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• OpenCV3.3.1 fails to read a video

  1er janvier 2018, par Kasparov92

  Here is the code I use

  file_name = 'movie.avi'
  
  cap = cv2.VideoCapture(file_name)
  
  
  
  success, frame = cap.read()
  
  
  
  i = 0
  
  
  
  while success:
  
      i +=1
  
      success, frame = cap.read()
  
  
  
  print "Frames successfully read:", i

  And I am getting this error :

  Unable to stop the stream: Inappropriate ioctl for device
  
  
  
  (python:139873): GLib-GObject-CRITICAL **: g_object_set: assertion 'G_IS_OBJECT (object)' failed
  
      Frames successfully read: 0

  On this particular video, it fails to read ! I tried the same code on other videos and they work fine. I also tried the same piece of code with another laptop (same operating system : Ubuntu 16.04) and it works.

  Is it a codec issue ? if so why other videos could be loaded and read successfully ?

  EDIT 1 :

  I recompiled opencv using -DWITH_LIBV4L=ON after sudo apt-get install libv4l-dev and Now I am getting this error :

  Failed to query video capabilities: Inappropriate ioctl for device
  
  libv4l2: error getting capabilities: Inappropriate ioctl for device
  
  VIDEOIO ERROR: V4L: device /root/datasets/UCF-101/TableTennisShot/v_TableTennisShot_g22_c02.avi: Unable to query number of channels
  
  
  
  (python:173084): GLib-GObject-CRITICAL **: g_object_set: assertion 'G_IS_OBJECT (object)' failed

• FFMPEG Audio Issues Youtube Live

  2 mars 2018, par Geige V

  This issue may have more to do with youtube than ffmpeg, but hopefully someone can help anyway.

  I am having the exact issue described in this post https://productforums.google.com/forum/# !topic/youtube/nHTb7ilKvrw. I would have added to it, but it is locked for some reason.

  I create a stream from a local webm file on my computer using ffmpeg. This file sounds perfectly fine, and still sounds fine when it is sent to platforms other than youtube live (twitch/facebook). On youtube live, however, the audio has static and crackles during the live feed, but the archive of the video on youtube (after processing) sounds perfectly fine. The ffmpeg command is

  ffmpeg -re -i test.webm -acodec aac -vcodec libx264 -ar 44100 -f flv rtmp://a.rtmp.youtube.com/live2/${your_key}

  Webm files from this fiddle (https://jsfiddle.net/2rgv7pgj/) will have the issue.

  If someone could offer advice it would be greatly appreciated.

• Sound in videos is full of static

  15 octobre 2017, par Shawn Blakesley

  I’m trying to play sound from an FFMpegFrameGrabber by getting the Frame and sending the audio samples to a SourceDataLine. Here’s what I have so far :

  Creating the SourceDataLine :

  int channels = _grabber.getAudioChannels();
  
  int format = _grabber.getSampleFormat();
  
  AudioFormat fmt = new AudioFormat(_grabber.getSampleRate(), format, channels, true, true);
  
  _sourceDataLine=(SourceDataLine)AudioSystem.getLine(new DataLine.Info(SourceDataLine.class, fmt));
  
  _sourceDataLine.open(fmt);
  
  _sourceDataLine.start();

  Attempting to play sound (images are handled in the else block) :

  org.bytedeco.javacv.Frame f = _grabber.grabFrame();
  
  
  
  if (f.samples != null && f.samples.length > 0)
  
  {
  
      byte[] bytes = new byte[4096];
  
      for (Buffer buffer : f.samples)
  
      {
  
          FloatBuffer floatBuffer = (FloatBuffer) buffer;
  
          ByteBuffer byteBuffer = ByteBuffer.allocate(floatBuffer.capacity() * 4);
  
          byteBuffer.asFloatBuffer().put(floatBuffer);
  
          byteBuffer.rewind();
  
          byteBuffer.get(bytes);
  
          _sourceDataLine.write(bytes, 0, bytes.length);
  
      }
  
  }

  (Note : I tried a few different versions of this and they all have static. The versions I tried included combining the buffers into one large buffer, only trying to play one sample instead of each channel, and changing the audio format to many different permutations.)

  The problem is the sound is full of static, and almost completely unintelligible. This is my first time doing any audio programming, so I’m sure I’m doing something completely ridiculous.

  I appreciate any help. Thank you.

  EDIT

  In response to Radiodef, I tried a number of AudioFormats, and I couldn’t find one that worked for PCM_FLOAT. I found an example that used this :

  fmt = new AudioFormat(AudioFormat.Encoding.PCM_FLOAT, _grabber.getSampleRate(), format, channels, channels, _grabber.getSampleRate(), true);

  Note : I tried a few different values for the framesize from examples : channels * format / 8, channels * 8 with a hardcoded samplerate of 64, channels * 4 with a hardcoded samplerate of 32, and any combinations of those

  But it give me this exception :

  java.lang.IllegalArgumentException: No line matching interface SourceDataLine supporting format PCM_FLOAT 44100.0 Hz, 8 bit, stereo, 2 bytes/frame,  is supported.
  
      at javax.sound.sampled.AudioSystem.getLine(Unknown Source)
  
      at com.enplug.player.video.Video.<init>(Video.java:52) &lt;- where I get the SourceDataLine
  
      ...
  
