From: W. Trevor King <wking@drexel.edu>
Date: Thu, 28 Apr 2011 00:07:58 +0000 (-0400)
Subject: Add screen recording post.
X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=337b39724b2150a8ab94dd0075fa0aadd0cea38a;p=mw2txt.git

Add screen recording post.
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+I've been learning about screen recording in Linux so I can make a
+demo/tutorial for [[Hooke]].  There seem to be a number of options
+([Xvidcap][], [recordMyDesktop][], etc.), but my favorite approach is
+to use [ffmpeg][] directly from the command line.  You may recall
+ffmpeg from my earlier post about [[video encoding|video]].  For those
+to lazy to read the man page, here are some highlights:
+
+Record audio:
+
+    $ ffmpeg -f alsa -i hw:0 out.wav
+
+Record video:
+
+    $ ffmpeg -f x11grab -r 30 -s 1280x1024 -i :0.0 out.mpg
+
+Record audio and video:
+
+    $ ffmpeg -f alsa -i hw:0 -f x11grab -r 30 -s svga -i :0.0 out.mpg
+
+The trouble will be getting your audio/video captured, encoded, and
+stored to disk fast enough to keep up with your desired frame rate.
+Smaller sizes, slower frame rates, simpler encodings, and writing to
+ramdisks will all help with that.  You can create a ramdisk with
+something like
+
+    $ mkdir /tmp/ramdisk
+    $ sudo mount -t tmpfs none /tmp/ramdisk -o size=256m
+
+It's also possible that passing the `-sameq` option to ffmpeg will
+help, but I'm not entirely convinced.
+
+Anything recorded or encoded by ffmpeg should be playable in mplayer
+(as far as I know), or you can transcode it into a format of your
+choice (see my [[video encoding|video]] post for hints.
+
+Note to Gentoo users: you'll need to compile ffmpeg with the `X` flag
+enabled to get the x11grab video input device.
+
+[Xvidcap]: http://xvidcap.sourceforge.net/
+[recordMyDesktop]: http://recordmydesktop.sourceforge.net/
+
+[[!tag tags/linux]]