base_audio_mixer

Base audio mixer for output transport integration.

Provides the abstract base class for audio mixers that can be integrated with output transports to mix incoming audio with generated audio from the mixer.

class pipecat.audio.mixers.base_audio_mixer.BaseAudioMixer

Bases: ABC

Base class for output transport audio mixers.

This is a base class for output transport audio mixers. If an audio mixer is provided to the output transport it will be used to mix the audio frames coming into to the transport with the audio generated from the mixer. There are control frames to update mixer settings or to enable or disable the mixer at runtime.

abstractmethod async start(sample_rate: int)

Initialize the mixer when the output transport starts.

This will be called from the output transport when the transport is started. It can be used to initialize the mixer. The output transport sample rate is provided so the mixer can adjust to that sample rate.

Parameters:

sample_rate – The sample rate of the output transport in Hz.

abstractmethod async stop()

Clean up the mixer when the output transport stops.

This will be called from the output transport when the transport is stopping.

abstractmethod async process_frame(frame: MixerControlFrame)

Process mixer control frames from the transport.

This will be called when the output transport receives a MixerControlFrame.

Parameters:

frame – The mixer control frame to process.

abstractmethod async mix(audio: bytes) → bytes

Mix transport audio with mixer-generated audio.

This is called with the audio that is about to be sent from the output transport and that should be mixed with the mixer audio if the mixer is enabled.

Parameters:

audio – Raw audio bytes from the transport to mix.

Returns:

Mixed audio bytes combining transport and mixer audio.