So working up to MWC in Barcelona this week we just announced a great new effort by Collabora and Fluendo around the GStreamer project. The goal is to ease adoption of GStreamer by making sure that no matter what platform you are in, there are well tested and easy to install and use binaries of GStreamer available. This means that not matter if you are running Windows, MacOS X or Linux, you will have a GStreamer SDK available to use. Eventually we will also cover various embedded platforms with this SDK, making it easier than ever to use GStreamer to create great cross platform multimedia applications. You can find out more about this effort by checking out the press release which have all the relevant details.
So as I talked about in my last blog post we had a great GStreamer hackfest. A lot of things got done and quite a few applications got an initial port over to 0.11. For instance Edward Hervey ended up working on porting the Totem video player, or rather trying to come up with a more optimized design for the Clutter-gst as the basis port was already done.
Jonathan Matthew had flown up all the way from Australia and made great progress in porting Rhythmbox over to the 0.11 API, a port which became hugely more useful after Wim Taymans and Tim-Phillip Muller fixed a bug that caused mp3 playback not to work :).
Peteris Krisjanis made huge strides in porting Jokosher to 0.11. Although like Jason DeRose from Novacut and myself on Transmageddon he did end up spending a lot of time on debugging issues related to gobject-introspection. The challenge for non-C applications like Jokosher, Novacut, Transmageddon and PiTiVi is a combination of the API having changed quite significantly due to the switch to gobject-introspection generated bindings, some general immaturity challenges with the gobject-introspection library and finally missing or wrong annotations in the GStreamer codebase. So once all these issues are sorted things should look a lot brighter for language bindings, but as we discovered there is a lot of heavy lifting to get there. For instance I thought I had Transmageddon running quite smoothly before I suddenly triggered this gobject-introspection bug.
There was a lot of activity around PiTiVi too, with Jean-François Fortin Tam, Thibault Saunier and Antigoni Papantoni working hard on porting PiTiVi to 0.11 and the GStreamer Editing Services library. And knowing Jean-François Fortin I am sure there will soon be a blog with a lot more details about that :).
Thomas Vander Stichele, who also wrote a nice blog entry about the event, was working with Andoni Morales Alastruey, both from Flumotion, on porting Flumotion to 0.11, but due to some of the plugins needed not having been ported yet most of their effort ended up being on porting the needed plugins in GStreamer and not so much application porting, but for those of you using plugins such as multifdsink, this effort will be of great value and Andoni also got started on porting some of the non-linux plugins, like the directsoundsink for Windows.
Josep Torra from Fluendo ended up working with Edward Hervey on hammering out the design for the clutter-gst sink at the conference, but he also found some time to do a port of his nice little tuner tool as you can see from the screenshot below.
In addition to the application work, Wim Taymans, Tim-Phillip Müller and Sebastian Dröge from Collabora did a lot of core GStreamer clean ups and improvements in addition to providing a lot of assistance, bugfixing and advice for the people doing application porting. All critical items are now sorted in 0.11 although there are some nice to have’s still on the radar, and Wim plans on putting out some new releases next week, to kickstart the countdown to the first 1.0 release.
As for my own little pet project Transmageddon, it is quite far along now, with both manually configured re-encodes and profile re-encodes working. Still debugging remuxing though and I am also waiting for the deinterlacer to get ported to re-enable deinterlacing in the new version. For a screenshot take a look at the one I posted in my previous blogpost.
Things have been going really well here at the GStreamer Hackfest in Malaga. Thanks to the help of Ara and Yaiza from Nido Malaga, we have a great venue in downtown Malaga and they have also helped us greatly with sorting out food.
We have a great group of people here and are making great progress, and by tomorrow I hope we will have screenshots of quite a few applications running with GStreamer 0.11, for instance both Rhythmbox and Jokosher for instance is already screen shootable, if not fully functional
Also making good progress on Transmageddon, even if the move to GObject Introspection bindings are making things a bit more complicated. Screenshot below of the progress so far.
Update: Yaiza took these photos from the hackfest
Tomorrow I will be heading off to attend the GStreamer Application Porting Hackfest in Malaga, Spain. I think we have managed to pull together an absolutely incredible group of people for this event and I have great hopes that by next weekend we will have squashed a ton of bugs in GStreamer 0.11/1.0 and also have initial ports of a long range of important applications and bindings. This is the first time in GStreamer history that we are trying to hold a hackfest focused on application developers, but hopefully it will be the first of many and that they can become a good way for the core GStreamer community and the application development community to interact and collaborate more closely.
