aboutsummaryrefslogtreecommitdiff
path: root/sound/mp3.cpp
blob: 642c2ba90a5147471dd3e0f4332e7d45fa928298 (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
/* 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/file.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 AudioStream {
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 _numLoops;
	uint _posInFrame;
	State _state;
	
	const mad_timer_t _startTime;
	const mad_timer_t _endTime;
	mad_timer_t _totalTime;
	
	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; }

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

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);

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

MP3InputStream::~MP3InputStream() {
	if (_state != MP3_STATE_INIT) {
		// Deinit MAD
		mad_synth_finish(&_synth);
		mad_frame_finish(&_frame);
		mad_stream_finish(&_stream);
	}

	if (_disposeAfterUse)
		delete _inStream;
}

void MP3InputStream::decodeMP3Data() {

	do {
		if (_state == MP3_STATE_INIT) {
			// 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();
		}
	
		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) {
			_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) {
					break; // Read more data
				} 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);
			
			// 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 && _numLoops != 1) {
			// If looping is on and there are loops left, rewind to the start
			if (_numLoops != 0)
				_numLoops--;

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


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 -


AudioStream *makeMP3Stream(Common::File *file, uint32 size) {
	assert(file);

	// FIXME: For now, just read the whole data into memory, and be done
	// with it. Of course this is in general *not* a nice thing to do...

	// If no size was specified, read the whole remainder of the file
	if (!size)
		size = file->size() - file->pos();

	// Read 'size' bytes of data into a MemoryReadStream
	Common::MemoryReadStream *stream = file->readStream(size);

	// .. and create an MP3InputStream from all this
	return new MP3InputStream(stream, true);
}

AudioStream *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);
}

} // End of namespace Audio

#endif // #ifdef USE_MAD