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• lavu/channel_layout : change av_get_channel_layout() behavior at the next bump

  4 octobre 2013, par Stefano Sabatini

  lavu/channel_layout : change av_get_channel_layout() behavior at the next bump
  The new syntax is preferred since it allows backward syntax compatibility
  
  with libswr when switching to the new option handling code with
  
  AV_OPT_TYPE_CHANNEL_LAYOUT.
  With the new parser the string :
  
  1234
  is interpreted as a channel layout mask, rather than as a number of
  
  channels, and thus it’s compatible with the current way to set a channel
  
  layout as an integer (e.g. for the icl and ocl options) making use of
  
  integer option values.
  ff_get_channel_layout() with compat=0 will be used in the
  
  AV_OPT_TYPE_CHANNEL handler code.
  The user is encouraged to switch to the new forward compatible syntax,
  
  which requires to put a trailing "c" when specifying a layout as a number
  
  of channels.
  

  • [DH] libavutil/channel_layout.c
  • [DH] libavutil/channel_layout.h
  • [DH] libavutil/internal.h
  • [DH] libavutil/version.h

• avcodec/ac3 : rename identifier used to select the fixed point variant

  1er avril 2014, par Michael Niedermayer

  avcodec/ac3 : rename identifier used to select the fixed point variant
  the CONFIG_ prefix is used by configure, using it for other things
  
  is potentially confusing to the reader
  Signed-off-by : Michael Niedermayer <michaelni@gmx.at>
  
  Signed-off-by : Nedeljko Babic <nbabic@mips.com>
  

  • [DH] libavcodec/ac3.h
  • [DH] libavcodec/ac3dec.c
  • [DH] libavcodec/ac3dec.h
  • [DH] libavcodec/ac3dec_fixed.c

• Python gets stuck at pipe.stdin.write(image.tostring())

  10 mars 2020, par Vandana Rajan

  I am reading each frame of video and adding time stamp to it as given below.

  command = ['ffmpeg',
  
              '-y', # (optional) overwrite output file if it exists
  
              '-f', 'rawvideo', #Input is raw video
  
              '-pix_fmt', 'bgr24', #Raw video format
  
              '-s', str(int(width)) + 'x' + str(int(height)), # size of one frame
  
              '-i', '-', # The input comes from a pipe
  
              '-an', # Tells FFMPEG not to expect any audio
  
              '-vcodec', 'mpeg4',
  
              '-b:v', '10M', #Sets a maximum bit rate
  
              Output_name]
  
      #Open the pipe
  
      pipe = sp.Popen(command, stdin=sp.PIPE, stderr=sp.PIPE)
  
  
  
      print('Processing....')
  
      print(' ')
  
      #Reads through each frame, calculates the timestamp, places it on the frame and exports the frame to the output video.
  
      #import pdb
  
      #pdb.set_trace()
  
      while current_frame < total_frames:
  
          success, image = video.read()
  
          if success:
  
              elapsed_time = video.get(cv2.CAP_PROP_POS_MSEC)
  
              current_frame = video.get(cv2.CAP_PROP_POS_FRAMES)
  
              timestamp = initial + dt.timedelta(microseconds = elapsed_time*1000)
  
              cv2.putText(image, 'Date: ' + str(timestamp)[0:10], (50,int(height-150)), cv2.FONT_HERSHEY_COMPLEX_SMALL, 2, (255, 255, 255), 3)
  
              cv2.putText(image, 'Time: ' + str(timestamp)[11:-4], (50,int(height-100)), cv2.FONT_HERSHEY_COMPLEX_SMALL, 2, (255, 255, 255), 3)
  
              pipe.stdin.write(image.tostring())
  
              print('frame number',current_frame)
  
          else:
  
              print('video reader fail')    
  
      video.release()
  
      pipe.stdin.close()
  
      pipe.stderr.close()

  However, after around 18k frames, Python gets stuck at ’pipe.stdin.write(image.tostring())’. It does not produce any error, but simply hangs. How to resolve this issue ?

  Thanks in advance.