A2DP example: Codec selection based on file type

Currently support SBC and AAC

.github/workflows/code-check.yml

@@ -33,7 +33,7 @@ jobs:
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip
-        python -m pip install ".[build,test,development]"
+        python -m pip install ".[build,examples,test,development]"
     - name: Check
       run: |
         invoke project.pre-commit

examples/run_a2dp_source.py

@@ -16,28 +16,43 @@
 # Imports
 # -----------------------------------------------------------------------------
 import asyncio
-import sys
-import os
 import logging
+import os
+import sys
+from dataclasses import dataclass
 
-from bumble.colors import color
+import ffmpeg
-from bumble.device import Device
+
-from bumble.transport import open_transport_or_link
+from bumble.a2dp import (
-from bumble.core import PhysicalTransport
+    A2DP_MPEG_2_4_AAC_CODEC_TYPE,
+    A2DP_SBC_CODEC_TYPE,
+    AacMediaCodecInformation,
+    AacPacketSource,
+    SbcMediaCodecInformation,
+    SbcPacketSource,
+    make_audio_source_service_sdp_records,
+)
 from bumble.avdtp import (
-    find_avdtp_service_with_connection,
     AVDTP_AUDIO_MEDIA_TYPE,
+    Listener,
     MediaCodecCapabilities,
     MediaPacketPump,
     Protocol,
-    Listener,
+    find_avdtp_service_with_connection,
-)
-from bumble.a2dp import (
-    make_audio_source_service_sdp_records,
-    A2DP_SBC_CODEC_TYPE,
-    SbcMediaCodecInformation,
-    SbcPacketSource,
 )
+from bumble.colors import color
+from bumble.core import PhysicalTransport
+from bumble.device import Device
+from bumble.transport import open_transport_or_link
+
+from typing import Dict, Union
+
+
+@dataclass
+class CodecCapabilities:
+    name: str
+    sample_rate: str
+    number_of_channels: str
 
 
 # -----------------------------------------------------------------------------
@@ -51,67 +66,147 @@ def sdp_records():
 
 
 # -----------------------------------------------------------------------------
-def codec_capabilities():
+def on_avdtp_connection(
-    # NOTE: this shouldn't be hardcoded, but should be inferred from the input file
+    read_function, protocol, codec_capabilities: MediaCodecCapabilities
-    # instead
+):
-    return MediaCodecCapabilities(
-        media_type=AVDTP_AUDIO_MEDIA_TYPE,
-        media_codec_type=A2DP_SBC_CODEC_TYPE,
-        media_codec_information=SbcMediaCodecInformation(
-            sampling_frequency=SbcMediaCodecInformation.SamplingFrequency.SF_44100,
-            channel_mode=SbcMediaCodecInformation.ChannelMode.JOINT_STEREO,
-            block_length=SbcMediaCodecInformation.BlockLength.BL_16,
-            subbands=SbcMediaCodecInformation.Subbands.S_8,
-            allocation_method=SbcMediaCodecInformation.AllocationMethod.LOUDNESS,
-            minimum_bitpool_value=2,
-            maximum_bitpool_value=53,
-        ),
-    )
-
-
-# -----------------------------------------------------------------------------
-def on_avdtp_connection(read_function, protocol):
     packet_source = SbcPacketSource(read_function, protocol.l2cap_channel.peer_mtu)
     packet_pump = MediaPacketPump(packet_source.packets)
-    protocol.add_source(codec_capabilities(), packet_pump)
+    protocol.add_source(codec_capabilities, packet_pump)
 
 
 # -----------------------------------------------------------------------------
-async def stream_packets(read_function, protocol):
+async def stream_packets(
+    read_function, protocol, codec_capabilities: MediaCodecCapabilities
+):
     # Discover all endpoints on the remote device
     endpoints = await protocol.discover_remote_endpoints()
     for endpoint in endpoints:
         print('@@@', endpoint)
 
