capture X11 to video

[vinnywright]

so I was playing around with ffmpeg last night and reading the man page when I saw that it had a section on X11 grabbing.

and after 2 attempts WOW I can make a vidio of my desktop 8)

the first attempt with

ffmpeg -f x11grab -s cif -r 25 -i :0.0 /tmp/out.mpg

only grabbed a 352x288 section of the upper left corner of the screen but some more reading got me to " -s xga " for 1024x768 (see man ffmpeg ) witch is what my display is and got the hole screen

I then made my mother a nice little video showing some of the cool window switching effects and 3D desktop that I had been trying to describe to her ...........she was amased.

VINNY

[Detonate]

Re: capture X11 to video

Next step. Add sound to make instructional videos.

[vinnywright]

Re: capture X11 to video

Aaaa yes you can merge an audio with a video but I dont have a Mic to test that out with

but that would be grate for the graygeek and all the people he supports

VINNY

[dibl]

Re: capture X11 to video

Hey Vinnie -- thanks for this! I'm a ffmpeg noob -- I only know how to rip the audio out of downloaded youtube videos. But this is very helpful for anyone who want to show a desktop maneuver -- thank you!

[vinnywright]

Re: capture X11 to video

Hey Vinnie -- thanks for this! I'm a ffmpeg noob -- I only know how to rip the audio out of downloaded youtube videos. But this is very helpful for anyone who want to show a desktop maneuver -- thank you!

Cool.....I use winff to do what your doing not the CLI and ffmpeg directly (me ffmpeg n00b as well)..... but the ffmpeg man page gives some good examples to build on for lots of cool things.

and though a vary long man page mencoder gives some good ones to.

VINNY

[GreyGeek]

Re: capture X11 to video

More than anything else (on my notebook) the size of the desired video controls how many FPS I can record without distortion or sound problems. The repository app, recorditnow, has worked well for me in the past.

Here's some of the commands I've played with, but I didn't originate any of them.

record_with_webcam.sh
#!/bin/bash
mencoder tv:// -tv driver=v4l2:width=320:height=240:device=/dev/video0:forceaudio:adevice=/dev/dsp -ovc lavc -oac mp3lame -lameopts cbr:br=64:mode=3 -o webcam.avi

which is a script I have in my home account for recording from my webcam.

Here are others...

mplayer -fps 15 tv:// -tv driver=v4l2:width=640:height=480:device=/dev/video0 

mencoder tv:// -tv driver=v4l2:width=60:height=40:fps=60:device=/dev/video0 -[b]nosound[/b] -ovc lavc -lavcopts vcodec=mjpeg -o test.avi

And, I no longer remember when or from where I obtained this discussion on using ffmpeg to
record videos in Linux, but ffmpeg seems to work well for me.

Capture video of a linux desktop using ffmpeg

Xdpyinfo is a utility for displaying information about an X server. It is used to examine the capabilities
of a server, the predefined values for various parameters used in communicating between clients and the server, and the different types of screens and visuals that are available. (see man xdpyinfo).

We use it as follows to determine the screen resolution:

xdpyinfo | grep 'dimensions:'|awk '{print $2}'

FFmpeg can grab the X11 display

ffmpeg -f x11grab -i :0.0 /tmp/out.mpg

0.0 is display.screen number of your X11 server, same as the DISPLAY environment variable.

-r will be used to set the output file to 25 fps.

Now you know how to capture video of a linux desktop using ffmpeg:

ffmpeg -f x11grab -s `xdpyinfo | grep 'dimensions:'|awk '{print $2}'` -r 25 -i :0.0 -sameq /tmp/out.mpg

========================
i am always having to look this up. now at least i'll have it here:

ffmpeg -f x11grab -vc theora -s vga -r 24 -b 1200 -g 300 -i :0.0 ~/Videos/screenCapture1.ogv



option by option:

-f x11grab = take video from X...ffmpeg must have been compiled with enable-x11grab included; 
your distro or version may or may not have this enabled!

-vc = Video Codec...usually you will have ogg theora, xvid, [ff]mpeg (the default), and x264 available

-s = size. see the ffmpeg man page for details; vga is something like 800x600 and there are many 
other sizes available. know that it starts from the top left corner counts pixels from there.

-r = frame rate. lower frame rate gives smaller file size but looks a little less smooth

-b = bitrate. higher bitrate looks better but makes for a larger file size

-g = GOP size...300 provides a pretty nice looking image without increasing file size too much; 
it's got one intra frame every...i dunno....300/24 = 12.5 seconds or so.

-i = input...in this case it's :0.0 meaning your main screen. or display. or whatever it's called.


As you can imagine, there are a LOT more options available to you via man ffmpeg. Probably 
the most notable would be the offset, so if you wanted the capture area to not start at the 
very top left, you could tell it to, say, go down 10 pixels and over 10 pixels and THEN capture 
vga-size images, or xga-size images, or whatever.

