drivers/audio/AudioOutputDevice.h

/***************************************************************************
 *                                                                         *
 *   LinuxSampler - modular, streaming capable sampler                     *
 *                                                                         *
 *   Copyright (C) 2003, 2004 by Benno Senoner and Christian Schoenebeck   *
 *                                                                         *
 *   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., 59 Temple Place, Suite 330, Boston,                 *
 *   MA  02111-1307  USA                                                   *
 ***************************************************************************/

#ifndef __LS_AUDIOOUTPUTDEVICE_H__
#define __LS_AUDIOOUTPUTDEVICE_H__

#include <set>
#include <map>
#include <vector>
#include <stdexcept>

#include "../../common/global.h"
#include "../../common/LinuxSamplerException.h"
#include "../Device.h"
#include "../DeviceParameter.h"
#include "../../engines/common/Engine.h"
#include "AudioChannel.h"

namespace LinuxSampler {

    // just symbol prototyping
    class Engine;

    /** Abstract base class for audio output drivers in LinuxSampler
     *
     * This class will be derived by specialized classes which implement the
     * connection to a specific audio output system (e.g. Alsa, Jack,
     * CoreAudio).
     */
    class AudioOutputDevice : public Device {
        public:

            /////////////////////////////////////////////////////////////////
            // Device parameters

            /** Device Parameter 'ACTIVE'
             *
             * Used to activate / deactivate the audio output device.
             */
            class ParameterActive : public DeviceCreationParameterBool {
                public:
                    ParameterActive( void ) : DeviceCreationParameterBool()                  { InitWithDefault();                                  }
                    ParameterActive( String s ) : DeviceCreationParameterBool(s)             {}
                    virtual String Description()                                             { return "Enable / disable device";                   }
                    virtual bool   Fix()                                                     { return false;                                       }
                    virtual bool   Mandatory()                                               { return false;                                       }
                    virtual std::map<String,DeviceCreationParameter*> DependsAsParameters()  { return std::map<String,DeviceCreationParameter*>(); }
                    virtual optional<bool> DefaultAsBool(std::map<String,String> Parameters) { return true;                                        }
                    virtual void OnSetValue(bool b) throw (LinuxSamplerException)            { if (b) ((AudioOutputDevice*)pDevice)->Play(); else ((AudioOutputDevice*)pDevice)->Stop();       }
                    static String Name() { return "ACTIVE"; }
            };

            /** Device Parameter 'SAMPLERATE'
             *
             * Used to set the sample rate of the audio output device.
             */
            class ParameterSampleRate : public DeviceCreationParameterInt {
                public:
                    ParameterSampleRate() : DeviceCreationParameterInt()                            { InitWithDefault();                                  }
                    ParameterSampleRate( String s ) : DeviceCreationParameterInt(s)                 {}
                    virtual String Description()                                                    { return "Output sample rate";                        }
                    virtual bool   Fix()                                                            { return true;                                        }
                    virtual bool   Mandatory()                                                      { return false;                                       }
                    virtual std::map<String,DeviceCreationParameter*> DependsAsParameters()         { return std::map<String,DeviceCreationParameter*>(); }
                    virtual optional<int>    DefaultAsInt(std::map<String,String> Parameters)       { return 44100;                                       }
                    virtual optional<int>    RangeMinAsInt(std::map<String,String> Parameters)      { return optional<int>::nothing;                      }
                    virtual optional<int>    RangeMaxAsInt(std::map<String,String> Parameters)      { return optional<int>::nothing;                      }
                    virtual std::vector<int> PossibilitiesAsInt(std::map<String,String> Parameters) { return std::vector<int>();                          }
                    virtual void             OnSetValue(int i) throw (LinuxSamplerException)        { /* cannot happen, as parameter is fix */            }
                    static String Name() { return "SAMPLERATE"; }
            };

