[Haskell-cafe] Making videos of your project

Ian Lynagh igloo at earth.li
Tue Mar 31 11:10:12 EDT 2009

On Tue, Mar 31, 2009 at 03:01:52PM +0100, Claus Reinke wrote:
> Is there anyone here with experience in screencasting of text-based
> applications, who could offer advice on how to produce screencasts
> on windows/xp? The basic screencasting (capture+annotation/editing)
> is not the problem, eg, CamStudio seems ok, and Wink gives me
> more control for mostly input-driven sessions (where I want
> screenshots whenever something useful happens, not long videos of
> my mousepointer wavering about the screen;-). Both can generate .swf.

This doesn't exactly answer your questions, but I figure it might be
useful to you or someone else anyway, so here goes:

This is what I found out when making:
(based on hazy memories and incomplete notes, so may not be entirely

YouTube recommends:
    * Video Format: MPEG4 (Divx, Xvid)
    * Resolution: 640x480 pixels
    * Audio Format: MP3
    * Frames per second: 30
    * Maximum length: 10 minutes (we recommend 2-3 minutes)
    * Maximum file size: 1 GB

Google video recommends:
    - MPEG4 (mp3 or mp4 audio) at 2 mbps
    - MPEG2 (mp3 or mp4 audio) at 5 mbps
    - 30 frames per second
    - 640x480 resolution
    - 4:3 frame
    - de-interlace

I think making .swf is a mistake, but I'm not sure.

I recorded sound and audio separately. I don't remember what I used for
sound, but that's the easy bit. I probably used either audacity or

To record the video, I think I did this:

    # Make an xserver-in-a-window, the same size as the video will be
    Xephyr :1 -screen 640x480 -br -dpi 100 -kb &
    # Give the X server a window manager
    sawfish --display :1 &
    # Put an xterm in it
    xterm -display :1 -rv &
    # Stop the shell telling me I have new mail
    # Record the video
    recordmydesktop -o v1.ogv --no-sound -fps 30 -display :1

Then, using audacity, I chopped the audio up into smaller files as

Finally, I used kdenlive to combine the audio files, the video (which
looks like actually ended up coming in 3 pieces, but I don't recall
why), and the opening/closing picture, with the pretty fades etc. This
bit was the hardest to find a good tool for, on Linux.

I rendered it in 2 or 3 formats (at 640x480 etc, following the you tube
/ google video recommendations), and uploaded the one that looked best.
You-tube immediately(ish) makes a low quality version available
(320x240?), and a high quality version(480x360?), with more readable
text etc, is available a little later.

> The problem comes when trying to scale down the size to
> what would fit in a browser window (what a viewer would see,
> without having to scroll around) - text becomes hard to read (quality,
> not size) if I scale from 1280x800 to 640x400, and if I try to work
> in a screen area that fits 640x400 in the first place (so no scaling
> would be needed), I can't really show anything..
> The intended topic is still haskellmode for Vim, updating the
> old screenshot tour from
> http://www.cs.kent.ac.uk/~cr3/toolbox/haskell/Vim/vim.html
> so there'd be a gvim window and a browser window (in real
> life, also a GHCi window, and quite possibly a cygwin window,
> but lets keep it simple), and the most interesting info is not in
> graphics, but in the texts, source code, menus, tooltips, ...,

I had two xterms 42 columns wide, and 10 and 11 lines tall. They could
have been 63 columns wide, but I wanted images to their right.

I would recommend working in a 640x480 screen area. If you can't show
anything in that area, then people won't be able to see anything in your
video (at the size/quality youtube shows it, at least).


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