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
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
|
/* GStreamer
* Copyright (C) 2009 Pioneers of the Inevitable <songbird@songbirdnest.com>
*
* Authors: Michael Smith <msmith@songbirdnest.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/* Based on ADPCM decoders in libsndfile,
Copyright (C) 1999-2002 Erik de Castro Lopo <erikd@zip.com.au
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <gst/gst.h>
#include <gst/audio/gstaudiodecoder.h>
#define GST_TYPE_ADPCM_DEC \
(adpcmdec_get_type ())
#define GST_ADPCM_DEC(obj) \
(G_TYPE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_ADPCM_DEC, ADPCMDec))
#define GST_CAT_DEFAULT adpcmdec_debug
GST_DEBUG_CATEGORY_STATIC (adpcmdec_debug);
static GstStaticPadTemplate adpcmdec_sink_template =
GST_STATIC_PAD_TEMPLATE ("sink",
GST_PAD_SINK,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("audio/x-adpcm, "
" layout=(string){microsoft, dvi}, "
" block_align = (int) [64, 8192], "
" rate = (int)[ 1, MAX ], " "channels = (int)[1,2];")
);
static GstStaticPadTemplate adpcmdec_src_template =
GST_STATIC_PAD_TEMPLATE ("src",
GST_PAD_SRC,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("audio/x-raw, "
"format = (string) " GST_AUDIO_NE (S16) ", "
"layout = (string) interleaved, "
"rate = (int) [1, MAX], channels = (int) [1,2]")
);
enum adpcm_layout
{
LAYOUT_ADPCM_MICROSOFT,
LAYOUT_ADPCM_DVI
};
typedef struct _ADPCMDecClass
{
GstAudioDecoderClass parent_class;
} ADPCMDecClass;
typedef struct _ADPCMDec
{
GstAudioDecoder parent;
enum adpcm_layout layout;
int rate;
int channels;
int blocksize;
} ADPCMDec;
GType adpcmdec_get_type (void);
G_DEFINE_TYPE (ADPCMDec, adpcmdec, GST_TYPE_AUDIO_DECODER);
static gboolean
adpcmdec_set_format (GstAudioDecoder * bdec, GstCaps * in_caps)
{
ADPCMDec *dec = (ADPCMDec *) (bdec);
GstStructure *structure = gst_caps_get_structure (in_caps, 0);
const gchar *layout;
GstAudioInfo info;
layout = gst_structure_get_string (structure, "layout");
if (!layout)
return FALSE;
if (g_str_equal (layout, "microsoft"))
dec->layout = LAYOUT_ADPCM_MICROSOFT;
else if (g_str_equal (layout, "dvi"))
dec->layout = LAYOUT_ADPCM_DVI;
else
return FALSE;
if (!gst_structure_get_int (structure, "block_align", &dec->blocksize))
dec->blocksize = -1; /* Not provided */
if (!gst_structure_get_int (structure, "rate", &dec->rate))
return FALSE;
if (!gst_structure_get_int (structure, "channels", &dec->channels))
return FALSE;
gst_audio_info_init (&info);
gst_audio_info_set_format (&info, GST_AUDIO_FORMAT_S16, dec->rate,
dec->channels, NULL);
gst_audio_decoder_set_output_format (bdec, &info);
return TRUE;
}
/*=====================================================================
* From libsndfile:
*
* MS ADPCM Block Layout.
* ======================
* Block is usually 256, 512 or 1024 bytes depending on sample rate.
* For a mono file, the block is laid out as follows:
* byte purpose
* 0 block predictor [0..6]
* 1,2 initial idelta (positive)
* 3,4 sample 1
* 5,6 sample 0
* 7..n packed bytecodes
*
* For a stereo file, the block is laid out as follows:
* byte purpose
* 0 block predictor [0..6] for left channel
* 1 block predictor [0..6] for right channel
* 2,3 initial idelta (positive) for left channel
* 4,5 initial idelta (positive) for right channel
* 6,7 sample 1 for left channel
* 8,9 sample 1 for right channel
* 10,11 sample 0 for left channel
* 12,13 sample 0 for right channel
* 14..n packed bytecodes
*
*=====================================================================
*/
static const int AdaptationTable[] = {
230, 230, 230, 230, 307, 409, 512, 614,
768, 614, 512, 409, 307, 230, 230, 230
};
static const int AdaptCoeff1[] = {
256, 512, 0, 192, 240, 460, 392
};
static const int AdaptCoeff2[] = {
0, -256, 0, 64, 0, -208, -232
};
static gint16
read_sample (const guint8 * data)
{
guint16 val = data[0] | (data[1] << 8);
return *((gint16 *) & val);
}
/* Decode a single block of data from 'data', storing 'n_samples' decoded 16 bit
samples in 'samples'.