     # Select a sink
+    assert codec_capabilities.media_codec_type in [
+        A2DP_SBC_CODEC_TYPE,
+        A2DP_MPEG_2_4_AAC_CODEC_TYPE,
+    ]
     sink = protocol.find_remote_sink_by_codec(
-        AVDTP_AUDIO_MEDIA_TYPE, A2DP_SBC_CODEC_TYPE
+        AVDTP_AUDIO_MEDIA_TYPE, codec_capabilities.media_codec_type
     )
     if sink is None:
-        print(color('!!! no SBC sink found', 'red'))
+        print(color('!!! no Sink found', 'red'))
         return
     print(f'### Selected sink: {sink.seid}')
 
     # Stream the packets
-    packet_source = SbcPacketSource(read_function, protocol.l2cap_channel.peer_mtu)
+    packet_sources = {
-    packet_pump = MediaPacketPump(packet_source.packets)
+        A2DP_SBC_CODEC_TYPE: SbcPacketSource(
-    source = protocol.add_source(codec_capabilities(), packet_pump)
+            read_function, protocol.l2cap_channel.peer_mtu
+        ),
+        A2DP_MPEG_2_4_AAC_CODEC_TYPE: AacPacketSource(
+            read_function, protocol.l2cap_channel.peer_mtu
+        ),
+    }
+    packet_source = packet_sources[codec_capabilities.media_codec_type]
+    packet_pump = MediaPacketPump(packet_source.packets)  # type: ignore
+    source = protocol.add_source(codec_capabilities, packet_pump)
     stream = await protocol.create_stream(source, sink)
     await stream.start()
-    await asyncio.sleep(5)
+    await asyncio.sleep(60)
-    await stream.stop()
-    await asyncio.sleep(5)
-    await stream.start()
-    await asyncio.sleep(5)
     await stream.stop()
     await stream.close()
 
 
+# -----------------------------------------------------------------------------
+def fetch_codec_informations(filepath) -> MediaCodecCapabilities:
+    probe = ffmpeg.probe(filepath)
+    assert 'streams' in probe
+    streams = probe['streams']
+
+    if not streams or len(streams) > 1:
+        print(streams)
+        print(color('!!! file not supported', 'red'))
+        exit()
+    audio_stream = streams[0]
+
+    media_codec_type = None
+    media_codec_information: Union[
+        SbcMediaCodecInformation, AacMediaCodecInformation, None
+    ] = None
+
+    assert 'codec_name' in audio_stream
+    codec_name: str = audio_stream['codec_name']
+    if codec_name == "sbc":
+        media_codec_type = A2DP_SBC_CODEC_TYPE
+        sbc_sampling_frequency: Dict[
+            str, SbcMediaCodecInformation.SamplingFrequency
+        ] = {
+            '16000': SbcMediaCodecInformation.SamplingFrequency.SF_16000,
+            '32000': SbcMediaCodecInformation.SamplingFrequency.SF_32000,
+            '44100': SbcMediaCodecInformation.SamplingFrequency.SF_44100,
+            '48000': SbcMediaCodecInformation.SamplingFrequency.SF_48000,
+        }
+        sbc_channel_mode: Dict[int, SbcMediaCodecInformation.ChannelMode] = {
+            1: SbcMediaCodecInformation.ChannelMode.MONO,
+            2: SbcMediaCodecInformation.ChannelMode.JOINT_STEREO,
+        }
+
+        assert 'sample_rate' in audio_stream
+        assert 'channels' in audio_stream
+        media_codec_information = SbcMediaCodecInformation(
+            sampling_frequency=sbc_sampling_frequency[audio_stream['sample_rate']],
+            channel_mode=sbc_channel_mode[audio_stream['channels']],
+            block_length=SbcMediaCodecInformation.BlockLength.BL_16,
+            subbands=SbcMediaCodecInformation.Subbands.S_8,
+            allocation_method=SbcMediaCodecInformation.AllocationMethod.LOUDNESS,
+            minimum_bitpool_value=2,
+            maximum_bitpool_value=53,
+        )
+    elif codec_name == "aac":
+        media_codec_type = A2DP_MPEG_2_4_AAC_CODEC_TYPE
+        object_type: Dict[str, AacMediaCodecInformation.ObjectType] = {
+            'LC': AacMediaCodecInformation.ObjectType.MPEG_2_AAC_LC,
+            'LTP': AacMediaCodecInformation.ObjectType.MPEG_4_AAC_LTP,
+            'SSR': AacMediaCodecInformation.ObjectType.MPEG_4_AAC_SCALABLE,
+        }
+        aac_sampling_frequency: Dict[
+            str, AacMediaCodecInformation.SamplingFrequency
+        ] = {
+            '44100': AacMediaCodecInformation.SamplingFrequency.SF_44100,
+            '48000': AacMediaCodecInformation.SamplingFrequency.SF_48000,
+        }
+        aac_channel_mode: Dict[int, AacMediaCodecInformation.Channels] = {
+            1: AacMediaCodecInformation.Channels.MONO,
+            2: AacMediaCodecInformation.Channels.STEREO,
+        }
+
+        assert 'profile' in audio_stream
+        assert 'sample_rate' in audio_stream
+        assert 'channels' in audio_stream
+        media_codec_information = AacMediaCodecInformation(
+            object_type=object_type[audio_stream['profile']],
+            sampling_frequency=aac_sampling_frequency[audio_stream['sample_rate']],
+            channels=aac_channel_mode[audio_stream['channels']],
+            vbr=1,
+            bitrate=128000,
+        )
+    else:
+        print(color('!!! codec not supported, only aac & sbc are supported', 'red'))
+        exit()
+
+    assert media_codec_type is not None
+    assert media_codec_information is not None
+
+    return MediaCodecCapabilities(
+        media_type=AVDTP_AUDIO_MEDIA_TYPE,
+        media_codec_type=media_codec_type,
+        media_codec_information=media_codec_information,
+    )
+
+
 # -----------------------------------------------------------------------------
 async def main() -> None:
     if len(sys.argv) < 4:
         print(
-            'Usage: run_a2dp_source.py <device-config> <transport-spec> <sbc-file> '
+            'Usage: run_a2dp_source.py <device-config> <transport-spec> <audio-file> '
             '[<bluetooth-address>]'
         )
         print(
@@ -135,11 +230,13 @@ async def main() -> None:
         # Start
         await device.power_on()
 
