Archive for April 19th, 2011

Best software available today for Linux video Desktop capturing on Debian

Tuesday, April 19th, 2011

I’ve been experimenting since some time in order to understand better what is the current situation with Video Desktop Capturing Software available today for Linux and FreeBSD.

My previous investigations has led me to write an article about xvidcap called How to make Video from your Linux Desktop with xvidcap

Though xvidcap works pretty well, it is currently uncapable of capturing the audio stream of a Linux Desktop env and hence part of the interactivity of the videos is missing when used.

A bit of further investigation on the topic has pointed me to 3 free software programs which are capable to record Desktop environment on Linux with sound embedded

The interesting screen video capturing Desktop tools I’ve found are:

1. recordMyDesktop
2. Istanbul
and
3. vnc2swf

Installing them on a Debian based distribution is pleasable, as there are installable debian packages of each one which I installed easily with apt:

debian:~# apt-get install istanbul recordmydesktop gtk-recordmydesktop vnc2swf

RecordMyDesktop‘s package contains a command line little tool which when started directly starts capturing video and audio of the Linux Desktop. After a Ctrl+C is pressed the program quits, saves and encodes the video in ogg-encapsulated theora-vorbis file format.

Here is the output I got in saving a sample file by launching recordmydesktop without any arguments:

hipo@debian:~/Desktop$ recordmydesktop
Initial recording window is set to:
X:0 Y:0 Width:1024 Height:768
Adjusted recording window is set to:
X:0 Y:0 Width:1024 Height:768
Your window manager appears to be Metacity

Initializing…
Buffer size adjusted to 4096 from 4096 frames.
Opened PCM device hw:0,0
Recording on device hw:0,0 is set to:
2 channels at 22050Hz
Capturing!
Broken pipe: Overrun occurred.
Broken pipe: Overrun occurred.
Broken pipe: Overrun occurred.
^C
*********************************************

Cached 5 MB, from 207 MB that were received.
Average cache compression ratio: 97.3 %

*********************************************
Saved 69 frames in a total of 69 requests
Shutting down..Broken pipe: Overrun occurred.
…
STATE:ENCODING
Encoding started!
This may take several minutes.
Pressing Ctrl-C will cancel the procedure (resuming will not be possible, but
any portion of the video, which is already encoded won’t be deleted).
Please wait…
Output file: out.ogv
[100%]
Encoding finished!
Wait a moment please…

Done.
Written 692529 bytes
(635547 of which were video data and 56982 audio data)

Cleanning up cache…
Done!!!
Goodbye!

The captured file as I you see in the above output is saved in file out.ogv

RecordMyDesktop has also a GUI interface (written in Python) called gtk-recordmydesktop

Below you see a screenshot of the GUI gtk-recordmydesktop:

RecordMyDesktop GTK interface entry screen

gtk-recordmydesktop is a super-easy to use as you already see in the picture, you can either configure it with Advanced button or use Save As button to select where you want the Desktop captured video and audio to be stored.

In Debian Squeeze 6.0, the Advanced GUI button interface button is not working but that’s not such an issue, as the rest of the buttons works fine.
After the recordmydesktop‘s Record button is pressed it will start capturing from your Desktop and the window seen in the above screenshot will disappear/hide in the system tray:

recordmydesktop recording minimized in system tray
When you press over the white little square in the system tray the screen capturing will be interrupted and a window will pop-up informing you that the captured video and audio is being encoded, here is another screenshot of recordmydesktop encoding a saved Desktop video stream:

recordmydesktop saving captured desktop video

After the final .ogv file is encoded and saved to further transfer it into (.flv) I used ffmpeg;

debian:~# ffmpeg -i test.ogv test.flv
...

Now let’s evaluate a bit on the the final results, the produced test.ogv‘s synchronization between sound and video was not good as the sound was starting earlier than the video and therefore even though recordmydesktop used to be highly praised on the net, the proggie developers still needs to do some bug fixing
Further on, I continued and (gave the other Desktop screen capturer) Istanbul a try hoping that at least with it the video and audio of my Linux desktop will be properly captured. But guess what, the results with Istanbul was even more unsatisfactory as the produced videos and sounds, were slow and a lot of frames from the screens were missing completely.
Moreover the sound which was supposed to accompany the video was completely 🙁

Thus I will skip on talking about Istanbul as in my view, this piece of software is far away from being production ready.

I also tested vnc2swf , launched it by: pressing alt+f2 and typing in vnc2swf in GNOME’s run application prompt, just to be surprised by an error …:

vnc2swf error no 111 Connection refused

The reason for this error is caused by the xserver (Xorg) port 5900 is being closed by default on Debian

However this error is easily solvable, by making the Xserver to listen to a the port 5900, to make the Xorg server on Debian to listen on this port you need to edit the file:

/etc/X11/xinit/xserverrc

and change inside it:

exec /usr/bin/X -nolisten tcp "$@"

with:

exec /usr/bin/X "$@"

and either reboot your Linux or restart only the Xorg server by pressing Ctrl+Alt+BackSpace

Now let me conclude, the results from my desktop video screen capturing experiments prooved that vnc2swf is superior (as it is capable of properly saving a movie with sound and video from a Linux Desktop). It appears this soft is actually the best one you can use to make a video of your Linux desktop.

Sadly my testing has proven that Linux is still lacking behind Windows and Mac in even doing the most simple tasks …
Let’s hope that situation will get better soon and Gnome or KDE developers will soon provide us with better software capable to save properly a video and audio captured from the Linux Desktop.

