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• i want to merge multiple images and videos together to create single video file by using ffmpeg

  19 février 2018, par Muhammad Ali

  I have tried this below thing
  First i am creating video using two images like this –

  String originalPath= “file “+”‘”+picturePath1+”‘”+”\n”+ “duration 3 \n”+”file “+”‘”+picturePath2+”‘”+”\n”+ “duration 3+”‘”+picturePath2+”‘””;  
  
  
  
  File myFile= generateTextFile(“MyTextFile”,originalPath); // here i convert into text file 

  After that executing command,

  String command[] = {“-y”, “-f”, “concat”, “-safe”, “0”, “-i”,myFile.getAbsolutePath(), “-vsync”, “vfr”, “-pix_fmt”, “yuv420p”, VideoSavePath};

  Able to create video and using the created video path (VideoSavePath ) in below command

  String mutipleVideo[] = {“-y”, “-i”, firstVideoPath, “-i”,secondVideoPath , “-i”, VideoSavePath, “-filter_complex”,
  
  “[0:v]scale=480×640,setsar=1[v0];[1:v]scale=480×640,setsar=1[v1];[2:v]scale=480×640,setsar=1[v2];[v0][0:a][v1][1:a][v2][2:a]concat=n=3:v=1:a=1”,
  
  “-ab”, “48000”, “-ac”, “2”, “-ar”, “22050”, “-s”, “480×640”, “-vcodec”, “libx264″,”-crf”,”27″,”-preset”, “ultrafast”, newFinalVideoPath};

  but i am getting error(matches no streams) while using videopath getting from first command and this second command is working fine if i am using some random videopath in place of VideoSavePath

• Unable to run ffmpeg with qProcess to extract a single frame from Vide

  24 janvier 2018, par user3840315

  I am trying to extract a single frame from a video using the QProcess in qt framework and ffmpeg and store it in a tmp folder. When I run the program in terminal command line it is able to extract it but not when QProcess runs it. I’m developing on a mac. What am I doing wrong.

  QString extractSingleFrame(QString videoPath, QDir tmpDir)
  
  {
  
      QString program = ffmpegPath();
  
      QProcess *ffmpegProcess = new QProcess();
  
      QString arguments;
  
      QFileInfo videoInfo(videoPath);
  
      QString videoName = videoInfo.fileName();
  
  
  
      QString firstFrameName(tmpDir.absolutePath() + "/" + videoName + ".jpg");
  
      arguments = " -y -i " + QDir::toNativeSeparators(videoPath)
  
                  + " -frames:v 1 -q:v 1 -f image2 " + QDir::toNativeSeparators(firstFrameName);
  
  
  
      QFile::remove(firstFrameName);
  
      qDebug() << "Starting program" << program + arguments;
  
      ffmpegProcess->start(program + arguments);
  
      // ffmpegProcess->start(program , QStringList() <<  arguments); this also doesnt work
  
      if (ffmpegProcess->state() == QProcess::Starting){
  
         qDebug() << "program is starting" + ffmpegProcess->state();
  
      }
  
      ffmpegProcess->waitForFinished(-1);
  
  
  
      qDebug() << "done";
  
  
  
      delete ffmpegProcess;
  
  
  
      return firstFrameName;
  
  }

  This is the printed command
  to start the program "ffmpeg -y -i "/Users/userX/test.mov" -vframes 1 -q:v 1 -f image2 "/var/folders/s1/vtv2cx36p3h0000gn/T/test-ywDBgj/test.mov.jpg""

• Change the sample rate by a factor with ffmpeg in a single command without using ffprobe ?

  22 décembre 2017, par Miha Zupan

  Is it possible to change the sample rate by a factor with ffmpeg in a single command without using ffprobe ?

  Considering there is a way to do something similar when cropping images by using in_w :

  ffmpeg -i input.jpg -vf crop=in_w/1.2 output.jpg

  Is there a similar aproach for asetrate, something like :

  ffmpeg -i input.wav -af asetrate=r=in_r*1.2 output.wav

  I found no mention of anything like that in the documentation.

  If this is not possible I can afford to run another ffprobe command to get the sample rate, but I was just wondering if there was a way to avoid it.