aboutsummaryrefslogtreecommitdiff
path: root/sound/mp3.cpp
blob: 7c590b0ef92d46306fea5244987839194ea9ebef (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
/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.

 * This program 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 General Public License for more details.

 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * $URL$
 * $Id$
 *
 */

#include "sound/mp3.h"

#ifdef USE_MAD

#include "common/debug.h"
#include "common/stream.h"
#include "common/util.h"

#include "sound/audiocd.h"
#include "sound/audiostream.h"

#include <mad.h>


namespace Audio {


#pragma mark -
#pragma mark --- MP3 (MAD) stream ---
#pragma mark -


class MP3InputStream : public SeekableAudioStream {
protected:
	enum State {
		MP3_STATE_INIT,	// Need to init the decoder
		MP3_STATE_READY,	// ready for processing data
		MP3_STATE_EOS		// end of data reached (may need to loop)
	};

	Common::SeekableReadStream *_inStream;
	bool _disposeAfterUse;

	uint _posInFrame;
	State _state;

	const mad_timer_t _startTime;
	const mad_timer_t _endTime;
	mad_timer_t _totalTime;

	int32 _totalPlayTime; // Length of one loop iteration
	uint32 _length;       // Total length of the MP3 stream

	uint _numLoops;			///< Number of loops to play
	uint _numPlayedLoops;	///< Number of loops which have been played

	mad_stream _stream;
	mad_frame _frame;
	mad_synth _synth;

	enum {
		BUFFER_SIZE = 5 * 8192
	};

	// This buffer contains a slab of input data
	byte _buf[BUFFER_SIZE + MAD_BUFFER_GUARD];

public:
	MP3InputStream(Common::SeekableReadStream *inStream,
	               bool dispose,
	               mad_timer_t start = mad_timer_zero,
	               mad_timer_t end = mad_timer_zero,
	               uint numLoops = 1);
	~MP3InputStream();

	int readBuffer(int16 *buffer, const int numSamples);

	bool endOfData() const		{ return _state == MP3_STATE_EOS; }
	bool isStereo() const		{ return MAD_NCHANNELS(&_frame.header) == 2; }
	int getRate() const			{ return _frame.header.samplerate; }

	bool seek(const Timestamp &where);
	// TODO: Maybe we can have a more precise implementation of this
	Timestamp getLength() const { return Timestamp(_totalPlayTime, getRate()); }

	void setNumLoops(uint numLoops) {
		_numLoops = numLoops;
		_numPlayedLoops = 0;
	}
	uint getNumPlayedLoops() { return _numPlayedLoops; }

protected:
	void decodeMP3Data();
	void readMP3Data();

	void initStream();
	void readHeader();
	void deinitStream();
};

MP3InputStream::MP3InputStream(Common::SeekableReadStream *inStream, bool dispose, mad_timer_t start, mad_timer_t end, uint numLoops) :
	_inStream(inStream),
	_disposeAfterUse(dispose),
	_numLoops(numLoops),
	_posInFrame(0),
	_state(MP3_STATE_INIT),
	_startTime(start),
	_endTime(end),
	_totalTime(mad_timer_zero) {

	// Make sure that either start < end, or end is zero (indicating "play until end")
	assert(mad_timer_compare(_startTime, _endTime) < 0 || mad_timer_sign(_endTime) == 0);

	// The MAD_BUFFER_GUARD must always contain zeros (the reason
	// for this is that the Layer III Huffman decoder of libMAD
	// may read a few bytes beyond the end of the input buffer).
	memset(_buf + BUFFER_SIZE, 0, MAD_BUFFER_GUARD);

	// Calculate the length of the stream
	initStream();

	while (_state != MP3_STATE_EOS)
		readHeader();

	_length = mad_timer_count(_totalTime, MAD_UNITS_MILLISECONDS);

	deinitStream();

	// Reinit stream
	_state = MP3_STATE_INIT;

	// Calculate play time
	mad_timer_t length;

	mad_timer_set(&length, 0, 0, 1000);
	mad_timer_add(&length, start);
	mad_timer_negate(&length);

	if (mad_timer_sign(end) != 0) {
		mad_timer_add(&length, end);
	} else {
		mad_timer_set(&_totalTime, _length / 1000, _length % 1000, 1000);
		mad_timer_add(&length, _totalTime);
		_totalTime = mad_timer_zero;
	}

