fwdv4

Usage

Overview

The fwdv driver provides DV frame capture from AV/C tape devices attached via IEEE 1394 (FireWire), including DV camcorders, VCRs, and DV converters.

The driver attaches to unit directories in the device CSR configuration ROM with unit_spec_id 0x00a02d (1394 Trade Association) and unit_sw_version 0x010001 (AV/C). When a matching device is present on the firewire(4) bus, the driver creates /dev/fwdvX and begins receiving IEC 61883 isochronous packets on first open, assembling complete DV frames. Applications read raw DV frames from the character device and control tape transport through ioctl(2).

Both NTSC and PAL SD-DV streams are detected from the incoming CIP header. DVCPRO HD frame sizing is also recognized.

Ioctls

FWDV_GINFO (struct fwdv_info)

Return driver state, active ISO channel, detected DV system, frame size, frame counters, dropped frame count, device EUI-64, and vendor/model strings from the device configuration ROM.

FWDV_PLAY

Send the AV/C play command to tape subunit 0.

FWDV_STOP

Send the AV/C stop command to tape subunit 0.

FWDV_FFWD

Send the AV/C fast-forward command to tape subunit 0.

FWDV_REW

Send the AV/C rewind command to tape subunit 0.

Sysctls

hw.firewire.fwdv.iso_channel

Fallback isochronous receive channel. The default is 63. If the device output plug control register reports an active channel, that device-reported channel is used instead. This value can be set as a tunable in loader.conf(5).

Files

/dev/fwdvX

DV capture character device. Read to obtain raw DV frames.