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• Getting know how much progress has ffmpeg done in C#

  29 décembre 2022, par Aenye_Cerbin

  I'm writing an app that uses ffmpeg to convert audio/video files.
I can call ffmpeg and specify it's options, I can see that it's working.
I want to be able to check how much of the job is done, so I can present it to user.
As I've read ffmpeg doesn't support any progress bar or percentage and ffmpeg console output is not very friendly, so I cannot simply show it's output to user, because it will look awful. I am not using any wrapper and do not plan to use any because I need to write my own backend that call ffmpeg and frontend to communicate with user.

  


  I'm using System.Threading to start ffmpeg in new process, I can say if the process is running, or get it's exit code, but I don't see any way to get info about how much of the job is done. I thought I can simply measure input file size and check periodically output file size, but it won't be any accurate, because the output file will have different size depending on what codec and container we use.
I've read I can also use frame progress, but the way of obtaining it is still not clear to me. I also need to do it for audio files.

  


  Is there any reasonable way to do so ?

  


• Failed to convert web-saved .wemb audio to .wav by using php "shell_exec" and javascript

  30 mai 2022, par Anirbasgnaw

  I'm working on an online experimenter which could record participants' audio from the browser. The audio data I get has an extension of .wemb, so I plan to use ffmpeg to convert it to .wav while I save the data.

  


  I tried to use PHP's shell_exec but nothing happens when I run the scripts. Then I found that my echo and print_r also did not work. I'm new to PHP and javascript, so I''m really confused now.

  


  Below are the relevant codes, I really appreciate it if you could help !

  


  write_data.php :

  


  <?php
  $post_data = json_decode(file_get_contents('php://input'), true); 
  // the directory "data" must be writable by the server
  $name = "../".$post_data['filename'];
  $data = $post_data['filedata'];
   // write the file to disk
  file_put_contents($name, $data);
  
  $INPUT = trim($name) . ".webm";
  $OUTPUT = trim($name) . ".wav";
  echo "start converting...";

  // check if ffmprg is available
  $ffmpeg = trim(shell_exec('which ffmpeg'));
  print_r($ffmpeg);
  // call ffmpeg
  shell_exec("ffmpeg -i '$INPUT' -ac 1 -f wav '$OUTPUT' 2>&1 ");
?>


  


  javascript :

  


    saveData: function(fileName,format){
    // save  as json by default
    if (!format){ format = 'json';}
    // add extension to filename
    fileName = `${fileName}.${format}`
    // create saveData object using fetch
    let saveData = [];
    if (format == 'json') {
        saveData = {
          type: 'call-function',
          async: true,
          func: async function(done) {
            let data = jsPsych.data.get().json();
            const response = await fetch("../write_data.php", {
              method: "POST",
              headers: {
                "content-type": "application/json"
              },
              body: JSON.stringify({ filename: fileName, filedata: data })
            });
            if (response.ok) {
              const responseBody = await response.text();
              done(responseBody);
            }
          }
        }
    } else {
        saveData = {
          type: 'call-function',
          async: true,
          func: async function(done) {
            let data = jsPsych.data.get().csv();
            const response = await fetch("../write_data.php", {
              method: "POST",
              headers: {
                "content-type": "application/json"
              },
              body: JSON.stringify({ filename: fileName, filedata: data })
            });
            if (response.ok) {
              const responseBody = await response.text();
              done(responseBody);
            }
          }
        }
    }
    return saveData;
  },


  


• How can I stream then play YUV format with/without VLC/FFMPEG ?

  13 janvier 2023, par orfruit

  I'm able to play a local YUV file through VLC (as expected)

  


  .\vlc.exe --demux rawvideo --rawvid-fps 25 --rawvid-width 480 --rawvid-height 360 --rawvid-chroma I420 out.yuv


  


  Also FFPLAY is playing well

  


  .\ffplay.exe -f rawvideo -pixel_format yuv420p -video_size 480x360 out.yuv


  


  Conversion to YUV was done with FFMPEG

  


  .\ffmpeg.exe -i "video.mp4" -c:v rawvideo -pixel_format yuv420p out.yuv


  


  However, I'm not able o stream it and play'it over local network.
I know, it sounds crazy :) but I plan to use VLC as a monitor/debugger for some YUV data.

  


  The original MP4 file is streamed/played fine with VLC (test on the same computer)

  


  .\vlc.exe "video.mp4" --sout="#std{access=http, mux=ts, dst=:55555/}"
.\vlc.exe http://192.168.0.174:55555/


  


  So the big question !
How can I stream the YUV format and VLC recognise an play it as well ?

  


  All that I tried with VLC is not playable.

  


  Thanks for any hints !