  </init>

  EDIT 2

  Sorry for the delay. I appreciate all the help Radiodef.

  Here is some output from the FFMpegGrabber that is automatically output.

  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'C:\Users\Shawn\AppData\Roaming\Enplug Display\Download\Resource\c7cb496d-96ea-4be8-a238-5ffd50955a3e.mp4':
  
    Metadata:
  
      major_brand     : qt
  
      minor_version   : 0
  
      compatible_brands: qt
  
      creation_time   : 2014-10-02 07:14:38
  
    Duration: 00:00:31.13, start: 0.000000, bitrate: 2412 kb/s
  
      Stream #0:0(und): Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 246 kb/s (default)
  
      Metadata:
  
        creation_time   : 2014-10-02 07:14:38
  
        handler_name    : Core Media Data Handler
  
      Stream #0:1(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709), 1280x720, 2157 kb/s, 30 fps, 30 tbr, 600 tbn, 1200 tbc (default)
  
      Metadata:
  
        creation_time   : 2014-10-02 07:14:38
  
        handler_name    : Core Media Data Handler
  
        encoder         : H.264

  I have two videos I’m testing with, and the first one (which is the one in the example above) has the following :

  Bit rate: 247 kbps
  
  Channels: 2 (stereo)
  
  Audio sample rate: 44 kHz

  And the second is :

  Bit rate: 161 kbps
  
  Channels: 2 (stereo)
  
  Audio sample rate: 48 kHz

  They’re both mp4s, and I can provide any details about the video itself if needed.

  As for the library, yeah I’m pretty locked into JavaCV. We already have videos running without sound, but we’re now trying to add sound to our program.

  When I run the sample program from your JSR link I get :

  PCM_UNSIGNED unknown sample rate, 8 bit, mono, 1 bytes/frame,
  
  PCM_SIGNED unknown sample rate, 8 bit, mono, 1 bytes/frame,
  
  PCM_SIGNED unknown sample rate, 16 bit, mono, 2 bytes/frame, little-endian
  
  PCM_SIGNED unknown sample rate, 16 bit, mono, 2 bytes/frame, big-endian
  
  PCM_UNSIGNED unknown sample rate, 8 bit, stereo, 2 bytes/frame,
  
  PCM_SIGNED unknown sample rate, 8 bit, stereo, 2 bytes/frame,
  
  PCM_SIGNED unknown sample rate, 16 bit, stereo, 4 bytes/frame, little-endian
  
  PCM_SIGNED unknown sample rate, 16 bit, stereo, 4 bytes/frame, big-endian
  
  PCM_UNSIGNED unknown sample rate, 8 bit, mono, 1 bytes/frame,
  
  PCM_SIGNED unknown sample rate, 8 bit, mono, 1 bytes/frame,
  
  PCM_SIGNED unknown sample rate, 16 bit, mono, 2 bytes/frame, little-endian
  
  PCM_SIGNED unknown sample rate, 16 bit, mono, 2 bytes/frame, big-endian
  
  PCM_UNSIGNED unknown sample rate, 8 bit, stereo, 2 bytes/frame,
  
  PCM_SIGNED unknown sample rate, 8 bit, stereo, 2 bytes/frame,
  
  PCM_SIGNED unknown sample rate, 16 bit, stereo, 4 bytes/frame, little-endian
  
  PCM_SIGNED unknown sample rate, 16 bit, stereo, 4 bytes/frame, big-endian
  
  PCM_UNSIGNED unknown sample rate, 8 bit, mono, 1 bytes/frame,
  
  PCM_SIGNED unknown sample rate, 8 bit, mono, 1 bytes/frame,
  
  PCM_SIGNED unknown sample rate, 16 bit, mono, 2 bytes/frame, little-endian
  
  PCM_SIGNED unknown sample rate, 16 bit, mono, 2 bytes/frame, big-endian
  
  PCM_UNSIGNED unknown sample rate, 8 bit, stereo, 2 bytes/frame,
  
  PCM_SIGNED unknown sample rate, 8 bit, stereo, 2 bytes/frame,
  
  PCM_SIGNED unknown sample rate, 16 bit, stereo, 4 bytes/frame, little-endian
  
  PCM_SIGNED unknown sample rate, 16 bit, stereo, 4 bytes/frame, big-endian
  
  PCM_UNSIGNED unknown sample rate, 8 bit, mono, 1 bytes/frame,
  
  PCM_SIGNED unknown sample rate, 8 bit, mono, 1 bytes/frame,
  
  PCM_SIGNED unknown sample rate, 16 bit, mono, 2 bytes/frame, little-endian
  
  PCM_SIGNED unknown sample rate, 16 bit, mono, 2 bytes/frame, big-endian
  
  PCM_UNSIGNED unknown sample rate, 8 bit, stereo, 2 bytes/frame,
  
  PCM_SIGNED unknown sample rate, 8 bit, stereo, 2 bytes/frame,
  
  PCM_SIGNED unknown sample rate, 16 bit, stereo, 4 bytes/frame, little-endian
  
  PCM_SIGNED unknown sample rate, 16 bit, stereo, 4 bytes/frame, big-endian