All buffer lengths have been verified by the caller
*/
static gboolean
adpcmdec_decode_ms_block (ADPCMDec * dec, int n_samples, const guint8 * data,
gint16 * samples)
{
gint16 pred[2];
gint16 idelta[2];
int idx; /* Current byte offset in 'data' */
int i; /* Current sample index in 'samples' */
/* Read the block header, verify for sanity */
if (dec->channels == 1) {
pred[0] = data[0];
idelta[0] = read_sample (data + 1);
samples[1] = read_sample (data + 3);
samples[0] = read_sample (data + 5);
idx = 7;
i = 2;
if (pred[0] < 0 || pred[0] > 6) {
GST_WARNING_OBJECT (dec, "Invalid block predictor");
return FALSE;
}
}
else {
pred[0] = data[0];
pred[1] = data[1];
idelta[0] = read_sample (data + 2);
idelta[1] = read_sample (data + 4);
samples[2] = read_sample (data + 6);
samples[3] = read_sample (data + 8);
samples[0] = read_sample (data + 10);
samples[1] = read_sample (data + 12);
idx = 14;
i = 4;
if (pred[0] < 0 || pred[0] > 6 || pred[1] < 0 || pred[1] > 6) {
GST_WARNING_OBJECT (dec, "Invalid block predictor");
return FALSE;
}
}
for (; i < n_samples; i++) {
int chan = i % dec->channels;
int bytecode;
int delta;
int current;
int predict;
if (i % 2 == 0) {
bytecode = (data[idx] >> 4) & 0x0F;
} else {
bytecode = data[idx] & 0x0F;
idx++;
}
delta = idelta[chan];
idelta[chan] = (AdaptationTable[bytecode] * delta) >> 8;
if (idelta[chan] < 16)
idelta[chan] = 16;
/* Bytecode is used above as an index into the table. Below, it's used
as a signed 4-bit value; convert appropriately */
if (bytecode & 0x8)
bytecode -= 0x10;
predict = ((samples[i - dec->channels] * AdaptCoeff1[pred[chan]]) +
(samples[i - 2 * dec->channels] * AdaptCoeff2[pred[chan]])
) >> 8;
current = (bytecode * delta) + predict;
/* Clamp to 16 bits, store decoded sample */
samples[i] = CLAMP (current, G_MININT16, G_MAXINT16);
}
return TRUE;
}
static const int ima_indx_adjust[16] = {
-1, -1, -1, -1, 2, 4, 6, 8, -1, -1, -1, -1, 2, 4, 6, 8,
};
static const int ima_step_size[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
};
/* Decode a single block of data from 'data', storing 'n_samples' decoded 16 bit
samples in 'samples'.
All buffer lengths have been verified by the caller
*/
static gboolean
adpcmdec_decode_ima_block (ADPCMDec * dec, int n_samples, const guint8 * data,
gint16 * samples)
{
gint16 stepindex[2];
int channel;
int idx;
int i, j;
int sample;
if ((n_samples - dec->channels) % 8 != 0) {
GST_WARNING_OBJECT (dec, "Input not correct size");
return FALSE;
}
for (channel = 0; channel < dec->channels; channel++) {
samples[channel] = read_sample (data + channel * 4);
stepindex[channel] = MIN (data[channel * 4 + 2], 88);
if (data[channel * 4 + 3] != 0) {
GST_WARNING_OBJECT (dec, "Synchronisation error");
return FALSE;
}
}
i = dec->channels;
idx = 4 * dec->channels;
while (i < n_samples) {
for (channel = 0; channel < dec->channels; channel++) {
sample = i + channel;
for (j = 0; j < 8; j++) {
int bytecode;
int step;
int diff;
if (j % 2 == 0) {
bytecode = data[idx] & 0x0F;
} else {
bytecode = (data[idx] >> 4) & 0x0F;
idx++;
}
step = ima_step_size[stepindex[channel]];
diff = (2 * (bytecode & 0x7) * step + step) / 8;
if (bytecode & 8)
diff = -diff;
samples[sample] =
CLAMP (samples[sample - dec->channels] + diff, G_MININT16,
G_MAXINT16);
stepindex[channel] =
CLAMP (stepindex[channel] + ima_indx_adjust[bytecode], 0, 88);
sample += dec->channels;
}
}
i += 8 * dec->channels;
}
return TRUE;
}
static GstBuffer *
adpcmdec_decode_block (ADPCMDec * dec, const guint8 * data, int blocksize)
{
gboolean res = FALSE;
GstBuffer *outbuf = NULL;
int outsize;
int samples;
GstMapInfo omap;
if (dec->layout == LAYOUT_ADPCM_MICROSOFT) {
/* Each block has a 3 byte header per channel, plus 4 bytes per channel to
give two initial sample values per channel. Then the remainder gives
two samples per byte */
if (blocksize < 7 * dec->channels)
goto exit;
samples = (blocksize - 7 * dec->channels) * 2 + 2 * dec->channels;
outsize = 2 * samples;
outbuf = gst_buffer_new_and_alloc (outsize);
gst_buffer_map (outbuf, &omap, GST_MAP_WRITE);
res = adpcmdec_decode_ms_block (dec, samples, data, (gint16 *) omap.data);
gst_buffer_unmap (outbuf, &omap);
} else if (dec->layout == LAYOUT_ADPCM_DVI) {
/* Each block has a 4 byte header per channel, include an initial sample.
