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• What’s So Hard About Building ?

  10 septembre 2011, par Multimedia Mike — Programming

  I finally had a revelation as to why so building software can be so difficult– because build systems are typically built on programming languages that you don’t normally use in your day to day programming activities. If the project is simple enough, the build system usually takes care of the complexities. If there are subtle complexities — and there always are — then you can to figure out how to customize the build system to meet your needs.

  First, there’s the Makefile. It’s easy to forget that the syntax which comprises a Makefile pretty well qualifies as a programming language. I wonder if it’s Turing-complete ? But writing and maintaining Makefiles manually is arduous and many systems have been created to generate Makefiles for you. At the end of the day, running ‘make’ still requires the presence of a Makefile and in the worst case scenario, you’re going to have to inspect and debug what was automatically generated for that Makefile.

  So there is the widespread GNU build system, a.k.a., “the autotools”, named due to its principle components such as autoconf and automake. In this situation, you have no fewer than 3 distinct languages at work. You write your general build instructions using a set of m4 macros (language #1). These get processed by the autotools in order to generate a shell script (language #2) called configure. When this is executed by the user, it eventually generates a Makefile (language #3).

  Over the years, a few challengers have attempted to dethrone autotools. One is CMake which configures a project using its own custom programming language that you will need to learn. Configuration generates a standard Makefile. So there are 2 languages involved in this approach.

  Another option is SCons, which is Python-based, top to bottom. Only one programming language is involved in the build system ; there’s no Makefile generated and run. Until I started writing this, I was guessing that the Python component generated a Makefile, but no.

  That actually makes SCons look fairly desirable, at least if your only metric when choosing a build system is to minimize friction against rarely-used programming languages.

  I should also make mention of a few others : Apache Ant is a build system in which the build process is described by an XML file. XML doesn’t qualify as a programming language (though that apparently doesn’t stop some people from using it as such). I see there’s also qmake, related to the Qt system. This system uses its own custom syntax.

• 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 -

• Piwik is now using Github issues as our Issue Tracker !

  9 juillet 2014, par Matthieu Aubry — Community, Development

  This is an announcement regarding the Issue Tracker used for the Piwik project. We are excited to announce that Piwik has migrated from Trac to now using Github issues for managing our issues !

  More than 5,400 tickets and 20,000+ comments from 1,000+ users were migrated to Github. Read on for more information.

  Where do I find Piwik Issue Tracker ?

  • Piwik main project issue tracker (piwik/piwik)
  • Piwik Mobile issues (piwik/mobile2)
  • Device Detector issues (piwik/device-detector)
  • Piwik iOS SDK (piwik/piwik-sdk-ios)
  • See other repositories at github.com/piwik

  Benefits of using Github Issues for the Piwik project

  There are several advantages of moving to Github issues :

  • Faster and responsive user interface
  • Better cross-project referencing of issues
  • Ability to notify people with the @username functionality
  • No spam
  • Integration with Pull requests and our Git repository

  How do I get notifications for all Piwik tickets ?

  To receive notifications for new tickets or new comments in the Piwik project, go to github.com/piwik/piwik, then click the Watch button at the top of the page.

  

  In Github, watching a repository lets you follow new commits, pull requests, and issues that are created.

  How do I report a bug in Piwik ?
  See Submitting a bug report.

  How do I suggest a new feature ?
  See Submitting a feature request.

  Next steps

  At Piwik we care a lot about Data ownership. For this reason we need to have an up to date copy of all our tickets and comments out of github.com servers. Our next step will be to create and release as open source a tool to let anyone create a Mirror of their Github issues. See #5299.

  For more information about the Trac->migration, see #5273.

  We look forward to reading your issues on Github !