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• How to convert a continues stream of images to h264 stream in realtime

  29 mars 2021, par Eytan Manor

  So basically I have a canvas, that keeps updating itself at a framerate of 24, and I would like to convert the sequence of images that it produces to H264. The ultimate goal is to send it to an RTMP server, but for now this will help me check if things are working properly before piping the output. The canvas API that I'm using (see node-canvas) allows me to capture a JPEG of the entire canvas surface at any given moment. Unfortunately, the input will only be submitted once I end the STDIN, which is not what I want. Instead of processing all the input in a batch, I would like to process incoming JPEGs as I go, so everything can be done live. This is the code snippet that I used to achieve the functionality in question (which unfortunately doesn't work) :

  


  // patches/canvas.js
const { Canvas } = require('canvas');
const execa = require('execa');
const $ffmpeg = require('ffmpeg-static');

Canvas.prototype.captureStream = function captureStream(frameRate = 24) {
  const refreshRate = 1000 / frameRate;

  const encoding = execa($ffmpeg, [
    '-f', 'image2pipe',
    '-r', frameRate,
    '-vcodec', 'mjpeg',
    '-s', `${this.width}x${this.height}`,
    '-i', '-',
    '-vcodec', 'libx264',
    '-preset', 'veryfast',
    '-crf', '18',
    '-pix_fmt', 'yuv420p',
    '-b:v', '500k',
    '-bufsize', '600k',
    '-vprofile', 'baseline',
    '-tune', 'zerolatency',
    '-g', '60',
    '-r', frameRate,
    '-s', `${this.width}x${this.height}`,
    '-f', 'rawvideo',
    '-',
  ], {
    stdio: 'pipe',
  });

  let lastFeed = Date.now();

  const feed = () => {
    const jpegStream = this.jpegStream();

    jpegStream.on('data', (data) => {
      encoding.stdin.push(data);
    });

    jpegStream.on('end', () => {
      const now = Date.now();
      const timeSpan = Math.max(refreshRate - (now - lastFeed), 0);
      lastFeed = now;

      setTimeout(feed, timeSpan);
    });
  };

  feed();

  return encoding.stdout;
};

module.exports = require('canvas');


  


  Any suggestions on how to make it work ?

  


• Download billboard hot 100 (but only 50) mp3 files

  4 mars 2021, par Atlas

  Yo yo yo. I got this insane idea to get 50 of the billboard hot 100 songs, download them into mp3 files, and then put them on private online radio.

  


  Problem is, the way I do it doesn't download each file one by one, it puts all the music together in one mp3 file. Here's my code so far (terrible, I know... I just wanna throw this together really quickly)

  


  const { getChart } = require("billboard-top-100");
const ffmpeg = require("fluent-ffmpeg");
const { mkdir } = require("fs");
const ytdl = require("ytdl-core");
const YT = require("scrape-youtube").default;

getChart('hot-100', (err, chart) => {
    if(err) console.log(err);
    chart.songs.length = 50;
    for (var i = 0; i < chart.songs.length; i++) {
        var song = chart.songs[i];
        song.artist = song.artist.replace("Featuring", "feat.");
        var name = `${song.artist} - ${song.title}`;
        YT.search(name).then(res => {
            downloadVideo(res.videos[0].link, name).then(_ => { console.log(""); }).catch(console.log);
        }).catch(err => console.log(err));
    };
});

function downloadVideo(url, name) {
    return new Promise((resolve, reject) => {
        var stream = ytdl(url, { filter: "audioonly", quality: "highestaudio" });
        var start = Date.now();

        ffmpeg(stream)
            .audioBitrate(128)
            .save(`${__dirname}/${new Date().getWeek()}/${name}.mp3`)
            .on("end", _ => {
                console.log(`Downloaded "${name}.mp3" - Took ${(Date.now() - start) / 1000} seconds.`);
                resolve(`${name}.mp3`);
            })
            .on("error", _ => reject("something went wong"));
    });
}

Date.prototype.getWeek = function() {
  var onejan = new Date(this.getFullYear(),0,1);
  return Math.ceil((((this - onejan) / 86400000) + onejan.getDay()+1)/7);
}


  


• avdevice/decklink_dec : mark get_frame_timecode and get_bmd_timecode static

  6 janvier 2021, par Christopher Degawa

  avdevice/decklink_dec : mark get_frame_timecode and get_bmd_timecode static
  The function is not used anywhere else and is causing mingw-w64 clang
  
  builds to fail with
  ffmpeg-git/libavdevice/decklink_dec.cpp:792:5 : error : no previous prototype for function 'get_bmd_timecode' [-Werror,-Wmissing-prototypes]
  
  int get_bmd_timecode(AVFormatContext *avctx, AVTimecode *tc, AVRational frame_rate, BMDTimecodeFormat tc_format, IDeckLinkVideoInputFrame *videoFrame)
  Signed-off-by : Christopher Degawa <ccom@randomderp.com>
  
  Signed-off-by : Marton Balint <cus@passwd.hu>
  

  • [DH] libavdevice/decklink_dec.cpp