor[channel_number] = av_clip_int16(predictor[channel_number]);
223            output_samples[out++] = predictor[channel_number];
224
225            /* toggle channel */
226            channel_number ^= s->channels - 1;
227        }
228
229        break;
230
231    case CODEC_ID_XAN_DPCM:
232        in = 0;
233        shift[0] = shift[1] = 4;
234        predictor[0] = AV_RL16(&buf[in]);
235        in += 2;
236        SE_16BIT(predictor[0]);
237        if (s->channels == 2) {
238            predictor[1] = AV_RL16(&buf[in]);
239            in += 2;
240            SE_16BIT(predictor[1]);
241        }
242
243        while (in < buf_size) {
244            byte = buf[in++];
245            diff = (byte & 0xFC) << 8;
246            if ((byte & 0x03) == 3)
247                shift[channel_number]++;
248            else
249                shift[channel_number] -= (2 * (byte & 3));
250            /* saturate the shifter to a lower limit of 0 */
251            if (shift[channel_number] < 0)
252                shift[channel_number] = 0;
253
254            diff >>= shift[channel_number];
255            predictor[channel_number] += diff;
256
257            predictor[channel_number] = av_clip_int16(predictor[channel_number]);
258            output_samples[out++] = predictor[channel_number];
259
260            /* toggle channel */
261            channel_number ^= s->channels - 1;
262        }
263        break;
264    case CODEC_ID_SOL_DPCM:
265        in = 0;
266        if (avctx->codec_tag != 3) {
267            if(*data_size/4 < buf_size)
268                return -1;
269            while (in < buf_size) {
270                int n1, n2;
271                n1 = (buf[in] >> 4) & 0xF;
272                n2 = buf[in++] & 0xF;
273                s->sample[0] += s->sol_table[n1];
274                if (s->sample[0] < 0) s->sample[0] = 0;
275                if (s->sample[0] > 255) s->sample[0] = 255;
276                output_samples[out++] = (s->sample[0] - 128) << 8;
277                s->sample[s->channels - 1] += s->sol_table[n2];
278                if (s->sample[s->channels - 1] < 0) s->sample[s->channels - 1] = 0;
279                if (s->sample[s->channels - 1] > 255) s->sample[s->channels - 1] = 255;
280                output_samples[out++] = (s->sample[s->channels - 1] - 128) << 8;
281            }
282        } else {
283            while (in < buf_size) {
284                int n;
285                n = buf[in++];
286                if (n & 0x80) s->sample[channel_number] -= s->sol_table[n & 0x7F];
287                else s->sample[channel_number] += s->sol_table[n & 0x7F];
288                s->sample[channel_number] = av_clip_int16(s->sample[channel_number]);
289                output_samples[out++] = s->sample[channel_number];
290                /* toggle channel */
291                channel_number ^= s->channels - 1;
292            }
293        }
294        break;
295    }
296
297    *data_size = out * sizeof(short);
298    return buf_size;
299}
300
301#define DPCM_DECODER(id, name, long_name_)      \
302AVCodec name ## _decoder = {                    \
303    #name,                                      \
304    AVMEDIA_TYPE_AUDIO,                         \
305    id,                                         \
306    sizeof(DPCMContext),                        \
307    dpcm_decode_init,                           \
308    NULL,                                       \
309    NULL,                                       \
310    dpcm_decode_frame,                          \
311    .long_name = NULL_IF_CONFIG_SMALL(long_name_), \
312};
313
314DPCM_DECODER(CODEC_ID_INTERPLAY_DPCM, interplay_dpcm, "DPCM Interplay");
315DPCM_DECODER(CODEC_ID_ROQ_DPCM, roq_dpcm, "DPCM id RoQ");
316DPCM_DECODER(CODEC_ID_SOL_DPCM, sol_dpcm, "DPCM Sol");
317DPCM_DECODER(CODEC_ID_XAN_DPCM, xan_dpcm, "DPCM Xan");
318