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/*
* libjingle
* Copyright 2004--2010, Google Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
* EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef TALK_SOUND_SOUNDSYSTEMINTERFACE_H_
#define TALK_SOUND_SOUNDSYSTEMINTERFACE_H_
#include <vector>
#include "talk/base/constructormagic.h"
namespace cricket {
class SoundDeviceLocator;
class SoundInputStreamInterface;
class SoundOutputStreamInterface;
// Interface for a platform's sound system.
// Implementations must guarantee thread-safety for at least the following use
// cases:
// 1) Concurrent enumeration and opening of devices from different threads.
// 2) Concurrent use of different Sound(Input|Output)StreamInterface
// instances from different threads (but concurrent use of the _same_ one from
// different threads need not be supported).
class SoundSystemInterface {
public:
typedef std::vector<SoundDeviceLocator *> SoundDeviceLocatorList;
enum SampleFormat {
// Only one supported sample format at this time.
// The values here may be used in lookup tables, so they shouldn't change.
FORMAT_S16LE = 0,
};
enum Flags {
// Enable reporting the current stream latency in
// Sound(Input|Output)StreamInterface. See those classes for more details.
FLAG_REPORT_LATENCY = (1 << 0),
};
struct OpenParams {
// Format for the sound stream.
SampleFormat format;
// Sampling frequency in hertz.
unsigned int freq;
// Number of channels in the PCM stream.
unsigned int channels;
// Misc flags. Should be taken from the Flags enum above.
int flags;
// Desired latency, measured as number of bytes of sample data
int latency;
};
// Special values for the "latency" field of OpenParams.
// Use this one to say you don't care what the latency is. The sound system
// will optimize for other things instead.
static const int kNoLatencyRequirements = -1;
// Use this one to say that you want the sound system to pick an appropriate
// small latency value. The sound system may pick the minimum allowed one, or
// a slightly higher one in the event that the true minimum requires an
// undesirable trade-off.
static const int kLowLatency = 0;
// Max value for the volume parameters for Sound(Input|Output)StreamInterface.
static const int kMaxVolume = 255;
// Min value for the volume parameters for Sound(Input|Output)StreamInterface.
static const int kMinVolume = 0;
// Helper for clearing a locator list and deleting the entries.
static void ClearSoundDeviceLocatorList(SoundDeviceLocatorList *devices);
virtual ~SoundSystemInterface() {}
virtual bool Init() = 0;
virtual void Terminate() = 0;
// Enumerates the available devices. (Any pre-existing locators in the lists
// are deleted.)
virtual bool EnumeratePlaybackDevices(SoundDeviceLocatorList *devices) = 0;
virtual bool EnumerateCaptureDevices(SoundDeviceLocatorList *devices) = 0;
// Gets a special locator for the default device.
virtual bool GetDefaultPlaybackDevice(SoundDeviceLocator **device) = 0;
virtual bool GetDefaultCaptureDevice(SoundDeviceLocator **device) = 0;
// Opens the given device, or returns NULL on error.
virtual SoundOutputStreamInterface *OpenPlaybackDevice(
const SoundDeviceLocator *device,
const OpenParams ¶ms) = 0;
virtual SoundInputStreamInterface *OpenCaptureDevice(
const SoundDeviceLocator *device,
const OpenParams ¶ms) = 0;
// A human-readable name for this sound system.
virtual const char *GetName() const = 0;
protected:
SoundSystemInterface() {}
private:
DISALLOW_COPY_AND_ASSIGN(SoundSystemInterface);
};
} // namespace cricket
#endif // TALK_SOUND_SOUNDSYSTEMINTERFACE_H_
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