drivers/audio/AudioOutputDevice.h

/***************************************************************************
 *                                                                         *
 *   LinuxSampler - modular, streaming capable sampler                     *
 *                                                                         *
 *   Copyright (C) 2003, 2004 by Benno Senoner and Christian Schoenebeck   *
 *   Copyright (C) 2005 - 2007 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/Exception.h"
#include "../Device.h"
#include "../DeviceParameter.h"
#include "../../engines/Engine.h"
#include "AudioChannel.h"
#include "../../common/SynchronizedConfig.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 (Exception);
                    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 int              ValueAsInt();
                    virtual void             OnSetValue(int i) throw (Exception);
                    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 (Exception);
                    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 the amount of audio channels (including the so called
             * "mix channels") the device is currently providing.
             */
            uint ChannelCount();

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

        protected:
            SynchronizedConfig<std::set<Engine*> >    Engines;     ///< All sampler engines that are connected to the audio output device.
            SynchronizedConfig<std::set<Engine*> >::Reader EnginesReader; ///< Audio thread access to Engines.
            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 Exception {
        public:
            AudioOutputException(const std::string& msg) : Exception(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	* Copyright (C) 2005 - 2007 Christian Schoenebeck *
7	* *
8	* This program is free software; you can redistribute it and/or modify *
9	* it under the terms of the GNU General Public License as published by *
10	* the Free Software Foundation; either version 2 of the License, or *
11	* (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 *
16	* GNU General Public License for more details. *
17	* *
18	* You should have received a copy of the GNU General Public License *
19	* along with this program; if not, write to the Free Software *
20	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, *
21	* MA 02111-1307 USA *
22	***************************************************************************/
23
24	#ifndef __LS_AUDIOOUTPUTDEVICE_H__
25	#define __LS_AUDIOOUTPUTDEVICE_H__
26
27	#include <set>
28	#include <map>
29	#include <vector>
30	#include <stdexcept>
31
32	#include "../../common/global.h"
33	#include "../../common/Exception.h"
34	#include "../Device.h"
35	#include "../DeviceParameter.h"
36	#include "../../engines/Engine.h"
37	#include "AudioChannel.h"
38	#include "../../common/SynchronizedConfig.h"
39
40	namespace LinuxSampler {
41
42	// just symbol prototyping
43	class Engine;
44
45	/** Abstract base class for audio output drivers in LinuxSampler
46	*
47	* This class will be derived by specialized classes which implement the
48	* connection to a specific audio output system (e.g. Alsa, Jack,
49	* CoreAudio).
50	*/
51	class AudioOutputDevice : public Device {
52	public:
53
54	/////////////////////////////////////////////////////////////////
55	// Device parameters
56
57	/** Device Parameter 'ACTIVE'
58	*
59	* Used to activate / deactivate the audio output device.
60	*/
61	class ParameterActive : public DeviceCreationParameterBool {
62	public:
63	ParameterActive();
64	ParameterActive(String s);
65	virtual String Description();
66	virtual bool Fix();
67	virtual bool Mandatory();
68	virtual std::map<String,DeviceCreationParameter*> DependsAsParameters();
69	virtual optional<bool> DefaultAsBool(std::map<String,String> Parameters);
70	virtual void OnSetValue(bool b) throw (Exception);
71	static String Name();
72	};
73
74	/** Device Parameter 'SAMPLERATE'
75	*
76	* Used to set the sample rate of the audio output device.
77	*/
78	class ParameterSampleRate : public DeviceCreationParameterInt {
79	public:
80	ParameterSampleRate();
81	ParameterSampleRate(String s);
82	virtual String Description();
83	virtual bool Fix();
84	virtual bool Mandatory();
85	virtual std::map<String,DeviceCreationParameter*> DependsAsParameters();
86	virtual optional<int> DefaultAsInt(std::map<String,String> Parameters);
87	virtual optional<int> RangeMinAsInt(std::map<String,String> Parameters);
88	virtual optional<int> RangeMaxAsInt(std::map<String,String> Parameters);
89	virtual std::vector<int> PossibilitiesAsInt(std::map<String,String> Parameters);
90	virtual int ValueAsInt();
91	virtual void OnSetValue(int i) throw (Exception);
92	static String Name();
93	};
94
95	/** Device Parameters 'CHANNELS'
96	*
97	* Used to increase / decrease the number of audio channels of
98	* audio output device.
99	*/
100	class ParameterChannels : public DeviceCreationParameterInt {
101	public:
102	ParameterChannels();
103	ParameterChannels(String s);
104	virtual String Description();
105	virtual bool Fix();
106	virtual bool Mandatory();
107	virtual std::map<String,DeviceCreationParameter*> DependsAsParameters();
108	virtual optional<int> DefaultAsInt(std::map<String,String> Parameters);
109	virtual optional<int> RangeMinAsInt(std::map<String,String> Parameters);
110	virtual optional<int> RangeMaxAsInt(std::map<String,String> Parameters);
111	virtual std::vector<int> PossibilitiesAsInt(std::map<String,String> Parameters);
112	virtual void OnSetValue(int i) throw (Exception);
113	static String Name();
114	};
115
116
117
118	/////////////////////////////////////////////////////////////////
119	// abstract methods
120	// (these have to be implemented by the descendant)
121
122	/**
123	* Start playback of audio signal on the audio device. It's the
124	* responsibility of the implementing audio device to call the
125	* RenderAudio(uint Samples) method of all connected engines.
