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• Piwik and Piwik PRO featured in VentureBeat Insight as “an obvious solution” for web analytics

  7 avril 2015, par Piwik Core Team — About

  We are proud to see Piwik and Piwik PRO featured in the recent report published by VentureBeat Insight. Published at the end of March 2015, Conversion Rate Optimisation : how to win at performance marketing was based on surveys of almost 3000 CRO tools users.

  

  Piwik earned a perfect score of 100 out of 100 for website analytics and was featured as an “obvious solution” for those who prefer to use open source products. The report also pointed out a very low abandonment rate of Piwik by its users, despite its growing popularity (3%).

  You can preview the “Conversion Rate Optimisation : how to win at performance marketing” report for free here
  (Note : there is a form to fill in before you can access it).

  View other awards won by Piwik here.

• How can I get matplotlib to show full subplots in an animation ?

  12 mars 2015, par Matt Stone

  I’m trying to write a simple immune system simulator. I’m modeling infected tissue as a simple grid of cells and various intracellular signals, and I’d like to animate movement of cells in one plot and the intensity of viral presence in another as the infection progresses. I’m doing so with the matshow function provided by matplotlib. However, when I plot the two next to each other, the full grid gets clipped unless I stretch out the window myself. I can’t address the problem at all when saving to an mp4.

  Here’s the default view, which is identical to what I observe when saving to mp4 :
  

  And here’s what it looks like after stretching out the viewer window
  

  I’m running Python 2.7.9 with matplotlib 1.4.2 on OS X 10.10.2, using ffmpeg 2.5.2 (installed via Homebrew). Below is the code I’m using to generate the animation. I tried using plt.tight_layout() but it didn’t affect the problem. If anyone has any advice as to how to solve this, I’d really appreciate it ! I’d especially like to be able to save it without viewing with plt.show(). Thanks !

  def animate(self, fname=None, frames=100):
  
      fig, (agent_ax, signal_ax) = plt.subplots(1, 2, sharey=True)
  
  
  
      agent_ax.set_ylim(0, self.grid.shape[0])
  
      agent_ax.set_xlim(0, self.grid.shape[1])
  
      signal_ax.set_ylim(0, self.grid.shape[0])
  
      signal_ax.set_xlim(0, self.grid.shape[1])
  
  
  
      agent_mat = agent_ax.matshow(self.display_grid(),
  
                                   vmin=0, vmax=10)
  
      signal_mat = signal_ax.matshow(self.signal_display(virus),
  
                                     vmin=0, vmax=20)
  
      fig.colorbar(signal_mat)
  
  
  
      def anim_update(tick):
  
          self.update()
  
          self.diffuse()
  
          agent_mat.set_data(self.display_grid())
  
          signal_mat.set_data(self.signal_display(virus))
  
          return agent_mat, signal_mat
  
  
  
      anim = animation.FuncAnimation(fig, anim_update, frames=frames,
  
                                     interval=3000, blit=False)
  
  
  
      if fname:
  
          anim.save(fname, fps=5, extra_args=['-vcodec', 'libx264'])
  
      else:
  
          plt.show()

• "Error opening filters !" when using fluent-ffmpeg with Node

  3 février 2015, par doremi

  I’m trying to get a basic example of html5 video streaming working in an express node app, but I keep running into ffmpeg errors that I’m unsure of how to resolve.

  The input file/stream is the sample.mp4 located here.

  Complete example :

  var ffmpeg = require('fluent-ffmpeg');
  
  var express    = require('express');
  
  var fs         = require('fs');
  
  var sampleApp  = express();
  
  var videoApp   = express();
  
  
  
  var SAMPLE_SERVER_PORT = 3000;
  
  var VIDEO_SERVER_PORT  = 5000;
  
  
  
  sampleApp.get('/:video', function (req, res) {
  
    var videoURL = 'http://localhost:' + VIDEO_SERVER_PORT + '/' + req.params.video;
  
    return res.end('<video controls="controls" src=" + videoURL +"></video>');
  
  });
  
  
  
  videoApp.get('/:video', function(req, res) {
  
  
  
    res.statusCode = 200;
  
    res.setHeader('content-type','video/mp4');
  
  
  
    var stream = fs.createReadStream('./samples/' + req.params.video);
  
  
  
    var proc = ffmpeg(stream)
  
  
  
      .format('mp4')
  
      .size('320x?')
  
      .videoBitrate('512k')
  
      .videoCodec('libx264')
  
      .fps(24)
  
      .audioBitrate('96k')
  
      .audioCodec('aac')
  
      .audioFrequency(22050)
  
      .audioChannels(2)
  
  
  
      .on('error', function(err) {
  
        console.log('an error happened: ' + err.message);
  
      })
  
  
  
      .pipe(res, { end:true });
  
  });
  
  
  
  var server = sampleApp.listen(SAMPLE_SERVER_PORT, function () {
  
    console.log('Example app listening at http://%s:%s', server.address().address, SAMPLE_SERVER_PORT);
  
  });
  
  
  
  
  
  var videoServer = videoApp.listen(VIDEO_SERVER_PORT, function () {
  
    console.log('Video Server listening at http://%s:%s', server.address().address, VIDEO_SERVER_PORT);
  
  });

  The error (via console) :

  an error happened: ffmpeg exited with code 1: Error opening filters!

  ffmpeg configuration :

  ./configure  --prefix=/usr/local --enable-gpl --enable-nonfree --enable-libass \                                                                         
  
  --enable-libfdk-aac --enable-libfreetype --enable-libmp3lame --enable-libopus \
  
  --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxvid --enable-libfaac --enable-libfdk-aac

  Any input would be greatly appreciated.