Also want to say a special thanks to the community members attending the event on their own and also to the companies sending their employees to the hackfest; Collabora, Fluendo, Flumotion and Igalia and finally a special thanks to the GNOME Foundation for sponsoring some of the attendees.
Hopefully I will be able to post some screenshots of a fully functional GStreamer 1.0 Transmageddon next weekend
After updating GStreamer and doing a couple of small fixes I managed to make Transmageddon work with the GTK3 and the 0.11 branch of GStreamer. Obligatory screenshot below. As you might guess from looking at the screenshot there are still some issues that needs solving, but
I am happy that I managed to get this far.
Hopefully it is a sign that the upcoming GStreamer hackfest in Malaga will be a great successful everyone who is participating.
I hope the remainder of the porting effort will be relatively simple as I would love to get back to working on real features instead of just updating old functionality to use a new backend to do the same. Having had a need for Transmageddon for a couple of work related tasks recently a couple of items, like batch job programming has moved up my priorities list.
Just posted another interview on the Collabora website, this time with Gustavo Noronha Silva talking about WebKit and some of the work he and Collabora are doing around that project. So be sure to check it out if you want to learn more about things like WebKit and Clutter integration and how WebKit impacts the GNOME platform.
I am desperately looking for someone familiar with Malaga, Spain, maybe a local LUG or similar. The reason is that we are interested in doing a GStreamer 1.0 application porting hackfest there in late January. So getting hold of someone with local knowledge who would be able to help us find a suitable venue would be great. Please get in touch with me on christian.schaller(at)gmail.com if you are in the area and willing to help or know someone would probably could help us.
First of all the first entry was using the term liberals, which I would suggest avoiding, because while in Europe it tends to mean people who are on the right wing of the political spectrum, because they are liberals in terms of economic policies, in North America a liberal is someone on the left side of the political spectrum as they tend to liberals in terms of social policies like gay marriage, abortion etc. Due to this I tend to try to refer to these groups as either social liberals, economic liberals (or libertarians if they are both for a free market and have socially liberal views.)
Anyway, I think the original article by Josselin was quite silly in its tone. There are a lot of reasons we have the current set of problems in the world economy, and economic liberal policies have only a small part of the blame. First of all the problems in Europe is, as Mathias says in his rebuttal, that you have mostly left leaning governments budgeting year after year after year with huge deficits, covering the deficits by pulling their countries deeper and deeper into debt. So when a crisis hits and it always will under any system, they have nothing to fall back on as they are already debted to the neck. Personally I think Keynesian policies is probably what is needed in a situation like this, but that is based on an assumption that they governments have made sure to have reserves or have low debt before a crisis hits, so they can use these reserves to help pull the economy through. In Europe the problem was that the governments where already so deep in debt that when they tried to stimulate their economies they just make it clear how much money they actually owed and how unable they would be in ever getting back on track again.
The US did something even more silly, they cut taxes and increased expenses at the same time. This idiot policy was called Reaganomics. And while it was definitively right wing in origin, I am not sure it can be easily placed in a libertarian versus socialist context. No matter if you are left wing or right wing, the most basic rule is that you keep your books in order. That means that if you want to increase spending you need to also increase your income, and if you want to decrease taxes and thus your income, you need to decrease your spending. The left wing governments of Europe only increased spending, but not income, and the right wing governments of the US only cut income, but not spending.
As for the depressed wages around the western world they are caused by a lot of different things, but the biggest of them all is that new technology combined with free trade agreements have undermined our ability to keep the rest of the world down in poverty and unable to develop their own industries. I assume we all accept this as a good thing in principle, but yes it does cause transitional pains and wage pressures here while we wait for the cost levels in the BRIC countries to catch up with us.
As for deregulation of the banking sector, which can be said to be a economically liberal policy, to be part of what caused the recent upheaval, yes it probably did play a part. But it does strike me as quite hypocritical that when the political drive to get people into the housing market, which was supported everywhere by people on both the left and the right, ends up getting banks in trouble due to the so called sub-prime loans collapsing, it is all about the banks and not about the politicians who supported such lending habits to support their own social policies. Subprime loans is not something impossible to understand, it is basically loans to poorer people. And politicians on both side of the aisle felt that encouraging house ownership was a great way to help raise such people into the middle class. And it worked quite well for a while in regard to improving the standard of life for a lot of people, but as we all know now, it was a bubble that had to burst at some point. Anyway, lending money to poorer people who might not be able to afford it, in order for them to buy their own house, doesn’t seem to be a clear fit under the headline ‘liberal economic policies’ to me.
