aboutsummaryrefslogtreecommitdiffhomepage
path: root/libmpcodecs/ad_dk3adpcm.c
blob: 4671f23ebecca5f9e57cc6aecef49cb33a599f7c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
/*
    DK3 ADPCM Decoder for MPlayer
      by Mike Melanson

    "This format number was used by Duck Corp. but not officially 
    registered with Microsoft"

    This file is responsible for decoding audio data encoded with
    Duck Corp's DK3 ADPCM algorithm. Details about the data format
    can be found here:
      http://www.pcisys.net/~melanson/codecs/
*/

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#include "config.h"
#include "bswap.h"
#include "ad_internal.h"

static ad_info_t info = 
{
	"Duck Corp. DK3 ADPCM decoder",
	"dk3adpcm",
	"Nick Kurshev",
	"Mike Melanson",
	""
};

LIBAD_EXTERN(dk3adpcm)

#define DK3_ADPCM_PREAMBLE_SIZE 16

#define LE_16(x) (le2me_16(*(unsigned short *)(x)))
#define LE_32(x) (le2me_32(*(unsigned int *)(x)))

// useful macros
// clamp a number between 0 and 88
#define CLAMP_0_TO_88(x)  if (x < 0) x = 0; else if (x > 88) x = 88;
// clamp a number within a signed 16-bit range
#define CLAMP_S16(x)  if (x < -32768) x = -32768; \
  else if (x > 32767) x = 32767;
// clamp a number above 16
#define CLAMP_ABOVE_16(x)  if (x < 16) x = 16;
// sign extend a 16-bit value
#define SE_16BIT(x)  if (x & 0x8000) x -= 0x10000;
// sign extend a 4-bit value
#define SE_4BIT(x)  if (x & 0x8) x -= 0x10;

// pertinent tables
static int adpcm_step[89] =
{
  7, 8, 9, 10, 11, 12, 13, 14, 16, 17,
  19, 21, 23, 25, 28, 31, 34, 37, 41, 45,
  50, 55, 60, 66, 73, 80, 88, 97, 107, 118,
  130, 143, 157, 173, 190, 209, 230, 253, 279, 307,
  337, 371, 408, 449, 494, 544, 598, 658, 724, 796,
  876, 963, 1060, 1166, 1282, 1411, 1552, 1707, 1878, 2066,
  2272, 2499, 2749, 3024, 3327, 3660, 4026, 4428, 4871, 5358,
  5894, 6484, 7132, 7845, 8630, 9493, 10442, 11487, 12635, 13899,
  15289, 16818, 18500, 20350, 22385, 24623, 27086, 29794, 32767
};

static int adpcm_index[16] =
{
  -1, -1, -1, -1, 2, 4, 6, 8,
  -1, -1, -1, -1, 2, 4, 6, 8
};

static int preinit(sh_audio_t *sh_audio)
{
  sh_audio->audio_out_minsize = sh_audio->wf->nBlockAlign * 6;
  sh_audio->ds->ss_div = 
    (sh_audio->wf->nBlockAlign - DK3_ADPCM_PREAMBLE_SIZE) * 8 / 3;
  sh_audio->audio_in_minsize=
  sh_audio->ds->ss_mul = sh_audio->wf->nBlockAlign;
  return 1;
}

static int init(sh_audio_t *sh_audio)
{
  sh_audio->channels = sh_audio->wf->nChannels;
  sh_audio->samplerate = sh_audio->wf->nSamplesPerSec;
  sh_audio->i_bps =
    (sh_audio->ds->ss_mul * sh_audio->samplerate) / sh_audio->ds->ss_div;
  sh_audio->samplesize=2;
  return 1;
}

static void uninit(sh_audio_t *sh_audio)
{
}

static int control(sh_audio_t *sh_audio,int cmd,void* arg, ...)
{
  if(cmd==ADCTRL_SKIP_FRAME){
    demux_read_data(sh_audio->ds, sh_audio->a_in_buffer,sh_audio->ds->ss_mul);
    return CONTROL_TRUE;
  }
  return CONTROL_UNKNOWN;
}

