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• Compress / Reduce file size of VIDEO

  2 avril 2014, par rishiJasapara

  I currently have a system in place where the user can upload a MP4 file and the same is available for download on mobile devices. But sometimes, the videos are more than 5MB in size and back here in my country, majority of the population uses 2G. So it typically takes 15-20 minutes to download large videos.

  Is there any way in which I can compress MP4 files while they are being uploaded and then save them in the folder so that instead of a 5MB video, I get a 2MB video which takes relatively less time to download. File format will always be MP4 only.

  I know of FFMPEG-PHP, but as far as I read, it only supports extracting information of the video and for video conversion. I could not find any reference for VIDEO COMPRESSION. I would be grateful if you could guide me on this.

• Node js request huge amount of pictures

  5 janvier 2019, par Manos Koutselakis

  I am trying to request a huge amount of images on node js (n > 3000)
  and then save them into a folder.
  I have tried using request library and request-promise.
  The problem is that if the number of pictures is too big some pictures do not complete downloading, leaving incomplete data or get an error(an empty .jpeg file). Is there a better way of downloading huge amounts of pictures ?
  Also i need when the pictures all download to request a function compile()
  to make them into a video. I am using ffmpeg for that.

  Below are 2 ways i tried doing this.

  const req = require('request');
  
  const request = require('request-promise');
  
  const fs = require('fs');
  
  const ffmpegPath = require('@ffmpeg-installer/ffmpeg').path;
  
  const ffmpeg = require('fluent-ffmpeg');
  
  ffmpeg.setFfmpegPath(ffmpegPath);
  
  
  
  function downloadImgs(imgUrls) {
  
    let promises = [];
  
    let prom;
  
    for (let i = 0; i < imgUrls.length; i++) {
  
      imgPath = `assets/pics/st_${pad(i + 1, 3)}.jpg`
  
  
  
      prom = request(imgUrls[i]);
  
      prom.on('error', () => console.log('err'));
  
      prom.pipe(fs.createWriteStream(imgPath));
  
      promises.push(prom);
  
    }
  
  
  
    Promise.all(promises).then(() => {
  
      console.log('I Run');
  
      compilee();
  
    });
  
  
  
    //SECOND TRY-----------------------------------------
  
    for (let i = 0; i < imgUrls.lengh; i++) {
  
      imgUrl = imgUrls[i];
  
      req(imgUrl)
  
        .on('error', () => console.log("img error", imgUrl))
  
        .pipe(fs.createWriteStream(`assets/pics/st_${pad(i + 1, 3)}.jpg`)).on('close', () => {
  
          console.log('downloaded', x)
  
        })
  
    }
  
    compilee();
  
  
  
  //---------------------------------------------------------
  
  
  
    function compilee() {
  
      command
  
        .on('end', onEnd)
  
        // .on('progress', onProgress)
  
        .on('error', onError)
  
        .input('assets/pics/st_%03d.jpg')
  
        .inputFPS(5)
  
        .output('assets/output/pepe.mp4')
  
        .outputFps(30)
  
        .run();
  
    }

  The errors i am getting for the first : UnhandledPromiseRejectionWarning : RequestError : Error : socket hang up

  and the second :
  Error : socket hang up
  at createHangUpError (_http_client.js:330:15)
  at TLSSocket.socketOnEnd (_http_client.js:433:23)
  at TLSSocket.emit (events.js:187:15)
  at endReadableNT (_stream_readable.js:1098:12)
  at process.internalTickCallback
  (internal/process/next_tick.js:72:19) code : ’ECONNRESET’ }

  Also, should i download the pictures on the server or on the client if i want to sent the video to the client immediately.

• FFmpeg compose, multi layers and filters, need kindly help 

  9 octobre 2019, par jadeshohy

  Pretty new to FFmpeg. We would like to use FFmpeg as a important part of an AR project.

  Currently, we find it is not easy for us.

  We want to compose the footages with FFmpeg.

  We got 5 layers, wanted to blend them with specific mode, like the things in After Effects.

  • layer-1/ [A.webm] video，vp9 codec, which has a transparent BG,has to be added as [normal mode]

  • layer-2/ [B.mp4] video, optical-flare things with black BG,has to be added as [screen mode]

  • layer-3/ [C.mp4] video, some motion graphic things with light BG,has to be added as [overlay mode]

  • layer-4/ [BG.MP4], backgound things, has to be added as [normal mode]

  After we blend those 4 (like pre-compose,use blend filter), we want to add another layer-5/[icon.png] which is the special icon.

  Layer-5 need to overlay the pre-compose. We have to overlay it at the special position (use overlay filter ?).

  Cause [icon.png] may change frequently. we want to deal with that after the 4 layer blending.

  But at the first step, when we set normal mode for layer-1 in blend filter, layer-1 [A.webm] lost the transparent BG，it gave us a black BG which block all other things.
  Blend filter can not handle the alpha channel of vp9 webm ?
  When we set the mode of layer-1 to screen mode,the translucent thing was not what we need.

  Could you please give us some commands to achieve the blend above ?

  The commands that are really work will be extremely useful for our FFmpeg initiation.