src/audiodriver/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 "../drivers/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:


            /////////////////////////////////////////////////////////////////
            // type definitions

            class ParameterActive : public DeviceCreationParameterBool {
                public:
                    ParameterActive(AudioOutputDevice* pDevice)                              { this->pDevice = pDevice;                            }
                    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 optional<bool>::nothing;                     }
                    virtual void OnSetValue(bool b) throw (LinuxSamplerException)            { if (b) pDevice->Play(); else pDevice->Stop();       }
                protected:
                    AudioOutputDevice* pDevice;
            };

            class ParameterSampleRate : public DeviceCreationParameterInt {
                public:
                    ParameterSampleRate(AudioOutputDevice* pDevice)                                 { this->pDevice = pDevice;                            }
                    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 optional<int>::nothing;                      }
                    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 */            }
                protected:
                    AudioOutputDevice* pDevice;
            };

            class ParameterChannels : public DeviceCreationParameterInt {
                public:
                    ParameterChannels(AudioOutputDevice* pDevice)                                   { this->pDevice = pDevice;                            }
                    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 optional<int>::nothing;                      }
                    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)        { pDevice->AcquireChannels(i);                        }
                protected:
                    AudioOutputDevice* pDevice;
            };


            /////////////////////////////////////////////////////////////////
            // 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;

            static std::map<String,DeviceCreationParameter*> AvailableParameters();


            /////////////////////////////////////////////////////////////////
            // 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);

            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

        private:
             static std::map<String,DeviceCreationParameter*> CreateAvailableParameters();
    };

