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dpcm.c
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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
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 #include "bytestream.h"
43 #include "internal.h"
44 #include "mathops.h"
45 
46 typedef struct DPCMContext {
47  int16_t roq_square_array[256];
48  int sample[2]; ///< previous sample (for SOL_DPCM)
49  const int8_t *sol_table; ///< delta table for SOL_DPCM
50 } DPCMContext;
51 
52 static const int16_t 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 
88 static const int8_t sol_table_old[16] = {
89  0x0, 0x1, 0x2, 0x3, 0x6, 0xA, 0xF, 0x15,
90  -0x15, -0xF, -0xA, -0x6, -0x3, -0x2, -0x1, 0x0
91 };
92 
93 static const int8_t sol_table_new[16] = {
94  0x0, 0x1, 0x2, 0x3, 0x6, 0xA, 0xF, 0x15,
95  0x0, -0x1, -0x2, -0x3, -0x6, -0xA, -0xF, -0x15
96 };
97 
98 static const int16_t sol_table_16[128] = {
99  0x000, 0x008, 0x010, 0x020, 0x030, 0x040, 0x050, 0x060, 0x070, 0x080,
100  0x090, 0x0A0, 0x0B0, 0x0C0, 0x0D0, 0x0E0, 0x0F0, 0x100, 0x110, 0x120,
101  0x130, 0x140, 0x150, 0x160, 0x170, 0x180, 0x190, 0x1A0, 0x1B0, 0x1C0,
102  0x1D0, 0x1E0, 0x1F0, 0x200, 0x208, 0x210, 0x218, 0x220, 0x228, 0x230,
103  0x238, 0x240, 0x248, 0x250, 0x258, 0x260, 0x268, 0x270, 0x278, 0x280,
104  0x288, 0x290, 0x298, 0x2A0, 0x2A8, 0x2B0, 0x2B8, 0x2C0, 0x2C8, 0x2D0,
105  0x2D8, 0x2E0, 0x2E8, 0x2F0, 0x2F8, 0x300, 0x308, 0x310, 0x318, 0x320,
106  0x328, 0x330, 0x338, 0x340, 0x348, 0x350, 0x358, 0x360, 0x368, 0x370,
107  0x378, 0x380, 0x388, 0x390, 0x398, 0x3A0, 0x3A8, 0x3B0, 0x3B8, 0x3C0,
108  0x3C8, 0x3D0, 0x3D8, 0x3E0, 0x3E8, 0x3F0, 0x3F8, 0x400, 0x440, 0x480,
109  0x4C0, 0x500, 0x540, 0x580, 0x5C0, 0x600, 0x640, 0x680, 0x6C0, 0x700,
110  0x740, 0x780, 0x7C0, 0x800, 0x900, 0xA00, 0xB00, 0xC00, 0xD00, 0xE00,
111  0xF00, 0x1000, 0x1400, 0x1800, 0x1C00, 0x2000, 0x3000, 0x4000
112 };
113 
114 
115 static av_cold int dpcm_decode_init(AVCodecContext *avctx)
116 {
117  DPCMContext *s = avctx->priv_data;
118  int i;
119 
120  if (avctx->channels < 1 || avctx->channels > 2) {
121  av_log(avctx, AV_LOG_ERROR, "invalid number of channels\n");
122  return AVERROR(EINVAL);
123  }
124 
125  s->sample[0] = s->sample[1] = 0;
126 
127  switch(avctx->codec->id) {
128 
129  case AV_CODEC_ID_ROQ_DPCM:
130  /* initialize square table */
131  for (i = 0; i < 128; i++) {
132  int16_t square = i * i;
133  s->roq_square_array[i ] = square;
134  s->roq_square_array[i + 128] = -square;
135  }
136  break;
137 
138  case AV_CODEC_ID_SOL_DPCM:
139  switch(avctx->codec_tag){
140  case 1:
141  s->sol_table = sol_table_old;
142  s->sample[0] = s->sample[1] = 0x80;
143  break;
144  case 2:
145  s->sol_table = sol_table_new;
146  s->sample[0] = s->sample[1] = 0x80;
147  break;
148  case 3:
149  break;
150  default:
151  av_log(avctx, AV_LOG_ERROR, "Unknown SOL subcodec\n");
152  return -1;
153  }
154  break;
155 
156  default:
157  break;
158  }
159 
160  if (avctx->codec->id == AV_CODEC_ID_SOL_DPCM && avctx->codec_tag != 3)
161  avctx->sample_fmt = AV_SAMPLE_FMT_U8;
162  else
163  avctx->sample_fmt = AV_SAMPLE_FMT_S16;
164 
165  return 0;
166 }
167 
168 
169 static int dpcm_decode_frame(AVCodecContext *avctx, void *data,
170  int *got_frame_ptr, AVPacket *avpkt)
171 {
172  int buf_size = avpkt->size;
173  DPCMContext *s = avctx->priv_data;
174  AVFrame *frame = data;
175  int out = 0, ret;
176  int predictor[2];
177  int ch = 0;
178  int stereo = avctx->channels - 1;
179  int16_t *output_samples, *samples_end;
180  GetByteContext gb;
181 
182  if (stereo && (buf_size & 1))
183  buf_size--;
184  bytestream2_init(&gb, avpkt->data, buf_size);
185 
186  /* calculate output size */
187  switch(avctx->codec->id) {
188  case AV_CODEC_ID_ROQ_DPCM:
189  out = buf_size - 8;
190  break;
191  case AV_CODEC_ID_INTERPLAY_DPCM:
192  out = buf_size - 6 - avctx->channels;
193  break;
194  case AV_CODEC_ID_XAN_DPCM:
195  out = buf_size - 2 * avctx->channels;
196  break;
197  case AV_CODEC_ID_SOL_DPCM:
198  if (avctx->codec_tag != 3)
199  out = buf_size * 2;
200  else
201  out = buf_size;
202  break;
203  }
204  if (out <= 0) {
205  av_log(avctx, AV_LOG_ERROR, "packet is too small\n");
206  return AVERROR(EINVAL);
207  }
208  if (out % avctx->channels) {
209  av_log(avctx, AV_LOG_WARNING, "channels have differing number of samples\n");
210  }
211 
212  /* get output buffer */
213  frame->nb_samples = (out + avctx->channels - 1) / avctx->channels;
214  if ((ret = ff_get_buffer(avctx, frame)) < 0) {
215  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
216  return ret;
217  }
218  output_samples = (int16_t *)frame->data[0];
219  samples_end = output_samples + out;
220 
221  switch(avctx->codec->id) {
222 
223  case AV_CODEC_ID_ROQ_DPCM:
224  bytestream2_skipu(&gb, 6);
225 
226  if (stereo) {
227  predictor[1] = sign_extend(bytestream2_get_byteu(&gb) << 8, 16);
228  predictor[0] = sign_extend(bytestream2_get_byteu(&gb) << 8, 16);
229  } else {
230  predictor[0] = sign_extend(bytestream2_get_le16u(&gb), 16);
231  }
232 
233  /* decode the samples */
234  while (output_samples < samples_end) {
235  predictor[ch] += s->roq_square_array[bytestream2_get_byteu(&gb)];
236  predictor[ch] = av_clip_int16(predictor[ch]);
237  *output_samples++ = predictor[ch];
238 
239  /* toggle channel */
240  ch ^= stereo;
241  }
242  break;
243 
244  case AV_CODEC_ID_INTERPLAY_DPCM:
245  bytestream2_skipu(&gb, 6); /* skip over the stream mask and stream length */
246 
247  for (ch = 0; ch < avctx->channels; ch++) {
248  predictor[ch] = sign_extend(bytestream2_get_le16u(&gb), 16);
249  *output_samples++ = predictor[ch];
