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();
                    ParameterActive(String s);
                    virtual String Description();
                    virtual bool   Fix();
                    virtual bool   Mandatory();
                    virtual std::map<String,DeviceCreationParameter*> DependsAsParameters();
                    virtual optional<bool> DefaultAsBool(std::map<String,String> Parameters);
                    virtual void OnSetValue(bool b) throw (LinuxSamplerException);
                    static String Name();
            };

            /** Device Parameter 'SAMPLERATE'
             *
             * Used to set the sample rate of the audio output device.
             */
            class ParameterSampleRate : public DeviceCreationParameterInt {
                public:
                    ParameterSampleRate();
                    ParameterSampleRate(String s);
                    virtual String Description();
                    virtual bool   Fix();
                    virtual bool   Mandatory();
                    virtual std::map<String,DeviceCreationParameter*> DependsAsParameters();
                    virtual optional<int>    DefaultAsInt(std::map<String,String> Parameters);
                    virtual optional<int>    RangeMinAsInt(std::map<String,String> Parameters);
                    virtual optional<int>    RangeMaxAsInt(std::map<String,String> Parameters);
                    virtual std::vector<int> PossibilitiesAsInt(std::map<String,String> Parameters);
                    virtual void             OnSetValue(int i) throw (LinuxSamplerException);
                    static String Name();
            };

            /** Device Parameters 'CHANNELS'
             *
             * Used to increase / decrease the number of audio channels of
             * audio output device.
             */
            class ParameterChannels : public DeviceCreationParameterInt {
                public:
                    ParameterChannels();
                    ParameterChannels(String s);
                    virtual String Description();
                    virtual bool   Fix();
                    virtual bool   Mandatory();
                    virtual std::map<String,DeviceCreationParameter*> DependsAsParameters();
                    virtual optional<int>    DefaultAsInt(std::map<String,String> Parameters);
                    virtual optional<int>    RangeMinAsInt(std::map<String,String> Parameters);
                    virtual optional<int>    RangeMaxAsInt(std::map<String,String> Parameters);
                    virtual std::vector<int> PossibilitiesAsInt(std::map<String,String> Parameters);
                    virtual void             OnSetValue(int i) throw (LinuxSamplerException);
                    static String Name();
            };


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

            /**
             * 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 name.
             */
            virtual String Driver() = 0;

            /**
             * Create new audio channel. This will be called by
             * AcquireChannels(). Each driver must implement it.
             */
            virtual AudioChannel* CreateChannel(uint ChannelNr) = 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);

            /**
             * 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
             */
            void AcquireChannels(uint Channels);

