[katello-devel] katello-devel Digest, Vol 15, Issue 26

[Vinny Valdez]

On Jul 19, 2012, at 6:42 AM, katello-devel-request at redhat.com wrote:

> Date: Thu, 19 Jul 2012 12:36:10 +0200
> From: Lukas Zapletal <lzap at redhat.com>
> To: katello-devel at redhat.com
> Subject: Re: [katello-devel] Do you want to be a movie star?
> Message-ID: <20120719103610.GG4554 at lzapx.brq.redhat.com>
> Content-Type: text/plain; charset=us-ascii
> 
> Nice, but why 30 fps? That's too much. Five to ten is way enough saving
> bandwidth so image is ultra-sharp. Here is my recordmydesktop script
> (kudos to Jeff Weiss and google.com):
> 
> https://gist.github.com/3142880
> 
> The only drawback is it always records whole screen (if you have
> multiple monitors then both screens) when using Gnome Shell and other
> modern desktops (it has only one screen from the X11 perspective).
> So the hack is to uncomment that RESOLUTION variable and set it
> properly, so it will only record the first screen (left one in my case).
> You need this only if you have multi-monitor setup!
> 
> Just run it in an empty folder and file will be recorded and encoded
> properly for YouTube. I like this approach very much, it's easy and it
> gives the best possible quality.
> 
> I have added the link on the page.

If no one has signed up to work on these, I'll take the lead on them. I've actually done quite a bit of testing with different screencasting software, and I will say that using ffmpeg directly is the most flexible. RecordMyDesktop is fast, simple, and easy. However, the encoded .ogv is difficult to edit, if you want to add transitions, insert additional graphics, and so forth, you really need to render the video out to individual frames first. This is where 30 fps is fantastic. Then you'd want to re-render it back to a movie after editing. If you just want to capture your screen and are not plagued with perfectionism, RMD is all you need. I posted a very lengthy (all FOSS) method for screencasting here:
http://vinnyvaldez.blogspot.com/2011/09/screencasting-and-video-production-with.html

Using ffmpeg isn't too difficult (these are similar to what Lukas posted, but without sound). First, determine X11 settings to use for capture:
$ xwininfo | grep -e Width -e Height -e Absolute

Then click on the target window to record. Output will look like this for a single-monitor system:
  Absolute upper-left X:  0
  Absolute upper-left Y:  0
  Width: 1920

Then start ffmpeg with these options:
$ ffmpeg -f x11grab -s hd1080 -r 30 -i :0.0+nomouse -vcodec libx264 -vpre lossless_ultrafast output.mp4

If you have a two-monitor setup, here is an example of using nthe 2nd monitor to record:
$ ffmpeg -f x11grab -s hd1080 -r 30 -i :0.0+1920,0+nomouse -vcodec libx264 -vpre lossless_ultrafast output.mp4

The advantage is the encoded output is directly editable in every software I've tried, with almost no quality loss. With RMD I tended to end up with dirty frames when editing it. You can always specify a different codec, or even use something like ffmpeg2theora when editing is done if you want open formats.

For editing, I prefer Blender, but it comes with a steep learning curve if you just want to use it for editing. OpenShot is a great alternative. If you have a Mac, I've found ScreenFlow is a dream and does everything: http://www.telestream.net/screen-flow/

I prefer editing the videos to near completion, then adding a narration track afterwards using Audacity.

In any case, I'll start on these soon unless work is already underway.

Vinny Valdez, RHCA, RHCSS, RHCVA (110-119-187)
Principal Architect
Global Solutions & Strategy Office
+1 (650) 260-4846
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