| // Copyright 2017 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. |
| |
| #ifndef CHROMECAST_PUBLIC_VOLUME_CONTROL_H_ |
| #define CHROMECAST_PUBLIC_VOLUME_CONTROL_H_ |
| |
| #include <string> |
| #include <vector> |
| |
| #include "chromecast_export.h" |
| |
| namespace chromecast { |
| namespace media { |
| |
| // Audio content types for volume control. Each content type has a separate |
| // volume and mute state. |
| // GENERATED_JAVA_ENUM_PACKAGE: org.chromium.chromecast.media |
| enum class AudioContentType { |
| kMedia, // Normal audio playback; also used for system sound effects. |
| kAlarm, // Alarm sounds. |
| kCommunication, // Voice communication, eg assistant TTS. |
| kOther, // No content type volume control (only per-stream control). |
| kNumTypes, // Not a valid type; should always be last in the enum. |
| }; |
| |
| // Different sources of volume changes. Used to change behaviour (eg feedback |
| // sounds) based on the source. |
| enum class VolumeChangeSource { |
| kUser, // User-initiated volume change. |
| kAutomatic, // Automatic volume change, no user involvement. |
| kAutoWithFeedback, // Automatic volume change, but we still want to have |
| // volume feedback UX. |
| }; |
| |
| // Observer for volume/mute state changes. This is useful to detect volume |
| // changes that occur outside of cast_shell. Add/RemoveVolumeObserver() must not |
| // be called synchronously from OnVolumeChange() or OnMuteChange(). Note that |
| // no volume/mute changes will occur for AudioContentType::kOther, so no |
| // observer methods will be called with that type. |
| class VolumeObserver { |
| public: |
| // Called whenever the volume changes for a given stream |type|. May be called |
| // on an arbitrary thread. |
| virtual void OnVolumeChange(VolumeChangeSource source, |
| AudioContentType type, |
| float new_volume) = 0; |
| |
| // Called whenever the mute state changes for a given stream |type|. May be |
| // called on an arbitrary thread. |
| virtual void OnMuteChange(VolumeChangeSource source, |
| AudioContentType type, |
| bool new_muted) = 0; |
| |
| protected: |
| virtual ~VolumeObserver() = default; |
| }; |
| |
| // Volume control is initialized once when cast_shell starts up, and finalized |
| // on shutdown. Revoking resources has no effect on volume control. All volume |
| // control methods are called on the same thread that calls Initialize(). |
| class CHROMECAST_EXPORT VolumeControl { |
| public: |
| // Initializes platform-specific volume control. Only called when volume |
| // control is in an uninitialized state. The implementation of this method |
| // should load previously set volume and mute states from persistent storage, |
| // so that the volume and mute are preserved across reboots. |
| static void Initialize(const std::vector<std::string>& argv); |
| |
| // Tears down platform-specific volume control and returns to the |
| // uninitialized state. |
| static void Finalize(); |
| |
| // Adds a volume observer. |
| static void AddVolumeObserver(VolumeObserver* observer); |
| // Removes a volume observer. After this is called, the implementation must |
| // not call any more methods on the observer. |
| static void RemoveVolumeObserver(VolumeObserver* observer); |
| |
| // Gets/sets the output volume for a given audio stream |type|. The volume |
| // |level| is in the range [0.0, 1.0]. AudioContentType::kOther is not a valid |
| // |type| for these methods. |
| static float GetVolume(AudioContentType type); |
| static void SetVolume(VolumeChangeSource source, |
| AudioContentType type, |
| float level); |
| |
| // Gets/sets the mute state for a given audio stream |type|. |
| // AudioContentType::kOther is not a valid |type| for these methods. |
| static bool IsMuted(AudioContentType type); |
| static void SetMuted(VolumeChangeSource source, |
| AudioContentType type, |
| bool muted); |
| |
| // Limits the output volume for a given stream |type| to no more than |limit|. |
| // This does not affect the logical volume for the stream type; the volume |
| // returned by GetVolume() should not change, and no OnVolumeChange() event |
| // should be sent to observers. AudioContentType::kOther is not a valid |type| |
| // for this method. |
| static void SetOutputLimit(AudioContentType type, float limit); |
| |
| // Called to enable power save mode when no audio is being played |
| // (|power_save_on| will be true in this case), and to disable power save mode |
| // when audio playback resumes (|power_save_on| will be false). |
| // NOTE: This is optional (therefore a weak symbol) because most platforms |
| // do not have any need to implement it. |
| static void SetPowerSaveMode(bool power_save_on) __attribute__((weak)); |
| |
| // Converts a volume level in the range [0.0, 1.0] to/from a volume in dB. |
| // The volume in dB should be full-scale (so a volume level of 1.0 would be |
| // 0.0 dBFS, and any lower volume level would be negative). |
| // NOTE: Unlike the other VolumeControl methods, these may be called before |
| // Initialize() or after Finalize(). May be called from multiple processes. |
| static float VolumeToDbFS(float volume); |
| static float DbFSToVolume(float dbfs); |
| }; |
| |
| } // namespace media |
| } // namespace chromecast |
| |
| #endif // CHROMECAST_PUBLIC_VOLUME_CONTROL_H_ |