250  }
251 
252  ch = 0;
253  while (output_samples < samples_end) {
254  predictor[ch] += interplay_delta_table[bytestream2_get_byteu(&gb)];
255  predictor[ch] = av_clip_int16(predictor[ch]);
256  *output_samples++ = predictor[ch];
257 
258  /* toggle channel */
259  ch ^= stereo;
260  }
261  break;
262 
263  case AV_CODEC_ID_XAN_DPCM:
264  {
265  int shift[2] = { 4, 4 };
266 
267  for (ch = 0; ch < avctx->channels; ch++)
268  predictor[ch] = sign_extend(bytestream2_get_le16u(&gb), 16);
269 
270  ch = 0;
271  while (output_samples < samples_end) {
272  int diff = bytestream2_get_byteu(&gb);
273  int n = diff & 3;
274 
275  if (n == 3)
276  shift[ch]++;
277  else
278  shift[ch] -= (2 * n);
279  diff = sign_extend((diff &~ 3) << 8, 16);
280 
281  /* saturate the shifter to a lower limit of 0 */
282  if (shift[ch] < 0)
283  shift[ch] = 0;
284 
285  diff >>= shift[ch];
286  predictor[ch] += diff;
287 
288  predictor[ch] = av_clip_int16(predictor[ch]);
289  *output_samples++ = predictor[ch];
290 
291  /* toggle channel */
292  ch ^= stereo;
293  }
294  break;
295  }
296  case AV_CODEC_ID_SOL_DPCM:
297  if (avctx->codec_tag != 3) {
298  uint8_t *output_samples_u8 = frame->data[0],
299  *samples_end_u8 = output_samples_u8 + out;
300  while (output_samples_u8 < samples_end_u8) {
301  int n = bytestream2_get_byteu(&gb);
302 
303  s->sample[0] += s->sol_table[n >> 4];
304  s->sample[0] = av_clip_uint8(s->sample[0]);
305  *output_samples_u8++ = s->sample[0];
306 
307  s->sample[stereo] += s->sol_table[n & 0x0F];
308  s->sample[stereo] = av_clip_uint8(s->sample[stereo]);
309  *output_samples_u8++ = s->sample[stereo];
310  }
311  } else {
312  while (output_samples < samples_end) {
313  int n = bytestream2_get_byteu(&gb);
314  if (n & 0x80) s->sample[ch] -= sol_table_16[n & 0x7F];
315  else s->sample[ch] += sol_table_16[n & 0x7F];
316  s->sample[ch] = av_clip_int16(s->sample[ch]);
317  *output_samples++ = s->sample[ch];
318  /* toggle channel */
319  ch ^= stereo;
320  }
321  }
322  break;
323  }
324 
325  *got_frame_ptr = 1;
326 
327  return avpkt->size;
328 }
329 
330 #define DPCM_DECODER(id_, name_, long_name_) \
331 AVCodec ff_ ## name_ ## _decoder = { \
332  .name = #name_, \
333  .type = AVMEDIA_TYPE_AUDIO, \
334  .id = id_, \
335  .priv_data_size = sizeof(DPCMContext), \
336  .init = dpcm_decode_init, \
337  .decode = dpcm_decode_frame, \
338  .capabilities = CODEC_CAP_DR1, \
339  .long_name = NULL_IF_CONFIG_SMALL(long_name_), \
340 }
341 
342 DPCM_DECODER(AV_CODEC_ID_INTERPLAY_DPCM, interplay_dpcm, "DPCM Interplay");
343 DPCM_DECODER(AV_CODEC_ID_ROQ_DPCM, roq_dpcm, "DPCM id RoQ");
344 DPCM_DECODER(AV_CODEC_ID_SOL_DPCM, sol_dpcm, "DPCM Sol");
345 DPCM_DECODER(AV_CODEC_ID_XAN_DPCM, xan_dpcm, "DPCM Xan");
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