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This directory contains the source for the "Virt tools in 60 seconds"
videos.
How to use it:
(1) You need a computer with a full sized keyboard (with keypad) and 3
button mouse. Blender is not usable with anything less. If all you
have is a laptop, then you will need to plug in an external keyboard
and 3 button mouse. You will also need a good quality external
microphone to record the voiceover.
(2) This is not a tutorial for Blender. If you are not familiar with
Blender, then you need to consult an online tutorial or buy a book.
You *cannot* just figure out Blender by messing around with it. It
won't work so don't even try it. Start at the Blender home page
(http://www.blender.org/) for suggested reading material and books.
(3) Decide on a topic. The virt tools project status has some
suggestions.
(4) Write a script. Jot this down on paper or in a new text file.
The math of "virt tools in 60 seconds" is quite simple: 5 seconds for
the title sequence + 5 seconds for the final card, means you have to
fit everything comfortably into 50 seconds. A little bit of time is
spent in fades too, so in reality it will be a few seconds less than
this.
What can you say in 50 seconds? *Not very much*. About 100 - 120
words *maximum*. You'll have to stick to one very simple point. You
should practice reading through your script and timing it. [On a side
note: Who owns a stopwatch, or even a watch these days? Certainly not
me. And GNOME doesn't seem to come with a stopwatch applet either. I
use my phone to time myself.]
Along with your script, note down what you'd like to appear on the
screen. Timing is less important here because you are allowed to (and
should) cut things out and even speed up parts.
(5) Copy everything from template/ into a new subdirectory. The files
in this directory are:
* title.blend - The "Virt tools in 60 seconds" title sequence which
generates a 5 second clip (without the final fade - that will be
added in Blender Video Sequence Editor). You have to modify the
title and render this as "title/*.exr". Make sure to enable
OpenEXR output, and also MBLUR (motion blur) when rendering.
* title/*.exr - The title sequence. Each *.exr file is a single
frame of the output. (5 seconds at 25 fps => 125 files).
* endcard.blend - The card displayed at the end which advertises the
website and other tutorials. This is 5 seconds long.
* endcard/*.exr - The rendered card (5 seconds). This is in OpenEXR
format (one file per frame). You could re-render this if you need
to change the end card for any reason.
* final.blend - The Blender VSE that ties everything together into
the finished 60 second video, including the title sequence, end
card, and fades. You have to add your demonstration to this (see
below) and render the final sequence. When rendering, don't
forget to select "Do Sequence" before pressing ANIM/F12.
* final/*.exr - The final video as separate OpenEXR files.
(6) Record (your) desktop.
We've found a GNOME program called "recordmydesktop" to be perfectly
good for recording what appears on the screen while you're running
through the demonstration. Three important points to note:
* You are going to throw away the soundtrack from the recording.
(You will record it separately later). It makes no sense to keep
it because the sound quality will be crap and no one wants to hear
you hammering away on the keyboard. This means it doesn't matter
what you say while you're recording the demonstration. Don't try
to read the script. [Update: Recent versions of recordmydesktop
have a checkbox which stops it from recording audio]
* You can going to shorten and edit this heavily. You need enough
video so that *after* editing, the demonstration will run to
exactly 50 seconds. *Before* editing, the video can be much
longer.
* Adjust the program or terminal so that fonts are as large as you
can get away with. People might watch this in a tiny YouTube
window, and small text will be completely unreadable. For the
same reason, adjust the area recorded so that there is as little
wasted space around the edges as possible.
Watch the recording back over with the sound turned off, and if
something's not right, record it all again.
(7) Edit the desktop recording down to 50 seconds.
Recordmydesktop generates OGG video by default. Convert this to
individual frames (PNG files):
mplayer video.ogv -vo png:z=9
You can "edit" just by deleting the frames you don't want before you
load the rest into Blender. Use any slideshow tool for this
(eg. GNOME "eog"). Do some simple arithmetic so that the final video
will be around 50 seconds. eg. If the original recording was 120
seconds long and the mplayer command creates 300 frames, then you will
need to remove approximately 160 frames in order for the final video
to be 50 seconds long and to run in real time. (You might want to
remove more or less frames in order to change the speed). Another
trick is to duplicate frames, where you want a pause in the video
while you say something on the voiceover.
Import the final directory of PNG files into VSE ("final.blend").
This isn't mentioned anywhere in the Blender documentation, but you
have to add a Speed Control Effect over the top of the Image Sequence
in order to get Blender to spread the frames out over the full 50
second length (otherwise Blender will add them all at 25 fps and
you'll get a very quick demo followed by 40 seconds of displaying a
single frame).
Once it is edited down, render this. Don't forget to select "Do
sequence" before rendering otherwise Blender will try to render from
the 3D view instead of the sequence.
(8) Plug in your high quality external microphone. Test that it works
and there's no background noise. We use Audacity for this, but there
are plenty of alternatives.
Now record your sweet voice reading the script as you play the
rendered video back. Again you might have to do this several times to
get it right.
(9) Back in Blender VSE ("final.blend") add the sound recording as an
extra track, then render the final video with voiceover.
Note that Blender will only render a video with sound if you enable
output format FFMPEG and on the audio tab click Multiplex Audio.
(10) We like to render the final video in several formats:
* H.264 video with MP2 audio. This is massively proprietary but
most people should be able to play it. In addition, the
compression ratio is reasonable. A 60 second video with sound
should compress to around 10-12 MB.
* Ogg Theora (OGV).
(11) Upload it to the website. Send a message to the virt-tools
mailing list so we can coordinate the upload. In addition you can
upload videos to external services like YouTube.
(12) Tell the world about it. The more people that see these videos,
the better.
Thanks for your participation in the virt tools project!
- Richard W.M. Jones, July 2010.
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