aboutsummaryrefslogtreecommitdiffhomepage
path: root/ima4.c
blob: 3dc7a1cd3a96eff8cd15ed727b26e284f2f9923f (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
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
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
/*
 IMA4:1 audio codec from QuickTime4Linux library. (http://www.heroinewarrior.com/)
*/

#include "ima4.h"

static int quicktime_ima4_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 quicktime_ima4_index[16] = 
{
    -1, -1, -1, -1, 2, 4, 6, 8,
    -1, -1, -1, -1, 2, 4, 6, 8
};

/* ================================== private for ima4 */


void ima4_decode_sample(int *predictor, int *nibble, int *index, int *step)
{
	int difference, sign;

/* Get new index value */
	*index += quicktime_ima4_index[*nibble];

	if(*index < 0) *index = 0; 
	else 
	if(*index > 88) *index = 88;

/* Get sign and magnitude from *nibble */
	sign = *nibble & 8;
	*nibble = *nibble & 7;

/* Get difference */
	difference = *step >> 3;
	if(*nibble & 4) difference += *step;
	if(*nibble & 2) difference += *step >> 1;
	if(*nibble & 1) difference += *step >> 2;

/* Predict value */
	if(sign) 
	*predictor -= difference;
	else 
	*predictor += difference;

	if(*predictor > 32767) *predictor = 32767;
	else
	if(*predictor < -32768) *predictor = -32768;

/* Update the step value */
	*step = quicktime_ima4_step[*index];
}

int ima4_decode_block(unsigned short *output, unsigned char *input, int maxlen)
{
	int predictor;
	int index;
	int step;
	int i, nibble, nibble_count, block_size;
	int olen = 0;
	unsigned char *block_ptr;
	unsigned char *input_end = input + IMA4_BLOCK_SIZE;
//	quicktime_ima4_codec_t *codec = ((quicktime_codec_t*)atrack->codec)->priv;

/* Get the chunk header */
	predictor = *input++ << 8;
	predictor |= *input++;

	index = predictor & 0x7f;
	if(index > 88) index = 88;

	predictor &= 0xff80;
	if(predictor & 0x8000) predictor -= 0x10000;
	step = quicktime_ima4_step[index];

/* Read the input buffer sequentially, one nibble at a time */
	nibble_count = 0;
	while(input < input_end)
	{
		nibble = nibble_count ? (*input++  >> 4) & 0x0f : *input & 0x0f;

		ima4_decode_sample(&predictor, &nibble, &index, &step);
		if (olen+1 > maxlen)
		    break;
		*output++ = predictor;
		olen++;

		nibble_count ^= 1;
	}
	return(olen);
}

#if 0
void ima4_encode_sample(int *last_sample, int *last_index, int *nibble, int next_sample)
{
	int difference, new_difference, mask, step;

	difference = next_sample - *last_sample;
	*nibble = 0;
	step = quicktime_ima4_step[*last_index];
	new_difference = step >> 3;

	if(difference < 0)
	{
		*nibble = 8;
		difference = -difference;
	}

	mask = 4;
	while(mask)
	{
		if(difference >= step)
		{
			*nibble |= mask;
			difference -= step;
			new_difference += step;
		}

		step >>= 1;
		mask >>= 1;
	}

	if(*nibble & 8)
		*last_sample -= new_difference;
	else
		*last_sample += new_difference;

	if(*last_sample > 32767) *last_sample = 32767;
	else
	if(*last_sample < -32767) *last_sample = -32767;

	*last_index += quicktime_ima4_index[*nibble];

	if(*last_index < 0) *last_index = 0;
	else
	if(*last_index > 88) *last_index= 88;
}

#if 0
void ima4_encode_block(quicktime_audio_map_t *atrack, unsigned char *output, int16_t *input, int step, int channel)
{
	quicktime_ima4_codec_t *codec = ((quicktime_codec_t*)atrack->codec)->priv;
	int i, nibble_count = 0, nibble, header;

