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• Can FFmpeg record audio on Android ?

  9 novembre 2022, par Pavel Poley

  Since MediaRecoreder not supports encoding to mp3 format.
Can ffmpeg to record audio directly from Android audio source (how to specify this) or it only encodes one file to other format ?

  


• It is possible to record and at the same

  29 avril 2022, par mylos

  ffmpeg -i cam.mkv -c copy 1.ts


  


  It is possible to record and at the same time to delete to have a lead 4s ??
as to see it in vlc
Sorry for my poor English

  


• Recording a webpage stream with multiple requests using PhantomJS & ffmpeg to /dev/stdout leads to ffmpeg error

  2 septembre 2016, par Allisson Ferreira

  First of all, sorry for my english.

  I’m in a quest for days. I’ve researched everywhere and I couldn’t find an answer to my problem.

  I’m using Nodejs, Phantomjs and ffmpeg in this scenary :

  • An user enters the site, login with facebook and he can ask for a video with his name and some random photos (gathered by /me/ & sent via JSON POST) ;
  • Node receive the user data, creates a child process (PhantomJS + ffmpeg) and awaits for a response to send the video URL to the user.

  When I run a single instance of this request, everything is working fine. BUT, when two or more users make the request, only one video is sent and the others process end up in a ffmpeg stream error.

  I think the reason is that all the ffmpeg processes are using the same place (/dev/stdout). Since one process is already using it, the others enters in a "can’t access" error. But it is a assumption, I don’t know how /dev/stdout really works.

  Here are my codes. (I have removed some lines and renamed some variables for better understanding, sorry for any mistake)

  index.js :

  var generateVideo = 'phantomjs phantom.js '+videoID+' '+userID+' | ffmpeg -vcodec png -f image2pipe -r 30 -i - -pix_fmt yuv420p public/videos/'+userID+'/'+videoID+'.mp4 -y';
  
  
  
  childProcess.exec(generateVideo, function(err, stdout, stderr) {
  
      var json    = {};
  
      json.video  = '/videos/'+userID+'/'+videoID+'.mp4';
  
      res.send(json);
  
  });

  phantom.js :

  var page            = require('webpage').create();
  
  page.viewportSize   = { width: 1366, height: 768 };
  
  page.settings.resourceTimeout = 10000;
  
  
  
  var args            = require('system').args;
  
  var videoID         = args[1];
  
  var userID          = args[2];
  
  
  
  page.open('http://localhost:3000/recordvideo/'+videoID, 'post', function(status){
  
      var frame       = 0;
  
      var target_fps  = 30;
  
      var maxframes   = page.evaluate(function () {
  
                          return getTotalDurationInSeconds();
  
                      }) * target_fps;
  
  
  
      setInterval(function(){
  
          page.render('/dev/stdout', { format: "png" });
  
          if( frame >= maxframes ){
  
              phantom.exit();
  
          }
  
          frame++;
  
      }, (1000 / target_fps));
  
  });

  And the error :

  [Error: Command failed: /bin/sh -c phantomjs phantom.js XXXXXXXX XXXXXXXX | ffmpeg -vcodec png -f image2pipe -r 30 -i - -pix_fmt yuv420p public/videos/XXXXXXXX/XXXXXXXX.mp4 -y
  
  www-0 ffmpeg version N-80901-gfebc862 Copyright (c) 2000-2016 the FFmpeg developers
  
  www-0   built with gcc 4.8 (Ubuntu 4.8.4-2ubuntu1~14.04.3)
  
  www-0   configuration: --extra-libs=-ldl --prefix=/opt/ffmpeg --mandir=/usr/share/man --enable-avresample --disable-debug --enable-nonfree --enable-gpl --enable-version3 --enable-libopencore-amrnb --enable-libopencore-amrwb --disable-decoder=amrnb --disable-decoder=amrwb --enable-libpulse --enable-libfreetype --enable-gnutls --enable-libx264 --enable-libx265 --enable-libfdk-aac --enable-libvorbis --enable-libmp3lame --enable-libopus --enable-libvpx --enable-libspeex --enable-libass --enable-avisynth --enable-libsoxr --enable-libxvid --enable-libvidstab
  
  www-0   libavutil      55. 28.100 / 55. 28.100
  
  www-0   libavcodec     57. 48.101 / 57. 48.101
  
  www-0   libavformat    57. 41.100 / 57. 41.100
  
  www-0   libavdevice    57.  0.102 / 57.  0.102
  
  www-0   libavfilter     6. 47.100 /  6. 47.100
  
  www-0   libavresample   3.  0.  0 /  3.  0.  0
  
  www-0   libswscale      4.  1.100 /  4.  1.100
  
  www-0   libswresample   2.  1.100 /  2.  1.100
  
  www-0   libpostproc    54.  0.100 / 54.  0.100
  
  www-0 [png @ 0x3d7c4a0] Invalid PNG signature 0x46726F6D20506861.
  
  www-0 [image2pipe @ 0x3d72780] decoding for stream 0 failed
  
  www-0 [image2pipe @ 0x3d72780] Could not find codec parameters for stream 0 (Video: png, none(pc)): unspecified size
  
  www-0 Consider increasing the value for the 'analyzeduration' and 'probesize' options
  
  www-0 Input #0, image2pipe, from 'pipe:':
  
  www-0   Duration: N/A, bitrate: N/A
  
  www-0     Stream #0:0: Video: png, none(pc), 30 tbr, 30 tbn, 30 tbc
  
  www-0 [buffer @ 0x3d81540] Unable to parse option value "0x0" as image size
  
  www-0 [buffer @ 0x3d81540] Unable to parse option value "-1" as pixel format
  
  www-0 [buffer @ 0x3d81540] Unable to parse option value "0x0" as image size
  
  www-0 [buffer @ 0x3d81540] Error setting option video_size to value 0x0.
  
  www-0 [graph 0 input from stream 0:0 @ 0x3d72600] Error applying options to the filter.
  
  www-0 Error opening filters!
  
  www-0 ]

  I really hope that I can find an answer here !
  And sorry if there already is an answer for this. But I researched for days.

  Thank you in advance !