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• Will the encoded YUV color be the same as the decoded color on ffmpeg ?

  27 juillet 2020, par Guerlando OCs

  If I have an h264 video encoded in the color format YUV444 and I decode it with ffmpeg (can be software or hardware decoding), then will the decoded image be in the format YUV444 ?

  


• How to maximize ffmpeg crop and overlay thousand block in same time ?

  22 juin 2022, par yuno saga

  I try to encrypt a frame of video to random of 16x16 block. so the result will be like artifact video. but exactly it can be decode back. only the creation that know the decode algorithm. but my problem is ffmpeg encode so slow. 3 minutes video, 854x480 (480p) https://www.youtube.com/watch?v=dyRsYk0LyA8. this example result frame that have been filter https://i.ibb.co/0nvLzkK/output-9.jpg. each frame have 1589 block. how to speed up this things ? 3 minutes only 24 frame done. the vido have 5000 thousand frame, so for 3 minutes video it takes 10 hours. i dont know why ffmpeg only take my cpu usage 25%.

  


  const { spawn } = require('child_process');
const fs = require('fs');

function shuffle(array) {
    let currentIndex = array.length,  randomIndex;
  
    // While there remain elements to shuffle.
    while (currentIndex != 0) {
  
      // Pick a remaining element.
      randomIndex = Math.floor(Math.random() * currentIndex);
      currentIndex--;
  
      // And swap it with the current element.
      [array[currentIndex], array[randomIndex]] = [
        array[randomIndex], array[currentIndex]];
    }
  
    return array;
  }

function filter(width, height) {
    const sizeBlock = 16;
    let filterCommands = '';
    let totalBlock = 0;
    const widthLengthBlock = Math.floor(width / sizeBlock);
    const heightLengthBlock = Math.floor(height / sizeBlock);
    let info = [];

    for (let i=0; i < widthLengthBlock; i++) {
        for (let j=0; j < heightLengthBlock; j++) {
            const xPos = i*sizeBlock;
            const yPos = j*sizeBlock;
            filterCommands += `[0]crop=${sizeBlock}:${sizeBlock}:${(xPos)}:${(yPos)}[c${totalBlock}];`;

            info.push({
                id: totalBlock,
                x: xPos,
                y: yPos
            });

            totalBlock += 1;
        }   
    }

    info = shuffle(info);

    for (let i=0; i < info.length; i++) {
        if (i == 0) filterCommands += '[0]';
        if (i != 0) filterCommands += `[o${i}]`;

        filterCommands += `[c${i}]overlay=x=${info[i].x}:y=${info[i].y}`;

        if (i != (info.length - 1)) filterCommands += `[o${i+1}];`;     
    }

    return filterCommands;
}

const query = filter(854, 480);

fs.writeFileSync('filter.txt', query);

const task = spawn('ffmpeg', [
    '-i',
    'C:\\Software Development\\ffmpeg\\blackpink.mp4',
    '-filter_complex_script',
    'C:\\Software Development\\project\\filter.txt',
    '-c:v',
    'libx264',
    '-preset',
    'ultrafast',
    '-pix_fmt',
    'yuv420p',
    '-c:a',
    'libopus',
    '-progress',
    '-',
    'output.mp4',
    '-y'
], {
    cwd: 'C:\\Software Development\\ffmpeg'
});

task.stdout.on('data', data => { 
    console.log(data.toString())
})


  


• Fastest way to create a multi-frame tiff

  23 octobre 2012, par user1414470

  I need to create a multi-frame tiff file to store large number of images. Time consumption is very important here. Also my initial format is an 'avi' video so if i can change it directly it'd be great. Can you tell me how to do that ? weather it is through programming or using some software isn't important but it would be great if it were through just ffmpeg(I'm already doing the frame separation with ffmpeg).

  Thank you