dvgrab — Capture DV or MPEG-2 Transport Stream (HDV) video and audio
data from FireWire
dvgrab [options] [base] [-]
dvgrab is a program that captures DV or HDV (MPEG2-TS) video and audio
data from digital camcorders via FireWire (IEEE 1394). The data is
stored in one or several files and can later be processed by video
editing software. dvgrab can remote control the camcorder but it does
not show the video’s content on screen.
dvgrab also supports UVC (USB Video Class) compliant DV devices using
Linux kernel module uvcvideo, which is a V4L2 driver. In this mode,
there is no AV/C VTR control and therefore interactive mode is almost
useless. interactive feature is
The base argument is used to construct the filename to store video
data: base-num.ext. num is a running number starting from 001, and ext
is the file name extension specifying the file format used, e.g. avi.
A different naming scheme is used whenever the -timestamp, -timecode,
or -timesys is given (see below). If base is a full filename including
extension, then dvgrab attempts to determine the output file format
from the extension, but it still inserts num. The default value for
base is "dvgrab-".
If you specify a trailing ’-’ then the format is forced to raw DV or
HDV and sent to stdout. dvgrab will also output raw DV or HDV to stdout
while capturing to a file if stdout is piped or redirected.
You can use dvgrab’s powerful file writing capabilities with other
programs that produce raw DV or HDV. Using the -stdin option and if
dvgrab detects that it is on the receiving end of a pipe and it is not
in interactive mode, then it will try to read raw DV or HDV on stdin.
Options longer than a single character can be specified with either one
or two leading hyphens. Also, you can use a space character or equal
sign to separate the option name and its argument value.
Try to detect whenever a new recording starts, and store it
into a separate file. This can be combined with the -frames
and -size options, and a split occurs whenever a specified
event arises. Autosplit is off by default.
num is optional. Without it, dvgrab determines when to split
using a flag in the stream or a discontinuity in the
timecode, where timecode discontinuity is anything backwards
or greater than one second. If you set the optional argument
num you can set the time sensitivity in seconds and ignore
the stream’s new-recording flag. This basically lets you
split on larger time increments such as minutes or hours. For
example, -autosplit=3600 splits the recording whenever there
is a gap in the recording that is an hour or longer.
The number of frames to use for buffering device I/O delays.
Defaults to 100.
-card num Tells dvgrab to receive data from FireWire card num. The
default behaviour is to automatically select the first card
containing the first discovered camera If used in conjunction
with -noavc, then no bus probing is performed If used in
conjunction with -guid hex, then only the specified bus is
probed for node with guid hex.
Isochronous channel to receive data from. Defaults to 63,
which is pretty much standard among DV camcorders these days.
If you specify anything different, no attempt is made at this
time to tell the device which channel to use. You must have
some manual way to tell the transmitting device which channel
This option is used to start the collection if a cut occurs
num megabytes (actually, mebibytes) prior to the end of the
collection. This option reduces small files being created
when using the -csize option. When a new collection is
started in this manner, the amount of free space in the
previous collection is stored, and while the following clips
fit within the previous collection, the new collection
starting point is reset.
This option tells dvgrab to split the files when the
collection of files exceeds num . This option is used to
create collections of files that fit perfectly into num
megabytes (actually, mebibytes) (i.e. for archiving onto
DVD). When this occurs, a new collection is started (See also
the -cmincutsize option)
Display HDV debug info, type is one or more of:
-d, -duration time
Set the maximum capture duration across all file splits for a
single capture session (multiple sessions are possible in
interactive mode). The time value is expressed in SMIL2
MediaClipping Time format. See http://w3.org/AudioVideo/ for
Briefly, the formats are:
XXX[.Y]h, XXX[.Y]min, XXX[.Y][s], XXXms,
[[HH:]MM:]SS[.ms], or smpte=[[[HH:]MM:]SS:]FF.
-every n This option tells dvgrab to write every n’th frame only
(default all frames).
-f, -format dv1 | dv2 | avi | raw | dif | qt | mov | jpeg | jpg | mpeg2
Specifies the format of the output file(s). File format can
also be determined if you include an extension on the base
name. The following extensions are recognizable: avi, dv,
dif, mov, jpg, jpeg, and m2t (HDV).
dv1 and dv2 both are AVI files with slightly different
formats. dv2 stores a separate audio track in addition to
the DV video track, which is more compatible with other
applications. dv1 only stores a single, integrated DV track
since the DV format natively interleaves audio with video.
