Found at: http://www.kinodv.org/article/print/98/-1/7/


Top level News

You might be surprised to find two new versions of dvgrab released at the same time! Well, 1.8 is the last bugfix release of the current major release, and 2.0 is the next generation release that requires a new library not everyone is ready to install.

dvgrab 1.8 is the newest stable release with the same dependencies as previous releases.

dvgrab 2.0 adds a new dependency on libiec61883 because it uses the third generation of media I/O technology from the Linux 1394 project. This exciting new library has benefits beyond DV capture that is already being leveraged in the MythTV and FreeBob FireWire pro audio projects. Get the library and dependent new version of libraw1394 from .

This release exclusively uses the new third generation Linux IEEE 1394 capture API available in raw1394 and libiec61883. The libiec61883 provides a protocol-specific layer over the raw foundation. This new approach is both robust and simpler than using protocol-specific kernel modules such as dv1394. As a result, dvgrab 2.0 requires Linux kernel 2.4.20 or newer.

Usage of the connection management procedures in libiec61883 also makes it rather easy to capture from multiple DV devices on the same bus by using the --guid option. This feature is not entirely foolproof due to the inconsistency of implementations of devices, but you can try. Most devices are only running at 100mbps speed, which limits it to two DV streams per bus. However, through dip switches or the output master plug register, some devices can run at 200 or 400 and therefore more streams can exist on the bus. For example, I have tested four Canopus ADVC-500 devices on a single bus using the connection management procedures. Also, multiple host adapters are transparently supported when using the --guid option.

Like dvconnect, now dvgrab will schedule with realtime scheduling policy and lock all memory resident to prevent paging when run with super user permission.

New options "--lockstep" and "--timecode" can be used together to provide a redundant capture system where multiple Linux hosts can capture from the same bus without knowledge of each other and still produce output files with the same name for the same segment of video.




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