-        with open(sys.argv[3], 'rb') as sbc_file:
+        with open(sys.argv[3], 'rb') as audio_file:
             # NOTE: this should be using asyncio file reading, but blocking reads are
             # good enough for testing
             async def read(byte_count):
-                return sbc_file.read(byte_count)
+                return audio_file.read(byte_count)
+
+            codec_capabilities = fetch_codec_informations(sys.argv[3])
 
             if len(sys.argv) > 4:
                 # Connect to a peer
@@ -170,12 +267,15 @@ async def main() -> None:
                 protocol = await Protocol.connect(connection, avdtp_version)
 
                 # Start streaming
-                await stream_packets(read, protocol)
+                await stream_packets(read, protocol, codec_capabilities)
             else:
                 # Create a listener to wait for AVDTP connections
                 listener = Listener.for_device(device=device, version=(1, 2))
                 listener.on(
-                    'connection', lambda protocol: on_avdtp_connection(read, protocol)
+                    'connection',
+                    lambda protocol: on_avdtp_connection(
+                        read, protocol, codec_capabilities
+                    ),
                 )
 
                 # Become connectable and wait for a connection

pyproject.toml

@@ -55,6 +55,9 @@ development = [
     "types-invoke >= 1.7.3",
     "types-protobuf >= 4.21.0",
 ]
+examples = [
+    "ffmpeg-python == 0.2.0",
+]
 avatar = [
     "pandora-avatar == 0.0.10",
     "rootcanal == 1.11.1 ; python_version>='3.10'",
@@ -184,6 +187,10 @@ ignore_missing_imports = true
 module = "construct.*"
 ignore_missing_imports = true
 
+[[tool.mypy.overrides]]
+module = "ffmpeg.*"
+ignore_missing_imports = true
+
 [[tool.mypy.overrides]]
 module = "grpc.*"
 ignore_missing_imports = true