include/AudioBackend.h

   1 /*
   2  * AudioBackend.h - base-class for audio-devices, used by LMMS-mixer
   3  *
   4  * Copyright (c) 2004-2009 Tobias Doerffel <tobydox/at/users.sourceforge.net>
   5  *
   6  * This file is part of Linux MultiMedia Studio - http://lmms.sourceforge.net
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2 of the License, or (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public
  19  * License along with this program (see COPYING); if not, write to the
  20  * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  21  * Boston, MA 02110-1301 USA.
  22  *
  23  */
  24
  25 #ifndef _AUDIO_DEVICE_H
  26 #define _AUDIO_DEVICE_H
  27
  28 #include <QtCore/QPair>
  29 #include <QtCore/QThread>
  30
  31 #include "Mixer.h"
  32 #include "tab_widget.h"
  33
  34
  35 class AudioPort;
  36
  37 /*! \brief The AudioBackend class is the base class for all kinds of AudioBackends.
  38  *
  39  * All classes derived from AudioBackend receive audio data so they can output
  40  * it.
  41  */
  42 class AudioBackend
  43 {
  44 public:
  45         /*! \brief Constructs an AudioBackend object for the given AudioOutputContext. */
  46         AudioBackend( const ch_cnt_t _channels, AudioOutputContext * context );
  47         virtual ~AudioBackend();
  48
  49         /*! If the audio backend supports ports, classes creating an AudioPort
  50          * (e.g. InstrumentTrack) can register themselves for making
  51          * audio backend able to collect their individual output and provide
  52          * them at a specific port - currently only supported by JACK
  53          */
  54         virtual void registerPort( AudioPort * _port );
  55         virtual void unregisterPort( AudioPort * _port );
  56         virtual void renamePort( AudioPort * _port );
  57
  58
  59         inline bool supportsCapture() const
  60         {
  61                 return m_supportsCapture;
  62         }
  63
  64         inline sample_rate_t sampleRate() const
  65         {
  66                 return m_sampleRate;
  67         }
  68
  69         ch_cnt_t channels() const
  70         {
  71                 return m_channels;
  72         }
  73
  74         /*! \brief Fetches one buffer and writes it to output device.
  75          *
  76          * \return Number of frames processed
  77          */
  78         int processNextBuffer();
  79
  80         virtual void startProcessing()
  81         {
  82         }
  83
  84         virtual void stopProcessing();
  85
  86         virtual void applyQualitySettings();
  87
  88
  89
  90         class setupWidget : public tabWidget
  91         {
  92         public:
  93                 setupWidget( const QString & _caption, QWidget * _parent ) :
  94                         tabWidget( tabWidget::tr( "Settings for %1" ).arg(
  95                                         tabWidget::tr( _caption.toAscii() ) ).
  96                                                         toUpper(), _parent )
  97                 {
  98                 }
  99
 100                 virtual ~setupWidget()
 101                 {
 102                 }
 103
 104                 virtual void saveSettings() = 0;
 105
 106                 virtual void show()
 107                 {
 108                         parentWidget()->show();
 109                         QWidget::show();
 110                 }
 111
 112         } ;
 113
 114
 115         /*! \brief Returns const pointer to AudioOutputContext this AudioBackend acts for. */
 116         const AudioOutputContext * outputContext() const
 117         {
 118                 return m_context;
 119         }
 120
 121         /*! \brief Returns const pointer to Mixer this AudioBackend acts for. */
 122         const Mixer * mixer() const;
 123
 124
 125 protected:
 126         /*! \brief Writes given buffer to actual device.
 127          *
 128          * Subclasses can reimplement this for being used in conjunction with
 129          * processNextBuffer()
 130          */
 131         virtual void writeBuffer( const sampleFrameA * /* _buf*/,
 132                                                 const fpp_t /*_frames*/,
 133                                                 const float /*_master_gain*/ )
 134         {
 135         }
 136
 137         /*! \brief Called by according backend for fetching new audio data. */
 138         int getNextBuffer( sampleFrameA * _ab );
 139
 140         /*! \brief Clears given signed-int-16-buffer. */
 141         void clearS16Buffer( intSampleFrameA * _outbuf, const fpp_t _frames );
 142
 143         inline void setSampleRate( const sample_rate_t _new_sr )
 144         {
 145                 m_sampleRate = _new_sr;
 146         }
 147
 148         bool hqAudio() const;
 149
 150         AudioOutputContext * outputContext()
 151         {
 152                 return m_context;
 153         }
 154
 155         Mixer * mixer();
 156
 157
 158 protected:
 159         bool m_supportsCapture;
 160
 161
 162 private:
 163         AudioOutputContext * m_context;
 164         sample_rate_t m_sampleRate;
 165         ch_cnt_t m_channels;
 166
 167         sampleFrameA * m_buffer;
 168
 169 } ;
 170
 171
 172 #endif