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• Create video Thumbnail using Node js Error

  15 juillet 2017, par Andrea

  I want to create a video thubmbnail through fluent-ffmpeg library, the problems are that I don´t know if I need to create a folder to store the images, and how and where to create it. Also Im getting this error ffmpeg stdout: undefined, the complete code below :

  ffmpeg("http://upload.wikimedia.org/wikipedia/commons/7/79/Big_Buck_Bunny_small.ogv")
  
                      .on('filenames', function(filenames) {
  
                          console.log('Will generate ' + filenames.join(', ') + ' into tempfiles.')
  
                      })
  
                      .on('end', function() {
  
                          console.log('1 Screen shot successfully taken');
  
  
  
                      })
  
                      .on('error', function(err, stdout, stderr) {
  
                          console.log("ffmpeg stdout:\n" + stdout);
  
                          console.log("ffmpeg stderr:\n" + stderr);
  
                      })
  
                      .screenshots({
  
                          count: 1,
  
                          filename: "file_name",
  
                          size: '240x240',
  
                      });

  also how can I get the byte[] from that screenshot, so I can use it later in my code ?

• Bitrate variation in x264 encode ? [closed]

  21 octobre 2012, par nightcrawler

  Under win732bit
  The following picture is the analysis of bitrateviewer from 2 different encodings :
  
  After learning a great deal I want to ask some basic questions

  • Are the jitters (huge variation of bitrate) in the encoded files
    (relative to original .wmv) usual or they refer to poor results ? (I
    used CBR this should have given me a nice smooth bitrate histogram ?)
  • Am I correct in setting level to 3.1 because this is enough to handle
    the input resolution & bitrate ?
    (http://en.wikipedia.org/wiki/H.264/MPEG-4_AVC#Levels)
  • Would you recommend me for CBR(currently used at 23) or
    2pass(2500kb/s) or ABR(2500kb/s) for this file ? (I assume that the
    latter of the two will reduce jitters but increase filesize because
    bitrate is kept constant even in those frames where its not needed or
    willlnt produce influential results)
  • Provided that I want good result under 260mb what are the setting I
    have to use ?

• 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.