/* Get a fake starting sample */
	header = codec->last_samples[channel];
/* Force rounding. */
	if(header < 0x7fc0) header += 0x40;
	if(header < 0) header += 0x10000;
	header &= 0xff80;
	*output++ = (header & 0xff00) >> 8;
	*output++ = (header & 0x80) + (codec->last_indexes[channel] & 0x7f);

	for(i = 0; i < SAMPLES_PER_BLOCK; i++)
	{
		ima4_encode_sample(&(codec->last_samples[channel]), 
							&(codec->last_indexes[channel]), 
							&nibble, 
							*input);

		if(nibble_count)
			*output++ |= (nibble << 4);
		else
			*output = nibble;

		input += step;
		nibble_count ^= 1;
	}
}
#endif
/* Convert the number of samples in a chunk into the number of bytes in that */
/* chunk.  The number of samples in a chunk should end on a block boundary. */
long ima4_samples_to_bytes(long samples, int channels)
{
	long bytes = samples / SAMPLES_PER_BLOCK * BLOCK_SIZE * channels;
	return bytes;
}

/* Decode the chunk into the work buffer */
int ima4_decode_chunk(quicktime_t *file, int track, long chunk, int channel)
{
	int result = 0;
	int i, j;
	long chunk_samples, chunk_bytes;
	unsigned char *chunk_ptr, *block_ptr;
	quicktime_trak_t *trak = file->atracks[track].track;
	quicktime_ima4_codec_t *codec = ((quicktime_codec_t*)file->atracks[track].codec)->priv;

/* Get the byte count to read. */
	chunk_samples = quicktime_chunk_samples(trak, chunk);
	chunk_bytes = ima4_samples_to_bytes(chunk_samples, file->atracks[track].channels);

/* Get the buffer to read into. */
	if(codec->work_buffer && codec->work_size < chunk_samples)
	{
		free(codec->work_buffer);
		codec->work_buffer = 0;
	}

	if(!codec->work_buffer)
	{
		codec->work_size = chunk_samples;
		codec->work_buffer = malloc(sizeof(int16_t) * codec->work_size);
	}

	if(codec->read_buffer && codec->read_size < chunk_bytes)
	{
		free(codec->read_buffer);
		codec->read_buffer = 0;
	}

	if(!codec->read_buffer)
	{
		codec->read_size = chunk_bytes;
		codec->read_buffer = malloc(codec->read_size);
	}

/* codec->work_size now holds the number of samples in the last chunk */
/* codec->read_size now holds number of bytes in the last read buffer */

/* Read the entire chunk regardless of where the desired sample range starts. */
	result = quicktime_read_chunk(file, codec->read_buffer, track, chunk, 0, chunk_bytes);

/* Now decode the chunk, one block at a time, until the total samples in the chunk */
/* is reached. */

	if(!result)
	{
		block_ptr = codec->read_buffer;
		for(i = 0; i < chunk_samples; i += SAMPLES_PER_BLOCK)
		{
			for(j = 0; j < file->atracks[track].channels; j++)
			{
				if(j == channel)
					ima4_decode_block(&(file->atracks[track]), &(codec->work_buffer[i]), block_ptr);

				block_ptr += BLOCK_SIZE;
			}
		}
	}
	codec->buffer_channel = channel;
	codec->chunk = chunk;

	return result;
}


/* =================================== public for ima4 */

static int quicktime_delete_codec_ima4(quicktime_audio_map_t *atrack)
{
	quicktime_ima4_codec_t *codec = ((quicktime_codec_t*)atrack->codec)->priv;

	if(codec->work_buffer) free(codec->work_buffer);
	if(codec->read_buffer) free(codec->read_buffer);
	if(codec->last_samples) free(codec->last_samples);
	if(codec->last_indexes) free(codec->last_indexes);
	codec->last_samples = 0;
	codec->last_indexes = 0;
	codec->read_buffer = 0;
	codec->work_buffer = 0;
	codec->chunk = 0;
	codec->buffer_channel = 0; /* Channel of work buffer */
	codec->work_size = 0;          /* Size of work buffer */
	codec->read_size = 0;
	free(codec);
	return 0;
}

static int quicktime_decode_ima4(quicktime_t *file, 
					int16_t *output_i, 
					float *output_f,
					long samples, 
					int track, 
					int channel)
{
	int result = 0;
	longest chunk, chunk_sample, chunk_bytes, chunk_samples;
	longest i, chunk_start, chunk_end;
	quicktime_trak_t *trak = file->atracks[track].track;
	quicktime_ima4_codec_t *codec = ((quicktime_codec_t*)file->atracks[track].codec)->priv;