Therefore, while dv1 produces smaller output, some
applications won’t grok it and require dv2 instead. dvgrab
is capable of creating extremely large AVI files—well over 2
or 4 GB—however, compatibility with other tools starts to
decrease over the 1 GB size.
raw stores the data unmodified and have the .dv extension.
These files are read by a number of GNU/Linux tools as well
as Apple Quicktime.
dif is a variation of raw DV that names files with a .dif
extension so they can be more immediately loaded into
qt is Quicktime, but requires that dvgrab be compiled with
jpg or jpeg is for a sequence of JPEG image files if dvgrab
was compiled with libdv and jpeglib. This option can only be
used with a DV input, not HDV (MPEG2-TS).
mpeg2 or hdv is for a MPEG-2 transport stream when using, for
example, a HDV camcorder or digital TV settop box.
Defaults to raw
-F, -frames num
This option tells dvgrab to store at most num frames per file
before splitting to a new file, where num = 0 means ulimited.
The corresponding time depends on the video system used. PAL
shows 25, NTSC about 30 frames per second.
-guid hex If you have more than one DV device, then select one using
the node’s GUID specified in hex (hexadecimal) format. This
is the format as displayed in /proc/bus/ieee1394/devices or
the new kernel 2.6 /sys filesystem. When you specify a GUID,
dvgrab will establish (or overlay) a peer-to-peer connection
with the device instead of listening to the device’s
broadcast. If you supply a hex value of 1, then dvgrab
attempts to discover the device as well as setup a peer-to-
peer connection. This is especially handy with MPEG2-TS
settop boxes, which typically require a connection management
procedure to start transmitting.
-h, -help Show summary of options.
-I, -input file
Read from file instead of FireWire. You can use ’-’ for stdin
instead of using -stdin.
Make dvgrab interactive where single keypresses on stdin
control the camera VTR or start and stop capture. Otherwise,
dvgrab runs in session mode, where it immediately starts
capture and stops as directed or interrupted (ctrl-c).
If using -format jpeg, deinterlace the output by doubling the
lines of the upper field. This is a cheap form of deinterlace
that results in an effective 50% loss in resolution.
If using -format jpeg, scale the output of the height to num
(1 - 2048).
Write to same image file for each frame, instead of creating
a sequence of image files.
If using -format jpeg, set the JPEG quality level from 0
(worst) to 100 (best).
-jpeg-temp name 10
Use a temporary file to create the jpeg, rename the file to
the target file name when done. Useful when using dvgrab with
-jpeg-overwrite for generating a webcam image.
If using -format jpeg, scale the output of the width to num
(1 - 2048).
The JPEG scaling width and height must be both either less
than or greater than the normal frame size. For example, the
scaled size of 700 wide by 525 high yields a nice 4:3 aspect
image with square pixels, but it is illegal for NTSC because
700 is less than the normal width of 720 while the height is
greater than the normal height of 480.
Since DV uses non-square pixels, it is nice to be able to
scale to an image based upon a 4:3 aspect ratio using square
pixels. For NTSC, example sizes are 800x600, 640x480, and
320x240. For PAL, example square pixel sizes are 384x270 and
-jvc-p25 Remove repeat_first_field flag and set frames per second to
25 to correct a stream recorded in JVC’s HDV P25 mode.
-lockstep Align capture to a multiple of -frames based on timecode.
This is useful for redundancy, when more than one machine is
capturing from the same FireWire device, and you want to
ensure each file contains the same footage. To ensure the
files from each machine have the same name use the -timecode
option and the same base name.
If num frames are dropped consecutively, then close the file
and resume capture on the next lockstop interval. If num is
-1, then permit an unlimited number of consecutively dropped
frames; this is the default.
If num frames are dropped in the current file, then close the
file and resume capture on the next lockstep interval. If num
is -1, then permit an unlimited number of total dropped
frames; this is the default.
-noavc Disable use of AV/C VTR control. This is useful if you are
capturing live video from a camera because in camera mode, an
AV/C play command tells the camera to start recording,
perhaps over material on the current tape. This applies to
either interactive more or non-interactive because non-
interactive stills sends a play and stop to the VTR upon
capture start and stop.
-nostop Disables sending the AV/C VTR stop command when exiting
-opendml If using -format dv2, create an OpenDML-compliant type 2 DV
AVI. This is required to support dv2 files >1GB. dv1 always
supports files >1GB.
When the camcorder is in record mode, this option causes
dvgrab to only capture when the camcorder is recording and
not paused. Normally, when in record mode, dvgrab always
captures to let you use the camcorder purely as a camera
where the computer operator is in control. This option makes
dvgrab act like the VCR where the camera operator controls
when capture takes place. This is very handy when used with
the -autosplit option to automatically create a new file for
each shot. This option requires AV/C and will not work with
the -noavc option.