            /** Device Parameters 'CHANNELS'
             *
             * Used to increase / decrease the number of audio channels of
             * audio output device.
             */
            class ParameterChannels : public DeviceCreationParameterInt {
                public:
                    ParameterChannels() : DeviceCreationParameterInt()                              { InitWithDefault();                                  }
                    ParameterChannels( String s ) : DeviceCreationParameterInt(s)                   {}
                    virtual String Description()                                                    { return "Number of output channels";                 }
                    virtual bool   Fix()                                                            { return false;                                       }
                    virtual bool   Mandatory()                                                      { return false;                                       }
                    virtual std::map<String,DeviceCreationParameter*> DependsAsParameters()         { return std::map<String,DeviceCreationParameter*>(); }
                    virtual optional<int>    DefaultAsInt(std::map<String,String> Parameters)       { return 2;                                           }
                    virtual optional<int>    RangeMinAsInt(std::map<String,String> Parameters)      { return optional<int>::nothing;                      }
                    virtual optional<int>    RangeMaxAsInt(std::map<String,String> Parameters)      { return optional<int>::nothing;                      }
                    virtual std::vector<int> PossibilitiesAsInt(std::map<String,String> Parameters) { return std::vector<int>();                          }
                    virtual void             OnSetValue(int i) throw (LinuxSamplerException)        { ((AudioOutputDevice*)pDevice)->AcquireChannels(i);    }
                    static String Name() { return "CHANNELS"; }
            };


            /////////////////////////////////////////////////////////////////
            // abstract methods
            //     (these have to be implemented by the descendant)

            /**
             * Start playback of audio signal on the audio device. It's the
             * responsibility of the implementing audio device to call the
             * RenderAudio(uint Samples) method of all connected engines.
             * This will cause the engines to continue to render 'Samples'
             * number of audio sample points and the engines will
             * automatically add their audio signals to the audio buffers of
             * the audio channels of this audio device. So the implementing
             * audio device just has to access the buffers of it's audio
             * channels.
             *
             * @throws AudioOutputException  if playback can not be started
             * @see AudioChannel
             */
            virtual void Play() = 0;

            /**
             * Returns true if the audio device is currently playing back.
             */
            virtual bool IsPlaying() = 0;

            /**
             * Stop playback of audio signal on the audio device. The
             * implementing audio device will stop calling the RenderAudio()
             * method of all connected engines and close it's connection to
             * audio output system.
             */
            virtual void Stop() = 0;

            /**
             * This method will usually be called by the sampler engines that
             * are connected to this audio device to inform the audio device
             * how much audio channels the engine(s) need. It's the
             * responsibility of the audio device to offer that amount of
             * audio channels - again: this is not an option this is a must!
             * The engines will assume to be able to access those audio
             * channels right after. If the audio driver is not able to offer
             * that much channels, it can simply create mix channels which
             * are then just mixed to the 'real' audio channels. See
             * AudioChannel.h for details about channels and mix channels.
             *
             * @param Channels - amount of output channels required by
             *                   a sampler engine
             * @throws AudioOutputException  if desired amount of channels
             *                               cannot be offered
             * @see AudioChannel
             */
            virtual void AcquireChannels(uint Channels) = 0;

            /**
             * Maximum amount of sample points the implementing audio
             * device will ever demand the sampler engines to write in one
             * fragment cycle / period. Simple audio device drivers usually
             * have a fixed fragment size, so those devices just would return
             * the fragment size in this method.
             *
             * @returns  max. amount of sample points ever
             */
            virtual uint MaxSamplesPerCycle() = 0;

            /**
             * Playback samplerate the audio device uses. The sampler engines
             * currently assume this to be a constant value for the whole
             * life time of an instance of the implementing audio device.
             *
             * @returns  sample rate in Hz
             */
            virtual uint SampleRate() = 0;

            /**
             * Return the audio output device driver type name.
             */
            virtual String Driver() = 0;

            /////////////////////////////////////////////////////////////////
            // normal methods
            //     (usually not to be overriden by descendant)

            /**
             * Connect given sampler engine to this audio output device. The
             * engine will be added to the Engines container of this audio
             * device and the engine will also automatically be informed
             * about the connection.
             *
             * @param pEngine - sampler engine
             */
            void Connect(Engine* pEngine);

            /**
             * Disconnect given sampler engine from this audio output device.
             * Removes given sampler engine reference from the Engines
             * container of this audio device.
             *
             * @param pEngine - sampler engine
             */
            void Disconnect(Engine* pEngine);

            /**
             * Returns audio channel with index \a ChannelIndex or NULL if
             * index out of bounds.
             */
            AudioChannel* Channel(uint ChannelIndex);

            /**
             * Returns all device parameter settings.
             */
            std::map<String,DeviceCreationParameter*> DeviceParameters();

        protected:
            std::set<Engine*>                         Engines;     ///< All sampler engines that are connected to the audio output device.
            std::vector<AudioChannel*>                Channels;    ///< All audio channels of the audio output device. This is just a container; the descendant has to create channels by himself.
            std::map<String,DeviceCreationParameter*> Parameters;  ///< All device parameters.

