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• lavu : fix memory leaks by using a mutex instead of atomics

  14 novembre 2014, par wm4

  lavu : fix memory leaks by using a mutex instead of atomics
  The buffer pool has to atomically add and remove entries from the linked
  
  list of available buffers. This was done by removing the entire list
  
  with a CAS operation, working on it, and then setting it back again
  
  (using a retry-loop in case another thread was doing the same thing).
  This could effectively cause memory leaks : while a thread was working on
  
  the buffer list, other threads would allocate new buffers, increasing
  
  the pool’s total size. There was no real leak, but since these extra
  
  buffers were not needed, but not free’d either (except when the buffer
  
  pool was destroyed), this had the same effects as a real leak. For some
  
  reason, growth was exponential, and could easily kill the process due
  
  to OOM in real-world uses.
  Fix this by using a mutex to protect the list operations. The fancy
  
  way atomics remove the whole list to work on it is not needed anymore,
  
  which also avoids the situation which was causing the leak.
  Signed-off-by : Anton Khirnov <anton@khirnov.net>
  

  • [DH] libavutil/buffer.c
  • [DH] libavutil/buffer_internal.h

• lavfi : add a libplacebo filter

  26 juillet 2021, par Niklas Haas

  lavfi : add a libplacebo filter
  This filter conceptually maps the libplacebo `pl_renderer` API into
  
  libavfilter, which is a high-level image rendering API designed to work
  
  with an RGB pipeline internally. As such, there's no way to avoid e.g.
  
  chroma interpolation with this filter, although new versions of
  
  libplacebo support outputting back to subsampled YCbCr after processing
  
  is done.
  That being said, `pl_renderer` supports automatic integration of the
  
  majority of libplacebo's shaders, ranging from debanding to tone
  
  mapping, and also supports loading custom mpv-style user shaders, making
  
  this API a natural candidate for getting a lot of functionality out of
  
  relatively little code.
  In the future, I may approach this problem either by rewriting this
  
  filter to also support a non-renderer codepath, or by upgrading
  
  libplacebo's renderer to support a full YCbCr pipeline.
  This unfortunately requires a very new version of libplacebo (unreleased
  
  at time of writing) for timeline semaphore support. But the amount of
  
  boilerplate needed to hack in backwards compatibility would have been
  
  very unreasonable.
  

  • [DH] configure
  • [DH] libavfilter/Makefile
  • [DH] libavfilter/allfilters.c
  • [DH] libavfilter/vf_libplacebo.c

• We are hiring engineers to build an awesome product and platform used by millions of people

  16 février 2016, par Piwik Core Team — Jobs

  Are you ready for a new challenge ? Or maybe you know someone who is looking for a change ? We have some exciting problems to solve and are looking for senior developers to work with us and our community on our open source Piwik Analytics platform. Piwik is used by more than one million websites all over the world. It is deployed on more than 300.000 servers and some users track more than 1 billion actions per month.

  What is it like to work on Piwik ?

  We develop this software using modern PHP, MySQL, Redis, AngularJS and more. We provide several kind of APIs and a plugin architecture to allow developers to extend and change Piwik to their needs. However, we would not be Piwik if we stopped at this point ! We want to turn Piwik into an even more awesome product and platform.
  You can imagine there is a lot to do and many challenges to face !

  While one part is to always make Piwik scale better and to improve UI and UX, we also want to provide simple APIs to make the life of developers as pleasant as possible. We aim to solve things the right way and our thousands of unit, integration, system, JavaScript and screenshot tests help us to innovate and to not be afraid of change. We like clean code and constant improvements.

  The Piwik team lives in New Zealand, Europe (Poland, Germany) and in the U.S. We do the vast majority of our collaboration online. Our values include being open, transparent and sharing knowledge. For this we use tools like GitHub and Slack to communicate and Quake servers to take our minds off complex challenges. We are a small, flexible team, so when you come aboard, you will play an integral part in engineering and have a big impact on the product loved by so many people. You’ll help to create a welcoming environment for new contributors and set an example with your development practices and communications skills.

  Apply now, or spread the word !

  If you have strong skills in PHP send us an email with your CV and tell us a little about yourself and your experience in engineering complex applications.

  Apply for a job here http://piwik.org/jobs/ and if you’re maybe not the right candidate, contribute to the project by sharing this blog post and by sending it to your friends !