            /**
             * 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	schoenebeck	200	/***************************************************************************
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	schoenebeck	207	#include "../Device.h"
34	schoenebeck	200	#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	schoenebeck	207	class AudioOutputDevice : public Device {
50	schoenebeck	200	public:
51
52			/////////////////////////////////////////////////////////////////
53			// Device parameters
54
55	schoenebeck	221	/** Device Parameter 'ACTIVE'
56			*
57			* Used to activate / deactivate the audio output device.
58			*/
59	schoenebeck	200	class ParameterActive : public DeviceCreationParameterBool {
60			public:
61	schoenebeck	226	ParameterActive();
62			ParameterActive(String s);
63			virtual String Description();
64			virtual bool Fix();
65			virtual bool Mandatory();
66			virtual std::map<String,DeviceCreationParameter*> DependsAsParameters();
67			virtual optional<bool> DefaultAsBool(std::map<String,String> Parameters);
68			virtual void OnSetValue(bool b) throw (LinuxSamplerException);
69			static String Name();
70	schoenebeck	200	};
71
72	schoenebeck	221	/** Device Parameter 'SAMPLERATE'
73			*
74			* Used to set the sample rate of the audio output device.
75			*/
76	schoenebeck	200	class ParameterSampleRate : public DeviceCreationParameterInt {
77			public:
78	schoenebeck	226	ParameterSampleRate();
79			ParameterSampleRate(String s);
80			virtual String Description();
81			virtual bool Fix();
82			virtual bool Mandatory();
83			virtual std::map<String,DeviceCreationParameter*> DependsAsParameters();
84			virtual optional<int> DefaultAsInt(std::map<String,String> Parameters);
85			virtual optional<int> RangeMinAsInt(std::map<String,String> Parameters);
86			virtual optional<int> RangeMaxAsInt(std::map<String,String> Parameters);
87			virtual std::vector<int> PossibilitiesAsInt(std::map<String,String> Parameters);
88			virtual void OnSetValue(int i) throw (LinuxSamplerException);
89			static String Name();
90	schoenebeck	200	};
91
92	schoenebeck	221	/** Device Parameters 'CHANNELS'
93			*
94			* Used to increase / decrease the number of audio channels of
95			* audio output device.
96			*/
97	schoenebeck	200	class ParameterChannels : public DeviceCreationParameterInt {
98			public:
99	schoenebeck	226	ParameterChannels();
100			ParameterChannels(String s);
101			virtual String Description();
102			virtual bool Fix();
103			virtual bool Mandatory();
104			virtual std::map<String,DeviceCreationParameter*> DependsAsParameters();
105			virtual optional<int> DefaultAsInt(std::map<String,String> Parameters);
106			virtual optional<int> RangeMinAsInt(std::map<String,String> Parameters);
107			virtual optional<int> RangeMaxAsInt(std::map<String,String> Parameters);
108			virtual std::vector<int> PossibilitiesAsInt(std::map<String,String> Parameters);
109			virtual void OnSetValue(int i) throw (LinuxSamplerException);
110			static String Name();
111	schoenebeck	200	};
112
113
114	schoenebeck	221
115	schoenebeck	200	/////////////////////////////////////////////////////////////////
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			* Maximum amount of sample points the implementing audio
150			* device will ever demand the sampler engines to write in one
151			* fragment cycle / period. Simple audio device drivers usually
152			* have a fixed fragment size, so those devices just would return
153			* the fragment size in this method.
154			*
155			* @returns max. amount of sample points ever
156			*/
157			virtual uint MaxSamplesPerCycle() = 0;
158
159			/**
160			* Playback samplerate the audio device uses. The sampler engines
161			* currently assume this to be a constant value for the whole
162			* life time of an instance of the implementing audio device.
163			*
164			* @returns sample rate in Hz
165			*/
166			virtual uint SampleRate() = 0;
167
168			/**
169	schoenebeck	226	* Return the audio output device driver name.
170	schoenebeck	200	*/
171			virtual String Driver() = 0;
172
173	schoenebeck	226	/**
174			* Create new audio channel. This will be called by
175			* AcquireChannels(). Each driver must implement it.
176			*/
177			virtual AudioChannel* CreateChannel(uint ChannelNr) = 0;
178
179
180
181	schoenebeck	200	/////////////////////////////////////////////////////////////////
182			// normal methods
183			// (usually not to be overriden by descendant)
184
185			/**
186			* Connect given sampler engine to this audio output device. The
187			* engine will be added to the Engines container of this audio
188			* device and the engine will also automatically be informed
189			* about the connection.
190			*
191			* @param pEngine - sampler engine
192			*/
193			void Connect(Engine* pEngine);
194
195			/**
196			* Disconnect given sampler engine from this audio output device.
197			* Removes given sampler engine reference from the Engines
198			* container of this audio device.
199			*
200			* @param pEngine - sampler engine
201			*/
202			void Disconnect(Engine* pEngine);
203
204			/**
205			* Returns audio channel with index \a ChannelIndex or NULL if
206			* index out of bounds.
207			*/
208			AudioChannel* Channel(uint ChannelIndex);
209
210	schoenebeck	221	/**
211	schoenebeck	226	* This method will usually be called by the sampler engines that
212			* are connected to this audio device to inform the audio device
213			* how much audio channels the engine(s) need. It's the
214			* responsibility of the audio device to offer that amount of
215			* audio channels - again: this is not an option this is a must!
216			* The engines will assume to be able to access those audio
217			* channels right after. If the audio driver is not able to offer
218			* that much channels, it can simply create mix channels which
219			* are then just mixed to the 'real' audio channels. See
220			* AudioChannel.h for details about channels and mix channels.
221			*
222			* @param Channels - amount of output channels required by
223			* a sampler engine
224			* @throws AudioOutputException if desired amount of channels
225			* cannot be offered
226			* @see AudioChannel
227			*/
228			void AcquireChannels(uint Channels);
229
230			/**
231	schoenebeck	221	* Returns all device parameter settings.
232			*/
233	schoenebeck	200	std::map<String,DeviceCreationParameter*> DeviceParameters();
234
235			protected:
236			std::set<Engine*> Engines; ///< All sampler engines that are connected to the audio output device.
237			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.
238			std::map<String,DeviceCreationParameter*> Parameters; ///< All device parameters.
239
240			AudioOutputDevice(std::map<String,DeviceCreationParameter*> DriverParameters);
241
242			virtual ~AudioOutputDevice();
243
244			/**
245			* This method should be called by the AudioOutputDevice
246			* descendant to let all connected engines proceed to render the
247			* given amount of sample points. The engines will place their
248			* calculated audio data by themselfes into the buffers of the
249			* respective AudioChannel objects, so the implementing audio
250			* output device just has to copy the AudioChannel buffers to
251			* the output buffer(s) of its audio system.
252			*
253			* @returns 0 on success or the last error return code of one
254			* engine
255			*/
256			int RenderAudio(uint Samples);
257
258			/**
259			* This can be called as an alternative to RenderAudio() for
260			* just writing silence to the audio output buffers and not
261			* calling the connected sampler engines for rendering audio, so
262			* to provide a method to stop playback if the used audio output
263			* system doesn't provide a better way.
264			*
265			* @returns 0 on success
266			*/
267			int RenderSilence(uint Samples);
268
269			friend class Sampler; // allow Sampler class to destroy audio devices
270
271			};
272
273			/**
274			* Audio output exception that should be thrown by the AudioOutputDevice
275			* descendants in case initialization of the audio output system failed
276			* (which should be done in the constructor of the AudioOutputDevice
277			* descendant).
278			*/
279			class AudioOutputException : public LinuxSamplerException {
280			public:
281			AudioOutputException(const std::string& msg) : LinuxSamplerException(msg) {}
282			};
283			}
284
285			#endif // __LS_AUDIOOUTPUTDEVICE_H__