Provided by: mjpegtools_2.1.0+debian-5_amd64 bug


       lavrec - Record MJPEG-video from a zoran/video4linux-device


       lavrec [options] filename(s)


       lavrec  can be used to record video in MJPEG format (either quicktime or AVI) from a zoran
       video-capture device, such as the Miro/Pinnacle DC10(+), the Iomega  Buz  or  Linux  Media
       Labs'  LML33, or from a generic video4linux device, such as the cheap Bt848 or Bt878 based
       TV-cards that are being sold in every computer shop around the corner.


       lavrec accepts the following options:

               The file to record to (*.avi, *.qt). Use a % to record to  multiple  files  (using
               file%02d.avi  will  record to file00.avi, file01.avi, etc). You can also give more
               than one filename, which will have the  same  effect.  This  will  avoid  problems
               resulting  from  filetype  or filesystem size limits. AVI, for example, has a 2 GB
               limit, as does ext2fs in 2.2.x kernels.

               By default, lavrec will capture in a mode that is only suitable for recording from
               hardware    MJPEG    devices.   Using   this   option   will   make   lavrec   use
               software-JPEG-encoding (using libjpeg) which enables MJPEG-video-capture from many
               generic video4linux devices (such as Bt848/Bt878-based ones).

               This option adds support for the EM28XX USB driver. As this driver is V4L2. As the
               original BTTV software implementation assumes that the driver supports V4L it will
               not  work  with  the  EM28XX  driver, not even with the V4L1 emulation layer. This
               option enables two things:
                 It enables the V4L2 calls to make interaction with this driver possible
                 It select the cards YUV Packed format and  converts  this  in  software  to  YUV
               Planar  The  process is after this the same as for the BTTV driver.  ome things of
               note are the fact that the EM28XX driver expects 48KHz  audio  recording.  If  you
               choose  slower  things will work, but a lot of deleted/inserted frames will occur.
               The lower the sample rate, the worse this problem  gets.  Recording  at  48KHz  is
               therefore  recommended.   This  code  was  tested  and found working with a DVC100
               Pinnacle Dazzle.  This option should work with any EM28XX,  but  this  hasnt  been
               tested.   It  might work for any other V4L2 device that outputs YUV packed format,
               this has however not been tested. Feedback would be appreciated.

       -f/--format [a|A|q|m]
               The format in which the video should be saved to the harddisk.
                 a - MJPEG AVI
                 A - MJPEG AVI with fields exchanged
                 q - Quicktime
               By default, lavrec will look at the extension of the first file (*.avi, *.qt)  and
               choose a format based on that.

       -i/--input [p|P|n|N|s|S|t|T|f|a]

       -i/--input input[:norm]
               The recording source and the video source standard format.
                p - PAL through Composite or 1st Bt8x8 input
                P - PAL through SVHS- or 2nd Bt8x8 input
                t - PAL through TV-tuner- or 3rd Bt8x8 input
                n - NTSC through Composite or 1st Bt8x8 input
                N - NTSC through SVHS- or 2nd Bt8x8 input
                T - NTSC through TV-tuner- or 3rd Bt8x8 input
                s - SECAM through Composite or 1st Bt8x8 input
                S - SECAM through SVHS- or 2nd Bt8x8 input
                f - SECAM through TV-tuner- or 3rd Bt8x8 input
                a - (or every other letter) Autosense (default)
               The  input can be specified using either single letters or an input number with an
               optional norm, where the number specifies the n'th input of the card, ranging from
               1 to 10. Using a numerical input is necessary when using input four or higher with
               a card that has more than three inputs, for instance the AverMedia 6  Eyes.   When
               using numeric input with the norm it must contain the whole norm name; valid names
               are pal, ntsc and secam. You can use numeric input selection for cards  with  only
               three  inputs,  too, which most Zoran based cards has.  "-i 2:pal" used with a Buz
               would be equivalent to "-i P", recording from the S-Video input in PAL format.

       -d/--decimation num
               Recording decimation, either 1, 2 or  4.  This  will  decimate  the  size  of  the
               recorded  video  horizontally  and  vertically.  To  use  different horizontal and
               vertical decimations, use two numbers, the first one being the horizontal and  the
               second  one being the vertical (-d 12).  Note: this option can only be used during
               hardware recording.

       -g/--geometry WxH(+X+Y)
               For hardware recording: An X-style geometry string, giving  the  geometry  of  the
               undecimated  subframe to record. The default is the full frame, so 720x576/480+0+0
               for  Buz/LML33-users  and  640x480+0+0  or  768x576+0+0  for  DC10(+)-users.   For
               software  recording:  The  size of the video to be captured.  Currently, width and
               height need to be a multiple of 16. You always capture the full frame  since  most
               video4linux devices donĀ“t support subframe capture.

