Category Archives: Open Source

Foundations of Open Media Software 2008

Digital Media, FOMS, LCA, Open Source

Good news, everybody: We are repeating the successful open audio/video developer workshop in 2008 – the CFP for FOMS 2008 is now public!

FOMS (Foundations of Open Media Software) will again take place in the week ahead of LCA (Australian’s Annual Conference for Linux and Open Source Developers) – whose CFP is also out. Get started submitting abstracts because LCA’s published deadline for submissions is 20th July.

To complete the pack, LCA MultiMedia is an a/v miniconf for LCA in planning, such that LCA attendees will also have a chance to hear the latest and most exciting news from the developer bench.

FOMS 2007 was a huge success. It brought face-to-face some of the core Linux audio and video developers, which promptly started attacking some of the key obstacles for an improved audio/video experience on Linux and with open media software in general.

Jean-Marc Valin (author of speex), Lennart Poettering (author of PulseAudio) a group of programmers from Nokia and a few others started designing libsydneyaudio – a library which is deemed to solve the mess of audio on Linux in a means that is also cross-platform compatible.

Also, a community started building around liboggplay, a library designed to allow drop-in playback of Xiph.Org media in an application. libogg is currently being prepared for a submission to Mozilla to provide native Ogg (and Annodex) support inside Firefox as part of the new HTML5 <video> tag. Then, Ogg Theora, Vorbis & Speex will play out of the box on a newly installed Firefox without requiring to install any further helpers software.

These are just the highlights from FOMS 2007 – expect more exiting news from FOMS 2008!

Xiph file extensions and MIME types

code, Digital Media, Open Source

Today we nailed down a policy for Xiph on what file extensions and mime types we recommend using for Xiph technology.

Basically, we have introduced some new file extensions to allow applications to more easily identify whether they are dealing with audio (.oga) or video (.ogv) files, or some random multiplexed codecs inside Ogg (.ogx).

We recognized the fact that existing Ogg Vorbis hardware players will need to continue to work with whatever scheme we come up and therefore decided to dedicate the extension .ogg to Ogg Vorbis I files – and deprecate all other use of it. That includes the deprecation of the use of Ogg Theora and Ogg Flac with this extension. In future, Ogg Theora files should have a .ogv extension and Ogg Flac a .oga extension. (For further details, check out the wiki page.)

MIME types will be changed accordingly and the RFCs required to register them will start to be authored now.

None of this has been written in stone yet though and there is still time to change this policy if it doesn’t make sense. So if you have any strong objections, speak up now!

Rails and plugins

code, Open Source, rails, vquence

I’ve come to really love working with Ruby on Rails – it forces a structured approach of Web development upon you which helps enough to get you organised, but doesn’t get in the way of being productive.

I’ve also learnt to search for plugins or gems whenever I need a specific functionality because more often than not somebody has already solved the problem that I am trying to address.

Today I played with Andy Singleton’s GUID plugin (global unique identifier) and found a bug. I haven’t found a way to publish the solution through the rails wiki (I’m really new to the community), so I’m posting it here. I’ve also sent Andy an email, so hopefully the issue will get addressed.

Here is what happend.

I got the plugin working on my development computer and wanted to test it on another machine. However, the plugin gave me the following error message:

#{RAILS_ROOT}/vendor/plugins/guid/lib/uuidtools.rb:235:in `timestamp_create'
#{RAILS_ROOT}/vendor/plugins/guid/lib/uuidtools.rb:225:in `timestamp_create'
#{RAILS_ROOT}/vendor/plugins/guid/lib/usesguid.rb:25:in `after_initialize'

After some digging I found that it uses the MAC address of the computer for seeding the GUID. To query the MAC address, it calls ifconfig (or ipconfig on a Windows machine) – which is fair enough. It has several cases that it goes through. However, the case of my machine was missing and the code did not address a nil return from the get_mac_address function.

