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• cv2.VideoCapture on python

  27 décembre 2015, par pandasarebest

  I am running the following code :

  import numpy as np
  
  import cv2
  
  import os
  
  
  
  count = 0
  
  
  
  cap = cv2.VideoCapture("/home/simon/PROJECT/real_data/00000020.mp4")
  
  
  
  while not cap.isOpened():
  
      cap = cv2.VideoCapture("./00000020.mp4")
  
      cv2.waitKey(1000)
  
      print "Wait for the header"
  
  
  
  pos_frame = cap.get(cv2.cv.CV_CAP_PROP_POS_FRAMES)
  
  while True:
  
      flag, frame = cap.read()
  
      if flag:
  
          # The frame is ready and already captured
  
          cv2.imshow('video', frame)
  
          pos_frame = cap.get(cv2.cv.CV_CAP_PROP_POS_FRAMES)
  
          print str(pos_frame)+" frames"
  
      else:
  
          # The next frame is not ready, so we try to read it again
  
          cap.set(cv2.cv.CV_CAP_PROP_POS_FRAMES, pos_frame-1)
  
          print "frame is not ready"
  
          # It is better to wait for a while for the next frame to be ready
  
          cv2.waitKey(1000)
  
  
  
      if cv2.waitKey(10) & 0xFF == 27:
  
          break
  
      if cap.get(cv2.cv.CV_CAP_PROP_POS_FRAMES) ==       cap.get(cv2.cv.CV_CAP_PROP_FRAME_COUNT):
  
      # If the number of captured frames is equal to the total number of frames,
  
      # we stop
  
      break
  
  
  
  
  
  if ret == True:
  
      frame = cv2.VideoCapture.grab()
  
      frame = 'frame%d' % count 
  
  
  
      cv2.imwrite('frame%d.png', frame)
  
  
  
      count += 1
  
  else:
  
      print 'stopped at' + count
  
      break

  And whenever I run it, it loops on the while not loop, printing "wait for header".
  There is never an error code or anything like that either.

  I have tried to run it as a more simple piece of code, where it doesnt have all these checks, and again that doesn’t throw any errors.

  I am attempting to run this code to open a video, and then save the frames as png files throughout the video.

  Does anyone spot any particular problems with the code ?
  Or alternatively does anyone know a piece of code that would do what i want more efficiently, as I have trawled through google searches and stack overflow a lot recently and haven’t found anything

  Thanks in advance
  Panda

• Mixing audio(aac) and video (h.264 in mp4 container) and write to mp4 container using Xuggler

  25 novembre 2015, par Handroid

  Here is the code I am using

      String filenamevideo = videoFilePath;(video.mp4)
  
  
  
      String filenameaudio = audioAACFilePath; (audio.aac)
  
  
  
  
  
  
  
      IMediaWriter mWriter = ToolFactory.makeWriter(videoWithAudioFilePath); // output
  
      // file
  
  
  
      IContainer containerVideo = IContainer.make();
  
      IContainer containerAudio = IContainer.make();
  
  
  
      if (containerVideo.open(filenamevideo, IContainer.Type.READ, null) < 0)
  
          throw new IllegalArgumentException("Cant find " + filenamevideo);
  
  
  
      if (containerAudio.open(filenameaudio, IContainer.Type.READ, null) < 0)
  
          throw new IllegalArgumentException("Cant find " + filenameaudio);
  
  
  
      int numStreamVideo = containerVideo.getNumStreams();
  
      int numStreamAudio = containerAudio.getNumStreams();    
  
  
  
      int videostreamt = -1; // this is the video stream id
  
      int audiostreamt = -1;
  
  
  
      IStreamCoder videocoder = null;
  
  
  
      for (int i = 0; i < numStreamVideo; i++) {
  
          IStream stream = containerVideo.getStream(i);
  
          IStreamCoder code = stream.getStreamCoder();
  
  
  
          if (code.getCodecType() == ICodec.Type.CODEC_TYPE_VIDEO) {
  
              videostreamt = i;
  
              videocoder = code;
  
              break;
  
          }
  
  
  
      }
  
  
  
      for (int i = 0; i < numStreamAudio; i++) {
  
          IStream stream = containerAudio.getStream(i);
  
          IStreamCoder code = stream.getStreamCoder();
  
