Simple guide to grab desktop with FFMPEG
How to grab desktop with FFMPEG
1. just desktop no sound
2. desktop with microphone sound
3. webcam with sound
4. desktop with onboard sound (music or video)
1.
Quote:
ffmpeg -f x11grab -s `xdpyinfo | grep 'dimensions:'|awk '{print $2}'` -r 25 -i :0.0 -sameq ./Desktop/mydesktop.mkv
higher quality
Quote:
ffmpeg -f x11grab -s `xdpyinfo | grep 'dimensions:'|awk '{print $2}'` -r 30 -qscale 1 -i :0.0 ./Desktop/mydesktop.mkv
2.
Quote:
ffmpeg -f alsa -ac 2 -i pulse -f x11grab -r 30 -s 1280x1024 -i :0.0 -acodec flac -vcodec libx264 -threads 0 ./Desktop/mydesktop.mkv
make sure 1280x1024 matches your specs .... if not change to suit your settings
3.
Quote:
ffmpeg -f alsa -ac 2 -i pulse -f video4linux2 -i /dev/video0 -vcodec libx264 -acodec flac -s 320x240 -r 30 -y ./Desktop/mywebcam.mkvi
4.
Quote:
sudo apt-get install pavucontrol
find pavucontrol in applications/sound and video
click on recording/click on box/pick monitor of internal audio
Nota Bene: you may need to run the code below in your terminal first to bring up the options on pavucontrol
Then run as in 2.
Quote:
ffmpeg -f alsa -ac 2 -i pulse -f x11grab -r 30 -s 1280x1024 -i :0.0 -acodec flac -vcodec libx264 -threads 0 ./Desktop/mydesktop.mkv
or .avi
DO NOT forget to reset your pavucontrol at the end otherwise next time you try do microphone recording settings will be wrong
Re: VERY simple guide to grab desktop with FFMPEG
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Re: VERY simple guide to grab desktop with FFMPEG
Thank You !!
Dropped it in a bash script :
Code:
#!/bin/bash
dir="$HOME/Poker/Screens/Vids"
size=$( xdpyinfo | grep 'dimensions:' | awk '{print $2}' )
name=$( date +'%b.%d_%I:%M%#p' )
video="$dir/$name.mkv"
term="gnome-terminal --geometry 78x2+5-2 -t "recording" -x"
$term ffmpeg -f x11grab -s $size -r 30 -qscale 1 -i :0.0 $video
Tied it to a hotkey( Ctrl+PrtSc ) :
Quote:
- Main Menu->System->Preferences->Keyboard Shortcuts
- add the full path -> (ie) "/home/me/bin/screencap.sh"
And caught a memory :
Re: VERY simple guide to grab desktop with FFMPEG
More options for x11grab - positioning of the grab area if less than your screen.
for example, if you want to capture 1024x768 from the middle of your 1920x1080 display
x position = 1920-1024 = 896 then /2 = 448
y position = 1080-768 = 312 then /2 = 156
then your command would read (using 1. from shantiq's examples):
Quote:
ffmpeg -f x11grab -s 1024x768 -r 25 -i :0.0+448,156 -sameq ./Desktop/mydesktop.mkv
Re: VERY simple guide to grab desktop with FFMPEG
Jose, I tried the modification you suggested
Code:
ffmpeg -f x11grab -s 1024x768 -r 25 -i :0.0+448,156 -sameq ./Desktop/mydesktop.mkv
but it failed & threw this error
Quote:
FFmpeg version SVN-r0.5.1-4:0.5.1-1ubuntu1.1, Copyright (c) 2000-2009 Fabrice Bellard, et al.
configuration: --extra-version=4:0.5.1-1ubuntu1.1 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib --disable-stripping --disable-vhook --enable-runtime-cpudetect --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --enable-libdc1394 --enable-shared --disable-static
libavutil 49.15. 0 / 49.15. 0
libavcodec 52.20. 1 / 52.20. 1
libavformat 52.31. 0 / 52.31. 0
libavdevice 52. 1. 0 / 52. 1. 0
libavfilter 0. 4. 0 / 0. 4. 0
libswscale 0. 7. 1 / 0. 7. 1
libpostproc 51. 2. 0 / 51. 2. 0
built on Mar 31 2011 18:53:20, gcc: 4.4.3
[x11grab @ 0x9619a60]device: :0.0+448,156 -> display: :0.0 x: 448 y: 156 width: 1024 height: 768
[x11grab @ 0x9619a60]shared memory extension found
X Error of failed request: BadMatch (invalid parameter attributes)
Major opcode of failed request: 145 (MIT-SHM)
Minor opcode of failed request: 4 (X_ShmGetImage)
Serial number of failed request: 11
Re: VERY simple guide to grab desktop with FFMPEG
Quote:
Originally Posted by
Jose Catre-Vandis
More options for x11grab - positioning of the grab area if less than your screen.
