examples/run_unicast_server.py

# Copyright 2021-2023 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# -----------------------------------------------------------------------------
# Imports
# -----------------------------------------------------------------------------
import asyncio
import datetime
import functools
import sys
import io
import struct
import secrets

from bumble.core import AdvertisingData
from bumble.device import Device
from bumble.hci import (
    CodecID,
    CodingFormat,
    HCI_IsoDataPacket,
)
from bumble.profiles.ascs import AseStateMachine, AudioStreamControlService
from bumble.profiles.bap import (
    UnicastServerAdvertisingData,
    CodecSpecificConfiguration,
    CodecSpecificCapabilities,
    ContextType,
    AudioLocation,
    SupportedSamplingFrequency,
    SupportedFrameDuration,
)
from bumble.profiles.cap import CommonAudioServiceService
from bumble.profiles.csip import CoordinatedSetIdentificationService, SirkType
from bumble.profiles.pacs import PacRecord, PublishedAudioCapabilitiesService
from bumble.transport import open_transport
import bumble.logging


def _sink_pac_record() -> PacRecord:
    return PacRecord(
        coding_format=CodingFormat(CodecID.LC3),
        codec_specific_capabilities=CodecSpecificCapabilities(
            supported_sampling_frequencies=(
                SupportedSamplingFrequency.FREQ_8000
                | SupportedSamplingFrequency.FREQ_16000
                | SupportedSamplingFrequency.FREQ_24000
                | SupportedSamplingFrequency.FREQ_32000
                | SupportedSamplingFrequency.FREQ_48000
            ),
            supported_frame_durations=(
                SupportedFrameDuration.DURATION_7500_US_SUPPORTED
                | SupportedFrameDuration.DURATION_10000_US_SUPPORTED
            ),
            supported_audio_channel_count=[1, 2],
            min_octets_per_codec_frame=26,
            max_octets_per_codec_frame=240,
            supported_max_codec_frames_per_sdu=2,
        ),
    )


file_outputs: dict[AseStateMachine, io.BufferedWriter] = {}


# -----------------------------------------------------------------------------
async def main() -> None:
    if len(sys.argv) < 3:
        print('Usage: run_cig_setup.py <config-file> <transport-spec-for-device>')
        return

    print('<<< connecting to HCI...')
    async with await open_transport(sys.argv[2]) as hci_transport:
        print('<<< connected')

        device = Device.from_config_file_with_hci(
            sys.argv[1], hci_transport.source, hci_transport.sink
        )
        device.cis_enabled = True

        await device.power_on()

        csis = CoordinatedSetIdentificationService(
            set_identity_resolving_key=secrets.token_bytes(16),
            set_identity_resolving_key_type=SirkType.PLAINTEXT,
        )
        device.add_service(CommonAudioServiceService(csis))
        device.add_service(
            PublishedAudioCapabilitiesService(
                supported_source_context=ContextType.PROHIBITED,
                available_source_context=ContextType.PROHIBITED,
                supported_sink_context=ContextType(0xFF),  # All context types
                available_sink_context=ContextType(0xFF),  # All context types
                sink_audio_locations=(
                    AudioLocation.FRONT_LEFT | AudioLocation.FRONT_RIGHT
                ),
                sink_pac=[_sink_pac_record()],
            )
        )

        ascs = AudioStreamControlService(device, sink_ase_id=[1], source_ase_id=[2])
        device.add_service(ascs)

        advertising_data = (
            bytes(
                AdvertisingData(
                    [
                        (
                            AdvertisingData.COMPLETE_LOCAL_NAME,
                            bytes('Bumble LE Audio', 'utf-8'),
                        ),
                        (
                            AdvertisingData.FLAGS,
                            bytes(
                                [
                                    AdvertisingData.LE_GENERAL_DISCOVERABLE_MODE_FLAG
                                    | AdvertisingData.BR_EDR_HOST_FLAG
                                    | AdvertisingData.BR_EDR_CONTROLLER_FLAG
                                ]
                            ),
                        ),
                        (
                            AdvertisingData.INCOMPLETE_LIST_OF_16_BIT_SERVICE_CLASS_UUIDS,
                            bytes(PublishedAudioCapabilitiesService.UUID),
                        ),
                    ]
                )
            )
            + csis.get_advertising_data()
            + bytes(UnicastServerAdvertisingData())
        )

        def on_pdu(ase: AseStateMachine, pdu: HCI_IsoDataPacket):
            # LC3 format: |frame_length(2)| + |frame(length)|.
            sdu = b''
            if pdu.iso_sdu_length:
                sdu = struct.pack('<H', pdu.iso_sdu_length)
            sdu += pdu.iso_sdu_fragment
            file_outputs[ase].write(sdu)

        def on_ase_state_change(ase: AseStateMachine) -> None:
            if ase.state != AseStateMachine.State.STREAMING:
                if file_output := file_outputs.pop(ase, None):
                    file_output.close()
            else:
                file_output = open(f'{datetime.datetime.now().isoformat()}.lc3', 'wb')
                codec_configuration = ase.codec_specific_configuration
                if (
                    not isinstance(codec_configuration, CodecSpecificConfiguration)
                    or codec_configuration.sampling_frequency is None
                    or codec_configuration.audio_channel_allocation is None
                    or codec_configuration.frame_duration is None
                ):
                    return
                # Write a LC3 header.
                file_output.write(
                    bytes([0x1C, 0xCC])  # Header.
                    + struct.pack(
                        '<HHHHHHI',
                        18,  # Header length.
                        codec_configuration.sampling_frequency.hz
                        // 100,  # Sampling Rate(/100Hz).
                        0,  # Bitrate(unused).
                        bin(codec_configuration.audio_channel_allocation).count(
                            '1'
                        ),  # Channels.
                        codec_configuration.frame_duration.us
                        // 10,  # Frame duration(/10us).
                        0,  # RFU.
                        0x0FFFFFFF,  # Frame counts.
                    )
                )
                file_outputs[ase] = file_output
                assert ase.cis_link
                ase.cis_link.sink = functools.partial(on_pdu, ase)

        for ase in ascs.ase_state_machines.values():
            ase.on(
                'state_change',
                functools.partial(on_ase_state_change, ase=ase),
            )

        await device.create_advertising_set(
            advertising_data=advertising_data,
            auto_restart=True,
        )

        await hci_transport.source.terminated


# -----------------------------------------------------------------------------
bumble.logging.setup_basic_logging('DEBUG')
asyncio.run(main())