My case was simple to solve: my MAC address comes in upper case characters, while the code only tested for lower-case characters. So, I added another parsing condition for my case:

if mac_addresses.size == 0
ifconfig_output = `/sbin/ifconfig | grep HWaddr | cut -c39-`
mac_addresses = ifconfig_output.scan(
Regexp.new("(#{(["[0-9A-F]{2}"] * 6).join(":")})"))
end

The generic problem is harder to solve – and maybe it should not be solved, but fail on the programmer, since he/she is trying to roll out GUID calculation on a machine where the program is unable to calculate a MAC address…..

Hmmm….

Extracting keyframes from Ogg Theora

Digital Media, Open Source

As I was playing with Ogg Theora lots for LCA, I needed to script the extraction of keyframes from Ogg Theora files.

There’s a manual way to achieve this through totem: you just use ctrl-s to capture a frame. However, I didn’t want to do this for every one of the hundreds of videos that we captured.

Here’s a script that I found somewhere and might work for you, but it didn’t work for me:

dumpvideo foo.ogg | yuv2ppm | pnmsplit - image-%d.ppm; for file in image-*.ppm; do convert $file `basename $file .ppm`.jpeg; done

What worked for me in the end was a nice and simple call to mplayer:

mplayer -ss 120 -frames 1 -vo jpeg $file

The Alcatel-Lucent against Microsoft case

Digital Media, Open Source

With a court ruling of $1.5bn (see http://news.com.com/2100-1027_3-6161760.html), the Alcatel-Lucent vs Microsoft case is rather amazing.

It is particularly amazing since to everyone who has licensed from the MP3 licensing consortium was held under the impression that with that license they are off the hook for all patents related to MP3.

Well, now that MP3 is coming of age and any related patents will be running out fairly soon, Alcatel-Lucent has decided to take a share of the cake – and a rather large one.

What is worrying is that through this step, all companies that are licensing “standardized” codecs and thought that getting a license through the standards body would cover all possible infringement, now have to fear that there is always another hidden patent somewhere, which somebody can pull out of the hat at any time to sue them.

Doesn’t that put the aim of standardization on its head?

To me it just confirms that standardized technology should be technology that is not covered by patents and that the standards body has to make sure that such patents don’t exist.

Unfortunately, ISO/MPEG – and other standardisation bodies – have worked in the exact opposite direction until now: everyone who participated in MPEG made sure to get as many patents registered with MPEG as possible so as to get as large a share of the licensing payments as possible.

The only solution out of this mess is to create media codecs that are not infringing patents. Luckily, Xiphophorus is doing exactly that. So, this should encourage media companies to use Ogg Vorbis and Ogg Theora.

And if these codecs are too “old” for you, expect the new Dirac codec from the BBC to shake up things a lot! Open source, open standard, and the latest wavelet technology – should be un-beatable!

FOMS – the birth of a new open media forum

code, Digital Media, FOMS, Open Source

The first FOMS (Foundations of Open Media Software) workshop is over and it was an overwhelming success – more than ever expected! And wow – we have videos of it, too – thanks to Ralph Giles and Thomas Vander Stichele.

The goal of FOMS was to bring a diverse group of people from all around the planet who are all working on open media software together for the first time so they could get to know each other, exchange ideas, and generally address the things that annoy us all with open media technologies.

Strategically placing FOMS in the week before LCA was a great idea: not only would some of the developers attend LCA anyway and thus would not need to use up extra travel time, but also would LCA provide opportunities for the newly forged relationships to flourish and create code.

A new forum for discussion was created and since the community has committed to achieving a set of community goals, we expect it will have some basic effect on the usability of open media software over time.

And yes … all participants are up for a repetition of FOMS – possibly as a precursor to other FLOSS conferences overseas, but at a minimum again at next year’s LCA in Melbourne. Let’s rock it!

LCA Video Team

Digital Media, LCA, Open Source

I keep getting asked how we did the technical setup, so let me share it here.

With Video at LCA, this year, we did not want a repetition of the more experimental setups of previous years. We set out with only one goal: to publish good quality video during LCA to increase the number of talks that people will be able to look at and discuss. Our only aim is the Ogg Theora format since it is the only open video codec and what would a conference on FLOSS be if we didn’t stick to our ideals even with codecs!

