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• Batch script to match two filenames in the same folder with different extension

  24 mai 2018, par Ahhhhhhhhhhhhhdfgbv

  I’ve been looking, but I don’t quite understand the regex of matching filenames. I have seen in SO that there are questions that match two filenames in different folders, but I’m looking within the same folder.

  file01.jpg
  
  file01.wav
  
  file02.jpg
  
  file03.jpg
  
  file04.jpg
  
  file04.wav

  I want it to match if there is a jpg and a wav to run a ffmpeg script, and if the wav doesn’t have a matching jpg then run another ffmpeg script, and if there is no matching wav to the jpg do another script.

  if( $jpg == $wav ) // matching filenames without extension
  
      do script1
  
  else if( $jpg != $wav ) // if there is no matching jpg to wav
  
      if( empty($jpg) && $wav )
  
          do script2
  
      if( empty($wav) && $jpg )
  
          do script3

• vf_colorspace : don’t enable passthrough if bitdepth doesn’t match.

  6 mai 2016, par Ronald S. Bultje

  vf_colorspace : don’t enable passthrough if bitdepth doesn’t match.
  Also check return value of av_frame_copy() in passthrough mode, so that
  
  if a copy fails (as it did here, because bitdepth didn’t match), the filter
  
  doesn’t return success, which would mean sending an uninitialized framebuffer
  
  further down the filtergraph.
  

  • [DH] libavfilter/vf_colorspace.c

• HTML Video Exporting Using MediaRecorder vs ffmpeg.js

  3 octobre 2020, par Owen Ovadoz

  TLDR

  


  Imagine I have one video and one image. I want to create another video that overlays the image (e.g. watermark) at the center for 2 seconds in the beginning of the video and export it as the final video. I need to do this on the client-side only. Is it possible to use MediaRecorder + Canvas or should I resort to using ffmpeg.js ?

  


  Context

  


  I am making a browser-based video editor where the user can upload videos and images and combine them. So far, I implemented this by embedding the video and images inside a canvas element appropriately. The data representation looks somewhat like this :

  


  video: {
  url: 'https://archive.com/video.mp4',
  duration: 34,
},
images: [{
  url: 'https://archive.com/img1.jpg',
  start_time: 0,
  end_time: 2,
  top: 30,
  left: 20,
  width: 50,
  height: 50,
}]


  


  Attempts

  


  

  1. I play the video and show/hide images in the canvas. Then, I can use the MediaRecorder to capture the canvas' stream and export it as a data blob at the end. The final output is as expected, but the problem with this approach is I need to play the video from the beginning to the end for me to capture the stream from the canvas. If the video is 60 seconds, exporting it also takes 60 seconds.

  


  


  


  


  function record(canvas) {
  return new Promise(function (res, rej) {
    const stream = canvas.captureStream();
    const mediaRecorder = new MediaRecorder(stream);
    const recordedData = [];

    // Register recorder events
    mediaRecorder.ondataavailable = function (event) {
      recordedData.push(event.data);
    };
    mediaRecorder.onstop = function (event) {
      var blob = new Blob(recordedData, {
        type: "video/webm",
      });
      var url = URL.createObjectURL(blob);
      res(url);
    };

    // Start the video and start recording
    videoRef.current.currentTime = 0;
    videoRef.current.addEventListener(
      "play",
      (e) => {
        mediaRecorder.start();
      },
      {
        once: true,
      }
    );
    videoRef.current.addEventListener(
      "ended",
      (e) => {
        mediaRecorder.stop();
      },
      {
        once: true,
      }
    );
    videoRef.current.play();
  });
}

  


  


  



  

  2. I can use ffmpeg.js to encode the video. I haven't tried this method yet as I will have to convert my image representation into ffmpeg args (I wonder how much work that is).