vendredi 27 mai 2011

I have been lurking and hacking Pitivi's source code for quite a while now, and I think it is now time for me to sum up my opinions about it.

The first time I launched it, I had just installed Ubuntu and the version I had was 0.13.4, without the effects and anything. I was new to coding, so the only thing I could judge about it was the user interface and how everything fitted together. And I must admit that I thought : "Wow ! This is not what I would use if I wanted to make a short movie or anything .."

Anyway, I started messing up with the code, making my way through the architecture with wild prints and crazy changes, and I quicly reckoned that Pitivi was only the visible part of a greater framework, namely GStreamer, and that this framework really rocked, and gave Pitivi an unprecedented advantage on what existed before : A solid community, with hundreds of active members, all of them dedicated on taming the wild beast which is media handling, writing a great number of plugins ranging from codec handling to effect creation or object transformation !

Pitivi was nothing but the editing emerged part of the iceberg, and a part which was still to grow to its real size. After all, the version naming is not random, the 0.13.x name means that it really is not mature yet, and misses a bunch of basic features essential to video editing, listing them would be too fastidious.

But the whole point of my argumentation is that I think Pitivi has bet on the good horse, cause now that I begin to know a little more about GStreamer's internals, I realize the power that lies in its architecture : Flexibility and Modularity, through the use of combinable elements to form new elements, which in turn can be combined to finally make complex pipelines, ready to be played or rendered at will.

I don't know well the other available frameworks, for example MLT, but what I know is that I love GStreamer, and a lot of other people look like they love it as well, shaping up the biggest media framework community by far.

That's why I stuck up to pitivi until now, eventually applying for a Summer of Code to be able to give it still more of my time, and I can say now I'm happy of my choice. Indeed, a long-awaited release has just arrived, shipping a whole lot of goodies, first of them being the effects handling, and I can see some lines moving. Pitivi's IRC channel has never been so active, and new enthusiastic developers wannabe's pop up every day. On top of that, Gstreamer and Gnome have allocated no less than 4 Summer of codes to us (against only one last year) which means we're gonna be able to take this software to a new level :
  1. One GSoCer is going to implement complex object recognition algorithms (robust estimation of Optical flow), which will make pitivi conscious of the different layers (background, foreground) and moving objects in a video.
  2. Another will use Gstreamer filters to provide object's transformation options to the user, and also give titling support to Pitivi, another essential feature that it was lacking until now.
  3. The third one will allow users to upload videos to streaming websites such as youtube or dailymotion, and also provide them with rendering presets (IPod, YouTube, Android Phone etc..).
  4. I will integrate a new C library in pitivi, which will replace a lot of its backend with C optimized functions, making it more performant in the process, and allowing new features
     integration (for example new kinds of transitions, the default one for now being the classical overused crossfade).
This is exciting isn't it ? I can't wait to see the next release, which will hopefully come way faster than the previous one. Kudos to thiblahute for bringing it to us !

My Google summer of code weekly report number 1.

Hi everyone !

I started working on my project before the actual Summer of Code began, and I already successfully compiled the static bindings with a code coverage of about 90 %, wrote the beginning of a test suite for them and a basic example script.

Since then, effects have been merged in GES master, so the .xptv file formatter I had written has got outdated, and since it's a critical component of my project, I decided to update it before going on with the bindings, in the hope of getting a near 100% code coverage.

This has involved some massive refactoring, since I had not clearly envisioned the way the formatter would work with the effects (shame on me ;), and I'm not done yet : effects are integrated, but I still have to re-integrate the transitions properly).

However, work is going well, and I'm not blocked anymore on my way to integrating GES in pitivi, given one of the members of the IRC channel gave me a hand on solving the problem of GST argtypes that were not properly handled by the code generator I use to create the bindings.

By the end of next week, I will surely have finished my work on the formatter (code cleanup, fixing of the tests), and I hope to have solved the GST argtypes problem completely as well (This could be the matter of 2 or 3 hours of coding if everything goes as intended). With some luck, I'll be able to write overrides for the last 10 or 12 functions as well, which will leave me free to attack the real meat of my project, i.e. integration in pitivi proper.

Most of my problems this week were very specific to my project, and I don't think they'd be very useful to anyone.