diff options
Diffstat (limited to 'media/audio/audio_io.h')
| -rw-r--r-- | media/audio/audio_io.h | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/media/audio/audio_io.h b/media/audio/audio_io.h index 990f7c1..6e1e289 100644 --- a/media/audio/audio_io.h +++ b/media/audio/audio_io.h @@ -107,6 +107,52 @@ class AudioOutputStream { virtual ~AudioOutputStream() {} }; +// Models an audio sink receiving recorded audio from the audio driver. +class AudioInputStream { + public: + class AudioInputCallback { + public: + virtual ~AudioInputCallback() {} + + // Called by the audio recorder when a full packet of audio data is + // available. This is called from a special audio thread and the + // implementation should return as soon as possible. + virtual void OnData(AudioInputStream* stream, const uint8* src, + uint32 size) = 0; + + // The stream is done with this callback, the last call received by this + // audio sink. + virtual void OnClose(AudioInputStream* stream) = 0; + + // There was an error while recording audio. The audio sink cannot be + // destroyed yet. No direct action needed by the AudioInputStream, but it + // is a good place to stop accumulating sound data since is is likely that + // recording will not continue. |code| is an error code that is platform + // specific. + virtual void OnError(AudioInputStream* stream, int code) = 0; + }; + + // Open the stream and prepares it for recording. Call Start() to actually + // begin recording. + virtual bool Open() = 0; + + // Starts recording audio and generating AudioInputCallback::OnData(). + // The input stream does not take ownership of this callback. + virtual void Start(AudioInputCallback* callback) = 0; + + // Stops recording audio. Effect might not be instantaneous as there could be + // pending audio callbacks in the queue which will be issued first before + // recording stops. + virtual void Stop() = 0; + + // Close the stream. This also generates AudioInputCallback::OnClose(). This + // should be the last call made on this object. + virtual void Close() = 0; + + protected: + virtual ~AudioInputStream() {} +}; + // Manages all audio resources. In particular it owns the AudioOutputStream // objects. Provides some convenience functions that avoid the need to provide // iterators over the existing streams. @@ -130,6 +176,11 @@ class AudioManager { // guarantee that the existing devices support all formats and sample rates. virtual bool HasAudioOutputDevices() = 0; + // Returns true if the OS reports existence of audio recording devices. This + // does not guarantee that the existing devices support all formats and + // sample rates. + virtual bool HasAudioInputDevices() = 0; + // Factory for all the supported stream formats. The |channels| can be 1 to 5. // The |sample_rate| is in hertz and can be any value supported by the // platform. For some future formats the |sample_rate| and |bits_per_sample| @@ -147,6 +198,23 @@ class AudioManager { int sample_rate, char bits_per_sample) = 0; + // Factory to create audio recording streams. + // |channels| can be 1 or 2. + // |sample_rate| is in hertz and can be any value supported by the platform. + // |bits_per_sample| can be any value supported by the platform. + // |samples_per_packet| is in hertz as well and can be 0 to |sample_rate|, + // with 0 suggesting that the implementation use a default value for that + // platform. + // Returns NULL if the combination of the parameters is not supported, or if + // we have reached some other platform specific limit. + // + // Do not free the returned AudioInputStream. It is owned by AudioManager. + // When you are done with it, call |Stop()| and |Close()| to release it. + virtual AudioInputStream* MakeAudioInputStream(Format format, int channels, + int sample_rate, + char bits_per_sample, + uint32 samples_per_packet) = 0; + // Muting continues playback but effectively the volume is set to zero. // Un-muting returns the volume to the previous level. virtual void MuteAll() = 0; |