Got black screen when recording screen from xvfb by ffmpeg x11grab device

Posted by shawnzhu on Super User See other posts from Super User or by shawnzhu
Published on 2014-03-11T02:20:11Z Indexed on 2014/06/07 15:28 UTC
Read the original article Hit count: 673

Filed under:

ffmpeg

|

xvfb

I'm trying to record video from a firefox run by xvfb-run but it always output nothing in the video file except black screen.

Here's what I did:

start a firefox, open google.com:

$ xvfb-run firefox https://google.com

Then it will use the default display server number 99. I can see the display information by command xdpyinfo -display :99.

A screenshot works very well by command:

$ xwd -root -silent -display :99.0 | xwdtopnm |pnmtojpeg > screen.jpg

Start using ffmpeg to record a video:

$ ffmpeg -f x11grab -i :99.0 out.mpg

When I play the video file out.mpg, there's black screen all the time.

Is there any parameter I missed?

Updates

I made progress that the video works instead of black screen only by this command:

$ ffmpeg -y -r 30 -g 300 -f x11grab -s 1024x768 -i :99 -vcodec qtrle out.mov

Notice it requires the screen resolution matches by specify more options to xvfb-run:

$ xvfb-run -s "-screen 0 1224x768x16" -a firefox http://google.com

But I still want to get more feedbacks and answers here.

© Super User or respective owner

Related posts about ffmpeg

how to install ffmpeg in cpanel

as seen on Super User - Search for 'Super User'
i'm using dedicated server(linux) so i need to install ffmpeg in cpanel so here ffmpeg i found in Main Software Install a Perl Module but i writing script in php so how can i install ffmpeg phpperl when i'am trying to install ffmpeg in perl module i get this response Checking C compiler… >>> More
FFMpeg-PHP Installation Error

as seen on Server Fault - Search for 'Server Fault'
While installing FFmpeg-PHP, I got this interesting error: /usr/downloads/ffmpeg-php-0.6.0/ffmpeg_movie.c: In function 'zim_ffmpeg_movie_getAudioStreamId': /usr/downloads/ffmpeg-php-0.6.0/ffmpeg_movie.c:1051: error: 'CODEC_TYPE_AUDIO' undeclared (first use in this function) /usr/downloads/ffmpeg-php-0… >>> More
git problems installing stuff [closed]

as seen on Super User - Search for 'Super User'
root@Frenzen:~# cd root@Frenzen:~# git clone --depth 1 git://source.ffmpeg.org/ffmpeg Initialized empty Git repository in /root/ffmpeg/.git/ root@Frenzen:~# cd root@Frenzen:~# git clone --depth 1 git://source.ffmpeg.org/ffmpeg Initialized empty Git repository in /root/ffmpeg/.git/ root@Frenzen:~#… >>> More
Unable to install ffmpeg-php

as seen on Server Fault - Search for 'Server Fault'
I followed the instructions on http://www.mysql-apache-php.com/ffmpeg-install.htm but ffmpeg-php does not show up in my phpinfo() The commands I ran (in order) #yum install ffmpeg ffmpeg-devel ... Public key for faac-1.26-1.el5.rf.x86_64.rpm is not installed #rpm -Uhv http://apt.sw.be/redhat/el5/en/i386/rpmforge/RPMS/rpmforge-release-0… >>> More
Unable to install ffmpeg-php

as seen on Server Fault - Search for 'Server Fault'
Hi, I followed the instructions on http://www.mysql-apache-php.com/ffmpeg-install.htm but ffmpeg-php does not show up in my phpinfo() The commands I ran (in order) #yum install ffmpeg ffmpeg-devel ... Public key for faac-1.26-1.el5.rf.x86_64.rpm is not installed #rpm -Uhv http://apt.sw.be/redhat/el5/en/i386/rpmforge/RPMS/rpmforge-release-0… >>> More

Related posts about xvfb

How to use Xvfb in Ubuntu 14.04 with/without RandR?

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I try to run Unit-Tests with Selenium running Firefox on my Ubuntu 14.04 Server. And I'm using Xvfb as described in this blog to simulate a virtual display to show Firefox in. But Xvfg somehow doesn't load/work with RandR. Because whenever I try this: sudo Xvfb :10 -ac & export DISPLAY=:10 firefox I… >>> More
Xvfb with 32 bit color.

as seen on Super User - Search for 'Super User'
For some machines this works, for some it doesn't. Xvfb :99 -screen 0 1280x1024x32 However, on most machines this works: Xvfb :99 -screen 0 1280x1024x24 What is the secret ingredient to getting Xvfb working with 32 bit color? Note: I'm running this on a Karmic box. >>> More
Memory allocation in Xvfb

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi, I have following this blog in setting Xvfb in my ubuntu environment: http://corpocrat.com/2008/08/19/how-to-install-xvfb-x11-server-in-linux-server/ So I did this: Xvfb :1 -screen 0 800x600x24& My question is does Xvfb only allocate memory during initialization? i.e. just enough for a… >>> More
Getting Xvfb working with 32 bit color.

as seen on Stack Overflow - Search for 'Stack Overflow'
For some machines this works, for some it doesn't. Xvfb :99 -screen 0 1280x1024x32 However, on most machines this works: Xvfb :99 -screen 0 1280x1024x24 What is the secret ingredient to getting Xvfb working with 32 bit color? >>> More
Running Selenium headless without using xvfb

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm trying to run Selenium headless (without the browser appearing). Other questions have pointed to xvfb as the tool to do this. However, it appears highly unstable, crashing all the time, so I'm looking for another alternative. Is there a non-xvfb way of running Selenium headless? >>> More