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allwinner_a64/android/compatibility/cdd/5_multimedia/5_5_audio-playback.md
August 78ea2404cd upload android base code part4
2018-08-08 17:00:29 +08:00

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5.5. Audio Playback

Android includes the support to allow apps to playback audio through the audio output peripheral as defined in section 7.8.2.

5.5.1. Raw Audio Playback

If device implementations declare android.hardware.audio.output, they:

  • [C-1-1] MUST allow playback of raw audio content with the following characteristics:

  • Format: Linear PCM, 16-bit

  • Sampling rates: 8000, 11025, 16000, 22050, 32000, 44100

  • Channels: Mono, Stereo

  • SHOULD allow playback of raw audio content with the following characteristics:

  • Sampling rates: 24000, 48000

5.5.2. Audio Effects

Android provides an API for audio effects for device implementations.

If device implementations declare the feature android.hardware.audio.output, they:

  • [C-1-1] MUST support the EFFECT_TYPE_EQUALIZER and EFFECT_TYPE_LOUDNESS_ENHANCER implementations controllable through the AudioEffect subclasses Equalizer, LoudnessEnhancer.
  • [C-1-2] MUST support the visualizer API implementation, controllable through the Visualizer class.
  • SHOULD support the EFFECT_TYPE_BASS_BOOST, EFFECT_TYPE_ENV_REVERB, EFFECT_TYPE_PRESET_REVERB, and EFFECT_TYPE_VIRTUALIZER implementations controllable through the AudioEffect sub-classes BassBoost, EnvironmentalReverb, PresetReverb, and Virtualizer.

5.5.3. Audio Output Volume

Television device implementations:

  • [T-0-1] MUST include support for system Master Volume and digital audio output volume attenuation on supported outputs, except for compressed audio passthrough output (where no audio decoding is done on the device).

Automotive device implementations:

  • SHOULD allow adjusting audio volume separately per each audio stream using the content type or usage as defined by AudioAttributes and car audio usage as publicly defined in android.car.CarAudioManager.