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• Realtime recording while listening for input

  28 octobre 2016, par Nyalmo

  I’m currently running a python 2.7 script, using two threads running concurrently. One thread consistently looking for input (raw_input at the moment) activating a global variable when it gets one. The other consistently records using bash ffmpeg commands with subprocess. When the global variable of the former thread is active the latter thread triggers an event.

  My problem is that while the second thread is recording video from a stream, I can’t input anything and the breaks between recordings are really short. So basically it keeps recording for 30 seconds and overwriting itself without allowing me to activate the variable to save the current file somewhere.

  I’ve tried to run the ffmpeg in subprocess in the background by using the & and by hiding it’s output but did not have much success there.

  Can anyone help me with this, preferably with a small example ?

  My basic recording thread currently :

  from subprocess import Popen
  
  Last30S_Command = (["ffmpeg", "-i", "rtsp://admin:12345@192.168.25.179:554/Streaming/Channels/1", "-r", "30", "-vcodec", "copy", "-an", "-t", "30", "-y", "/Path/Last30S.mp4"])
  
  
  
  subprocess.call(Last30S_Command)

• Compressing videos from a smartphone

  9 novembre 2016, par fejesjoco

  I have a Nexus 6p with the stock camera. It’s set to record at 1080p, 30fps. Here’s a 5 second sample (11 MB).

  Videos from this phone come out at about 17 Mbps on average. I tried to compress it with ffmpeg with -c:v libx264 -crf 23 -preset veryslow, the result comes out at about 5.5 MB, which is about 9 Mbps.

  I think this bitrate is a bit too much. When I look at torrent file listings, I can see high quality videos at 3 GB in size on average, and if such a movie is 90 minutes long on average, that is about 4-5 Mbps which sounds okay.

  I’m wondering, why the big difference ? I can notice that my video is noisy/grainy (which is expected from a phone), and that might reduce compressibility. I tried a few ffmpeg filters, like hqdn3d and atadenoise, but the noise mostly remained (maybe I didn’t play with it enough). Then I figured, the video is also shaky (which is also expected), and that might reduce compressibility too (and even makes temporal noise filtering less effective). I tried to stabilize it with the deshake filter, but that didn’t help either.

  I know I could just limit the bandwidth to whatever I like, but there must be a reason why ffmpeg thinks it needs a high bandwidth to maintain a certain quality, and a lower bandwidth would just decrease the quality.

  Why do these videos have such a high bitrate ? What’s the best way to compress them more while keeping or even increasing their quality ?

• Try out the latest Piwik 3.0.0 beta version : Piwik 3.0.0 is almost here !

  15 novembre 2016, par Matthieu Aubry — Uncategorized

  Dear Piwik community,

  We are excited today to announce our publicly available Piwik 3.0.0 beta 3 release. We have been been working hard behind the scenes on the new 3.0.0 release for almost one year now. We, the passionate team at Piwik, are dedicated to bringing you a new and improved Piwik experience and invite you to join our beta channel to switch to Piwik 3 today !

  Enable the beta release channel

  Ready to enjoy a much faster Piwik experience and the magic of a modern user interface ? Follow the instructions here and you can upgrade to Piwik 3.0.0 beta in just one click.

  Please note that beta versions have a risk of containing bugs so we don’t recommend to use on a production server. If you find and report a bug in a beta version, we will aim to fix it as quickly as possible.

  Premium plugins in Piwik 3

  In the Piwik Marketplace you can discover & download plugins to enrich the functionality of your Piwik, as well as themes to change the look and feel of your Piwik user interface. The Marketplace integration was much improved in this new release, most notably : you can now purchase and download Premium plugins within Piwik !

  Important changes

  The Piwik 3 upgrade comes with some important changes that may require your attention which we detail in this blog post and in the developer changelog.

  The full list of more than 150 changes can be found in the Piwik 3 beta changelogs : beta 1, beta 2, beta 3.

  What to do next

  When you use the Piwik beta channel and if you come across any issues in Piwik such as a bug, feature missing, regression… let us know on our tracker and create a new issue so we can get this sorted.

  As we are in the final days of Piwik 3 development, we are looking forward to your feedback and help testing !

  Welcome to the future of Piwik,

  Happy Analytics !