/* Get the first chunk with this routine and then increase the chunk number. */
	quicktime_chunk_of_sample(&chunk_sample, &chunk, trak, file->atracks[track].current_position);

/* Read chunks and extract ranges of samples until the output is full. */
	for(i = 0; i < samples && !result; )
	{
/* Get chunk we're on. */
		chunk_samples = quicktime_chunk_samples(trak, chunk);

		if(!codec->work_buffer ||
			codec->chunk != chunk ||
			codec->buffer_channel != channel)
		{
/* read a new chunk if necessary */
			result = ima4_decode_chunk(file, track, chunk, channel);
		}

/* Get boundaries from the chunk */
		chunk_start = 0;
		if(chunk_sample < file->atracks[track].current_position)
			chunk_start = file->atracks[track].current_position - chunk_sample;

		chunk_end = chunk_samples;
		if(chunk_sample + chunk_end > file->atracks[track].current_position + samples)
			chunk_end = file->atracks[track].current_position + samples - chunk_sample;

/* Read from the chunk */
		if(output_i)
		{
/*printf("decode_ima4 1 chunk %ld %ld-%ld output %ld\n", chunk, chunk_start + chunk_sample, chunk_end + chunk_sample, i); */
			while(chunk_start < chunk_end)
			{
				output_i[i++] = codec->work_buffer[chunk_start++];
			}
/*printf("decode_ima4 2\n"); */
		}
		else
		if(output_f)
		{
			while(chunk_start < chunk_end)
			{
				output_f[i++] = (float)codec->work_buffer[chunk_start++] / 32767;
			}
		}

		chunk++;
		chunk_sample += chunk_samples;
	}

	return result;
}

static int quicktime_encode_ima4(quicktime_t *file, 
						int16_t **input_i, 
						float **input_f, 
						int track, 
						long samples)
{
	int result = 0;
	longest i, j, step;
	longest chunk_bytes;
	longest overflow_start;
	longest offset;
	longest chunk_samples; /* Samples in the current chunk to be written */
	quicktime_audio_map_t *track_map = &(file->atracks[track]);
	quicktime_ima4_codec_t *codec = ((quicktime_codec_t*)track_map->codec)->priv;
	int16_t *input_ptr;
	unsigned char *output_ptr;

/* Get buffer sizes */
	if(codec->work_buffer && codec->work_size < (samples + codec->work_overflow + 1) * track_map->channels)
	{
/* Create new buffer */
		longest new_size = (samples + codec->work_overflow + 1) * track_map->channels;
		int16_t *new_buffer = malloc(sizeof(int16_t) * new_size);

/* Copy overflow */
		for(i = 0; i < codec->work_overflow * track_map->channels; i++)
			new_buffer[i] = codec->work_buffer[i];

/* Swap pointers. */
		free(codec->work_buffer);
		codec->work_buffer = new_buffer;
		codec->work_size = new_size;
	}
	else
	if(!codec->work_buffer)
	{
/* No buffer in the first place. */
		codec->work_size = (samples + codec->work_overflow) * track_map->channels;
/* Make the allocation enough for at least the flush routine. */
		if(codec->work_size < SAMPLES_PER_BLOCK * track_map->channels)
			codec->work_size = SAMPLES_PER_BLOCK * track_map->channels;
		codec->work_buffer = malloc(sizeof(int16_t) * codec->work_size);
	}

/* Get output size */
	chunk_bytes = ima4_samples_to_bytes(samples + codec->work_overflow, track_map->channels);
	if(codec->read_buffer && codec->read_size < chunk_bytes)
	{
		free(codec->read_buffer);
		codec->read_buffer = 0;
	}

	if(!codec->read_buffer)
	{
		codec->read_buffer = malloc(chunk_bytes);
		codec->read_size = chunk_bytes;
	}

	if(!codec->last_samples)
	{
		codec->last_samples = malloc(sizeof(int) * track_map->channels);
		for(i = 0; i < track_map->channels; i++)
		{
			codec->last_samples[i] = 0;
		}
	}

	if(!codec->last_indexes)
	{
		codec->last_indexes = malloc(sizeof(int) * track_map->channels);
		for(i = 0; i < track_map->channels; i++)
		{
			codec->last_indexes[i] = 0;
		}
	}

