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• The Future of the VP8 Bitstream

  18 juin 2010, par noreply@blogger.com (John Luther) — vp8

  Recently we’ve seen software products such as VLC, FFmpeg, Logitech Vid, Flumotion and Tixeo adopting and using WebM and VP8 (the video codec in WebM) in exciting new ways.

  In addition to software developers, many hardware vendors have committed to shipping VP8-accelerated products based on our current bitstream in 2011 . Devices that use hardware acceleration for video are a very small percentage of overall web traffic today, but they are a rapidly growing segment of the market and our project must be mindful of these vendors’ needs. Given the longer lead times for changes in chipsets, hardware companies implementing the codec today need to be confident that it will be stable and supported as VP8 content proliferates.

  Like every codec, WebM is not immune to change ; the difference in our project is that the improvements are publicly visible, and compatibility and implementation issues can be worked through in an open forum.

  So, to maintain codec stability while also allowing for quality and performance improvements in VP8, we have added an experimental branch to the VP8 source tree. The WebM community can use this unstable branch to propose changes to VP8 that will produce the best video codec possible, but without the constraints of a frozen bitstream. At some point in the future, when the experimental branch proves significantly better than the stable branch, we will create a new version of the codec.

  Teams dedicated to improving WebM are actively investigating and evaluating new techniques, and are committed to do so for the long term. We encourage the WebM community to keep contributing as well. To learn more about the experimental branch and get involved, see our repository layout page.

  Jim Bankoski is Codec Engineering Manager at Google.

  

• Ffmpeg AVAudioFifo memory leak

  10 août 2020, par Expressingx

  I'm encoding audio to AAC with encoder. Because it requires I'm using AVAudioFifo following https://ffmpeg.org/doxygen/4.0/transcode_aac_8c-example.html

  


  Everything works, but I can see my memory slowly growing up. If I comment out PushToFifo() no memory leaks. And not sure why. I've profiled the app with ANTS Profiler and I can see a lot of unmanaged memory allocated by avutil-x.dll.

  


  while (ffmpeg.av_read_frame(_inputContext.InputFormatContext, pkt) >= 0)
{
   // decode
   int ret = ffmpeg.avcodec_send_packet(decCtx, pkt);

        if (ret < 0)
        {
            ffmpeg.av_packet_unref(pkt);
            return;
        }

        while (ret >= 0)
        {
            ret = ffmpeg.avcodec_receive_frame(decCtx, frame);

            if (ret == ffmpeg.AVERROR(ffmpeg.EAGAIN) || ret == ffmpeg.AVERROR_EOF)
            {
                return;
            }
            
            // push to fifo
            PushToFifo();
            TryFlushSamples();
        }
}


  


  PushToFifo()

  


              byte* samples = null;

            if (ffmpeg.av_samples_alloc(&samples, null, _outputContext->channels, inputFrame->nb_samples, _outputContext->sample_fmt, 0) < 0)
            {
              ffmpeg.av_freep(&samples[0]);
              ffmpeg.av_free(samples);
              // throw
            }

            if (ffmpeg.swr_convert(_resamplerCtx, &samples, inputFrame->nb_samples, inputFrame->extended_data, inputFrame->nb_samples) < 0)
            {
              throw new Exception();
            }

            if (ffmpeg.av_audio_fifo_realloc(AudioFifo, ffmpeg.av_audio_fifo_size(AudioFifo) + inputFrame->nb_samples) < 0)
            {
              throw new Exception();
            }

            if (ffmpeg.av_audio_fifo_write(AudioFifo, (void**)&samples, inputFrame->nb_samples) < 0)
            {
               throw new Exception();
            }


  


  And in TryFlushSamples();

  


          while (ffmpeg.av_audio_fifo_size(_audioFifo.AudioFifo) >= _outputContext.AudioEncodeContext->frame_size)
        {
            int fifoSize = ffmpeg.av_audio_fifo_size(_audioFifo.AudioFifo);
            int frameSize = fifoSize > _outputContext.AudioEncodeContext->frame_size
                ? _outputContext.AudioEncodeContext->frame_size
                : fifoSize;

            var outputContext = _outputContext.AudioEncodeContext;
            var frame = ffmpeg.av_frame_alloc();
            frame->nb_samples = frameSize;
            frame->channel_layout = outputContext->channel_layout;
            frame->format = (int)outputContext->sample_fmt;
            frame->sample_rate = outputContext->sample_rate;

            if (ffmpeg.av_frame_get_buffer(frame, 0) < 0)
                ffmpeg.av_frame_free(&frame);

            // read frame
            if (ffmpeg.av_audio_fifo_read(_audioFifo.AudioFifo, (void**)&frame->data, frameSize) < frameSize)
            {
                ffmpeg.av_frame_free(&frame);
                return;
            }

            frame->pts = _audioFrameCount;
            _audioFrameCount += frame->nb_samples;

            // send to encoder 

            ffmpeg.av_frame_free(&frame);
        }


  


• Piwik PRO is hiring a Project Coordinator (Job description)

  18 février 2015, par Matthieu Aubry — Jobs

  At Piwik and Piwik PRO we develop the leading open source web analytics platform, used by more than one million websites worldwide. Our vision is to build the best open alternative to Google Universal Analytics. We are growing and now looking for a Project Coordinator !

  What will you be doing ?

  • Participating in calls with Piwik PRO clients and analyzing requirements for enterprise customers
  • Planning and coordinating the implementation of projects
  • Helping customers to improve and adjust data reporting methods to suit their needs
  • Functioning as the voice of the customer and provide internal feedback on how Piwik PRO can better serve our customers

  What do we expect from you ?

  • Fluent command of English (both in writing and speaking), confidence to communicate in formal conversations and a good knowledge of business English
  • Previous experience in working with corporate clients
  • Great communication skills
  • A proactive attitude and the ability to use your initiative
  • Ability to achieve goals without detailed instructions

  Possessing these assets would be an advantage :

  • Technical knowledge associated with using data analytics platforms
  • Data analysis and interpretation skills
  • Knowledge of German or French
  • Knowledge of Piwik Analytics

  What can you expect from us ?

  • Flexible cooperation
  • An attractive salary
  • The opportunity to develop your skills and gain more experience by working on exceptional projects
  • Multisport Card
  • Access to a regularly updated resource library and the opportunity to contribute to it
  • Flexible working hours
  • Unforgettable parties and integration trips
  • A completely unique work atmosphere – we really like to keep things informal

  Location

  We have offices in Poland and New Zealand, and Remote work is possible.

  Ideally you will be located in the USA or in Europe where most of our clients are based.

  Apply online

  To apply for this position, please Apply online here. We look forward to receiving your applications !