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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>
  

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

• Call for Speakers : Share Your Voice at MatomoCamp 2025 !

  10 juillet, par Alex Carmona

  MatomoCamp is back for its 2025 edition — and the Call for Speakers is now open until July 31st !

  As proud sponsors of this unique, community-driven event, we’re excited to invite experts, enthusiasts, and curious minds to contribute to MatomoCamp 2025, the annual online gathering dedicated to web analytics, open source, digital privacy, and of course — Matomo. MatomoCamp is the premier free online conference for the Matomo Analytics community in Europe, sponsored by Matomo Analytics. Taking place online on Wednesday 26 November 2025 from 9:30 AM to 5:30 PM CET, this event brings together professionals passionate about ethical analytics, data privacy, and building a better web.

  Whether you’re a long-time user, developer, marketer, researcher, or just someone with a fresh perspective on ethical analytics, your voice belongs at MatomoCamp. Last year, we welcomed over 1,000 attendees from around the world. This year, we’re aiming even higher with an expanded programme designed to serve everyone from analytics beginners to enterprise architects.

  What is MatomoCamp ?

  MatomoCamp is a free, fully online event bringing together the global Matomo community. Across two days of talks, panels, demos, and workshops, participants explore :

  • Web analytics & measurement
  • Digital marketing & SEO
  • Open source projects & collaboration
  • Privacy-first data strategies
  • Case studies, experiments, and more

  With sessions in English, French, German, and beyond, MatomoCamp aims to make digital analytics more accessible, ethical, and transparent for everyone.

  MatomoCamp returns this November 2025 with an exciting new vision. For the first time, we’re expanding beyond purely technical content to welcome speakers from all backgrounds who can contribute insights on analytics, privacy, marketing, and the ethical web. Whether you’re a developer, marketer, analyst, or privacy advocate, we want to hear from you.

  Who can apply ?

  Anyone ! We’re looking for people from all backgrounds who want to share :

  • A practical tip or use case with Matomo
  • Insights into digital analytics, privacy, or open source
  • A success (or failure !) story from your own journey
  • A workshop or hands-on demonstration
  • A bold opinion on the future of web data
  • A behind-the-scenes look at your work or research

  You don’t have to be a professional speaker. We welcome first-time speakers, underrepresented voices, and community members who want to share something valuable — no matter how niche or broad.

  What makes a great talk ?

  There’s no one right formula. But here’s what works well :

  • Real-world experience
  • Specific, actionable insights
  • A clear structure (15–45 minutes)
  • Something you care deeply about
  • A story only you can tell

  And remember — this isn’t just about Matomo. Topics that touch on ethical analytics, open source values, or digital sovereignty are more than welcome.

  Key info

  • Where : Online (free & open to all)
  • When : November 2025 (exact dates to be announced)
  • Languages : English, French, German (other languages welcome !)
  • Deadline to apply : July 31, 2025
  • Submit your talk here

  Why does this matter ?

  At Matomo, we believe that data should empower, not exploit. MatomoCamp is more than just an event — it’s a celebration of what’s possible when communities come together to build a better digital future.

  As sponsors, we’re proud to support this independent, open source event. But more importantly, we want to amplify your voice — because every perspective shared brings us closer to a more ethical, transparent, and inclusive analytics ecosystem.

  Have a story to share ?

  Don’t overthink it. If it matters to you, it will matter to someone else. Apply to speak before July 31st and join us at MatomoCamp 2025 !

  Submit your session here !

  Let’s build the future of analytics — together.

  

• FFmpeg muxing to avi

  2 septembre 2015, par Uncia

  sI have program, that succefully shows h264 stream using SDL : I’m getting h264 frame, decode it using ffmpeg and draw using SDL.
  Also I can write frames to file (using fwrite) and play this file through ffplay.

  But I want to mux data to the avi and face some problems in av_write_frame.

  Here is my code :

  ...
  
  /*Initializing format context - outFormatContext is the member of my class*/
  
  AVOutputFormat *outFormat;
  
  outFormat = av_guess_format(NULL,"out.avi",NULL);
  
  outFormat->video_codec = AV_CODEC_ID_H264;
  
  outFormat->audio_codec = AV_CODEC_ID_NONE;
  
  avformat_alloc_output_context2(&outFormatContext, outFormat, NULL, "out.avi");
  
  AVCodec *outCodec;
  
  AVStream *outStream = add_stream(outFormatContext, &outCodec, outFormatContext->oformat->video_codec);
  
  avcodec_open2(outStream->codec, outCodec, NULL);
  
  av_dump_format(outFormatContext, 0, "out.avi", 1);
  
  if (avio_open(&outFormatContext->pb, "out.avi", AVIO_FLAG_WRITE) < 0) 
  
      throw Exception("Couldn't open file");
  
  if (avformat_write_header(outFormatContext, NULL) < 0)
  
      throw Exception("Couldn't write to file");
  
   //I don't have exceptions here - so there is 6KB header in out.avi.
  
   ...
  
  
  
  static AVStream *add_stream(AVFormatContext *oc, AVCodec **codec,
  
                          enum AVCodecID codec_id)
  
  {
  
  AVCodecContext *c;
  
  AVStream *st;
  
  /* find the encoder */
  
  *codec = avcodec_find_encoder(codec_id);
  
  if (!(*codec)) 
  
      throw("Could not find encoder");
  
  st = avformat_new_stream(oc, *codec);
  
  if (!st) 
  
      throw ("Could not allocate stream");
  
  st->id = oc->nb_streams-1;
  
  c = st->codec;
  
  c->bit_rate = 400000;
  
  /* Resolution must be a multiple of two. */
  
  c->width    = 1920;
  
  c->height   = 1080;
  
  c->pix_fmt  = PIX_FMT_YUV420P;
  
  c->flags = 0;
  
  c->time_base.num = 1;
  
  c->time_base.den = 25;
  
  c->gop_size      = 12; /* emit one intra frame every twelve frames at most */
  
  return st;
  
  }
  
  ...
  
  /* Part of decoding loop. There is AVPacket packet - h264 packet;
  
  int ret = av_write_frame(outFormatContext, &packet); //it return -22 code - Invadlid argument;
  
  if (avcodec_decode_video2(pCodecCtx, pFrame, &frameDecoded, &packet) < 0) 
  
      return;
  
  if (frameDecoded)
  
  {
  
     //SDL stuff
  
  }

  Also i tried to use avcodec_encode_video2 (encode pFrame back to the H264) next to the SDL stuff but encoding is not working - i’ve got empty packets :( It is the second problem.

  Using av_interleaved_write_frame causes acces violation.

  Code of the muxing part i copied from ffmpeg muxing example (https://www.ffmpeg.org/doxygen/2.1/doc_2examples_2muxing_8c-example.html)