Monthly Archives: February 2012

Apple Mail craps pants when trying to send huge attachments via Gmail

As in, it tends to break rather badly. In short, the solution here worked for me on Apple Mail 5.2:

Many thanks to the above poster.

Edit: fixed the link.


Screencasting on Ubuntu using ffmpeg

Updated 8th January 2013: It appears that at some stage ffmpeg was forked into libav, and the latter is what is included with Ubuntu 12.04. As it turns out, the ffmpeg commands below (which are still accepted) will result in a video that is severely choppy – practically unusable. I don’t have time to get to the bottom of this, so following are two links which describe how to uninstall the libav tools bundled with Ubuntu 12.04 and how to install the original ffmpeg packages from a PPA. The original packages work fine, but a side effect is that your media playback applications may cease to function normally (the second link describes this in detail). I only use this system for video capture so for me it isn’t an issue – but as they say, your mileage may vary…

The original guide now follows.


This is a very brief guide to using the FFmpeg Linux utility to record a live screencast. I’ve used this method (which is quite well documented out there) after discovering that the recordMyDesktop utility is unsuitable in certain critical areas for my needs.

The first thing to note here is that FFmpeg consists of a suite of libraries and codecs for handling A/V media, and, the ffmpeg command line utility itself. The latter is what we will be using to capture our screencast.

Our example system is running Ubuntu Linux 11.10 x86. Note that at this stage we are only capturing live video, not live audio.

First, use Ubuntu Software Center to install FFmpeg:

Installing FFmpeg using Ubuntu Software Center

Once installed, launch a Terminal window: it’s time to enter a text command, but don’t worry, it’s straightforward and you can cut and paste the below example to get started. Simply enter the following command, noting that this will save a video recording of your live session to an example file named “testscreencast.mp4” on your Desktop.

ffmpeg -f x11grab -r 25 -s 1280x1024 -i :0.0 -sameq ~/Desktop/testscreencast.mp4

To stop the recording, press Ctrl+C with the terminal window in focus. To view the video file, you can use VLC or a similar media player.


Let’s look at the various options and parameters of the above command in more detail:

  • ffmpeg – this is the ffmpeg command itself being invoked
  • -f – force the input or output file format (note – not the file itself). In this example, we are forcing the file input format to be the X11 display (see below)
  • x11grab – use the X11 display
  • -r – frame rate in frames per second. This defaults to 25 fps
  • -s – set frame size. It can be set either as WidthxHeight pixels, (e.g. 1280×1024), or accepts a variety of preset abbreviations (e.g. sxga which corresponds to 1280×1024)
  • -i – set the input file. This does not have to be a “file” per se, and indeed in this example the input file is the value :0.0, which corresponds to the value of the $DISPLAY environment variable (in display.screen format). See: for more information
  • -sameq – this option sets the transcoding quality to be the same as the source input.

The last portion of the command simply sets the location for the output file. Also, the default video codec for ffmpeg (you’ll note that we haven’t explicitly set a codec anywhere) is MPEG-4 (note, not MPEG-4 Part 10), which for screencasts is fine.

Once you’ve captured your screencast, you can use an application like OpenShot to perform the editing.

Freedom in video media production

ffmpeg to do screen captures: $0
Audacity to capture audio, perform clean-up and EQ: $0
GIMP to design titles and watermarks: $0
OpenShot to edit footage, add transitions and effects: $0
Web delivery transcoding to the free, patent-unencumbered Theora codec: $0
The Ubuntu OS to run it all on: $0

And seamless video playback (without stupid plugins) using Firefox

Theora playback in Firefox

Freedom rules.

OpenShot video editor for Linux – watch out iMovie…

I’ve recently begun to use OpenShot on Ubuntu Linux to edit a series of short screencasts with, and holy smoke what a pleasant surprise. Stable, easy to use (including a polished and smoothly responsive UI), a nice selection of effects and transitions, and pretty darn stable to boot:

OpenShot running on Ubuntu 11.10 x86

It’s pretty much based on the iMovie paradigm, before Apple screwed too badly with it. Lots of advanced goodies which the competition doesn’t have, like fancy 3D animated and SVG titles via integration with Blender and Inkscape. Built-in support for insta-upload to YouTube. Even the documentation is great. Between Ubuntu, ffmpeg, and OpenShot (oh, and Audacity for the audio), it’s entirely possible to put together high-quality screencasts for zero software cost.

OpenShot is totally worthy of a donation, which I have happily made.

recordMyDesktop, Ogg video files, and OpenShot – part 2

A quick follow up to my post here. As it turns out, VLC refuses to play back any Ogg file generated by recordMyDesktop at normal speed: playback jumps all over the shop, with the net effect of it appearing to run much faster than the speed it was actually originally captured. So, we are shit out of luck with using it to transcode recordMyDesktop files for editing in OpenShot.

You can read what the VLC core developers thought of this issue in posts 8 and 9 here:

Frustrating that recordMyDesktop is so close to being perfect for my needs, but as it’s a defunct project I am forced to look elsewhere. Turns out that the ffmpeg command line utility can be used to capture a live desktop (loads of guides on the web on this topic), so in a follow up post I will outline my efforts to use this instead.

recordMyDesktop, Ogg video files, and OpenShot – part 1

Quick post before bed – I am playing around with using recordMyDesktop on an Ubuntu Linux 11.10 x86 system to create screencasts with, using OpenShot (which looks great by the way) to import and edit video files recordMyDesktop spits out.

To cut a long story short, it seems OpenShot doesn’t like the Theora-encoded video produced by recordMyDesktop:

Ogg video played with ffplay

Numerous postings on the web finger recordMyDesktop as the problematic application – and because recordMyDesktop only outputs Ogg video (which is entirely fair enough), I’m kind of stuck without transcoding it to another format which OpenShot can use without trouble.

In a future post I’ll outline the settings I’m using in VLC Media Player to transcode files created by recordMyDesktop into H264-encoded video in MP4 container format, which can then be imported into OpenShot for editing – and subsequently exported back out as Ogg video (yes, because I actually want my users to be able to view the resulting screencasts in Firefox or Chrome without a bloody plug-in…). Some quality loss is inevitable, so it’s not ideal, but with the right settings it looks like something entirely acceptable is fairly easy to do.

Clear Mobile History add-on for Firefox Mobile

Although I’m sure plenty of users lump in their “private” data with their browsing history when using Firefox for mobile devices, it becomes a right pain in the butt when you are also using a local Firefox sync server, and clearing your private data (clearing your browsing history only is not an option) also hoses your passwords – along with your Sync account and settings.

The following add-on is therefore indispensable if you are using Firefox mobile with Firefox Sync:

More information here.

Weird that it’s not included with Firefox, but hey, that’s what a plug-in ecosystem is for I guess 🙂