======================
ffmpeg -f x11grab -s wxga -r 25 -i :0.0 -sameq /tmp/out.mpg
===================
Creating screencasts using ffmpeg

While experimenting with creating demo videos for QBoard, i had to tinker quite a lot to get 
the video capture working how i wanted it. For anyone doing screencasts (whether of QBoard 
or not), here's a simple shell script which can simplify the process:

#!/bin/bash
# Generates an ffmpeg command line for capturing a given X11 window.
# Usage: $0 [optional output file name]
# It will prompt you to click on the window you want to capture.
# Output is simply echoed, for use in copy/pasting (adjusting/adding
# parameters as needed).
# Tip: the command uses screen coordinates, so do not resize or move
# the target window once capturing as begun.
echo "Click the window to capture..."

tmpfile=/tmp/screengrab.tmp.$$
trap 'touch $tmpfile; rm -f $tmpfile' 0

xwininfo > $tmpfile 2>/dev/null
left=$(grep 'Absolute upper-left X:' $tmpfile | awk '{print $4}');
top=$(grep 'Absolute upper-left Y:' $tmpfile | awk '{print $4}');
width=$(grep 'Width:' $tmpfile | awk '{print $2}');
height=$(grep 'Height:' $tmpfile | awk '{print $2}');
geom="-geometry ${width}x${height}+${left}+${top}"
echo "Geometry: ${geom}"
size="${width}x${height}"
pos="${left},${top}"
echo "pos=$pos size=$size"

out=${1-screengrab.avi}
#test -f $out && rm $out

framerate=4
echo "# ffmpeg command"
echo -n "sleep 2; " # give caller time to switch to captured window
echo ffmpeg -f x11grab \
  -r ${framerate} \
  -s ${size} \
  -i ${DISPLAY-0:0}+${pos} \
  -sameq \
  $out

It's used like this:

stephan@jareth:/space/stephan$ ./screencap.sh
Click the window to capture...
Geometry:  -geometry 598x686+764+0
pos=764,0 size=598x686
# ffmpeg command
sleep 2; ffmpeg -f x11grab -r 4 -s 598x686 -i :0.0+764,0 -sameq screengrab.avi

The output is intended to be copy/pasted to your shell (or script, or whatever), adding 
or adjusting parameters as necessary. The sleep call is helpful when running the command 
from a shell, as it gives the caller time to click on the target window before ffmpeg starts 
capturing. 
===================================

[Rog131]

Re: capture X11 to video

A Qt gui

> Qt-Apps.org >> qx11grab:

Description:
qt4 applet for recording x11 windows with ffmpeg

Developers home > About qx11grab

is a systray program that uses FFmpeg for recording X11 desktop windows. this program grab window dimensions with xevent and prepare the command line for ffmpeg with configuration options. it sends the generated parameter list to a new FFmpeg process. qx11grab is not the recording software it prepare all commands for FFmpeg....

There are both the sources and the binaries available.

apt-cache show qx11grab:

Package: qx11grab
Version: 0.2.1-1
Architecture: i386
Maintainer: Juergen Heinemann
...
Homepage: http://qx11grab.hjcms.de
Description: a systray program that uses FFmpeg for recording X11 desktop windows
this program grab window dimensions with xevent and prepare the
command line for ffmpeg with configuration options.
it sends the generated parameter list to a new FFmpeg process.
.
qx11grab is not the recording software it prepare all commands for FFmpeg.

[img width=388 height=400]http://img530.imageshack.us/img530/1710/grab.jpg[/img]

[GreyGeek]

Re: capture X11 to video

Thanks Rog!


It wasn't in the Ubuntu repository but I found it from the link you supplied. However .... it is only for the 32bit OS. Gdbi does not install it.

EDIT:
I dl'd the source and ran cmake. It failed because it could not find the alsa-lib library, which isn't on my system. My system has the directories
/usr/lib/alsa-lib
/usr/lib32/alsa-lib
but they do not meet the cmakelist.txt "FIND_PACKAGE (ALSA REQUIRED)" requirements and I am not going to mess up my sound installing the necessary alsa requirements.

[dibl]

Re: capture X11 to video

It's not in the Debian repos either -- at least not in 64-bit arch.

But that's good to know -- thanks Rog and GG. I did do a practice run on my 1600x1200 desktop with:

~$ ffmpeg -f x11grab -s uxga -r 30 -i :0.0 /tmp/out.mpg

Worked perfectly!

[Rog131]

Re: capture X11 to video

64


> Personal Package Archives for Ubuntu >> PPA for Rog131 >>> Package name contains: qx11grab


Older:

qx11grab (0.1.8~karmic~ppa2) karmic

- qx11grab_0.1.8~karmic~ppa2_amd64.deb
- qx11grab_0.1.8~karmic~ppa2_i386.deb
- qx11grab_0.1.8~karmic~ppa2_lpia.deb


Latest:

qx11grab (0.2.3~rc1~maverick~ppa2) maverick

- qx11grab_0.2.3~rc1~maverick~ppa2_amd64.deb (273.9 KiB)
- qx11grab_0.2.3~rc1~maverick~ppa2_i386.deb (274.5 KiB)



More links:

> FAQ: Repositories
> Using the PPA repositories

[dibl]

Re: capture X11 to video

~maverick~ppa2_

Aha!

Thank you Rog!

[GreyGeek]

Re: capture X11 to video

Too bad, so sad ... none of those offerings work in a 64bit LL

[dibl]

Re: capture X11 to video

Yep, it installed correctly from the Rog repo -- 64-bit -- looks good. Now I must think of a screen maneuver worth recording!

[GreyGeek]

Re: capture X11 to video

Hey, maybe you can use CDE to package up a copy of your gx11grabber and email it to me?

[Rog131]

Re: capture X11 to video

Lucid packages

The standard Lucid packages are a bit older:

-- checking for modules 'libavformat>=52.38.0;libavcodec>=52.35.0'
-- package 'libavformat>=52.38.0' not found
-- package 'libavcodec>=52.35.0' not found
CMake Error at modules/FindPkgConfig.cmake:259 (message):
A required package was not found

Adding a patch to reduce the needed libavformat version to 52.31.0 and libavcodec version to 52.20.1.

=>

-- checking for modules 'libavformat>=52.31.0;libavcodec>=52.20.1'
-- found libavformat, version 52.31.0
-- found libavcodec, version 52.20.1

=>

qx11grab_0.2.3~rc1~lucid~ppa1_amd64.deb
qx11grab_0.2.3~rc1~lucid~ppa1_i386.deb


The qx11grab (i386) seems to work without problems.