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• How to re-encode a 120fps (or higher) MP4 from my Samsung Galaxy to a 30fps (example) so it plays on Windows like it does on the Samsung

  21 septembre 2022, par remark70

  I have some high fps slow-motion videos (mp4) that I've recorded on my phone, but when I copy them to windows and play them back, they play at the normal speed (or they play really fast), unless I slow down playback but this isn't a good result.

  


  What I'd like to do is re-encode (if that's the right word) the video to a standard fps (such as 30) to get a longer video (keeping all the frames), i.e. a 10 second 120fps would end up being a 40 second video at 30fps.

  


• File input of avformat_open_input in ffmpeg

  28 février 2016, par Justin Chang

  I’m trying to use function avformat_open_input in FFmpeg to open the file which contains Chinese word.

  For example :

  char* file="C:/測試/baby.mp4";
  
  
  
  avformat_open_input(&pFormatCtx, file, NULL, NULL);

  But, it seems to be failed.

  My question is how do I pass the file path which contains Chinese (or other languages except for English) ?

• How to read raw audio data using FFmpeg ?

  6 juin 2020, par Yousef Alaqra

  I'm trying to use this command to get the audio stream using UDP :

  



  ffmpeg -i udp://192.168.1.1:6980 -acodec copy


  



  I got an error when I execute it, which says :

  



  [udp @ 00000157a76b9a40] bind failed: Error number -10048 occurred
udp://192.168.1.1:6980: I/O error


  



  What's the meaning of this error ?

  



  Update :

  



  I was able to read raw audio data using FFmpeg and output into a wave file, using the following command :

  



  ffmpeg -f u16be -ar 44100 -ac 2 -i 'udp://127.0.0.1:1223' output.wav


  



  The problem now, Sine there is surrounding metadata in the network packets being received, it needs to be stripped out or it will result in noise.

  



  In C# I used Skip() to trim the first 28 bytes of the received packet, how would I achieve this using FFmpeg ?

  



  Update :

  



  I was able to read the raw bytes from UDP packets using by executing child process in node js :

  



  var http = require("http");
var port = 8888;
var host = "localhost";
var children = require("child_process");

http
  .createServer(function (req, res) {
    //ffmpeg -f s16le -ar 48000 -ac 2 -i 'udp://192.168.1.230:65535' -b:a 128k -f webm -
    var ffm = children.spawn(
      "ffmpeg",
      "-f s16le -ar 48000 -ac 2 -i udp://192.168.1.230:65535 -b:a 128k -f webm -".split(
        " "
      )
    );

    res.writeHead(200, { "Content-Type": "audio/webm" });
    ffm.stdout.on("data", (data) => {
      console.log(data);
      res.write(data);
    });
  })
  .listen(port, host);

console.log("Server running at http://" + host + ":" + port + "/");


  



  As you can see in the code sample above, I'm trying to pipe the output of the child process into the response, so I would be able to hear the audio in the browser.

  



  I'm receiving the data, after executing the child process, but the browser unable to play audio for some reason that I need to figure it out.

  



  Do you have an idea of what am I missing ?