NAME
fwisound – Apple FireWire audio driver
SYNOPSIS
device firewire device fwisound device sound
DESCRIPTION
The fwisound driver provides audio capture from Apple FireWire devices that use a proprietary isochronous audio protocol (not IEC 61883/AMDTP).
The driver attaches to unit directories in the device CSR configuration ROM with Apple OUI (0x000a27) and decodes the "sght" packet signature to deliver stereo PCM audio to the sound(4) framework.
The device attaches as a standard sound(4) capture device accessible at /dev/dspX. The fixed audio format is 48000 Hz, 2-channel, signed 16-bit big-endian (S16BE).
HARDWARE
The fwisound driver supports Apple FireWire devices with the following unit directory:
- unit_spec_ID
-
0x000a27 (Apple OUI)
- unit_sw_version
-
0x000010
Known compatible hardware:
-
Apple iSight (FireWire cylinder)
SYSCTLS
- hw.firewire.fwisound.iso_channel
-
Isochronous receive channel (default 1). Can be set as a tunable in loader.conf(5). Must not conflict with hw.firewire.fwcam.iso_channel (default 0).
FILES
- /dev/dspX
-
PCM capture device created by sound(4).
EXAMPLES
Record five seconds of audio:
rec -r 48000 -c 2 -e signed-integer -b 16 -B /tmp/out.wav trim 5
If multiple sound devices are present, address the device explicitly:
sox -t ossdsp /dev/dsp4 -r 48000 -c 2 -e signed-integer -b 16 \
/tmp/out.wav trim 5
SEE ALSO
HISTORY
The fwisound driver first appeared in FreeBSD 16.0.
AUTHORS
Abdelkader Boudih ⟨[email protected]⟩
Protocol reverse-engineered by Clemens Ladisch.