aboutsummaryrefslogtreecommitdiffstats
path: root/mediaplugin/src/plugins/media/ffmpeg/ffmpeg_audio_convert.h
blob: ee4c5a81edcb1f00897fb5557ea163c489af309c (plain) (blame)
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
/* UltraStar Deluxe - Karaoke Game
 *
 * UltraStar Deluxe 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; see the file COPYING. If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 * $URL$
 * $Id$
 */
#ifndef _FFMPEG_AUDIO_CONVERT_H_
#define _FFMPEG_AUDIO_CONVERT_H_

#include "ffmpeg_core.h"
#include "core/plugin_audio_convert.h"
#include <math.h>

extern const audioConverterInfo_t audioConverterInfo;

// Note: FFmpeg seems to be using "kaiser windowed sinc" for resampling, so
// the quality should be good.
class FFmpegAudioConvertStream : public AudioConvertStream {
private:
	ReSampleContext *_resampleContext;
	double _ratio;

protected:
	FFmpegAudioConvertStream(const AudioFormatInfo &srcFormatInfo, const AudioFormatInfo &dstFormatInfo) :
		AudioConvertStream(srcFormatInfo, dstFormatInfo),
		_resampleContext(NULL),
		_ratio(0) {}

	bool init() {
		// Note: FFmpeg does not support resampling for more than 2 input channels

		if (_srcFormatInfo.getFormat() != asfS16) {
			logger.error("Unsupported format", "TAudioConverter_FFmpeg.Init");
			return false;
		}

		if (_srcFormatInfo.getFormat() != _dstFormatInfo.getFormat()) {
			logger.error("Incompatible formats", "TAudioConverter_FFmpeg.Init");
			return false;
		}

#if LIBAVCODEC_VERSION_INT >= AV_VERSION_INT(52,15,0)
		// use same values as the deprecated audio_resample_init()
		const int TAPS = 16;
		_resampleContext = av_audio_resample_init(
				_dstFormatInfo.getChannels(),
				_srcFormatInfo.getChannels(),
				lround(_dstFormatInfo.getSampleRate()),
				lround(_srcFormatInfo.getSampleRate()),
				SAMPLE_FMT_S16, SAMPLE_FMT_S16,
				TAPS, 10, 0, 0.8);
#else
		_resampleContext = audio_resample_init(
				_dstFormatInfo.getChannels(),
				_srcFormatInfo.getChannels(),
				lround(_dstFormatInfo.getSampleRate()),
				lround(_srcFormatInfo.getSampleRate()));
#endif

		if (!_resampleContext) {
			logger.error("audio_resample_init() failed", "TAudioConverter_FFmpeg.Init");
			return false;
		}

		// calculate ratio
		_ratio = ((double)_dstFormatInfo.getChannels() / _srcFormatInfo.getChannels()) *
		        (_dstFormatInfo.getSampleRate() / _srcFormatInfo.getSampleRate());

		return true;
	}

public:
	virtual ~FFmpegAudioConvertStream() {
		if (_resampleContext)
			audio_resample_close(_resampleContext);
	}

	static FFmpegAudioConvertStream* open(const AudioFormatInfo &srcFormatInfo, const AudioFormatInfo &dstFormatInfo) {
		FFmpegAudioConvertStream *converter = new FFmpegAudioConvertStream(srcFormatInfo, dstFormatInfo);
		if (!converter->init()) {
			delete converter;
			return 0;
		}
		return converter;
	}

	virtual int convert(uint8_t *inputBuffer, uint8_t *outputBuffer, int &inputSize) {
		if (inputSize <= 0) {
			// avoid div-by-zero in audio_resample()
			return (inputSize == 0) ? 0 : -1;
		}

		int inputSampleCount = inputSize / _srcFormatInfo.getFrameSize();
		int outputSampleCount = audio_resample(_resampleContext,
				(short*)outputBuffer, (short*)inputBuffer, inputSampleCount);
		if (outputSampleCount == -1) {
			logger.error("audio_resample() failed", "TAudioConverter_FFmpeg.Convert");
			return -1;
		}
		return outputSampleCount * _dstFormatInfo.getFrameSize();
	}

	/**
	 * Destination/Source size ratio
	 */
	virtual double getRatio() {
		return _ratio;
	}

	virtual int getOutputBufferSize(int inputSize) {
		return ceil(inputSize * getRatio());
	}
};

#endif /* _FFMPEG_AUDIO_CONVERT_H_ */