            AudioOutputDevice(std::map<String,DeviceCreationParameter*> DriverParameters);

            virtual ~AudioOutputDevice();

            /**
             * This method should be called by the AudioOutputDevice
             * descendant to let all connected engines proceed to render the
             * given amount of sample points. The engines will place their
             * calculated audio data by themselfes into the buffers of the
             * respective AudioChannel objects, so the implementing audio
             * output device just has to copy the AudioChannel buffers to
             * the output buffer(s) of its audio system.
             *
             * @returns  0 on success or the last error return code of one
             *           engine
             */
            int RenderAudio(uint Samples);

            /**
             * This can be called as an alternative to RenderAudio() for
             * just writing silence to the audio output buffers and not
             * calling the connected sampler engines for rendering audio, so
             * to provide a method to stop playback if the used audio output
             * system doesn't provide a better way.
             *
             * @returns  0 on success
             */
            int RenderSilence(uint Samples);

            friend class Sampler; // allow Sampler class to destroy audio devices

    };

    /**
     * Audio output exception that should be thrown by the AudioOutputDevice
     * descendants in case initialization of the audio output system failed
     * (which should be done in the constructor of the AudioOutputDevice
     * descendant).
     */
    class AudioOutputException : public LinuxSamplerException {
        public:
            AudioOutputException(const std::string& msg) : LinuxSamplerException(msg) {}
    };
}