-rewind Rewind the tape completely to the beginning prior to starting
capture. Naturally, this requires AV/C; however, perhaps not
so obvious is that this does not apply to interactive mode.
Normally, the capture status information is displayed after
finished writing to each file. This option makes it show the
capture status during capture, updated for each frame.
-s, -size num
This option tells dvgrab to store at most num megabytes
(actually, mebibytes) per file, where num = 0 means unlimited
file size for large files. The default size limit is 1024 MB.
-srt Generate subtitle files containing the recording date and
time in SRT format. For each video file that is created two
additional files with the extension .srt0 and .srt1 are
created. They contain the recording date and time as
subtitles in the SRT format. The .srt0 file contains the
subtitles with timing based on the running time from the
start of the current file. Use this file if you transcode to
a format like AVI. The .srt1 file contains the subtitles with
timing based on the time code as delivered by the camera.
The mplayer program understands this type of subtitles.
-stdin Read the DV stream from a pipe on stdin instead of FireWire.
-timecode Put the timecode of the first frame of each file into the
Put information on date and time of recording into file name.
-timesys Put system rather than recording date and time into file
name. This is useful when using converter devices that do
not change the recording date time in the DV stream.
-V, -v4l2 Capture from a USB Video Class (UVC) device that supports DV.
This uses the uvcvideo kernel module via V4L2. The default
device file is /dev/video. Use the -input option to set a
different device file.
Show version of program.
-24p For Quicktime DV, set the frame rate as 24 fps in the
Quicktime file. This only works as expected when the video
has been shot in 24p mode.
-24pa For Quicktime, DV, in addition to setting the frame rate to
24 in the Quicktime file, also reverse the 2:3:3:2 pulldown
process by removing the interlaced "C" frame. This only works
as expected when the video has been shot in 24p Advanced
mode. See http://www.adamwilt.com/24p/
Captures video data from the default FireWire source and
stores it to files foo-001.avi, foo-002.avi, etc.
dvgrab -frames 25 foo-
Assuming a PAL video source, this command records one
second’s worth of video data per file.
dvgrab -autosplit -frames 750 -timestamp foo-
Records video data from the default FireWire source, cuts it
into chunks of 30 seconds (assuming PAL) or when a new
recording starts and names the resulting files according to
date and time info in the videostream.
dvgrab -autosplit -size 1998 -csize 4400 -cmincutsize 10 foo-
Records video data from the default FireWire source, cuts it
into chunks when a new recording starts or when the current
file exceeds 1998 megabytes (actually, mebibytes), or the
current collection of files exceeds 4400 megabytes. It also
reduces the size of the smallest file made due to a
collection size cut to 10 megabytes.
This option is perfect for backing up DV to DVD’s as 2 Gb is
around the maximum file size that (the current) linux
implementation of the ISO9660 filesystem can handle!
Warning: It is possible to make ISO9660 filesystems with
files greater than 2 Gb, but the current linux IS09660 driver
can’t read them! Newer linux kernels may be able to handle
ISO9660 filesystems with filesizes greater than 2 Gb.
dvgrab -format hdv -autosplit
Capture from a HDV camcorder.
dvgrab -format mpeg2 -guid 1
Record from a digital TV settop box.
dvgrab -jpeg-over -jpeg-w=320 -jpeg-h=240 -d smpte=1 webcam.jpeg
Capture a single frame, save it as a JPEG named webcam.jpg
and exit. This example also demonstrates option handling.
You only need to specify enough of a long option name to
uniquely identify it. You can use space or equal sign to
separate option name and argument. The file format is
inferred from the filename extension. Also, since -jpeg-
overwrite is used, the filename will be exactly "webcam.jpeg"
and not include any numbers.
dvgrab -V Capture over USB from a UVC compliant DV device.
dvgrab -v4l -input /dev/video1
Capture over USB from a UVC compliant DV device using device
dvgrab -format=hdv -autosplit=28800 -srt foo-
Capture from a HDV camcorder, splitting whenever there is a
gap in the recording that lasts longer than 8 hours. This
will likely generate a separate file for each day (useful for
holiday videos). It will also generate subtitle files.
Assuming that the files foo-001.m2t and foo-002.m2t are
generated, the corresponding subtitle files will be
foo-001.srt0, foo-001.srt1 and foo-002.srt0, foo-002.srt1.
You can use the subtitle files to show the recording date and
time while viewing the video.
Dan Dennedy <email@example.com> and Daniel Kobras firstname.lastname@example.org>
See http://www.kinodv.org/ for more information and support.