    /**
     * 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 "../drivers/DeviceParameter.h"
34	#include "../engines/common/Engine.h"
35	#include "AudioChannel.h"
36
37	namespace LinuxSampler {
38
39	// just symbol prototyping
40	class Engine;
41
42	/** Abstract base class for audio output drivers in LinuxSampler
43	*
44	* This class will be derived by specialized classes which implement the
45	* connection to a specific audio output system (e.g. Alsa, Jack,
46	* CoreAudio).
47	*/
48	class AudioOutputDevice {
49	public:
50
51
52	/////////////////////////////////////////////////////////////////
53	// type definitions
54
55	class ParameterActive : public DeviceCreationParameterBool {
56	public:
57	ParameterActive(AudioOutputDevice* pDevice) { this->pDevice = pDevice; }
58	virtual String Description() { return "Enable / disable device"; }
59	virtual bool Fix() { return false; }
60	virtual bool Mandatory() { return false; }
61	virtual std::map<String,DeviceCreationParameter> DependsAsParameters() { return std::map<String,DeviceCreationParameter>(); }
62	virtual optional<bool> DefaultAsBool(std::map<String,String> Parameters) { return optional<bool>::nothing; }
63	virtual void OnSetValue(bool b) throw (LinuxSamplerException) { if (b) pDevice->Play(); else pDevice->Stop(); }
64	protected:
65	AudioOutputDevice* pDevice;
66	};
67
68	class ParameterSampleRate : public DeviceCreationParameterInt {
69	public:
70	ParameterSampleRate(AudioOutputDevice* pDevice) { this->pDevice = pDevice; }
71	virtual String Description() { return "Output sample rate"; }
72	virtual bool Fix() { return true; }
73	virtual bool Mandatory() { return false; }
74	virtual std::map<String,DeviceCreationParameter> DependsAsParameters() { return std::map<String,DeviceCreationParameter>(); }
75	virtual optional<int> DefaultAsInt(std::map<String,String> Parameters) { return optional<int>::nothing; }
76	virtual optional<int> RangeMinAsInt(std::map<String,String> Parameters) { return optional<int>::nothing; }
77	virtual optional<int> RangeMaxAsInt(std::map<String,String> Parameters) { return optional<int>::nothing; }
78	virtual std::vector<int> PossibilitiesAsInt(std::map<String,String> Parameters) { return std::vector<int>(); }
79	virtual void OnSetValue(int i) throw (LinuxSamplerException) { /* cannot happen, as parameter is fix */ }
80	protected:
81	AudioOutputDevice* pDevice;
82	};
83
84	class ParameterChannels : public DeviceCreationParameterInt {
85	public:
86	ParameterChannels(AudioOutputDevice* pDevice) { this->pDevice = pDevice; }
87	virtual String Description() { return "Number of output channels"; }
88	virtual bool Fix() { return false; }
89	virtual bool Mandatory() { return false; }
90	virtual std::map<String,DeviceCreationParameter> DependsAsParameters() { return std::map<String,DeviceCreationParameter>(); }
91	virtual optional<int> DefaultAsInt(std::map<String,String> Parameters) { return optional<int>::nothing; }
92	virtual optional<int> RangeMinAsInt(std::map<String,String> Parameters) { return optional<int>::nothing; }
93	virtual optional<int> RangeMaxAsInt(std::map<String,String> Parameters) { return optional<int>::nothing; }
94	virtual std::vector<int> PossibilitiesAsInt(std::map<String,String> Parameters) { return std::vector<int>(); }
95	virtual void OnSetValue(int i) throw (LinuxSamplerException) { pDevice->AcquireChannels(i); }
96	protected:
97	AudioOutputDevice* pDevice;
98	};
99
100
101
102	/////////////////////////////////////////////////////////////////
103	// abstract methods
104	// (these have to be implemented by the descendant)
105
106	/**
107	* Start playback of audio signal on the audio device. It's the
108	* responsibility of the implementing audio device to call the
109	* RenderAudio(uint Samples) method of all connected engines.
110	* This will cause the engines to continue to render 'Samples'
111	* number of audio sample points and the engines will
112	* automatically add their audio signals to the audio buffers of
113	* the audio channels of this audio device. So the implementing
114	* audio device just has to access the buffers of it's audio
115	* channels.
116	*
117	* @throws AudioOutputException if playback can not be started
118	* @see AudioChannel
119	*/
120	virtual void Play() = 0;
121
122	/**
123	* Returns true if the audio device is currently playing back.
124	*/
125	virtual bool IsPlaying() = 0;
126
127	/**
128	* Stop playback of audio signal on the audio device. The
129	* implementing audio device will stop calling the RenderAudio()
130	* method of all connected engines and close it's connection to
131	* audio output system.
132	*/
133	virtual void Stop() = 0;
134
135	/**
136	* This method will usually be called by the sampler engines that
137	* are connected to this audio device to inform the audio device
138	* how much audio channels the engine(s) need. It's the
139	* responsibility of the audio device to offer that amount of
140	* audio channels - again: this is not an option this is a must!
141	* The engines will assume to be able to access those audio
142	* channels right after. If the audio driver is not able to offer
143	* that much channels, it can simply create mix channels which
144	* are then just mixed to the 'real' audio channels. See
145	* AudioChannel.h for details about channels and mix channels.
146	*
147	* @param Channels - amount of output channels required by
148	* a sampler engine
149	* @throws AudioOutputException if desired amount of channels
150	* cannot be offered
151	* @see AudioChannel
152	*/
153	virtual void AcquireChannels(uint Channels) = 0;
154
155	/**
156	* Maximum amount of sample points the implementing audio
157	* device will ever demand the sampler engines to write in one
158	* fragment cycle / period. Simple audio device drivers usually
159	* have a fixed fragment size, so those devices just would return
160	* the fragment size in this method.
161	*
162	* @returns max. amount of sample points ever
163	*/
164	virtual uint MaxSamplesPerCycle() = 0;
165
166	/**
167	* Playback samplerate the audio device uses. The sampler engines
168	* currently assume this to be a constant value for the whole
169	* life time of an instance of the implementing audio device.
170	*
171	* @returns sample rate in Hz
172	*/
173	virtual uint SampleRate() = 0;
174
175	static std::map<String,DeviceCreationParameter*> AvailableParameters();
176
177
178
179	/////////////////////////////////////////////////////////////////
180	// normal methods
181	// (usually not to be overriden by descendant)
182
183	/**
184	* Connect given sampler engine to this audio output device. The
185	* engine will be added to the Engines container of this audio
186	* device and the engine will also automatically be informed
187	* about the connection.
188	*
189	* @param pEngine - sampler engine
190	*/
191	void Connect(Engine* pEngine);
192
193	/**
194	* Disconnect given sampler engine from this audio output device.
195	* Removes given sampler engine reference from the Engines
196	* container of this audio device.
197	*
198	* @param pEngine - sampler engine
199	*/
200	void Disconnect(Engine* pEngine);
201
202	/**
203	* Returns audio channel with index \a ChannelIndex or NULL if
204	* index out of bounds.
205	*/
206	AudioChannel* Channel(uint ChannelIndex);
207
208	std::map<String,DeviceCreationParameter*> DeviceParameters();
209
210
211	protected:
212	std::set<Engine*> Engines; ///< All sampler engines that are connected to the audio output device.
213	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.
214	std::map<String,DeviceCreationParameter*> Parameters; ///< All device parameters.
215
216	AudioOutputDevice(std::map<String,DeviceCreationParameter*> DriverParameters);
217
218	virtual ~AudioOutputDevice();
219
220	/**
221	* This method should be called by the AudioOutputDevice
222	* descendant to let all connected engines proceed to render the
223	* given amount of sample points. The engines will place their
224	* calculated audio data by themselfes into the buffers of the
225	* respective AudioChannel objects, so the implementing audio
226	* output device just has to copy the AudioChannel buffers to
227	* the output buffer(s) of its audio system.
228	*
229	* @returns 0 on success or the last error return code of one
230	* engine
231	*/
232	int RenderAudio(uint Samples);
233
234	/**
235	* This can be called as an alternative to RenderAudio() for
236	* just writing silence to the audio output buffers and not
237	* calling the connected sampler engines for rendering audio, so
238	* to provide a method to stop playback if the used audio output
239	* system doesn't provide a better way.
240	*
241	* @returns 0 on success
242	*/
243	int RenderSilence(uint Samples);
244
245	friend class Sampler; // allow Sampler class to destroy audio devices
246
247	private:
248	static std::map<String,DeviceCreationParameter*> CreateAvailableParameters();
249	};
250
251	/**
252	* Audio output exception that should be thrown by the AudioOutputDevice
253	* descendants in case initialization of the audio output system failed
254	* (which should be done in the constructor of the AudioOutputDevice
255	* descendant).
256	*/
257	class AudioOutputException : public LinuxSamplerException {
258	public:
259	AudioOutputException(const std::string& msg) : LinuxSamplerException(msg) {}
260	};
261	}
262
263	#endif // __LS_AUDIOOUTPUTDEVICE_H__