[sugar] Announce: Screencast activity.

Eben Eliason eben.eliason
Fri Oct 17 09:01:59 EDT 2008

On Fri, Oct 17, 2008 at 3:08 AM, Chris Ball <cjb at laptop.org> wrote:
> Hi,
> I started work on a Screencast activity tonight.  It's a frontend to
> recordMyDesktop, which is the program Scott used for his screencasts.
> Having a program on the XO that's capable of preparing shareable
> tutorials could help out a lot with support, by allowing walkthroughs
> to be prepared by children, teachers, and the rest of us.


> The activity is (barely) functional now, including Journal integration.
> The UI is entirely unpolished.
> Large bugs:
>  * When you're resuming a screencast from the Journal, you have to
>    mouseover "Resume" and choose Browse from the dropdown, rather than
>    just clicking Resume.  Is there a way to tell Sugar that I don't want
>    my activity to be an option for opening the video/ogg files that it
>    creates but doesn't know how to play?

It seems that the activity might actually create both a Screencast
instance as well as a resulting screencast movie file.  The former
would be resumable in Screencast, the latter in the default activity
for video.  As to the usefulness of resuming, it might be possible to
add support for callouts (boxes, or arrows, or highlights, etc.) for
accentuating a specific part of the screen, or for adding textboxes to
the flow either as description aids (if no mic is used) or to break
the screencast into short, named chapters, etc.

If there truly is nothing that makes sense to resume within Screencast
itself for now, we can simply store the artifact instead.

>  * Recordmydesktop is using /tmp as an intermediate location, which
>    means that a long screencast runs the XO into OOM (or worse).
>  * It reuses the icon from "Words".

I'll think about this. I can see a 4:3 rect with a tiny XO in it being
a good starting point, perhaps with an offset record button in one
corner. Any better ideas?  I can hack an icon together if we get
consensus on something reasonable.

>  * I think the Totem plugin might be having a scaling issue when playing
>    back a screencast.

What res do you store the final movie at, out of curiosity?

> Missing features:
>  * There should be a checkbox for whether to include sound from the
>    microphone in the screencast, which should pass --no-sound to
>    recordmydesktop if unchecked.

Great idea.

>  * Limits on how long to record, illustration of disk full percentage,
>    progress meter for encoding stage?

All good.  The first seems quite necessary. Ideally all three of these
things would a) be visible all the time while recording b) not appear
within the screencast output.  I'm not sure that either (a) or (b) is
possible, sadly.

>  * i18n, icons for the buttons.
>  * Find the optimal FPS setting to use.
>  * We should avoid having the activity itself be present in the videos;
>    perhaps by minimizing it immediately before starting recording,
>    and then setting up a globally-bound keyboard shortcut for stop?

I'd recommend transitioning immediately to the Home view when
recording starts, so that screencasts always begin from the same
familiar place.  This is a natural starting point.  However, is it
possible for an activity to trigger that event?

I'm even less sure about stopping.  Ideally a stop button would be
another piece of ever-present, non-recorded info on the screen.  A
keyboard shortcut might work, but can you bind it globally even if the
app isn't focused?  Another option is to offer (really basic)
cropping, with a simple bar beneath the video with two endpoints which
can be dragged independently, to trim beginning and end of the
screencast as needed.  If kids didn't bother, at worst they'd have a
2-3 second part at the end where they focus the screencast activity
and press a stop button.

Another alternative is to automatically stop recording when the
activity is focused, but a) you'd still see the action of selecting
the activity again and b) this would prevent any screencasts of the
Screencast activity from being made.

> Would anyone be interested in owning this activity?  I don't have time
> to finish it off properly at the moment, but I'd happily work with a
> volunteer to answer questions and propose changes.

I wish I had time or experience to be able to, but I don't yet.  I'd
be happy to lend some graphical assistance, such as layout, button
icons, etc. to anyone who takes this up.

- Eben

> There's source here:
>   http://dev.laptop.org/git/users/cjb/screencast-activity
> and a bundle here:
>   http://dev.laptop.org/~cjb/screencast/
> Thanks,
> - Chris.
> --
> Chris Ball   <cjb at laptop.org>
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> Sugar at lists.laptop.org
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