Programmable audio source about streamlit-webrtc HOT 2 OPEN

class AudioStreamTrack(MediaStreamTrack):
    """
    A dummy audio track which reads silence.
    """
    def __init__(self, callback: AudioSourceCallback) -> None:
        super().__init__()
        self.kind = "audio"
        self._callback = callback
        self._started_at: Optional[float] = None
        self._pts: Optional[int] = None

    # _start: float
    # _timestamp: int

    async def recv(self) -> av.frame.Frame:
        print('sending some stuff')
        if self.readyState != "live":
            raise MediaStreamError

        sample_rate = 8000
        samples = int(AUDIO_PTIME * sample_rate)

        if hasattr(self, "_timestamp"):
            self._timestamp += samples
            wait = self._start + (self._timestamp / sample_rate) - time.time()
            print(wait)
            await asyncio.sleep(wait)
        else:
            self._start = time.time()
            self._timestamp = 0

        frame = AudioFrame(format="s16", layout="mono", samples=samples)
        for p in frame.planes:
            p.update(bytes(p.buffer_size))
        frame.pts = self._timestamp
        frame.sample_rate = sample_rate
        frame.time_base = fractions.Fraction(1, sample_rate)

        return frame

    def _call_callback(self) -> av.AudioFrame:
        try:
            frame = self._callback()
        except Exception as exc:
            logger.error(
                "AudioSourceCallbackTrack: Audio frame callback raised an exception: %s",  # noqa: E501
                exc,
            )
            raise
        return frame

webrtc_streamer(
    key="player",
    mode=WebRtcMode.SENDRECV,
    audio_frame_callback=process_audio,
    source_audio_track=AudioStreamTrack(audio_source_callback),
    media_stream_constraints={"video": False, "audio": True},
    on_change=on_change,
    async_processing=True
)