One consequence of our narrow goal is that you will not find any live video streaming at LCA in 2007. The reasoning behind this is that we reach maybe a few hundred people with streaming, but that publishing reaches millions. Another reason is that previous years of video recordings at LCA have mostly had problems with one particular part in this picture: computers. So, we decided to take the computer out of the recording process and only use it in the transcoding, uploading and publishing part of the conference.

We are therefore recording from the DV cameras straight to DVD, which provides us with a physical backup as well as a quick way to get the data into the computer (in comparison to using DV tapes). Though this means that we use a non-free compression format in the middle of our process, it makes it a lot less error-prone. We’re waiting for the day when we can replace our camera – DVD recorder setup with Ogg Theora recording hard-disk cameras!

But the technical part of the video recordings is only one part of the picture. If you want good quality footage, you have to put people behind the cameras at all times. Speakers do weird things and a recording of slides with voice-over is not a very sensible video recording of conference talks. You really require a minimum of 2 people per lecture hall to cover the semi-professional setup that was required for the Mathews theatres: one looking after the audio and the other after the video, with a bit of slack time to give each other a break.

In parallel to the camera crews, we have a transcoding and upload team, which constantly receives the DVDs (and the DV tape backups) from the recording rooms. You also need stand-by people for relief. The upload process involves editing of the start and end points of videos, then a transcode to Ogg Theora and an upload to a local file server at the conference. This video gets mirrored to a Linux Australia Server and published into the conference Wiki through an automatic script.

We are very lucky to have a competent and reliable A/V team of volunteers at LCA 2007 who give up their opportunities to attend the conference for the greater good of all of us. Each team member covers all the days and it takes a lot of dedication to be up in the morning before everyone else (and possible after a hard night’s partying) and working a full day behind the camera or the computer. One of the team members even spent his birthday behind the camera!

I’d like to thank everyone on the A/V Team (in no particular order):

  • Timothy Terriberry,
  • James Courtier-Dutton,
  • Michael Dale,
  • Holger Levsen,
  • Nick Seow,
  • Sridhar Dhanapalan,
  • Chris Deigan,
  • Jeremy Apthorp,
  • Andrew Sinclair,
  • Andreas Fischer,
  • Adam Nelson,
  • Ryan Vernon, and
  • Ken Wilson.

In addition, the networking people have worked hard to make the uploading and publishing process as smooth as possible – I’d like to thank in particular John Ferlito and Matt Moor for their hard work.

It was a great experience to work with such a large team in such a professional setup where we managed to overcome many technical and human challenges and get the first video published even during LCA!

Editing video for LCA

code, Digital Media, Open Source

I’ve just finished writing a small script that will help us edit and transcode video recorded at LCA 2007. Since we will record directly to DVD, we will need a simple laptop with a DVD drive and the installed software gmplayer and ffmpeg2theora to do the editing and transcoding, before uploading to a Web server. Which means that just about all LCA participants are potential helpers for making sure the video material gets published on the same day.

If you happen to be a LCA participant and want to help ascertain video publishing happens, please walk up to the video guys and offer your editing & transcoding help.

Ah yes, and here is the script – in case anyone is interested:


#!/bin/sh

# usage function
function func_usage () {
echo "Usage: VOB2Theora.sh "
echo " starttime/endtime given as HH:MM:SS"
echo " filename input file for conversion"
}

# convert from SMPTE to seconds
function func_convert2sec () {
tspec=$1;
tlen=${#tspec} #strlen

# parse seconds out of string
tsecstart=$[ ${tlen} - 2 ]
tsec=${tspec:$tsecstart:2} #substr

# parse minutes
tminstart=$[ ${tlen} - 5 ]
if test $tminstart -ge 0; then
tmin=${tspec:$tminstart:2} #substr
else
tmin=0
fi

# parse hours
thrsstart=$[ ${tlen} - 8 ]
if test $thrsstart -ge 0; then
thrs=${tspec:$thrsstart:2} #substr
else
thrs=0
fi