#define DK3_GET_NEXT_NIBBLE() \
    if (decode_top_nibble_next) \
    { \
      nibble = (last_byte >> 4) & 0x0F; \
      decode_top_nibble_next = 0; \
    } \
    else \
    { \
      last_byte = input[in_ptr++]; \
      nibble = last_byte & 0x0F; \
      decode_top_nibble_next = 1; \
    }

// note: This decoder assumes the format 0x62 data always comes in
// stereo flavor
static int dk3_adpcm_decode_block(unsigned short *output, unsigned char *input,
  int block_size)
{
  int sum_pred;
  int diff_pred;
  int sum_index;
  int diff_index;
  int diff_channel;
  int in_ptr = 0x10;
  int out_ptr = 0;

  unsigned char last_byte = 0;
  unsigned char nibble;
  int decode_top_nibble_next = 0;

  // ADPCM work variables
  int sign;
  int delta;
  int step;
  int diff;

  sum_pred = LE_16(&input[10]);
  diff_pred = LE_16(&input[12]);
  SE_16BIT(sum_pred);
  SE_16BIT(diff_pred);
  diff_channel = diff_pred;
  sum_index = input[14];
  diff_index = input[15];

  while (in_ptr < block_size)
//  while (in_ptr < 2048)
  {
    // process the first predictor of the sum channel
    DK3_GET_NEXT_NIBBLE();

    step = adpcm_step[sum_index];

    sign = nibble & 8;
    delta = nibble & 7;

    diff = step >> 3;
    if (delta & 4) diff += step;
    if (delta & 2) diff += step >> 1;
    if (delta & 1) diff += step >> 2;

    if (sign)
      sum_pred -= diff;
    else
      sum_pred += diff;

    CLAMP_S16(sum_pred);

    sum_index += adpcm_index[nibble];
    CLAMP_0_TO_88(sum_index);

    // process the diff channel predictor
    DK3_GET_NEXT_NIBBLE();

    step = adpcm_step[diff_index];

    sign = nibble & 8;
    delta = nibble & 7;

    diff = step >> 3;
    if (delta & 4) diff += step;
    if (delta & 2) diff += step >> 1;
    if (delta & 1) diff += step >> 2;

    if (sign)
      diff_pred -= diff;
    else
      diff_pred += diff;

    CLAMP_S16(diff_pred);

    diff_index += adpcm_index[nibble];
    CLAMP_0_TO_88(diff_index);

    // output the first pair of stereo PCM samples
    diff_channel = (diff_channel + diff_pred) / 2;
    output[out_ptr++] = sum_pred + diff_channel;
    output[out_ptr++] = sum_pred - diff_channel;

    // process the second predictor of the sum channel
    DK3_GET_NEXT_NIBBLE();

    step = adpcm_step[sum_index];

    sign = nibble & 8;
    delta = nibble & 7;

    diff = step >> 3;
    if (delta & 4) diff += step;
    if (delta & 2) diff += step >> 1;
    if (delta & 1) diff += step >> 2;

    if (sign)
      sum_pred -= diff;
    else
      sum_pred += diff;

    CLAMP_S16(sum_pred);

    sum_index += adpcm_index[nibble];
    CLAMP_0_TO_88(sum_index);

    // output the second pair of stereo PCM samples
    output[out_ptr++] = sum_pred + diff_channel;
    output[out_ptr++] = sum_pred - diff_channel;
  }

  return out_ptr;
}

static int decode_audio(sh_audio_t *sh_audio,unsigned char *buf,int minlen,int maxlen)
{
  if (demux_read_data(sh_audio->ds, sh_audio->a_in_buffer,
    sh_audio->ds->ss_mul) != 
    sh_audio->ds->ss_mul) 
      return -1; /* EOF */

  return 2 * dk3_adpcm_decode_block(
    (unsigned short*)buf, sh_audio->a_in_buffer,
    sh_audio->wf->nBlockAlign);
}