#endif // __LS_AUDIOOUTPUTDEVICE_H__
1	/***************************************************************************
2	* *
3	* LinuxSampler - modular, streaming capable sampler *
4	* *
5	* Copyright (C) 2003, 2004 by Benno Senoner and Christian Schoenebeck *
6	* *
7	* This program is free software; you can redistribute it and/or modify *
8	* it under the terms of the GNU General Public License as published by *
9	* the Free Software Foundation; either version 2 of the License, or *
10	* (at your option) any later version. *
11	* *
12	* This program is distributed in the hope that it will be useful, *
13	* but WITHOUT ANY WARRANTY; without even the implied warranty of *
14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
15	* GNU General Public License for more details. *
16	* *
17	* You should have received a copy of the GNU General Public License *
18	* along with this program; if not, write to the Free Software *
19	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, *
20	* MA 02111-1307 USA *
21	***************************************************************************/
22
23	#ifndef __LS_AUDIOOUTPUTDEVICE_H__
24	#define __LS_AUDIOOUTPUTDEVICE_H__
25
26	#include <set>
27	#include <map>
28	#include <vector>
29	#include <stdexcept>
30
31	#include "../../common/global.h"
32	#include "../../common/LinuxSamplerException.h"
33	#include "../Device.h"
34	#include "../DeviceParameter.h"
35	#include "../../engines/common/Engine.h"
36	#include "AudioChannel.h"
37
38	namespace LinuxSampler {
39
40	// just symbol prototyping
41	class Engine;
42
43	/** Abstract base class for audio output drivers in LinuxSampler
44	*
45	* This class will be derived by specialized classes which implement the
46	* connection to a specific audio output system (e.g. Alsa, Jack,
47	* CoreAudio).
48	*/
49	class AudioOutputDevice : public Device {
50	public:
51
52	/////////////////////////////////////////////////////////////////
53	// Device parameters
54
55	/** Device Parameter 'ACTIVE'
56	*
57	* Used to activate / deactivate the audio output device.
58	*/
59	class ParameterActive : public DeviceCreationParameterBool {
60	public:
61	ParameterActive( void ) : DeviceCreationParameterBool() { InitWithDefault(); }
62	ParameterActive( String s ) : DeviceCreationParameterBool(s) {}
63	virtual String Description() { return "Enable / disable device"; }
64	virtual bool Fix() { return false; }
65	virtual bool Mandatory() { return false; }
66	virtual std::map<String,DeviceCreationParameter> DependsAsParameters() { return std::map<String,DeviceCreationParameter>(); }
67	virtual optional<bool> DefaultAsBool(std::map<String,String> Parameters) { return true; }
68	virtual void OnSetValue(bool b) throw (LinuxSamplerException) { if (b) ((AudioOutputDevice)pDevice)->Play(); else ((AudioOutputDevice)pDevice)->Stop(); }
69	static String Name() { return "ACTIVE"; }
70	};
71
72	/** Device Parameter 'SAMPLERATE'
73	*
74	* Used to set the sample rate of the audio output device.
75	*/
76	class ParameterSampleRate : public DeviceCreationParameterInt {
77	public:
78	ParameterSampleRate() : DeviceCreationParameterInt() { InitWithDefault(); }
79	ParameterSampleRate( String s ) : DeviceCreationParameterInt(s) {}
80	virtual String Description() { return "Output sample rate"; }
81	virtual bool Fix() { return true; }
82	virtual bool Mandatory() { return false; }
83	virtual std::map<String,DeviceCreationParameter> DependsAsParameters() { return std::map<String,DeviceCreationParameter>(); }
84	virtual optional<int> DefaultAsInt(std::map<String,String> Parameters) { return 44100; }
85	virtual optional<int> RangeMinAsInt(std::map<String,String> Parameters) { return optional<int>::nothing; }
86	virtual optional<int> RangeMaxAsInt(std::map<String,String> Parameters) { return optional<int>::nothing; }
87	virtual std::vector<int> PossibilitiesAsInt(std::map<String,String> Parameters) { return std::vector<int>(); }
88	virtual void OnSetValue(int i) throw (LinuxSamplerException) { /* cannot happen, as parameter is fix */ }
89	static String Name() { return "SAMPLERATE"; }
90	};
91
92	/** Device Parameters 'CHANNELS'
93	*
94	* Used to increase / decrease the number of audio channels of
95	* audio output device.
96	*/
97	class ParameterChannels : public DeviceCreationParameterInt {
98	public:
99	ParameterChannels() : DeviceCreationParameterInt() { InitWithDefault(); }
100	ParameterChannels( String s ) : DeviceCreationParameterInt(s) {}
101	virtual String Description() { return "Number of output channels"; }
102	virtual bool Fix() { return false; }
103	virtual bool Mandatory() { return false; }
104	virtual std::map<String,DeviceCreationParameter> DependsAsParameters() { return std::map<String,DeviceCreationParameter>(); }
105	virtual optional<int> DefaultAsInt(std::map<String,String> Parameters) { return 2; }
106	virtual optional<int> RangeMinAsInt(std::map<String,String> Parameters) { return optional<int>::nothing; }
107	virtual optional<int> RangeMaxAsInt(std::map<String,String> Parameters) { return optional<int>::nothing; }
108	virtual std::vector<int> PossibilitiesAsInt(std::map<String,String> Parameters) { return std::vector<int>(); }
109	virtual void OnSetValue(int i) throw (LinuxSamplerException) { ((AudioOutputDevice*)pDevice)->AcquireChannels(i); }
110	static String Name() { return "CHANNELS"; }
111	};
112
113
114
115	/////////////////////////////////////////////////////////////////
116	// abstract methods
117	// (these have to be implemented by the descendant)
118
119	/**
120	* Start playback of audio signal on the audio device. It's the
121	* responsibility of the implementing audio device to call the
122	* RenderAudio(uint Samples) method of all connected engines.
