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• Static image and a folder of mp3's ?

  28 juin 2013, par Shirohige

  I want to create a bunch of videos consisting of an single image which is shown throughout the whole video but each video has a different audio file. I can do it manually with various tools but the problem is that I have a lot of audio files and I can't optimize the frame rate (more on that later) and it takes a lot of time to do it that way but ffmpeg offers everything I need but the problem is that I don't know how to batch process everything.

  The basic code :
  ffmpeg -i song-name.mp3 -loop 1 -i cover.jpg -r frame-rate -t song-length -acodec copy output.mp4

  What I want to achieve :
  Let's say that I have a folder which consists of several audio files : song-name-1.mp3, song-name-2.mp3, ..., song-name-n.mp3 and cover.jpg.

  I need a batch file which takes the name of every mp3 file in a folder (a FOR loop I suppose) and processes it with the same command :
  ffmpeg -i song-name.mp3 -loop 1 -i cover.jpg -r frame-rate -t song-length -acodec copy output.mp4

  So the image is always the same for every video. The song length can be taken with the tool mp3info and the corresponding command :
  mp3info.exe -p %S song-name.mp3

  Since I only have one image throughout the whole video, the optimal frame rate would be the inverse of the video length which is 1/length (where length is a variable in seconds which we get from mp3info).

  So the final code should look something like this :
  ffmpeg -i song-name.mp3 -loop 1 -i cover.jpg -r 1/length -t length -acodec copy song-name.mp4

  Where "song-name" is a variable which changes for every iteration of the FOR loop (i.e. for every audio file in the folder) and length is a variable whose value we get with the command :
  mp3info.exe -p %S song-name.mp3

  I found examples of a FOR loop to fetch all file names of all mp3's in a specific folder but I do not know how to integrate mp3info. I hope that somebody can help me and I have some knowledge of the C programming language if that can be used in any way.

• Play audio from ffmpegframegrabber

  5 juillet 2013, par Shataya

  For an augmented reality app which should play videos, adjusted to the detected marker.
  I can't use the android video view as it is not possible to rotate it.
  Therefor I have imported the javacv and ffmpeg libraries.
  So far I can successfully render my video with opengl es but I have problems with the audio playback.

  I extract the frames with FFmpegFrameGrabber :

  grabber = new MyFFmpegFrameGrabber(Environment.getExternalStorageDirectory()+"/arvideo_"+fileName+".mp4");
  
  Frame frame = grabber.grabFrame();
  
  ....
  
  if(frame.samples != null) {     
  
     // I have my audio samples and then?     
  
  }

  I tried to playback the audio with the AudioTrack class.

  int bufferSize = AudioTrack.getMinBufferSize(grabber.getSampleRate(),AudioFormat.CHANNEL_CONFIGURATION_MONO, AudioFormat.ENCODING_PCM_16BIT);
  
  track = new AudioTrack(AudioManager.STREAM_MUSIC, grabber.getSampleRate(), AudioFormat.CHANNEL_CONFIGURATION_MONO, AudioFormat.ENCODING_PCM_16BIT, bufferSize, AudioTrack.MODE_STREAM);
  
  track.play();
  
  
  
  // call track.write(....) ???

  I get only a static noise. I have read that the sample format is AV_SAMPLE_FMT_FLTP but android needs AV_SAMPLE_FMT_S16. That's why I tried to convert the samples with com.googlecode.javacv.cpp.swresample class. I think that I'm doing something wrong because I still have only noise.

  swrcontext = com.googlecode.javacv.cpp.swresample.swr_alloc();
  
  com.googlecode.javacv.cpp.swresample.swr_alloc_set_opts(swrcontext,AV_CH_LAYOUT_STEREO, avutil.AV_SAMPLE_FMT_FLTP, getSampleRate(), AV_CH_LAYOUT_STEREO, avutil.AV_SAMPLE_FMT_S16, getSampleRate(), 0, null);
  
  com.googlecode.javacv.cpp.swresample.swr_init(swrcontext);
  
  // ....
  
  PointerPointer inData =  samples_frame.data();
  
  PointerPointer outData = samples_frame.data();            
  
  com.googlecode.javacv.cpp.swresample.swr_convert(swrcontext, outData, samples_frame.nb_samples(), inData,  samples_frame.nb_samples());
  
  samples_frame = new AVFrame(outData);

  I really have no idea anymore... I hope anybody can help me. Thanks.

• How to capture and store a video in h.264 format using web browsers ?

  24 juillet 2013, par 2vision2

  How to capture a video and store it in h.264 format using web browsers ?

  As per my analysis, HTML5 can be used to access the camera and microphone without any additional plug-ins as in this link. "http://www.html5rocks.com/en/tutorials/getusermedia/intro/"

  However, i don't know the possibility of storing the video in h.264 format.

  I would prefer not to install any additional plugin**s. However if its not possible without any additional plugins, i would accept it. I can also use **Java Applets if needed.

  Is HTML 5 the only option or it possible with JScript itself ? I also hope that ffmpeg can help me too.