  
  
          if (code.getCodecType() == ICodec.Type.CODEC_TYPE_AUDIO) {
  
              audiostreamt = i;
  
              break;
  
          }
  
  
  
      }
  
  
  
      if (videostreamt == -1)
  
          throw new RuntimeException("No video steam found");
  
      if (audiostreamt == -1)
  
          throw new RuntimeException("No audio steam found");
  
  
  
      if (videocoder.open() < 0)
  
          throw new RuntimeException("Cant open video coder");
  
      IPacket packetvideo = IPacket.make();
  
  
  
      IStreamCoder audioCoder = containerAudio.getStream(audiostreamt).getStreamCoder();
  
  
  
      if (audioCoder.open() < 0)
  
          throw new RuntimeException("Cant open audio coder");
  
  
  
      mWriter.addAudioStream(0, 0, ICodec.ID.CODEC_ID_AAC, audioCoder.getChannels(),audioCoder.getSampleRate());
  
  
  
      mWriter.addVideoStream(1, 0, ICodec.ID.CODEC_ID_H264, videocoder.getWidth(), videocoder.getHeight());
  
  
  
  
  
      IPacket packetaudio = IPacket.make();
  
  
  
      while (containerVideo.readNextPacket(packetvideo) >= 0 || containerAudio.readNextPacket(packetaudio) >= 0) {
  
  
  
          if (packetvideo.getStreamIndex() == videostreamt) {
  
  
  
              // video packet
  
              IVideoPicture picture = IVideoPicture.make(videocoder.getPixelType(), videocoder.getWidth(),
  
                      videocoder.getHeight());
  
              int offset = 0;
  
              while (offset < packetvideo.getSize()) {
  
                  int bytesDecoded = videocoder.decodeVideo(picture, packetvideo, offset);
  
                  if (bytesDecoded < 0)
  
                      throw new RuntimeException("bytesDecoded not working");
  
                  offset += bytesDecoded;
  
                  if (picture.isComplete()) {
  
                      // System.out.println(picture.getPixelType());
  
                      mWriter.encodeVideo(1, picture);
  
                  }
  
              }
  
          }
  
  
  
          if (packetaudio.getStreamIndex() == audiostreamt) {
  
              // audio packet
  
              IAudioSamples samples = IAudioSamples.make(512, audioCoder.getChannels(), IAudioSamples.Format.FMT_S32);
  
              int offset = 0;
  
              while (offset < packetaudio.getSize()) {
  
                  int bytesDecodedaudio = audioCoder.decodeAudio(samples, packetaudio, offset);
  
                  if (bytesDecodedaudio < 0)
  
                      throw new RuntimeException("could not detect audio");
  
                  offset += bytesDecodedaudio;
  
                  if (samples.isComplete()) {
  
                      mWriter.encodeAudio(0, samples);
  
                  }
  
              }
  
  
  
          }           
  
      }

  The output file (mp4) is generating , but unable to play it using (vlc) and in JavaFX scene media.

  Please help me with the inputs on the above code I’m using it in a correct way (Or) help me with the possible solution for mixing audio(aac) and video(h264) to mp4 container.

  Thank in advance.

• Parsed_concat_1 @ 02ad98e0 Failed to configure output pad on Parsed_concat_1

  3 décembre 2015, par user650922

  I am using NReco.VideoConverter(FFMPegConverter) to ConcatMedia. However, I am getting error as Parsed_concat_1 @ 02ad98e0 Failed to configure output pad on Parsed_concat_1.

  Here is the code snippet of my code :

  try
  
          {
  
              var ffMpeg = new FFMpegConverter();
  
              var set = new ConcatSettings
  
              {
  
                  ConcatAudioStream = false
  
              };
  
              set.SetVideoFrameSize(1080, 720);
  
              set.MaxDuration = 500;
  
              ffMpeg.ConcatMedia(videos, output + ".mp4", Format.mp4, set);
  
              return output + ".mp4";
  
          }
  
          catch (Exception ex)
  
          {
  
              var text = new List<string>();
  
              text.AddRange(videos);
  
              text.Add(ex.Message);
  
              throw new Exception(string.Join(", ", text), ex);
  
          }
  
  </string>

  VideoFrameSize of all the videos is(1080, 720) and FrameRate is 25.

  Could some one please help me to resolve the issue.