drivers/audio/AudioOutputDevice.h

/***************************************************************************
 *                                                                         *
 *   LinuxSampler - modular, streaming capable sampler                     *
 *                                                                         *
 *   Copyright (C) 2003, 2004 by Benno Senoner and Christian Schoenebeck   *
 *   Copyright (C) 2005 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	/***************************************************************************
2	* *
3	* LinuxSampler - modular, streaming capable sampler *
4	* *
5	* Copyright (C) 2003, 2004 by Benno Senoner and Christian Schoenebeck *
6	* Copyright (C) 2005 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/LinuxSamplerException.h"
34	#include "../Device.h"
35	#include "../DeviceParameter.h"
36	#include "../../engines/common/Engine.h"
37	#include "AudioChannel.h"
38
39	namespace LinuxSampler {
40
41	// just symbol prototyping
42	class Engine;
43
44	/** Abstract base class for audio output drivers in LinuxSampler
45	*
46	* This class will be derived by specialized classes which implement the
47	* connection to a specific audio output system (e.g. Alsa, Jack,
48	* CoreAudio).
49	*/
50	class AudioOutputDevice : public Device {
51	public:
52
53	/////////////////////////////////////////////////////////////////
54	// Device parameters
55
56	/** Device Parameter 'ACTIVE'
57	*
58	* Used to activate / deactivate the audio output device.
59	*/
60	class ParameterActive : public DeviceCreationParameterBool {
61	public:
62	ParameterActive();
63	ParameterActive(String s);
64	virtual String Description();
65	virtual bool Fix();
66	virtual bool Mandatory();
67	virtual std::map<String,DeviceCreationParameter*> DependsAsParameters();
68	virtual optional<bool> DefaultAsBool(std::map<String,String> Parameters);
69	virtual void OnSetValue(bool b) throw (LinuxSamplerException);
70	static String Name();
71	};
72
73	/** Device Parameter 'SAMPLERATE'
74	*
75	* Used to set the sample rate of the audio output device.
76	*/
77	class ParameterSampleRate : public DeviceCreationParameterInt {
78	public:
79	ParameterSampleRate();
80	ParameterSampleRate(String s);
81	virtual String Description();
82	virtual bool Fix();
83	virtual bool Mandatory();
84	virtual std::map<String,DeviceCreationParameter*> DependsAsParameters();
85	virtual optional<int> DefaultAsInt(std::map<String,String> Parameters);
86	virtual optional<int> RangeMinAsInt(std::map<String,String> Parameters);
87	virtual optional<int> RangeMaxAsInt(std::map<String,String> Parameters);
88	virtual std::vector<int> PossibilitiesAsInt(std::map<String,String> Parameters);
89	virtual void OnSetValue(int i) throw (LinuxSamplerException);
90	static String Name();
91	};
92
93	/** Device Parameters 'CHANNELS'
94	*
95	* Used to increase / decrease the number of audio channels of
96	* audio output device.
97	*/
98	class ParameterChannels : public DeviceCreationParameterInt {
99	public:
100	ParameterChannels();
101	ParameterChannels(String s);
102	virtual String Description();
103	virtual bool Fix();
104	virtual bool Mandatory();
105	virtual std::map<String,DeviceCreationParameter*> DependsAsParameters();
106	virtual optional<int> DefaultAsInt(std::map<String,String> Parameters);
107	virtual optional<int> RangeMinAsInt(std::map<String,String> Parameters);
108	virtual optional<int> RangeMaxAsInt(std::map<String,String> Parameters);
109	virtual std::vector<int> PossibilitiesAsInt(std::map<String,String> Parameters);
110	virtual void OnSetValue(int i) throw (LinuxSamplerException);
111	static String Name();
112	};
113
114
115
116	/////////////////////////////////////////////////////////////////
117	// abstract methods
118	// (these have to be implemented by the descendant)
119
120	/**
121	* Start playback of audio signal on the audio device. It's the
122	* responsibility of the implementing audio device to call the
123	* RenderAudio(uint Samples) method of all connected engines.
124	* This will cause the engines to continue to render 'Samples'
125	* number of audio sample points and the engines will
126	* automatically add their audio signals to the audio buffers of
127	* the audio channels of this audio device. So the implementing
128	* audio device just has to access the buffers of it's audio
129	* channels.
130	*
131	* @throws AudioOutputException if playback can not be started
132	* @see AudioChannel
133	*/
134	virtual void Play() = 0;
135
136	/**
137	* Returns true if the audio device is currently playing back.
138	*/
139	virtual bool IsPlaying() = 0;
140
141	/**
142	* Stop playback of audio signal on the audio device. The
143	* implementing audio device will stop calling the RenderAudio()
144	* method of all connected engines and close it's connection to
145	* audio output system.
