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• Convert image sequence to video using ffmpeg and list of files

  13 mai 2015, par rensa

  I have a camera taking time-lapse shots every 2–3 seconds, and I keep a rolling record of a few days’ worth. Because that’s a lot of files, I keep them in subdirectories by day and hour :

  images/
  
      2015-05-02/
  
          00/
  
              2015-05-02-0000-02
  
              2015-05-02-0000-05
  
              2015-05-02-0000-07
  
          01/
  
              (etc.)
  
      2015-05-03/

  I’m writing a script to automatically upload a timelapse of the sunrise to YouTube each day. I can get the sunrise time from the web in advance, then go back after the sunrise and get a list of the files that were taken in that period using find :

  touch -d "$SUNRISE_START" sunrise-start.txt
  
  touch -d "$SUNRISE_END" sunrise-end.txt
  
  find images/"$TODAY" -type f -anewer sunrise-start.txt ! -anewer sunrise-end.txt

  Now I want to convert those files to a video with ffmpeg. Ideally I’d like to do this without making a copy of all the files (because we’re talking 3.5 GB per hour of images), and I’d prefer not to rename them to something like image000n.jpg because other users may want to access the images. Copying the images is my fallback.

  But I’m getting stuck sending the results of find to ffmpeg. I understand that ffmpeg can expand wildcards internally, but I’m not sure that this is going to work where the files aren’t all in one directory. I also see a few people using find’s --exec option with ffmpeg to do batch conversions, but I’m not sure if this is going to work with image sequence input (as opposed to, say, converting 1000 images into 1000 single-frame videos).

  Any ideas on how I can connect the two—or, failing that, a better way to get files in a date range across several subdirectories into ffmpeg as an image sequence ?

• ffmpeg - title to display throughout the video duration

  25 mars 2016, par TTZ

  I have used the ffmpeg package to create a wmv file from gif (please see below). The title displays for a few seconds, then disappears. Is there a setting I can apply, in order to have the title appearing in the video throughout the duration ?

  ffmpeg -i Input.gif -s 300x300 -metadata title="Testing" Output.wmv 

  Following the suggestion by Maxito, I have modified the code to

  ffmpeg -i Input.gif -vf drawtext="text='Text to write is this one,     overlaid':fontsize=20:fontcolor=red:x=100:y=100" Output_Text.wmv

  The following error message was received :

  [AVFilterGraph @ 0x100115cc0] No such filter: 'drawtext'
  
  Error opening filters!

  This is the version of ffmpeg I used on Mac 10.6.8. Is there a need to re-compile ?

  ffmpeg version 2.5.3
  
  built on Jan 19 2015 13:08:24 with llvm-gcc 4.2.1 (LLVM build 2336.11.00)
  
    configuration: --prefix=/Volumes/Ramdisk/sw --enable-gpl --enable-pthreads --enable-version3 --enable-libspeex --enable-libvpx --disable-decoder=libvpx --enable-libmp3lame --enable-libtheora --enable-libvorbis --enable-libx264 --enable-avfilter --enable-libopencore_amrwb --enable-libopencore_amrnb --enable-filters --enable-libgsm --enable-libvidstab --enable-libx265 --arch=x86_64 --enable-runtime-cpudetect
  
    libavutil      54. 15.100 / 54. 15.100
  
    libavcodec     56. 13.100 / 56. 13.100
  
    libavformat    56. 15.102 / 56. 15.102
  
    libavdevice    56.  3.100 / 56.  3.100
  
    libavfilter     5.  2.103 /  5.  2.103
  
    libswscale      3.  1.101 /  3.  1.101
  
    libswresample   1.  1.100 /  1.  1.100
  
    libpostproc    53.  3.100 / 53.  3.100

• Stopping Referrer Spam

  13 mai 2015, par Piwik Core Team — Community

  In this blog post we explain what is Referrer spam, this new kind of spam that has recently appeared on the Internet. We also provide solutions to stop it and preserve the quality of your analytics data.

  What is Referrer Spam ?

  Referrer spam (also known as log spam or referrer bombing) is a kind of spamming aimed at web analytics tools. A spammer bot makes repeated web site requests using a fake referrer URL to the site the spammer wishes to advertise.

  Here is an example of referrer spam in action :

  

  Half of those referrers are spams, here are some well know spammers that you may have seen in your logs : buttons-for-you-website.com, best-seo-offer.com, semalt.com…

  The benefit for spammers is that their website will appear in analytics tools like Piwik or Google Analytics :

  • public analytics reports (or logs) will be indexed by search engines : links to the spammer’s website will improve its ranking
  • curious webmasters are likely to visit their referrers, thus bringing traffic to the spammer’s website

  How to deal with Referrer Spam ?

  Referrer spam is still new and analytics tools are all handling it differently.

  Referrer Spam in Piwik

  At Piwik we started working on mitigating Referrer spam more than a year ago. If you use Piwik and keep it up to date, you do not need to do anything.

  Referrer spammers are automatically excluded from your reports to keep your data clean and useful.

  New spammers are continuously detected and added to Piwik’s blacklist on each update. If you find a new spammer in your analytics data, you can even report it so that it is added to the Piwik’s open referrer blacklist and blocked for everyone.

  Referrer Spam in Google Analytics

  Google Analytics doesn’t offer any spam protection by default. It can however be configured manually using a custom Filter.

  To create a filter in Google Analytics go to the Admin section and click on All Filters. Create a new custom filter that excludes based on the Campaign Source field. In the Filter pattern enter the spammers domains you want to exclude (this is a regular expression) :

  

  If new spammers arise you will need to update this list. You can also use Piwik’s referrer blacklist to exclude all the spammers currently detected.

  Other Analytics Tools

  Many web analytics tools do not yet handle Referrer spam and when using these tools, you will often find a lot of spam data in your Referrer Websites analytics reports.

  If you use an analytics tool that does not exclude Referrer spam, we recommend to contact the vendor and ask them to implement a mechanism to remove these referrer spammers. As of today many analytics vendors still have not mitigated this issue.

  Public List of Referrer Spammers

  At Piwik with the help of our large community we have decided to tackle this growing spam issue. We have created a list of up to date referrer spammers that anyone can edit.

  The list is available in a simple text file on Github : github.com/piwik/referrer-spam-blacklist.

  The list is released under the Public Domain and anyone can use it within their applications to exclude referrer spammers.

  Many people have already contributed new spammers to the list. We invite you to use the list in your apps and websites and help us keep the list up to date !

  Let’s unite and fight the spammers together.

  Happy Analytics !