Section: Misc. Reference Manual Pages (1)
dvgrab --- Capture DV or MPEG-2 Transport Stream (HDV) video and audio data from FireWire
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.
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.
- -a[num], -autosplit[=num]
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.
- -buffers num
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.
- -channel num
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 to use.
- -cmincutsize num
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
- -csize num
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)
- -debug type
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 the specification.
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 | hdv
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).
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 MainConcept MainActor5.
qt is Quicktime, but requires that dvgrab be compiled with libquicktime.
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
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.
- -i, -interactive
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.
- -jpeg-height num
If using -format jpeg, scale the output of the height to num
(1 - 2048).
- -jpeg-overwrite name
Write to same image file for each frame, instead of creating a sequence of
- -jpeg-quality num
If using -format jpeg, set the JPEG quality level from 0 (worst) to
- -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.
- -jpeg-width num
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
Remove repeat_first_field flag and set frames per second to 25 to correct a
stream recorded in JVC's HDV P25 mode.
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.
- -lockstep_maxdrops num
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.
- -lockstep_totaldrops num
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.
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
Disables sending the AV/C VTR stop command when exiting dvgrab.
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.
- -r, -recordonly
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 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.
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.
Read the DV stream from a pipe on stdin instead of FireWire.
Put the timecode of the first frame of each file into the file name.
- -t, -timestamp
Put information on date and time of recording into file name.
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.
- -v, -version
Show version of program.
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.
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/
- dvgrab foo-
Captures video data from the default FireWire source
and stores it to files foo-001.avi,
- 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
- 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 file /dev/video1.
- 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
Dan Dennedy <firstname.lastname@example.org
> and Daniel Kobras email@example.com
See http://www.kinodv.org/ for more information and support.