efficient terminal/console screencasting

Kevin Downey redchin at gmail.com
Thu Nov 22 02:46:06 PST 2007


On 11/21/07, Andrew Pantyukhin <infofarmer at freebsd.org> wrote:
> A while ago I needed to screencast a terminal to a class of
> students in real-time. It turned out to be quite straightforward
> with screen(1) in multiuser mode.
>
> Now I want to record screencasts and allow people to watch them
> later. I'm looking at recordmydesktop, but the innefficiency
> strikes me: I'm operating in text-only environment, there's no
> need to record every frame as a flat bitmap. Whatever codec I
> choose, the files will be huge and of low quality.
>
> What I need is something like script(1) on steroids:
> - accurately record the complete state of my terminal window at
>   any given moment
> - store it as a succession of updates, each represented in a
>   text-based format (as opposed to pixel-based)
> - record timings correctly
> - allow for a method to record speech in the background
> - allow for a method to play it all back in sync
>
> Has anyone heard about any tool which would help me achieve at
> least some of my requirements?

Oh man, do I have an idea for you:
subtitles!

use mjpeg for video with just a black frame
use whatever audio you want
a modern container format and a modern subtitle method will let you
put whatever characters you want where ever you want on the video.
Boom a video that plays and the "textual" information is kept intact
and can even be demuxed from the multimedia stuff.

I leave the actual implementation as an exercise for the reader.


-- 
The Mafia way is that we pursue larger goals under the guise of
personal relationships.
    Fisheye


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