I think most people agree that a ideologically pure system of any type is not likely to work or be deployable. In my view, the problem these days is that the system has moved from being one leaning towards being a free market economy, supporting entrepreneurship and healthy competition, to one of protecting established players. So we have policies through things like the tax system, government aid and the patent system, in most western countries, functioning in a way that protects established companies and disadvantages small companies who try to compete with them. I would rather define that as government lead capitalism and not free market liberalism.
So it doesn’t matter if we are talking about North America or Europe here, most times when politicians talk about new policies to help the economy or stimulate job growth, it is policies to support big established companies or groups. So every year these companies and industries grows more bureaucratic and less efficient, while more innovative and nimble startups faces an uphill struggle against the establishment.
So while I readily admit that there are a million other factors also playing in and that the root cause of issues wary from country to country somewhat, lets avoid silly name calling and pretend that populist policies is what is needed to improve the situation. Because if there is one ‘ism that is to blame for where we are at, it is not liberalism or socialism, it is populism. The populism supporting 5 minute news cycle which means politics is about 10 second long snazzy slogans and handsome faces, and not in-depth discussion or detailed review.
Edward Hervey pointed out to me this morning that there are some nice articles online about an effort between ST Microelectronics and Frauenhofer, around the 3GP DASH (Dynamic Adaptive Streaming over HTTP) standard. There is for instance this article in Thinq magazine and this article on TMCnet. What you might not know and which is even cooler is that Emanuele Quacchio will be speaking this GStreamer based DASH implementation at the the GStreamer Conference later this Month. So if you haven’t signed up for the GStreamer Conference already, then maybe this is the time to do it
I am really excited about this years GStreamer Conference as we have a lot of ongoing efforts about to come to fruits. From Collabora we got Wim Taymans will be talking about GStreamer 1.0 effort, which we expect to have out before years end and Tim-Philipp Müller will speak about a lot of the other incredible advances we made over the last year. Being in the middle of it I think its easy to go a bit blind due to the gradual process, but things like the new parsing libraries that Thibault Saunier have been working on, which will enable much quicker and better support for things like libva and vdpau plugins in GStreamer. Or the new baseclasses that Mark Nauwelaerts have ported most of our plugins over to now, which in one fell swoop improved our plugin quality by leaps and bounds. And of course there are things like the GStreamer Editing services (GES), discoverer and encodebin which Edward Hervey created, which will make applications like Transmageddon video transcoder and remuxer and the PiTiVi video editor a lot easier to develop.
We will also be doing some real cool demonstrations of stuff we have been working on at Collabora at the Linux Con Showcase on Thursday. Thanks to GES we have a great demo of a mobile editing solution using either QML or HTML5. We have HTML5 video calling using Telepathy and we have Video calling using Telepathy from the Media explorer media center solution.
Another talk that I will be sure not to miss is Jan Schmidt who will be talking about Blu-Ray playback with GStreamer. In addition to being technically interesting Jans talks are always fun, like last year he did his presentation using GStreamer instead of something like LibreOffice, having created his slides as a DVD menu through a small program he wrote to turn SVG files into DVD menus
I have wanted to write about programming with GStreamer and Python for a while. Jono Bacon wrote a nice introduction to GStreamer and Python a long time ago, but I want to share with you some specific tips.
At Collabora we work a lot with GStreamer including helping train developers at our customers to be better at GStreamer development. Being the lowly marketing guy at the company I don’t have the programming chops to teach the hard stuff, but I figured I should be able to put together a very simple article which explains some basics and shows of a little GStreamer development trick I have used to great success in Transmageddon.
Part of what triggered getting this little tutorial done was that I am looking into porting Transmageddon to GTK3 after its next release of Transmageddon. To understand how to write a GTK 3 Python application, using the introspection bindings, I decided a good learning tool for myself would be to try to port the 0.0.1 version of Transmageddon. This version was never released, in fact it was me trying to figure out the very basics of programming with GTK+ and GStreamer in Python.
The application litterally consists of a GTK+ UI with two buttons. One is a ‘transcode’ button which when pressed starts a GStreamer transcoding pipeline. The other is my little secret trick, called ‘Debug’. It will when pressed generate a png of the pipeline being run, or not being run for that matter. It has helped me solve a ton of bugs and issues in Transmageddon since I started the project and hopefully it can be a useful trick for you too.
