зеркало из https://github.com/mozilla/gecko-dev.git
107 строки
3.6 KiB
C++
107 строки
3.6 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim:set ts=2 sw=2 sts=2 et cindent: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#if !defined(AudioStream_h_)
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#define AudioStream_h_
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#include "nscore.h"
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#include "nsISupportsImpl.h"
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#include "nsIThread.h"
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#include "nsAutoPtr.h"
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#include "AudioSampleFormat.h"
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#include "AudioChannelCommon.h"
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namespace mozilla {
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// Access to a single instance of this class must be synchronized by
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// callers, or made from a single thread. One exception is that access to
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// GetPosition, GetPositionInFrames, SetVolume, and Get{Rate,Channels}
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// is thread-safe without external synchronization.
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class AudioStream : public nsISupports
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{
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public:
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AudioStream()
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: mRate(0),
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mChannels(0)
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{}
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virtual ~AudioStream();
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// Initialize Audio Library. Some Audio backends require initializing the
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// library before using it.
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static void InitLibrary();
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// Shutdown Audio Library. Some Audio backends require shutting down the
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// library after using it.
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static void ShutdownLibrary();
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// Thread that is shared between audio streams.
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// This may return null in the child process
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nsIThread *GetThread();
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// AllocateStream will return either a local stream or a remoted stream
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// depending on where you call it from. If you call this from a child process,
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// you may receive an implementation which forwards to a compositing process.
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static AudioStream* AllocateStream();
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// Initialize the audio stream. aNumChannels is the number of audio
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// channels (1 for mono, 2 for stereo, etc) and aRate is the sample rate
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// (22050Hz, 44100Hz, etc).
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virtual nsresult Init(int32_t aNumChannels, int32_t aRate,
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const dom::AudioChannelType aAudioStreamType) = 0;
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// Closes the stream. All future use of the stream is an error.
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virtual void Shutdown() = 0;
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// Write audio data to the audio hardware. aBuf is an array of AudioDataValues
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// AudioDataValue of length aFrames*mChannels. If aFrames is larger
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// than the result of Available(), the write will block until sufficient
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// buffer space is available.
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virtual nsresult Write(const mozilla::AudioDataValue* aBuf, uint32_t aFrames) = 0;
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// Return the number of audio frames that can be written without blocking.
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virtual uint32_t Available() = 0;
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// Set the current volume of the audio playback. This is a value from
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// 0 (meaning muted) to 1 (meaning full volume). Thread-safe.
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virtual void SetVolume(double aVolume) = 0;
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// Block until buffered audio data has been consumed.
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virtual void Drain() = 0;
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// Pause audio playback
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virtual void Pause() = 0;
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// Resume audio playback
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virtual void Resume() = 0;
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// Return the position in microseconds of the audio frame being played by
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// the audio hardware. Thread-safe.
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virtual int64_t GetPosition() = 0;
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// Return the position, measured in audio frames played since the stream
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// was opened, of the audio hardware. Thread-safe.
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virtual int64_t GetPositionInFrames() = 0;
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// Returns true when the audio stream is paused.
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virtual bool IsPaused() = 0;
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// Returns the minimum number of audio frames which must be written before
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// you can be sure that something will be played.
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virtual int32_t GetMinWriteSize() = 0;
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int GetRate() { return mRate; }
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int GetChannels() { return mChannels; }
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protected:
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nsCOMPtr<nsIThread> mAudioPlaybackThread;
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int mRate;
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int mChannels;
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};
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} // namespace mozilla
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#endif
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