/* Arm the input buffer after the last overflow */
	step = track_map->channels;
	for(j = 0; j < track_map->channels; j++)
	{
		input_ptr = codec->work_buffer + codec->work_overflow * track_map->channels + j;

		if(input_i)
		{
			for(i = 0; i < samples; i++)
			{
				*input_ptr = input_i[j][i];
				input_ptr += step;
			}
		}
		else
		if(input_f)
		{
			for(i = 0; i < samples; i++)
			{
				*input_ptr = (int16_t)(input_f[j][i] * 32767);
				input_ptr += step;
			}
		}
	}

/* Encode from the input buffer to the read_buffer up to a multiple of  */
/* blocks. */
	input_ptr = codec->work_buffer;
	output_ptr = codec->read_buffer;

	for(i = 0; 
		i + SAMPLES_PER_BLOCK <= samples + codec->work_overflow; 
		i += SAMPLES_PER_BLOCK)
	{
		for(j = 0; j < track_map->channels; j++)
		{
			ima4_encode_block(track_map, output_ptr, input_ptr + j, track_map->channels, j);

			output_ptr += BLOCK_SIZE;
		}
		input_ptr += SAMPLES_PER_BLOCK * track_map->channels;
	}

/* Write to disk */
	chunk_samples = (longest)((samples + codec->work_overflow) / SAMPLES_PER_BLOCK) * SAMPLES_PER_BLOCK;

/*printf("quicktime_encode_ima4 1 %ld\n", chunk_samples); */
/* The block division may result in 0 samples getting encoded. */
/* Don't write 0 samples. */
	if(chunk_samples)
	{
		offset = quicktime_position(file);
		result = quicktime_write_data(file, codec->read_buffer, chunk_bytes);
		if(result) result = 0; else result = 1; /* defeat fwrite's return */
		quicktime_update_tables(file,
							track_map->track, 
							offset, 
							track_map->current_chunk, 
							track_map->current_position, 
							chunk_samples, 
							0);
		file->atracks[track].current_chunk++;
	}

/* Move the last overflow to the front */
	overflow_start = i;
	input_ptr = codec->work_buffer;
	for(i = overflow_start * track_map->channels ; 
		i < (samples + codec->work_overflow) * track_map->channels; 
		i++)
	{
		*input_ptr++ = codec->work_buffer[i];
	}
	codec->work_overflow = samples + codec->work_overflow - overflow_start;

	return result;
}

int quicktime_flush_ima4(quicktime_t *file, int track)
{
	quicktime_audio_map_t *track_map = &(file->atracks[track]);
	quicktime_ima4_codec_t *codec = ((quicktime_codec_t*)track_map->codec)->priv;
	int result = 0;
	int i;

/*printf("quicktime_flush_ima4 %ld\n", codec->work_overflow); */
	if(codec->work_overflow)
	{
/* Zero out enough to get a block */
		i = codec->work_overflow * track_map->channels;
		while(i < SAMPLES_PER_BLOCK * track_map->channels)
		{
			codec->work_buffer[i++] = 0;
		}
		codec->work_overflow = i / track_map->channels + 1;
/* Write the work_overflow only. */
		result = quicktime_encode_ima4(file, 0, 0, track, 0);
	}
	return result;
}

void quicktime_init_codec_ima4(quicktime_audio_map_t *atrack)
{
	quicktime_ima4_codec_t *codec;

/* Init public items */
	((quicktime_codec_t*)atrack->codec)->priv = calloc(1, sizeof(quicktime_ima4_codec_t));
	((quicktime_codec_t*)atrack->codec)->delete_acodec = quicktime_delete_codec_ima4;
	((quicktime_codec_t*)atrack->codec)->decode_video = 0;
	((quicktime_codec_t*)atrack->codec)->encode_video = 0;
	((quicktime_codec_t*)atrack->codec)->decode_audio = quicktime_decode_ima4;
	((quicktime_codec_t*)atrack->codec)->encode_audio = quicktime_encode_ima4;

/* Init private items */
	codec = ((quicktime_codec_t*)atrack->codec)->priv;
	codec->work_buffer = 0;
	codec->read_buffer = 0;
	codec->chunk = 0;
	codec->buffer_channel = 0;
	codec->work_overflow = 0;
	codec->work_size = 0;
	codec->read_size = 0;
	codec->last_samples = 0;
	codec->last_indexes = 0;
}
#endif