You can find a tarball here with the code below, the .ui file from Glade and a which.py file (which.py is a python version of the Unix which tool, which I found online).
First let me give you the code of the application, I tried to annotate the code in detail to make it easy to follow, even if you haven’t played with either GTK3 or GStreamer before.
The first thing happening in the file after importing the basis system classes and the which.py tool, is that we set the ‘GST_DEBUG_DUMP_DOT_DIR’ environment variable. When you set this value, GStreamer will be able to at any time dump the pipeline and elements to a ‘dot’ file, which can be turned into a nice looking png by the graphviz command line tool (should be available in most distributions).
Next I import GTK and GStreamer, as you see I don’t yet use the gobject introspection version of GStreamer as that is not fully working yet, but I plan to try to port this simple application to GStreamer 1.0, in which gobject introspection will be the supported way of using Python.
Next is setting up the GStreamer pipeline. You always start by creating a pipeline object, consider this the canvas onto which you will paint the GStreamer streaming pipelines. The next step is to assemble all the GStreamer plugins we want to use in the application. First I create a filesrc object pointing to the file I want to transcode, be sure to point that to a file of your own if trying this application. Next is creating the decodebin2 element. Decodebin2 is one of a set of high level elements in GStreamer, called bins, which contains a wide range of plugins inside. These high level elements are there to make things a lot simpler, and in the case of decodebin2 it will automatically put together the plugins needed to convert your incoming file to raw audio and video (or just demux the file). This means your input doesn’t need to be a mp3 file, like I used, as decodebin2 will reconfigure itself to handle any file you throw at it. After this I create a series of elements to enable me to encode the data into a Ogg Vorbis file. I am doing that to help explain how elements are stringed together, but there is another high level element, encodebin, which I could have used instead. Transmageddon uses encodebin in its git version.
Once all the elements are created you can think of them as boxes spread around on your pipeline canvas, but in order for GStreamer to know how you want to connect them together you need to link them together, as you can see I do with statements like ‘self.filesrc.link(self.decoder)’, which connects the filesrc element I created with the decoder element.
The one special element here is decodebin, which being a dynamic element I need to link it once the pad found signal is fired. Also to link I need to request a compatible pad from the element I am linking with, in this case the audioconverter element.
The last part of the GStreamer setup is setting the pipeline to playing state, which is the state where the pipeline is running. While not a big concern in this very simple application, dealing with state changes in GStreamer is going to be one of the major items you look out for. The GStreamer plugin writers guide contains a chapter discussing the basics of the four states "NULL", "READY", "PAUSED" and "PLAYING". Your pipeline (and all elements) always start at Null state and will go through each of the other stanges to reach Playing. So while we only set state to PLAYING in this simple application, GStreamer will in the background go through READY and PAUSED. The reason the intermediary states matter is because certain things happen at each, so for instance if you want to do some analysis of a file before starting to run your pipeline fully you want to be in PAUSED state as GStreamer will then start pulling the initial data through the pipeline and thus allow you to get information from your elements about the stream or file. One important thing to keep in mind as you develop more advanced applications is that the individual elements can have a different state than the pipeline, but when the state of the pipeline changes it will change the state of the plugins along with it, so you never want your pipeline to be more than one level lower than any of your elements, as that will cause the element to jump down to that state and thus lose the negotiation and information it had assembled.
I am not going to go into a lot of detail about the GUI, it is a very simple GTK user interface built using Glade, and hooked up using the GTK3 gobject introspection bindings. If you got any questions about it post a comment and I be happy to talk about it. What I want to talk about instead is the on_debug_activate function. I wrote this for Transmageddon, but my hope is that it will be useful for anyone writing a Python application with GStreamer (and I guess it shouldn’t be to hard to port to another language). It will allow you to add a menu entry or button in your application that outputs a png file, like the one you see below, which gives you a nice full view of the pipeline used by GStreamer. Especially if you use things like decodebin2 and encodebin, or have a lot of code dynamically adding/removing elements, it can be really useful to see what pipeline ended up being used. And if you have elements that you created, but forgot to link inn, they will appear as orphaned boxes in the file, allowing you to detect such issues. The important thing to remember is that it needs the graphwiz application to be installed on your system and available in the executable path.
Anyway, I hope this has been useful and I plan to post and updated version of this simple application, ported to use encodebin and GStreamer 1.0.