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• libvpx 0.9.1 and FFmpeg 0.6

  18 juin 2010, par Multimedia Mike — VP8

  Great news : Hot on the heels of FFmpeg’s 0.6 release, the WebM project released version 0.9.1 of their libvpx. I can finally obsolete my last set of instructions on getting FFmpeg-svn working with libvpx 0.9.

  Building libvpx 0.9.1
  Do this to build libvpx 0.9.1 on Unix-like systems :

  • Download libvpx 0.9.1 from http://code.google.com/p/webm/downloads/list
  • Unpack, chdir to the source dir, ’./configure && make && make install’

  libvpx’s build system has been firmed up a bit since version 0.9. It’s now smart enough to install when said target is invoked and it also builds the assembly language optimizations. Be advised that on 32- and 64-bit x86 machines, Yasm must be present (install either from source or through your package manager).

  Building FFmpeg 0.6
  To build the newly-released FFmpeg 0.6 :

  • Install Vorbis through your package manager if you care to encode WebM files with audio ; e.g., ’libvorbis-dev’ is the package you want on Ubuntu
  • Download FFmpeg 0.6 from the project’s download page
  • Configure FFmpeg with at least these options : ./configure --enable-libvpx --enable-libvorbis --enable-pthreads ; the final link step still seems to fail on Linux if the pthreads option is disabled
  • ’make’

  Verifying
  Check this out :

  $ ./ffmpeg -formats 2> /dev/null | grep WebM
    E webm            WebM file format
  $ ./ffmpeg -codecs 2> /dev/null | grep libvpx
  
   DEV    libvpx          libvpx VP8
  

  That means that this FFmpeg binary can mux a WebM file and can both decode and encode VP8 video via libvpx. If you’re wondering why the WebM format does not list a ’D’ indicating the ability to demux a WebM file, that’s because demuxing WebM is handled by the general Matroska demuxer.

  Doing Work
  Encode a WebM file :

  ffmpeg -i <input_file> <output_file.webm>

  FFmpeg just does the right thing when it seems that .webm extension on the output file. It’s almost magical.

  For instant gratification that the encoded file is valid, you can view it immediately using ’ffplay’, if that binary was built (done by default if the right support libraries are present). If ffplay is not present, you can always execute this command line to see some decode operation :

  ffmpeg -i <output_file.webm> -f framecrc -

• Add partial_tukey and punchout_tukey apodization functions

  10 août 2014, par Martijn van Beurden

  Add partial_tukey and punchout_tukey apodization functions
  Adds two new apodization functions that seem to perform better than
  
  the apodization functions currently in the codebase and fixes three
  
  existing windows as well.
  Its important to note that this patch only affects the encoder stage
  
  that evaluates various possible predictors. Audio encoded with these
  
  new windows will still decode with existing legacy decoders.
  = Theory =
  
  These functions are used to window the  audio data at the predictor
  
  stage. These news functions enable the use of only part of the signal
  
  to generate a predictor. This helps  because short transients can
  
  introduce noise into the predictor. The  predictor becomes very good
  
  at prediciting one part of the  signal, instead of mediocre for the
  
  whole block.
  Signed-off-by : Erik de Castro Lopo <erikd@mega-nerd.com>
  

  • [DH] doc/html/documentation_tools_flac.html
  • [DH] include/FLAC/stream_encoder.h
  • [DH] man/flac.1
  • [DH] man/flac.sgml
  • [DH] src/libFLAC/include/private/window.h
  • [DH] src/libFLAC/include/protected/stream_encoder.h
  • [DH] src/libFLAC/stream_encoder.c
  • [DH] src/libFLAC/window.c

• It’s Piwik Analytics Survey time : Your Opinion Matters !

  8 janvier 2017, par Piwik Core Team — Community

  It’s been almost two years since our last survey. We were so happy to get the participation we did from the community last time and hope that you will once again share your thoughts !

  

  Fill in the survey

  Looking back on the previous survey, several features were implemented as a direct result :

  • New modern and beautiful app design in Piwik 3.0 !
  • Responsive Piwik User Interface
  • Custom Dimensions plugin
  • User ID for accurate cross device tracking
  • No more Referrer Spam in Piwik
  • Glossary of all terms used in Piwik
  • Huge performance improvements across the board
  • And much more…

  Now it is time to ask for your opinion again. Sure it’s only 15 short questions, but your time you take and energy you place in this endeavour will shape Piwik development and features for the near future. We really look forward to your ideas, your opinions and your suggestions. To get started click the box (or link) below :

  

  Fill in the survey !

  By the way, if you haven’t already make sure you sign up for our newsletter to make sure you get the latest Piwik news and information to your inbox ! You can subscribe here.