Audio Player Service¶

This service is responsible for playing all sounds on the frontend. This includes:

• LLM audio response (voice chat)
• Text to speech

service AudioPlayerService¶

To facilitate audio streaming from LLM voice responses, it implements an audio queue system. Audio blobs are played in the sequence they are added in. This implementation was due to how audio files of the LLM response was received on the frontend.

Attributes¶

private attr audioElement¶

HTMLMediaElementWithCaptureStream source of audio being played.

private attr queue¶

Blob[] contains audio files to be played.

attr $stream¶

BehaviorSubject<MediaStream|null> keeping track of the current audio stream. This will be consumed by the waveform visualiser.

attr $playing¶

BehaviorSubject<boolean> to keep track of the current playing state.

Methods¶

private meth Play Next in Queue¶

private playNextInQueue(): void

Description

This method will play the next audio in the queue.

meth Get Audio Stream¶

getAudioStream(): BehaviorSubject<MediaStream|null>

Description

Public method to retrieve the BehaviorSubject to track the current audio stream source.

Returns

BehaviorSubject<MediaStream|null>

meth Play¶

play(...blob: Blob[]): void

Description

Method to add an audio file to the queue to be played.

Parameters

...blob (...Blob[]): Destructed array of Blobs to be played. Will be added to a queue.

meth Force Play¶

forcePlayAndReplace(blob: Blob): void

Description

This method is to clear the current queue of audio files, and play the provided Blob audio.

Parameters

blob (Blob): Audio file to be played

meth Stop and Clear¶

stopAndClear(): void

Description

This method clears the current queue, stops the audio from being played and updates local states.

meth Play Start Voice Audio¶

playStartVoiceAudio(): void

Description

This method plays a pre-defined audio file (startvoice.mp3) from the app's assets, used to signal the start of voice interaction.

meth Play Stop Voice Audio¶

playStopVoiceAudio(): void

Description

This method plays a pre-defined audio file (stopvoice.mp3) from the app's assets, used to signal the end of voice interaction.

Updated 23 Oct 2024

Contributor Ong Tsien Jin