       -q/--quality num
               Quality  of  the  JPEG-video  to  be  recorded (in percent). This must be a number
               between 0 and 100. Lower quality should  generally  mean  lower  filesize,  higher
               quality  will  take  more diskspace but will give more detailed perfectness in the
               resulting recorded video. Default is 50%.

       -C/--channel LIST:CHAN
               Choose the channel to record from (xawtv-style). By default, lavrec will just  use
               the current TV channel.

       -t/--time num
               Recording time in seconds. The default is unlimited. To stop capturing video while
               recording, use Ctrl-C.

               Single-frame capture mode. This means that one can capture individual frames  from
               the capture device.

       -T/--time-lapse num
               time-lapse  factor,  which  means  that  only  every <num>th frame is saved to the
               recording file.

               If this option is given, lavrec will wait for  the  user  to  press  enter  before
               starting to record.

               This option turns off all possible interactivity options and limits console output
               as much as possible. Useful for cron/scheduled recordings.

       -a/--audio-bitsize num
               Audio size in bits, either 0, 8 or 16 (default). 0 means no audio.

       -r/--audio-bitrate num
               Audio sampling rate in Hz. This must be a sampling rate which is supported by  the
               soundcard.  Often-supported  audio  sampling rate values are 11025, 22050 or 44100

               Capture in stereo. By default, lavrec captures in mono.

       -l/--audio-volume num
               Recording level. This must  be  a  value  between  0  (no  sound)  and  100  (loud
               recording). -1 (default) means to not touch the mixer settings at all.

               Mute  sound  output  while recording. This can be useful when recording sound from
               the microphone to disable echos. This option is disabled by default.

       -R/--audio-source [l|m|c]
               Recording source, either (l)ine-in, (m)icrophone or (c)d-rom. The  default  is  to
               record from line-in (l).

               Use the read() system call rather than the mmap() system call for audio recording.
               This may fix many audio recording problems.

       -c/--synchronization [0|1|2]
               Audio/video synchronization level efforts. (0) means no synchronization, (1) means
               that  lavrec  will  replicate  frames  for lost frames. (2) means that lavrec will
               replicate frames for lost frames and do sync correction.  Default is 2.

       -n/--mjpeg-buffers num
               Number of MJPEG-buffers. Default is 32. Try changing this number if you have  many
               lost frames.

       -b/--mjpeg-buffer-size num
               MJPEG buffersize in kilobytes. The default is 256 kB.

       --max-file-size num
               The  maximum file size per JPEG file. By default, lavrec uses the maximum possible
               size for that specific recording format.

       --max-file-frames num
               The maximum number of frames per per JPEG file. By default, the number  of  frames
               is only limited by other factors, such as maximum file size.

       --file-flush num
               Flush the file to disk after every num frames captured.

       -v/--verbose num
               Verbosity level (0, 1 or 2). Default is 0.


       The following environment variables can be recognized by lavrec:

               The video device. Default is /dev/video

               The audio device. Default is /dev/dsp

               The mixer device. Default is /dev/mixer


       Lavrec will output the current recording state. Typically, this looks like:
       0.06.14:22 int: 00040 lst:0 ins:0 del:0 ae:0 td1=0.014 td2=0.029
       The  first  part  is  the  time that has been spent recording (hours - minutes - seconds -
       frames).  int is the interval (in milliseconds) between two captured frames  (this  should
       be  around  40 for PAL/SECAM and 33 for NTSC).  lst is the number of lost frames.  ins and
       del are the number of frames inserted and deleted for sync correction.  ae is  the  number
       of audio errors.  td1 and td2 are the audio/video time-difference (out-of-sync'ness).


       Okay,  that's  a  lot of options. Now how would I normally record video?  Let's assume you
       want to record at VCD resolution (352x288) from PAL source.  You might  want  some  higher
       quality  than default (80%). You use default audio options and record to an AVI file. That
       having said, your recording command line would look like:

       From hardware MJPEG devices (S-video input)
               lavrec --format=a --input=P --quality=80 --decimation=2 /path/to/file.avi

       From normal video4linux devices
               lavrec --software-encoding --format=a  --input=p  --quality=80  --geometry=352x288


       lavrec  should  be  able  to detect automatically whether to use software JPEG encoding or
       whether to use the card's hardware JPEG encoding features (if available).

       Besides that, software JPEG encoding seems,  for  some  people,  to  cause  small  out-of-
       sync'ness. SMP support for JPEG encoding is currently work-in-progress.


       This man page was written by Ronald Bultje.
       If  you  have questions, remarks, problems or you just want to contact the developers, the
       main mailing list for the MJPEG-tools is:
       For more info, see our website at


       mjpegtools(1), lavplay(1)