Then the remainder gives two samples per byte */
if (blocksize < 4 * dec->channels)
goto exit;
samples = (blocksize - 4 * dec->channels) * 2 + dec->channels;
outsize = 2 * samples;
outbuf = gst_buffer_new_and_alloc (outsize);
gst_buffer_map (outbuf, &omap, GST_MAP_WRITE);
res = adpcmdec_decode_ima_block (dec, samples, data, (gint16 *) omap.data);
gst_buffer_unmap (outbuf, &omap);
} else {
GST_WARNING_OBJECT (dec, "Unknown layout");
}
if (!res) {
if (outbuf)
gst_buffer_unref (outbuf);
outbuf = NULL;
GST_WARNING_OBJECT (dec, "Decode of block failed");
}
exit:
return outbuf;
}
static GstFlowReturn
adpcmdec_parse (GstAudioDecoder * bdec, GstAdapter * adapter,
gint * offset, gint * length)
{
ADPCMDec *dec = (ADPCMDec *) (bdec);
guint size;
size = gst_adapter_available (adapter);
g_return_val_if_fail (size > 0, GST_FLOW_ERROR);
if (dec->blocksize < 0) {
/* No explicit blocksize; we just process one input buffer at a time */
*offset = 0;
*length = size;
} else {
if (size >= dec->blocksize) {
*offset = 0;
*length = dec->blocksize;
} else {
return GST_FLOW_EOS;
}
}
return GST_FLOW_OK;
}
static GstFlowReturn
adpcmdec_handle_frame (GstAudioDecoder * bdec, GstBuffer * buffer)
{
ADPCMDec *dec = (ADPCMDec *) (bdec);
GstFlowReturn ret = GST_FLOW_OK;
GstMapInfo map;
GstBuffer *outbuf = NULL;
/* no fancy draining */
if (G_UNLIKELY (!buffer))
return GST_FLOW_OK;
if (!dec->blocksize)
return GST_FLOW_NOT_NEGOTIATED;
gst_buffer_map (buffer, &map, GST_MAP_READ);
outbuf = adpcmdec_decode_block (dec, map.data, dec->blocksize);
gst_buffer_unmap (buffer, &map);
if (outbuf == NULL) {
GST_AUDIO_DECODER_ERROR (bdec, 1, STREAM, DECODE, (NULL),
("frame decode failed"), ret);
}
if (ret == GST_FLOW_OK)
ret = gst_audio_decoder_finish_frame (bdec, outbuf, 1);
return ret;
}
static gboolean
adpcmdec_start (GstAudioDecoder * bdec)
{
ADPCMDec *dec = (ADPCMDec *) bdec;
GST_DEBUG_OBJECT (dec, "start");
dec->blocksize = 0;
dec->rate = 0;
dec->channels = 0;
return TRUE;
}
static gboolean
adpcmdec_stop (GstAudioDecoder * dec)
{
GST_DEBUG_OBJECT (dec, "stop");
return TRUE;
}
static void
adpcmdec_init (ADPCMDec * dec)
{
}
static void
adpcmdec_class_init (ADPCMDecClass * klass)
{
GstElementClass *element_class = (GstElementClass *) klass;
GstAudioDecoderClass *base_class = (GstAudioDecoderClass *) klass;
gst_element_class_add_pad_template (element_class,
gst_static_pad_template_get (&adpcmdec_sink_template));
gst_element_class_add_pad_template (element_class,
gst_static_pad_template_get (&adpcmdec_src_template));
gst_element_class_set_metadata (element_class, "ADPCM decoder",
"Codec/Decoder/Audio",
"Decode MS and IMA ADPCM audio",
"Pioneers of the Inevitable <songbird@songbirdnest.com>");
base_class->start = GST_DEBUG_FUNCPTR (adpcmdec_start);
base_class->stop = GST_DEBUG_FUNCPTR (adpcmdec_stop);
base_class->set_format = GST_DEBUG_FUNCPTR (adpcmdec_set_format);
base_class->parse = GST_DEBUG_FUNCPTR (adpcmdec_parse);
base_class->handle_frame = GST_DEBUG_FUNCPTR (adpcmdec_handle_frame);
}
static gboolean
plugin_init (GstPlugin * plugin)
{
GST_DEBUG_CATEGORY_INIT (adpcmdec_debug, "adpcmdec", 0, "ADPCM Decoders");
if (!gst_element_register (plugin, "adpcmdec", GST_RANK_PRIMARY,
GST_TYPE_ADPCM_DEC)) {
return FALSE;
}
return TRUE;
}
GST_PLUGIN_DEFINE (GST_VERSION_MAJOR, GST_VERSION_MINOR, adpcmdec,
"ADPCM decoder", plugin_init, VERSION, "LGPL", GST_PACKAGE_NAME,
GST_PACKAGE_ORIGIN);
|