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• Can not use the jsmpeg in react "Unexpected use of 'self'"

  5 mai 2020, par Muhammad Anas Khan

  code that i want to convert in React

  



   &#xA;    &#xA;    <code class="echappe-js">&lt;script type=&quot;text/javascript&quot; src='http://stackoverflow.com/feeds/tag/jsmpeg.min.js'&gt;&lt;/script&gt;&#xA;&#xA;    &lt;script type=&quot;text/javascript&quot;&gt;&amp;#xA;      var canvas = document.getElementById(&quot;videoCanvas&quot;);&amp;#xA;      console.log(document.location.hostname);&amp;#xA;     var url = &quot;ws://localhost:9999/&quot;;&amp;#xA;    &lt;/script&gt;&#xA;    &#xA;&#xA;

  



  Can not change it to react format.When i try to convert it is giving jsmpeg error 
i.e

  



  code that i tried but get an error

  



  import React from &#x27;react&#x27;;&#xA;import ReactDOM from &#x27;react-dom&#x27;;&#xA;import "./jsmpeg.min.js"&#xA;const App =()=>{&#xA;    return(&#xA;        <h1>Hello</h1>&#xA;    )&#xA;}&#xA;&#xA;&#xA;ReactDOM.render(<app></app>,document.getElementById(&#x27;root&#x27;));&#xA;

  



  Error

  



  /src/jsmpeg.min.js
Line 606:9 : Unexpected use of 'self' no-restricted-globals
 Line 2771:13 : Expected an assignment or function call and instead saw an expression no-unused-expressions

  



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• "Format" or style the output of showwaves/showwavespic in ffmpeg

  9 avril 2020, par flomei

  I'm trying to get my head wrapped around ffmpeg and its functions and filters.

  



  showwaves and showwavespic already create nice output, but I'm looking to style it even more. Lots of audioplayers for example create a "waveform" like the following, which would be a job for showwavespic, I think. (I think soundcloud for example does create a form like this with actual data.)


  



  I wonder if I can use ffmpeg to create something like this directly from my raw input data. I thought I might need to split my audio track into X parts, calculate the average distance from the Y-axis and then create a bar. But I'm not sure if I can manage to do that with ffmpeg or if I need to build more of a toolchain for that.

  



  If I could create the output of showwaves to look like that above, that would be great. On the other hand I'd already be happy if I could just increase the stroke width of the showwaves output.

  



  Didn't found anything about the in the documentation or I looked at the wrong places, because I don't yet get the big picture of ffmpeg.

  


• FFMPEG "volumedetect" filter in C++

  20 mars 2020, par Hrethric

  I am hoping to use FFMPEG to calculate the volume of my audio files, but find the documentation a bit lacking on this particular issue. Basically I’m trying to do something similar to the following command :

  ffmpeg -i "myfile.mp3" -filter:a volumedetect -f null /dev/null

  But in C++. So creating the filter, and passing my audio frames to the filter seems relatively straightforward by doing something along the lines of :

  avfilter_register_all();
  
  _volumeFilter = avfilter_get_by_name("volumedetect");
  
  
  
  _filterGraph = avfilter_graph_alloc();
  
  
  
  _volumeFilterCtx = avfilter_graph_alloc_filter(_filterGraph, _volumeFilter, "volumedetect");

  The above code is all successful from a standpoint of initializing the filter. Then when I read a frame I basically do :

  if (frameFinished) 
  
  {
  
      /* push the audio data from decoded frame into the filtergraph */
  
      if (av_buffersrc_add_frame_flags(_volumeFilterCtx, _audioFrame, 0) < 0) 
  
      {
  
          av_log(NULL, AV_LOG_ERROR, "Error while feeding the audio filtergraph\n");
  
          break;
  
      }
  
      /* pull filtered audio from the filtergraph */
  
      while (1) 
  
      {
  
          ret = av_buffersink_get_frame(_volumeFilterCtx, _filteredFrame);
  
          if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
  
                  break;
  
      }
  
  }

  This is where I’m not sure what to do. With regular audio filters it affects the underlying data, and you can just use the resulting frame. With this though, I need to pull data out of the filter to tell me what the volume is. How do I do this ? Or am I going about this the wrong way ?

  Again I simply can’t find any documentation on this, so thanks in advance for the help !