	_totalPlayTime = mad_timer_count(length, MAD_UNITS_MILLISECONDS);

	if (mad_timer_sign(length) < 0)
		_totalPlayTime = 0;

	// Decode the first chunk of data. This is necessary so that _frame
	// is setup and isStereo() and getRate() return correct results.
	decodeMP3Data();
}

MP3InputStream::~MP3InputStream() {
	deinitStream();

	if (_disposeAfterUse)
		delete _inStream;
}

void MP3InputStream::decodeMP3Data() {
	do {
		if (_state == MP3_STATE_INIT)
			initStream();

		if (_state == MP3_STATE_EOS)
			return;

		// If necessary, load more data into the stream decoder
		if (_stream.error == MAD_ERROR_BUFLEN)
			readMP3Data();

		while (_state == MP3_STATE_READY) {
			readHeader();

			// If we have not yet reached the start point, skip to the next frame
			if (mad_timer_compare(_totalTime, _startTime) < 0)
				continue;

			// If an end time is specified and we are past it, stop
			if (mad_timer_sign(_endTime) > 0 && mad_timer_compare(_totalTime, _endTime) >= 0) {
				_state = MP3_STATE_EOS;
				break;
			}

			// Decode the next frame
			if (mad_frame_decode(&_frame, &_stream) == -1) {
				if (_stream.error == MAD_ERROR_BUFLEN) {
					break; // Read more data
				} else if (MAD_RECOVERABLE(_stream.error)) {
					// Note: we will occasionally see MAD_ERROR_BADDATAPTR errors here.
					// These are normal and expected (caused by our frame skipping (i.e. "seeking")
					// code above).
					debug(6, "MP3InputStream: Recoverable error in mad_frame_decode (%s)", mad_stream_errorstr(&_stream));
					continue;
				} else {
					warning("MP3InputStream: Unrecoverable error in mad_frame_decode (%s)", mad_stream_errorstr(&_stream));
					break;
				}
			}

			// Synthesize PCM data
			mad_synth_frame(&_synth, &_frame);
			_posInFrame = 0;
			break;
		}

		if (_state == MP3_STATE_EOS) {
			++_numPlayedLoops;
			// If looping is on and there are loops left, rewind to the start
			if (!_numLoops || _numPlayedLoops < _numLoops) {
				deinitStream();

				// Reset the decoder state to indicate we should start over
				_state = MP3_STATE_INIT;
			}
		}

	} while (_state != MP3_STATE_EOS && _stream.error == MAD_ERROR_BUFLEN);

	if (_stream.error != MAD_ERROR_NONE)
		_state = MP3_STATE_EOS;
}

void MP3InputStream::readMP3Data() {
	uint32 remaining = 0;

	// Give up immediately if we already used up all data in the stream
	if (_inStream->eos()) {
		_state = MP3_STATE_EOS;
		return;
	}

	if (_stream.next_frame) {
		// If there is still data in the MAD stream, we need to preserve it.
		// Note that we use memmove, as we are reusing the same buffer,
		// and hence the data regions we copy from and to may overlap.
		remaining = _stream.bufend - _stream.next_frame;
		assert(remaining < BUFFER_SIZE);	// Paranoia check
		memmove(_buf, _stream.next_frame, remaining);
	}

	// Try to read the next block
	uint32 size = _inStream->read(_buf + remaining, BUFFER_SIZE - remaining);
	if (size <= 0) {
		_state = MP3_STATE_EOS;
		return;
	}

	// Feed the data we just read into the stream decoder
	_stream.error = MAD_ERROR_NONE;
	mad_stream_buffer(&_stream, _buf, size + remaining);
}

bool MP3InputStream::seek(const Timestamp &where) {
	const uint32 time = where.msecs();

	if (time == _length) {
		_state = MP3_STATE_EOS;
		return true;
	} else if (time > _length) {
		return false;
	}

	mad_timer_t destination;
	mad_timer_set(&destination, time / 1000, time % 1000, 1000);

	if (_state != MP3_STATE_READY || mad_timer_compare(destination, _totalTime) < 0)
		initStream();

	while (mad_timer_compare(destination, _totalTime) > 0 && _state != MP3_STATE_EOS)
		readHeader();

	return (_state != MP3_STATE_EOS);
}

void MP3InputStream::initStream() {
	if (_state != MP3_STATE_INIT)
		deinitStream();

	// Init MAD
	mad_stream_init(&_stream);
	mad_frame_init(&_frame);
	mad_synth_init(&_synth);