123	* This will cause the engines to continue to render 'Samples'
124	* number of audio sample points and the engines will
125	* automatically add their audio signals to the audio buffers of
126	* the audio channels of this audio device. So the implementing
127	* audio device just has to access the buffers of it's audio
128	* channels.
129	*
130	* @throws AudioOutputException if playback can not be started
131	* @see AudioChannel
132	*/
133	virtual void Play() = 0;
134
135	/**
136	* Returns true if the audio device is currently playing back.
137	*/
138	virtual bool IsPlaying() = 0;
139
140	/**
141	* Stop playback of audio signal on the audio device. The
142	* implementing audio device will stop calling the RenderAudio()
143	* method of all connected engines and close it's connection to
144	* audio output system.
145	*/
146	virtual void Stop() = 0;
147
148	/**
149	* This method will usually be called by the sampler engines that
150	* are connected to this audio device to inform the audio device
151	* how much audio channels the engine(s) need. It's the
152	* responsibility of the audio device to offer that amount of
153	* audio channels - again: this is not an option this is a must!
154	* The engines will assume to be able to access those audio
155	* channels right after. If the audio driver is not able to offer
156	* that much channels, it can simply create mix channels which
157	* are then just mixed to the 'real' audio channels. See
158	* AudioChannel.h for details about channels and mix channels.
159	*
160	* @param Channels - amount of output channels required by
161	* a sampler engine
162	* @throws AudioOutputException if desired amount of channels
163	* cannot be offered
164	* @see AudioChannel
165	*/
166	virtual void AcquireChannels(uint Channels) = 0;
167
168	/**
169	* Maximum amount of sample points the implementing audio
170	* device will ever demand the sampler engines to write in one
171	* fragment cycle / period. Simple audio device drivers usually
172	* have a fixed fragment size, so those devices just would return
173	* the fragment size in this method.
174	*
175	* @returns max. amount of sample points ever
176	*/
177	virtual uint MaxSamplesPerCycle() = 0;
178
179	/**
180	* Playback samplerate the audio device uses. The sampler engines
181	* currently assume this to be a constant value for the whole
182	* life time of an instance of the implementing audio device.
183	*
184	* @returns sample rate in Hz
185	*/
186	virtual uint SampleRate() = 0;
187
188	/**
189	* Return the audio output device driver type name.
190	*/
191	virtual String Driver() = 0;
192
193	/////////////////////////////////////////////////////////////////
194	// normal methods
195	// (usually not to be overriden by descendant)
196
197	/**
198	* Connect given sampler engine to this audio output device. The
199	* engine will be added to the Engines container of this audio
200	* device and the engine will also automatically be informed
201	* about the connection.
202	*
203	* @param pEngine - sampler engine
204	*/
205	void Connect(Engine* pEngine);
206
207	/**
208	* Disconnect given sampler engine from this audio output device.
209	* Removes given sampler engine reference from the Engines
210	* container of this audio device.
211	*
212	* @param pEngine - sampler engine
213	*/
214	void Disconnect(Engine* pEngine);
215
216	/**
217	* Returns audio channel with index \a ChannelIndex or NULL if
218	* index out of bounds.
219	*/
220	AudioChannel* Channel(uint ChannelIndex);
221
222	/**
223	* Returns all device parameter settings.
224	*/
225	std::map<String,DeviceCreationParameter*> DeviceParameters();
226
227	protected:
228	std::set<Engine*> Engines; ///< All sampler engines that are connected to the audio output device.
229	std::vector<AudioChannel*> Channels; ///< All audio channels of the audio output device. This is just a container; the descendant has to create channels by himself.
230	std::map<String,DeviceCreationParameter*> Parameters; ///< All device parameters.
231
232	AudioOutputDevice(std::map<String,DeviceCreationParameter*> DriverParameters);
233
234	virtual ~AudioOutputDevice();
235
236	/**
237	* This method should be called by the AudioOutputDevice
238	* descendant to let all connected engines proceed to render the
239	* given amount of sample points. The engines will place their
240	* calculated audio data by themselfes into the buffers of the
241	* respective AudioChannel objects, so the implementing audio
242	* output device just has to copy the AudioChannel buffers to
243	* the output buffer(s) of its audio system.
244	*
245	* @returns 0 on success or the last error return code of one
246	* engine
247	*/
248	int RenderAudio(uint Samples);
249
250	/**
251	* This can be called as an alternative to RenderAudio() for
252	* just writing silence to the audio output buffers and not
253	* calling the connected sampler engines for rendering audio, so
254	* to provide a method to stop playback if the used audio output
255	* system doesn't provide a better way.
256	*
257	* @returns 0 on success
258	*/
259	int RenderSilence(uint Samples);
260
261	friend class Sampler; // allow Sampler class to destroy audio devices
262
263	};
264
265	/**
266	* Audio output exception that should be thrown by the AudioOutputDevice
267	* descendants in case initialization of the audio output system failed
268	* (which should be done in the constructor of the AudioOutputDevice
269	* descendant).
270	*/
271	class AudioOutputException : public LinuxSamplerException {
272	public:
273	AudioOutputException(const std::string& msg) : LinuxSamplerException(msg) {}
274	};
275	}
276
277	#endif // __LS_AUDIOOUTPUTDEVICE_H__