Introduction
This is a tutorial
- How many know what screencasting is?
What is Screencasting?
Screencasting is recording your computer's screen and posting that online as a demonstration.
A demonstration of your software, or your arrangement of other people's software.
Screencasting is Screenshots + Podcasting (in a very loose way).
This is a tutorial
- How many have made a screen recording?
Outline
- boring part where I fumble about
- fun part where we all fumble about
- break into groups for evaluation
- some notes
- second draft
- uploading
- advanced topics...
History
History
In the beginning, there was the command line
History
History
History
History
History
Future?
Future?
Future?
The future is always in motion
Screenshot tools
- Ksnapshot
- Gnome "Take Screenshot"
- import -window root screen.png
- xwd > screen.xwd && convert screen.xwd screen.png
Screenshot tools
Demo
Screenshots -> Screen movies
- while (1) { get_screenshot() }
- still image capture tools too slow
- need a dedicated tool
Screen movies -> Screencasts
- Sequence of images is a movie
- Must compress video for online distribution
A note on formats
- Most casual web video is now in FLV
- Screencasts in MPEG and WMV from certain proprietary operating systems
- These are patented formats!
A note on formats
Free format alternatives
- Animated GIF
- Ogg Theora
- Others: pnm, mjeg, mng, etc.
A note on formats
Animated GIF
- Playback everywhere!
- limited to 256 colours -> dither
- otherwise lossless
- poor compression
A note on formats
Ogg Theora
- Native playback only on Linux
- good compression
- sound support
- Designed for smooth images -> blurring at low bitrates
A note on formats
Summary
- Animated GIF
- Best for small, short elements, embedded in a web page.
- Ogg Theora
- Best for full screen movies, demonstrations, long sequences
Screen recording tools
Pick one:
- Istanbul (Gnome, Gstreamer, Ogg Theora)
- Byzanz (Gnome, Animated GIF)
- recordmydesktop (commandline, Ogg Theora)
- xvidcap (X11, pnm)
- vncrec (patch for yuv4mpeg -> theora encoder)
Screen recording
DEMO
Uploading
- It's just a file on the internet
- Link from your blog
- poster image is nice, but not essential
- export a frame from your video player if you want one
Uploading
- If you host your own blog you're fine
- Not a lot of free options
- YouTube and Google Video are the flickr of screencasts
Make your (first) recording
Time for the fun part!
Make your (first) recording
Time for the fun part!
Evaluation and critique
- You are performing your software!
- What's performance without critique?
- Break into groups of ~4, share your videos
- Tell each othe what you liked, what could be better
- Be constructive!
Evaluation
How did we do?
Make your (second) recording
Let's do it again!
Performance pointers
- Think about size, resolution
- Think about pacing. Keep it interesting!
- Move the mouse confidently
- Practical function
- Eye candy
Finishing up
Any questions?
Thanks for coming!
- Thanks to all of you for coming.
- Thanks to the tool developers for making this possible on free software.
Go forth and Screencast!