	// Reset the stream data
	_inStream->seek(0, SEEK_SET);
	_totalTime = mad_timer_zero;
	_posInFrame = 0;

	// Update state
	_state = MP3_STATE_READY;

	// Read the first few sample bytes
	readMP3Data();
}

void MP3InputStream::readHeader() {
	if (_state != MP3_STATE_READY)
		return;

	// If necessary, load more data into the stream decoder
	if (_stream.error == MAD_ERROR_BUFLEN)
		readMP3Data();

	while (_state != MP3_STATE_EOS) {
		_stream.error = MAD_ERROR_NONE;

		// Decode the next header. Note: mad_frame_decode would do this for us, too.
		// However, for seeking we don't want to decode the full frame (else it would
		// be far too slow). Hence we perform this explicitly in a separate step.
		if (mad_header_decode(&_frame.header, &_stream) == -1) {
			if (_stream.error == MAD_ERROR_BUFLEN) {
				readMP3Data();  // Read more data
				continue;
			} else if (MAD_RECOVERABLE(_stream.error)) {
				debug(6, "MP3InputStream: Recoverable error in mad_header_decode (%s)", mad_stream_errorstr(&_stream));
				continue;
			} else {
				warning("MP3InputStream: Unrecoverable error in mad_header_decode (%s)", mad_stream_errorstr(&_stream));
				break;
			}
		}

		// Sum up the total playback time so far
		mad_timer_add(&_totalTime, _frame.header.duration);
		break;
	}

	if (_stream.error != MAD_ERROR_NONE)
		_state = MP3_STATE_EOS;
}

void MP3InputStream::deinitStream() {
	if (_state == MP3_STATE_INIT)
		return;

	// Deinit MAD
	mad_synth_finish(&_synth);
	mad_frame_finish(&_frame);
	mad_stream_finish(&_stream);

	_state = MP3_STATE_EOS;
}

static inline int scale_sample(mad_fixed_t sample) {
	// round
	sample += (1L << (MAD_F_FRACBITS - 16));

	// clip
	if (sample > MAD_F_ONE - 1)
		sample = MAD_F_ONE - 1;
	else if (sample < -MAD_F_ONE)
		sample = -MAD_F_ONE;

	// quantize and scale to not saturate when mixing a lot of channels
	return sample >> (MAD_F_FRACBITS + 1 - 16);
}

int MP3InputStream::readBuffer(int16 *buffer, const int numSamples) {
	int samples = 0;
	// Keep going as long as we have input available
	while (samples < numSamples && _state != MP3_STATE_EOS) {
		const int len = MIN(numSamples, samples + (int)(_synth.pcm.length - _posInFrame) * MAD_NCHANNELS(&_frame.header));
		while (samples < len) {
			*buffer++ = (int16)scale_sample(_synth.pcm.samples[0][_posInFrame]);
			samples++;
			if (MAD_NCHANNELS(&_frame.header) == 2) {
				*buffer++ = (int16)scale_sample(_synth.pcm.samples[1][_posInFrame]);
				samples++;
			}
			_posInFrame++;
		}
		if (_posInFrame >= _synth.pcm.length) {
			// We used up all PCM data in the current frame -- read & decode more
			decodeMP3Data();
		}
	}
	return samples;
}


#pragma mark -
#pragma mark --- MP3 factory functions ---
#pragma mark -

SeekableAudioStream *makeMP3Stream(
	Common::SeekableReadStream *stream,
	bool disposeAfterUse,
	uint32 startTime,
	uint32 duration,
	uint numLoops) {

	mad_timer_t start;
	mad_timer_t end;

	// Both startTime and duration are given in milliseconds.
	// Calculate the appropriate mad_timer_t values from them.
	mad_timer_set(&start, startTime / 1000, startTime % 1000, 1000);
	if (duration == 0) {
		end = mad_timer_zero;
	} else {
		int endTime = startTime + duration;
		mad_timer_set(&end, endTime / 1000, endTime % 1000, 1000);
	}

	return new MP3InputStream(stream, disposeAfterUse, start, end, numLoops);
}

SeekableAudioStream *makeMP3Stream(
	Common::SeekableReadStream *stream,
	bool disposeAfterUse) {
	return makeMP3Stream(stream, disposeAfterUse, 0, 0, 1);
}

} // End of namespace Audio

#endif // #ifdef USE_MAD