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Posted in Linux, Linux and FreeBSD Desktop, Linux Audio & Video | 4 Comments »

How to edit, convert, join, split and re-time movie subtitle files on Linux (Fix Subtitles bad timing) / Install subtitle manipulation console tools for Linux

Tuesday, April 19th, 2011

As a Linux user I sometimes face difficulties with watching subtitled, movies. I mostly use Mplayer, Totem or VLC to watch the common video files.
The most common problems I face with subtitles are caused by bad timing, many times the solution to the bad timing issues is very simpleand comes up to changing the default movie player I use MPlayer to VLC or Totem.

However at many occasions trying to watch the movie with different kind of movie player does not help.
In this dark moments I get seriously irritated I am not a regular Windows user, where such kind of problems are almost none as many of the Windows movie player problems does fix bad timing issues automatically.

Luckily there is a work-around to this subtitles timing issues and other mishaps caused by guys who created a Movie subtitle files with a Windows subtitle editor program, subtitles timing, the Linux work-around takes a few more minutes to install a package called Subtitles

The Subtitles text utility is written in Perl and contains two executables subplay and subs .

Subtitles is the Linux subtitle Swiss Army Knife as it is capable of convert, join, split, and re-time of subtitles files

Installing Subtitles tools on Linux is a trivial job and it comes to download and installation of the 2 perl executables.
Here is how:

1. Download Subtitles.tar.gz toolsI have mirrored Linux Subtitles (Subtitles.tar.gz) here originally the binaries are to be found on URL address: http://karasik.eu.org/software/ , issue the commands:

linux:~# cd /usr/local/src
linux:/usr/local/src# wget https://www.pc-freak.net/files/Subtitles.tar.gz
... 2. Unarchive it

linux:/usr/local/src# tar -zxvvf tar -zxvvf Subtitles.tar.gz...
linux:/usr/local/src# cd Subtitles-1.0

3. Compile and install Subtitles system widePitily the Subtitles tools are not currently available as a packages in the repositories of Debian and Ubuntu Linux and thus easy installation without compilation via apt-get is unfortunately not available.

Here is the commands with which to compile and install Subtitles:

linux:/usr/local/src/Subtitles-1.0# perl Makefile.PL
...
linux:/usr/local/src/Subtitles-1.0# make
...
linux:/usr/local/src/Subtitles-1.0# make test
...

All tests successful.Files=1, Tests=17, 1 wallclock secs ( 0.05 usr 0.00 sys + 0.06 cusr 0.01 csys = 0.12 CPU)Result: PASS

linux:/usr/local/src/Subtitles-1.0# make install

Installing /usr/local/share/perl/5.10.1/Subtitles.pm
Installing /usr/local/man/man1/subplay.1p
Installing /usr/local/man/man1/subs.1p
Installing /usr/local/man/man3/Subtitles.3pm
Installing /usr/local/bin/subplay
Installing /usr/local/bin/subs
Appending installation info to /usr/local/lib/perl/5.10.1/perllocal.pod

Now as we have the subs executable installed, Let’s say your movie subtitles displays 5 seconds earlier before the movie scenes (bad timing), all you need to do to adjust your subtitles to show up in correct movie scenes is issue:

hipo@linux:/home/hipo/Movies$ subs -i -b 5 your_movie_subtitle_file_name.sub

now check out the subtitle files once again with your favourite player and the early subtitles display on your movie should be fixed.
Let’s have another scenario, say that your movie file is encoded to display 24 frames per seconds (fps) but the subtitle file is created to display the subtitles for a 25 fps, to solve this situation issue:

hipo@linux:~# subs -i -a 24/25 your_movie_subtitle_file.sub

Another possible scenario where subs command will be a precious asset is if you for example want to merge two subtitle files into one.Let’s say you have subtitles for a movie which are split over in 2 parts and the corresponding subtitles are in 2 different files, but eventually you find a better quality of the movie (DVD quality) in a single file and therefore you need the movie subtitles to be stored in one single file.
In that case to merge the subtitle files from let’s say the files movie_subtitle_file1.sub and movie_subtitle_file2.sub use the command:

subs -z movie_subtitle_file1.sub movie_subtitle_file2.sub

Some few other helpful things you can do with subs on Linux, are for example: splitting a file after a determined period of time, separating overlapped lines, and joining files into a single subtitle.

If you want to remove all the comments of gestures, facial expressions loud laughing etc. which displays usually the annoying (‘[Sneezing]’ or ‘[Music playing]) during the movie screen play, issue:

subs -e 's/[s-]*[.*]s*n*//gs' movie_subtitle_file.sub

Also other interesting Linux tool which is useful if you want to make conversions between subtitle in a (.sub) format to (.srt) format is called sub2srt perl script:

sub2srt’s home page is located on the URL address: http://www.robelix.com/sub2srt/, just to ensure it won’t just disappear with time I have created sub2srt mirror here

The most basic usage of sub2srt linux converting tool is by simply passing input sub and output srt file names like so:

linux:~# ./sub2srt 5rFF-pop.sub 5rFF-pop.srt

sub2srt supports changing of fps rate per second during conversion with the -f option as well as creationg of converted files in dos like end of file (CR+LF) with the –dos option.

Hope this article makes sense. If you find it useful, please drop me a thanks comment 😉

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Posted in Entertainment, Linux, Linux and FreeBSD Desktop, Linux Audio & Video | 1 Comment »