Recording desktop

[andrew.46]

Hi Dirk,

I use ffmpeg to capture the screen and it does a good job

You might be interested to read another thread running in parallel with this one that has discussed x11grab in some detail:

gtk-recordmydesktop + compiz cube effects = severe tearing
http://ubuntuforums.org/showthread.php?t=1179861

This thread certainly gave me a few more ideas. Full credit to Nixie who has been investigating x11grab.

Andrew

[LepeKaname]

UPDATE:

To perform screencast with xvidcap:

1) In the preference menu (right click over the filename -> preferences) select "Multi-Frame" then choose for Video Codec: FFmpeg Video 1. Adjust your desired FPS rate. For a simple screencast I recommend something around 12 FPS, you can even use values as low as 1 FPS.

In the case that the codec "FFmpeg Video 1" is not working try to install ffmpeg from medibuntu repositories. I'm not sure if something else is require.

If that doesn't work try this:

2) choose the default codec: MPEG (DIVX). In this case you can not use values lower than 15 FPS. The resulting video, for some reason, plays at a high speed. To fix that use these commands which will change the video speed (FPS rate):

ffmpeg -i input.mpeg -f yuv4mpegpipe - | yuvfps -s 10:1 -r 10:1  | ffmpeg -f yuv4mpegpipe -i - -vcodec copy -y -f avi output.avi
ffmpeg -i output.avi -vcodec mpeg4 -b 10000k -f avi new.avi

Where "10:1" means change to 10 FPS. The first command will generate a large file size (source) but the second one will re-encode it.

You will need to install "mpegtools" to make this work.

Enjoy

[Feelin_froggy8877]

Well I am back at this again. Gave up on it because I did not have the hardware necessary (to weak of a system). Not no more, I have been able to get some pretty decent screencasts, W/ xvid, istanbul-no sound, not much luck w/ gtk-recordmydesktop. Best results have been w/ this command....

ffmpeg -an -s 1366x768 -r 25 -f x11grab -i :0.0 \
-s 1366x768 -r 25 -vcodec libxvid -aspect 1.3333 -sameq video-nosound.avi

Only thing is, I would like to change the screen ratio if possible. Mine is in 16:9, but that is recording in 4:3 (I believe)

[LepeKaname]

Finally after so many months I can now say the quality problem is solved (at least for me).

For those, who found this thread, this is how to produce 100% quality screencasts with XVidCap:

Choose "Quality:100" and one of the following:

1. Use deafult codec (MPEG4): will output near 100% quality but a smaller file size
2. Use FFmpeg Video 1 codec for lossless compression: larger file size
3. Use SWF file format with "Flash video" codec: lossless and relative small file size (you will need to create the HTML in order to display it in a browser).

I haven't test other codecs alternatives, but I guess almost any configuration will produce 100% or near 100% quality.

I was getting really frustrated with the idea that I wasn't able to get a very high quality in my videos. I tried anything, even recording to PNG files, etc.

In order to watch your mpeg videos with full quality, you NEED to use OpenGL as driver in Mplayer (for some reason it doesn't work in VLC the same way).

All this time was the decoder but not the encoder! I feel shame.

Anyway, if you want to produce high quality screencasts and you have enough time after recording (to add messages, change cursor, etc) then I recommend to use wink. If you don't have so much time, just use XvidCap.

As additional suggestion, you can convert your video formats using ffmpeg. The easy way is:

$ ffmpeg -i input.mpeg -sameq output.avi

This will convert to MPEG4 (Default) but if you want other codec, you can use the option -vcodec ***** (see ffmpeg -formats to display all the codec list. Look for those with "EV" = "Encoding Video")

For further information on how to screencast in Ubuntu, follow this link:

http://screencasts.ubuntu.com/Creating_Screencasts

[millspaw]

I am using gtk-RecordMyDesktop in 10.04, and works fine to produce math tutorial videos produced with animated Impress slides, with voice over.

I change Impress Slideshow Settings to 'Run in a Window', and 'Mouse always visible'.
I start the slideshow, slide one appears in a window, allowing the top menu bar to remain visible.
I start RecordMyDesktop, select a recording window that is the now running slide one.
Allow a few seconds for users to see the first 'clip', then start the voice over. I put a 'stop sign' icon on the last slide, as a reminder to myself. I also put message at the end of the last slide notifying the user that the tutorial will conclude in approximately 10 seconds. During this time (I count to myself), I move the mouse out of the recording area, to the top menu bar, and stop RecordMyDesktop to end the capture.
RecordMyDesktop renders to *.ogv. I use mencoder to convert this to an *.avi file. As an *.avi file I can edit, clip, append the clips using Avidemux, or command line utilities. The *.avi files are smaller than the corresponding *.ogv and *.wmv files.