146	*/
147	virtual void Stop() = 0;
148
149	/**
150	* Maximum amount of sample points the implementing audio
151	* device will ever demand the sampler engines to write in one
152	* fragment cycle / period. Simple audio device drivers usually
153	* have a fixed fragment size, so those devices just would return
154	* the fragment size in this method.
155	*
156	* @returns max. amount of sample points ever
157	*/
158	virtual uint MaxSamplesPerCycle() = 0;
159
160	/**
161	* Playback samplerate the audio device uses. The sampler engines
162	* currently assume this to be a constant value for the whole
163	* life time of an instance of the implementing audio device.
164	*
165	* @returns sample rate in Hz
166	*/
167	virtual uint SampleRate() = 0;
168
169	/**
170	* Return the audio output device driver name.
171	*/
172	virtual String Driver() = 0;
173
174	/**
175	* Create new audio channel. This will be called by
176	* AcquireChannels(). Each driver must implement it.
177	*/
178	virtual AudioChannel* CreateChannel(uint ChannelNr) = 0;
179
180
181
182	/////////////////////////////////////////////////////////////////
183	// normal methods
184	// (usually not to be overriden by descendant)
185
186	/**
187	* Connect given sampler engine to this audio output device. The
188	* engine will be added to the Engines container of this audio
189	* device and the engine will also automatically be informed
190	* about the connection.
191	*
192	* @param pEngine - sampler engine
193	*/
194	void Connect(Engine* pEngine);
195
196	/**
197	* Disconnect given sampler engine from this audio output device.
198	* Removes given sampler engine reference from the Engines
199	* container of this audio device.
200	*
201	* @param pEngine - sampler engine
202	*/
203	void Disconnect(Engine* pEngine);
204
205	/**
206	* Returns audio channel with index \a ChannelIndex or NULL if
207	* index out of bounds.
208	*/
209	AudioChannel* Channel(uint ChannelIndex);
210
211	/**
212	* This method will usually be called by the sampler engines that
213	* are connected to this audio device to inform the audio device
214	* how much audio channels the engine(s) need. It's the
215	* responsibility of the audio device to offer that amount of
216	* audio channels - again: this is not an option this is a must!
217	* The engines will assume to be able to access those audio
218	* channels right after. If the audio driver is not able to offer
219	* that much channels, it can simply create mix channels which
220	* are then just mixed to the 'real' audio channels. See
221	* AudioChannel.h for details about channels and mix channels.
222	*
223	* @param Channels - amount of output channels required by
224	* a sampler engine
225	* @throws AudioOutputException if desired amount of channels
226	* cannot be offered
227	* @see AudioChannel
228	*/
229	void AcquireChannels(uint Channels);
230
231	/**
232	* Returns all device parameter settings.
233	*/
234	std::map<String,DeviceCreationParameter*> DeviceParameters();
235
236	protected:
237	std::set<Engine*> Engines; ///< All sampler engines that are connected to the audio output device.
238	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.
239	std::map<String,DeviceCreationParameter*> Parameters; ///< All device parameters.
240
241	AudioOutputDevice(std::map<String,DeviceCreationParameter*> DriverParameters);
242
243	virtual ~AudioOutputDevice();
244
245	/**
246	* This method should be called by the AudioOutputDevice
247	* descendant to let all connected engines proceed to render the
248	* given amount of sample points. The engines will place their
249	* calculated audio data by themselfes into the buffers of the
250	* respective AudioChannel objects, so the implementing audio
251	* output device just has to copy the AudioChannel buffers to
252	* the output buffer(s) of its audio system.
253	*
254	* @returns 0 on success or the last error return code of one
255	* engine
256	*/
257	int RenderAudio(uint Samples);
258
259	/**
260	* This can be called as an alternative to RenderAudio() for
261	* just writing silence to the audio output buffers and not
262	* calling the connected sampler engines for rendering audio, so
263	* to provide a method to stop playback if the used audio output
264	* system doesn't provide a better way.
265	*
266	* @returns 0 on success
267	*/
268	int RenderSilence(uint Samples);
269
270	friend class Sampler; // allow Sampler class to destroy audio devices
271
272	};
273
274	/**
275	* Audio output exception that should be thrown by the AudioOutputDevice
276	* descendants in case initialization of the audio output system failed
277	* (which should be done in the constructor of the AudioOutputDevice
278	* descendant).
279	*/
280	class AudioOutputException : public LinuxSamplerException {
281	public:
282	AudioOutputException(const std::string& msg) : LinuxSamplerException(msg) {}
283	};
284	}
285
286	#endif // __LS_AUDIOOUTPUTDEVICE_H__