126	* This will cause the engines to continue to render 'Samples'
127	* number of audio sample points and the engines will
128	* automatically add their audio signals to the audio buffers of
129	* the audio channels of this audio device. So the implementing
130	* audio device just has to access the buffers of it's audio
131	* channels.
132	*
133	* @throws AudioOutputException if playback can not be started
134	* @see AudioChannel
135	*/
136	virtual void Play() = 0;
137
138	/**
139	* Returns true if the audio device is currently playing back.
140	*/
141	virtual bool IsPlaying() = 0;
142
143	/**
144	* Stop playback of audio signal on the audio device. The
145	* implementing audio device will stop calling the RenderAudio()
146	* method of all connected engines and close it's connection to
147	* audio output system.
148	*/
149	virtual void Stop() = 0;
150
151	/**
152	* Maximum amount of sample points the implementing audio
153	* device will ever demand the sampler engines to write in one
154	* fragment cycle / period. Simple audio device drivers usually
155	* have a fixed fragment size, so those devices just would return
156	* the fragment size in this method.
157	*
158	* @returns max. amount of sample points ever
159	*/
160	virtual uint MaxSamplesPerCycle() = 0;
161
162	/**
163	* Playback samplerate the audio device uses. The sampler engines
164	* currently assume this to be a constant value for the whole
165	* life time of an instance of the implementing audio device.
166	*
167	* @returns sample rate in Hz
168	*/
169	virtual uint SampleRate() = 0;
170
171	/**
172	* Return the audio output device driver name.
173	*/
174	virtual String Driver() = 0;
175
176	/**
177	* Create new audio channel. This will be called by
178	* AcquireChannels(). Each driver must implement it.
179	*/
180	virtual AudioChannel* CreateChannel(uint ChannelNr) = 0;
181
182
183
184	/////////////////////////////////////////////////////////////////
185	// normal methods
186	// (usually not to be overriden by descendant)
187
188	/**
189	* Connect given sampler engine to this audio output device. The
190	* engine will be added to the Engines container of this audio
191	* device and the engine will also automatically be informed
192	* about the connection.
193	*
194	* @param pEngine - sampler engine
195	*/
196	void Connect(Engine* pEngine);
197
198	/**
199	* Disconnect given sampler engine from this audio output device.
200	* Removes given sampler engine reference from the Engines
201	* container of this audio device.
202	*
203	* @param pEngine - sampler engine
204	*/
205	void Disconnect(Engine* pEngine);
206
207	/**
208	* Returns audio channel with index \a ChannelIndex or NULL if
209	* index out of bounds.
210	*/
211	AudioChannel* Channel(uint ChannelIndex);
212
213	/**
214	* This method will usually be called by the sampler engines that
215	* are connected to this audio device to inform the audio device
216	* how much audio channels the engine(s) need. It's the
217	* responsibility of the audio device to offer that amount of
218	* audio channels - again: this is not an option this is a must!
219	* The engines will assume to be able to access those audio
220	* channels right after. If the audio driver is not able to offer
221	* that much channels, it can simply create mix channels which
222	* are then just mixed to the 'real' audio channels. See
223	* AudioChannel.h for details about channels and mix channels.
224	*
225	* @param Channels - amount of output channels required by
226	* a sampler engine
227	* @throws AudioOutputException if desired amount of channels
228	* cannot be offered
229	* @see AudioChannel
230	*/
231	void AcquireChannels(uint Channels);
232
233	/**
234	* Returns the amount of audio channels (including the so called
235	* "mix channels") the device is currently providing.
236	*/
237	uint ChannelCount();
238
239	/**
240	* Returns all device parameter settings.
241	*/
242	std::map<String,DeviceCreationParameter*> DeviceParameters();
243
244	protected:
245	SynchronizedConfig<std::set<Engine*> > Engines; ///< All sampler engines that are connected to the audio output device.
246	SynchronizedConfig<std::set<Engine*> >::Reader EnginesReader; ///< Audio thread access to Engines.
247	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.
248	std::map<String,DeviceCreationParameter*> Parameters; ///< All device parameters.
249
250	AudioOutputDevice(std::map<String,DeviceCreationParameter*> DriverParameters);
251
252	virtual ~AudioOutputDevice();
253
254	/**
255	* This method should be called by the AudioOutputDevice
256	* descendant to let all connected engines proceed to render the
257	* given amount of sample points. The engines will place their
258	* calculated audio data by themselfes into the buffers of the
259	* respective AudioChannel objects, so the implementing audio
260	* output device just has to copy the AudioChannel buffers to
261	* the output buffer(s) of its audio system.
262	*
263	* @returns 0 on success or the last error return code of one
264	* engine
265	*/
266	int RenderAudio(uint Samples);
267
268	/**
269	* This can be called as an alternative to RenderAudio() for
270	* just writing silence to the audio output buffers and not
271	* calling the connected sampler engines for rendering audio, so
272	* to provide a method to stop playback if the used audio output
273	* system doesn't provide a better way.
274	*
275	* @returns 0 on success
276	*/
277	int RenderSilence(uint Samples);
278
279	friend class Sampler; // allow Sampler class to destroy audio devices
280
281	};
282
283	/**
284	* Audio output exception that should be thrown by the AudioOutputDevice
285	* descendants in case initialization of the audio output system failed
286	* (which should be done in the constructor of the AudioOutputDevice
287	* descendant).
288	*/
289	class AudioOutputException : public Exception {
290	public:
291	AudioOutputException(const std::string& msg) : Exception(msg) {}
292	};
293	}
294
295	#endif // __LS_AUDIOOUTPUTDEVICE_H__