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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <string>
#include <windows.h>
#include <mmsystem.h>
#include "base/basictypes.h"
#include "base/compiler_specific.h"
#include "base/synchronization/lock.h"
#include "base/threading/thread_checker.h"
#include "base/win/scoped_handle.h"
#include "media/audio/audio_io.h"
#include "media/audio/audio_parameters.h"
namespace media {
class AudioManagerWin;
class PCMWaveInAudioInputStream : public AudioInputStream {
// The ctor takes all the usual parameters, plus |manager| which is the
// the audio manager who is creating this object and |device_id| which
// is provided by the operating system.
PCMWaveInAudioInputStream(AudioManagerWin* manager,
const AudioParameters& params,
int num_buffers,
const std::string& device_id);
virtual ~PCMWaveInAudioInputStream();
// Implementation of AudioInputStream.
virtual bool Open() OVERRIDE;
virtual void Start(AudioInputCallback* callback) OVERRIDE;
virtual void Stop() OVERRIDE;
virtual void Close() OVERRIDE;
// TODO(henrika): Add volume support using the Audio Mixer API.
virtual double GetMaxVolume() OVERRIDE;
virtual void SetVolume(double volume) OVERRIDE;
virtual double GetVolume() OVERRIDE;
virtual void SetAutomaticGainControl(bool enabled) OVERRIDE;
virtual bool GetAutomaticGainControl() OVERRIDE;
enum State {
kStateEmpty, // Initial state.
kStateReady, // Device obtained and ready to record.
kStateRecording, // Recording audio.
kStateStopping, // Trying to stop, waiting for callback to finish.
kStateStopped, // Stopped. Device was reset.
kStateClosed // Device has been released.
// Allow unit tests to query the device ID.
friend class AudioManagerTest;
// Windows calls us back with the recorded audio data here. See msdn
// documentation for 'waveInProc' for details about the parameters.
static void CALLBACK WaveCallback(HWAVEIN hwi, UINT msg, DWORD_PTR instance,
DWORD_PTR param1, DWORD_PTR param2);
// If windows reports an error this function handles it and passes it to
// the attached AudioInputCallback::OnError().
void HandleError(MMRESULT error);
// Allocates and prepares the memory that will be used for recording.
void SetupBuffers();
// Deallocates the memory allocated in SetupBuffers.
void FreeBuffers();
// Sends a buffer to the audio driver for recording.
void QueueNextPacket(WAVEHDR* buffer);
// Converts the stored device id string into an unsigned integer which
// can be used by waveInOpen() to open the specified capture device.
bool GetDeviceId(UINT* device_index);
base::ThreadChecker thread_checker_;
// Reader beware. Visual C has stronger guarantees on volatile vars than
// most people expect. In fact, it has release semantics on write and
// acquire semantics on reads. See the msdn documentation.
volatile State state_;
// The audio manager that created this input stream. We notify it when
// we close so it can release its own resources.
AudioManagerWin* manager_;
// We use the callback mostly to periodically give the recorded audio data.
AudioInputCallback* callback_;
// The number of buffers of size |buffer_size_| each to use.
const int num_buffers_;
// The size in bytes of each audio buffer.
uint32 buffer_size_;
// Channels, 1 or 2.
const int channels_;
// Contains the unique name of the selected endpoint device.
// Note that AudioManagerBase::kDefaultDeviceId represents the default
// device role and is not a valid ID as such.
std::string device_id_;
// Windows native structure to encode the format parameters.
// Handle to the instance of the wave device.
HWAVEIN wavein_;
// Pointer to the first allocated audio buffer. This object owns it.
WAVEHDR* buffer_;
// An event that is signaled when the callback thread is ready to stop.
base::win::ScopedHandle stopped_event_;
// Lock used to avoid conflicts when Stop() is called during a callback.
base::Lock lock_;
} // namespace media