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--- wiki:screencasttutorial [2012/04/16 01:08] – CLzWBtujl 188.143.232.12
+++ wiki:screencasttutorial [2013/06/02 13:45] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
-Nice Nice Record. I really loved your rcored. Youtube can be a fantastic asset for you. If you need any help getting your rcored exposed, check out this site called tubeviews [dot net] It has really done wonders for me, I have built 3 Channels up with videos at top in position and this is my forth channel i'm vacant to working on.Be Blessed!!!
+====== Screencasting with FFmpeg, jack_capture and Xephyr ======
+===== Introduction =====
+Not satisfied with the quality of the screencasts made with [[http://recordmydesktop.sourceforge.net/about.php|recordMyDesktop]] I started looking for an alternative that might yield better results, especially the video part. The JACK support of recordMyDesktop is a big plus and quite solid too but recordMyDesktop converts all video to Theora only and this has proved inconvenient when uploaded to a webservice like YouTube. The video quality just degraded too much.\\
+So I needed a different toolset. For the video part I chose [[http://www.ffmpeg.org/|FFmpeg]] for its unrivaled flexibility and support for input and output formats. FFmpeg also has JACK support but I found the JACK input client to be too xrun prone so for the audio part I chose [[apps:all:jack_capture|jack_capture]], a lightweight, flexible commandline driven recording tool.\\
+To prevent webservices like YouTube having to downscale or upscale your videos, which deteriorates the quality of your videos drastically, you can optionally run the whole screencast session in a nested X server with the help of [[http://www.freedesktop.org/wiki/Software/Xephyr|Xephyr]].
+===== Requirements =====
+  * A recent version of FFmpeg compiled with support for the h.264 protocol
+  * [[apps:all:jack_capture|jack_capture]]
+  * Xephyr [optional]
+  * A video editor, I use [[http://www.openshotvideo.com/|OpenShot]] or [[http://www.kdenlive.org/|kdenlive]] myself
+  * A screen with a minimal horizontal resolution of 1280 pixels
+===== Screencast script =====
+I use a simple script like this:
+<code>#!/bin/bash
+DATE=`date +%Y%m%d`
+TIME=`date +%Hh%M`
+# Start screencast
+xterm -e jack_capture -b 24 $HOME/Screencasts/screencast_audio_$DATE-$TIME.wav &
+ffmpeg -an -f x11grab -r 30 -s 1280x720 -i 0:0 -vcodec libx264 -vpre lossless_ultrafast -threads 4 $HOME/Screencasts/screencast_video_$DATE-$TIME.mkv
+killall jack_capture</code>
+You might need to adjust the number of threads for the ffmpeg -threads parameter to match the number of cores of your CPU. If unsure, set it to 0, ffmpeg should then set the numbers of threads automatically.
+jack_capture by default captures all the audio that is connected to system:ouput. If you want to be able to manually make connections to jack_capture with jack_connect, qjackctl or whatever, you have to pass it the -mc option (you need at least version 0.9.58 for this)
+===== Optional Xephyr script  =====
+Set up a Xephyr nested X server with a resolution of 1280x720 as this resolution yields the best result when uploading the final video to a webservice like YouTube. I use a little script for this:
+<code>#!/bin/bash
+# Set up nested X server
+Xephyr -keybd ephyr,,,xkbmodel=evdev -br -reset -host-cursor -screen 1280x720x24 -dpi 96 :2 &
+sleep 3
+export DISPLAY=:2.0
+/etc/X11/Xsession &</code>
+As you can see I set up a session by calling /etc/X11/Xsession. In Ubuntu >= 9.10 this starts up a new fresh Gnome session and because I use IceWM for my main session in which I run Xephyr this works very well. If you're using Gnome as your DE using /etc/X11/Xsession won't work properly so in that case you will have to resort to a different start-up option. This also holds for distributions that don't use /etc/X11/Xsession.
+TODO:other distros
+After you ran this Xephyr script, you should run the above screencast script, taking care of making the following changes to it:
+  * add the line "export DISPLAY=:2.0" after the TIME line.
+  * change -i 0:0 ffmpeg option to -i :2.
+  * add the -display 0:0 option to the xterm line (so it won't appear in your screencast).
+Within the Xephyr session I also use a [[http://gnome-look.org/content/show.php/Basic?content=126559|plain cursor theme without drop shadow]] because ffmpeg doesn't capture the drop shadow properly. As of [[http://git.ffmpeg.org/?p=ffmpeg;a=commit;h=191a50db964768ca4418bdf00b26159a77879b9c|FFmpeg revision 25690]] this has been fixed.
+===== Editing, rendering and uploading to a webservice =====
+Now you have two separate files, an .mkv and a .wav file and because jack_capture was started right after ffmpeg audio should be no more out of sync then just a few millisecs. You can now edit the audio and video parts to your liking:
+  * Edit the .wav file in Audacity or Rezound if necessary. I use some extra gain and compression if necessary.
+  * Import the two files in OpenShot and crop start and end to your liking.
+  * With VLC I made some stills from the video file and with Gimp I edited these to create the titling.
+  * Create transitions, fade-ins and fade-outs to your liking with OpenShot.
+For rendering/exporting I use the following settings in OpenShot:
+  * Video: 1280x720, 30 fps (this should match the settings of ffmpeg), mp4 videoformat, 40 Mb/s (Blu-ray quality), libx264 videocodec.
+  * Audio: mp3 (libmp3lame), 256 Kb/s and 44.1 Khz sample rate.
+Now you can upload the resulting mp4 file to a webservice. The settings I've used will yield optimal results for YouTube.
+===== Examples =====
+[[http://www.youtube.com/watch?v=tusCeI1aQ4c|Tiny Tutorial: Vocoding in Qtractor]]
+[[http://www.youtube.com/watch?v=azj7OAzP_GI|The Infinite Repeat - Unaware of a Direction]]
+[[http://www.youtube.com/watch?v=peMR6Agc7Es|The Infinite Repeat - Money or Love (DJ AutoStatic Remix)]]