[kwy404]

bumble-player, and anything else that reads Ogg Opus files with a2dp.OpusParser, cannot use a mono file: parsing stops with ValueError: first packet is not OpusHead, so the mono branch in the player's opus_codec_capabilities is never reached.

Root cause

When OpusParser.packets reads the OpusHead packet, it stores the channel mode in packet_count instead of channel_mode:

packet_count = (
    OpusPacket.ChannelMode.MONO
    if packet[9] == 1
    else OpusPacket.ChannelMode.STEREO
)

For a mono stream this sets packet_count back to 0 (ChannelMode.MONO), so the next packet (OpusTags) is checked again as the identification header and the parser raises. Stereo streams only work because ChannelMode.STEREO happens to be 1, and channel_mode always keeps its initial STEREO value.

Fix

Assign the value to channel_mode.

Test

test_opus_parser_mono in tests/a2dp_test.py feeds a one page Ogg stream with a 1 channel OpusHead, an OpusTags packet and one audio packet, and checks that the parser yields a single MONO packet with the audio payload. It fails before the change with the ValueError above and passes after it. The existing stereo tests still pass, and black -S --check is clean on the changed files.