# calculate number of seconds from hrs, min, sec
tseconds=$[ $tsec + (($tmin + ($thrs * 60)) * 60) ]
}

# test number of parameters of script
if test $# -lt 3; then
func_usage
exit 0
fi

# convert start time
func_convert2sec $1
tstart=$tseconds

# convert end time
func_convert2sec $2
tstop=$tseconds

# input file
inputfile=$3
if test -e $inputfile; then
echo "Converting $3 from $tstart sec to $tstop sec ..."
echo ""
else
echo "File $inputfile does not exist"
exit 1;
fi

# convert using ffmpeg2theora
strdate=`date`;
strorga="LCA";
strcopy="LCA 2007";
strlicense="Creative Commons BY SA 2.5";
strcommand="ffmpeg2theora -s $tstart -e $tstop --date '$strdate' --organization '$strorga' --copyright '$strcopy' --license '$strlicense' --sync $inputfile"

echo $strcommand;

sh -c "$strcommand";

—

Ralph Giles made an improved version of the VOB2Theora script. It can be found at http://mirror.linux.org.au/linux.conf.au/2007/video/VOB2Theora_v2.sh.

Why we need a open media developer conference

Digital Media, FOMS, Open Source

Have you ever been stuck with a video file that does not play in any of your video players or the Web Browser? It happens frequently because the media technology landscape is still a very fragmented one where a lot of energy is put into the creation of proprietary compression technologies. But the consumer is unwilling to follow every new encoding format and to pay for codecs which he/she may only need for this one file.

Just as the use of free and unencumbered text encoding formats (ASCII, UTF-8) is a prerequisite to the development of novel applications and an enabler of email, the Web, and many other common applications, free video and audio formats enable the creation of novel applications with media.

Free and unencumbered codecs are starting to become mature. The codecs from Xiph.org cover audio (Vorbis, Speex, FLAC) and video (Theora) are readily available and supported on many platforms. The BBC’s next-generation video codec called Dirac is still in the labs, but is one of the few cutting-edge codecs built on Wevelets, a novel transform that promises higher compression rates with less artefacts – and it is free and unencumbered.

However, the availability of codecs is not all that matters. Audio-visual applications that make use of these codecs need to be developed, too. Applications such as video editors, desktop audio/video players, Webbrowser embedded players, and streaming technology are fundamental to enable the full production-to-publishing chain. And then there are the higher-level applications such as playlist and collections manager (iTunes-like), video Web hosting, video search, or Internet video conferencing applications which provide the real value to people.

Foundations of Open Media Software is the first conference ever to bring together the architects of open media software systems from around the world to address technical issues and further the development of a open media ecology where the focus is on the development of new high-value applications rather than a tiring and unproductive competition of formats.

FOMS furthers the development of media technology on Linux, addresses support of open media codecs across platforms, and works towards the creation of an ecosystem of rich media applications.

The principles of creative commons content around a free exchange of ideas through digital media requires adequate licenses to be attached to media files, which in turn will only work in an environment where the media formats of such content is unrestricted and unencumbered, too.

Foundations of Open Media Software takes place in Sydney, Australia 11th-12th January 2007. Since it is a conference organised by developers for developers, donations are highly welcome. There are also some spaces for professional delegates available still. Details are at http://www.annodex.org/events/foms2007/ .

FOMS: Foundations of Open Media Software

Digital Media, FOMS, Open Source

From Thursday 11 – Friday 12 January 2007 we will have some of the world’s top open media software developers gather in Sydney at a workshop titled “Foundations of Open Media Software” (FOMS).

The workshop takes place in the week before linux.conf.au (LCA), thus enabling developers to cross-pollinate with the developers and attendants of LCA. FOMS is supported by LCA with venue and other logistics.

I’m happy to be one of the core organisers of this workshop and very excited about the vibe that this will bring to the open media software developer community. FOMS creates a venue for a community that has thus far not had its own gathering place.

In January: Sydney will rock the FOSS world doubly!!