for example, if you want to capture 1024x768 from the middle of your 1920x1080 display
x position = 1920-1024 = 896 then /2 = 448
y position = 1080-768 = 312 then /2 = 156
You can use xwininfo to figure out the coordinates for you by simply clicking on the window. More info about that (and much more):
HOWTO: Proper Screencasting on Linux
Quote:
Originally Posted by
Jose Catre-Vandis
then your command would read (using 1. from shantiq's examples):
Code:
ffmpeg -f x11grab -s 1024x768 -r 25 -i :0.0+448,156 -sameq ./Desktop/mydesktop.mkv
-sameq does not mean same quality. The documentation was misleading, but it has been changed in recent FFmpeg to "use same quantizer as source". It's generally recommended to use -qscale instead of -sameq, and "-qscale 2" is generally considered visually lossless for MPEG-1/2/4.
Re: VERY simple guide to grab desktop with FFMPEG
thnx for clarification Fake One
Yes Verb3k knows his stuff
This is the section you refer to no doubt
Quote:
FAQ:
Q: How do I get the exact size and coordinates of a specific window I want to capture?
A: Use a command called “xwininfo“. Basically, you run this command and then click on the window that you want to capture. It will then print the window information to the terminal. This command prints a lot of information, but what you need are the following lines:
Absolute upper-left X:
Absolute upper-left Y:
Width:
Height:
If the command, for example, prints:
Absolute upper-left X: 383
Absolute upper-left Y: 184
Width: 665
Height: 486
Then, you will adapt it to FFmpeg like this:
Code:
-s 664x486 -i :0.0+383,184
Note that we used 664 instead of 665 for the width since ffmpeg only accepts resolutions divisible by 2.
You can use the following command line combination with "xwininfo" to only print the information you’ll be needing:
Code:
xwininfo | grep -e Width -e Height -e Absolute
Works like a dream! Great tool
Re: VERY simple guide to grab desktop with FFMPEG
Love the forums.
Thanks everyone
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Re: VERY simple guide to grab desktop with FFMPEG
also i find sometimes one wants to just grab desktop sound
and this here really works well
1. Install pavucontrol and sox ( pavucontrol for sound monitoring and sox for recording)
Code:
sudo apt-get install pavucontrol sox
2. Play music or video on desktop
3. open pavucontrol or from applications/sound and video
4.
Run
Code:
rec nameyouwant.flac
5. On pavucontrol click on recording then pick "Monitor of analogue internal audio stereo " see image
6. Stop recording and start again now you have the correct sound monitoring
7. At the end make sure to return pavucontrol to original setting of "internal analogue audio stereo"
===================================
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ps if you want other formats
for lossless sound use flac above or for a thinner file ogg (112k)
Code:
rec nameyouwant.ogg
you can override settings thus
Quote:
By default the encoding quality level is 3
(which gives an encoded rate of approx. 112kbps), but this can
be changed using the -C option (see above) with a number from -1
to 10; fractional numbers (e.g. 3.6) are also allowed.
example
Code:
rec -c 9 nameyouwant.ogg
OR if you want a 128k mp3 you can add this functionality to sox thus (thanx Andrew46)
Code:
sudo apt-get install sox libsox-fmt-all
then run
Code:
rec nameyouwant.mp3
And override this too
Quote:
MP3 compression parameters can be selected using SoX's -C option
as follows (note that the current syntax is subject to change):
The primary parameter to the LAME encoder is the bit rate. If
the value of the -C value is a positive integer, it's taken as
the bitrate in kbps (e.g. if you specify 128, it uses 128 kbps).
Example
Code:
rec -C 256 nameyouwant.mp3
or
Code:
rec -C 320 nameyouwant.mp3
other formats info here formats like dat cdda ircam are available if you like really high-end formats
Code:
rec nameyouwant.dat
gives you a really heavy file of extremely good quality
Re: VERY simple guide to grab desktop with FFMPEG
Thanks shantiq now I can record my desktop without problems
