[PowerPlay] Integrate Audio Effect Into PowerPlay

[madebymozart]

Summary

This PR introduces a comprehensive audio effects system to the PowerPlay sample app. It leverages Android's native audio effects (Equalizer, Bass Boost, Reverb, and Loudness Enhancer) by attaching them to the Oboe audio stream via session ID allocation. It also adds a polished UI with a bottom sheet containing tabs for each effect, allowing users to customize their audio experience in real-time.

Changes

C++ Engine (PowerPlayMultiPlayer.cpp)

• Session ID Allocation: Enabled session ID allocation in the Oboe stream builder (SessionId::Allocate) to allow attaching Android audio effects.
• Exposed Session ID: Added getSessionId() to retrieve the allocated session ID from the stream.

JNI (PowerPlayJNI.cpp)

• JNI Bridging: Added getSessionIdNative to expose the stream's session ID to the Kotlin layer.

Kotlin Audio Player (PowerPlayAudioPlayer.kt)

• Effects Lifecycle Management: Integrated EffectsController to initialize and release audio effects when the stream is created or when the performance mode changes (which recreates the stream).

Audio Effects Managers (EffectsController.kt)

• New Component: Created EffectsController to query supported effects and manage instances of EqualizerManager, BassBoostManager, ReverbManager, and LoudnessManager.
• Modular Effect Wrappers: Added dedicated manager classes for each effect to encapsulate Android's AudioEffect APIs.

Jetpack Compose UI (MainActivity.kt)

• Effects Bottom Sheet Integration: Added a button to open the Effects Bottom Sheet and integrated the EffectsBottomSheet composable.
• Renamed UI Elements: Refactored variables and content descriptions from "Equalizer" to "Effects" to better reflect that the sheet now contains multiple audio effects beyond just the equalizer.
• New UI Tabs: Added custom UI tabs for each effect (EqualizerTab, BassBoostTab, ReverbTab, LoudnessTab) inside the bottom sheet.

Effects Support Matrix

The availability of effects depends on hardware support and is queried dynamically at runtime:

Effect	Supported	Notes
Equalizer	Dynamically Checked	Standard multi-band equalizer
Bass Boost	Dynamically Checked	Enhances low frequencies
Environmental Reverb	Dynamically Checked	Simulates different room acoustics
Loudness Enhancer	Dynamically Checked	Safe volume boosting

Note

If an effect is not supported by the device's hardware/HAL, it will not be initialized and its tab will not appear or will be disabled.

How to Test

1. Open the PowerPlay sample app.
2. Play any track.
3. Click the menu icon (Effects) at the bottom center.
4. Verify that the bottom sheet opens with tabs for Equalizer, Bass Boost, Reverb, and Loudness.
5. Adjust the sliders and toggles in each tab and verify that the audio effect is applied in real-time.
6. Change performance modes (e.g., switch to Low Latency or PCM Offload) and verify that the effects are re-applied correctly to the new stream.

Visuals

[madebymozart]

Are we good to merge this?

[flamme]

Why setting sharing mode to shared for offload? MMAP PCM offload only supports exclusive.

[flamme]

I have a quick talk with Robert offline. We are okay with setting the session id by default for flexibility of testing audio effects. But also note that when the app asks for allocating session id, the audio framework right now is not allowed to use mmap low latency path. In that case, it will be better to give a hint from the UI that the stream is not mmap low latency or just remove the mmap low latency option given PowerPlay more focus on testing music playback via Oboe API.

[madebymozart]

I will take that feedback and open another PR