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• Python ffmpeg subprocess : Broken pipe [closed]

  11 décembre 2022, par Pikkostack

  The following script reads a video with OpenCV, applies a transformation to each frame and attempts to write it with ffmpeg. My problem is, that I don't get ffmpeg working with the subprocess module. I always get the error BrokenPipeError: [Errno 32] Broken pipe in the line where I try to write to stdin. Why is that, what am I doing wrong ?

  



  # Open input video with OpenCV
video_in = cv.VideoCapture(src_video_path)
frame_width = int(video_in.get(cv.CAP_PROP_FRAME_WIDTH))
frame_height = int(video_in.get(cv.CAP_PROP_FRAME_HEIGHT))
fps = video_in.get(cv.CAP_PROP_FPS)
frame_count = int(video_in.get(cv.CAP_PROP_FRAME_COUNT))
bitrate = bitrate * 4096 * 2160 / (frame_width * frame_height)

# Process video in ffmpeg pipe
# See http://zulko.github.io/blog/2013/09/27/read-and-write-video-frames-in-python-using-ffmpeg/
command = ['ffmpeg',
           '-loglevel', 'error',
           '-y',
           # Input
           '-f', 'rawvideo',
           '-vcodec', 'rawvideo'
           '-pix_fmt', 'bgr24',
           '-s', str(frame_width) + 'x' + str(frame_height),
           '-r', str(fps),
           # Output
           '-i', '-',
           '-an',
           '-vcodec', 'h264',
           '-r', str(fps),
           '-b:v', str(bitrate) + 'M',
           '-pix_fmt', 'bgr24',
           dst_video_path
           ]
pipe = sp.Popen(command, stdin=sp.PIPE)

for i_frame in range(frame_count):
    ret, frame = video_in.read()
    if ret:
        warped_frame = cv.warpPerspective(frame, homography, (frame_width, frame_height))
        pipe.stdin.write(warped_frame.astype(np.uint8).tobytes())
    else:
        print('Stopped early.')
        break
print('Done!')


  


• Pipe input GIF to FFmpeg error, does it have size limit ?

  3 février 2020, par SerKo

  I am trying to pipe input a GIF file to FFmpeg and get output from it. And I get an error when I input a GIF file size bigger than 1MB (maybe even smaller, didn’t try).

  I am running on Debian GNU/Linux 10 (buster) and install FFmpeg by apt-get install ffmpeg.

  What’s problem ?

  After reading the FFmpeg pipe document and I have try execute command below :
  cat big_size.gif | ffmpeg -i pipe:0 -f gif output.gif

  And it shows error :
  pipe:: Input/output error

  What have I tried to fix ?

  If I input the GIF file directly the FFmpeg instead of using pipe input, I can output the GIF successfully.
  ffmpeg -i big_size.gif -f gif output.gif

  I was think of system pipe size limit, but I can pipe the GIF by using cat to cat and save successfully.
  cat big_size.gif | cat > output.gif

  So I don’t think the system pipe size limit cause the problem.

  Sample GIF

  Or you may try other GIF file size bigger then 1MB.

  

• Pipe ffmpeg output as mjpeg on multicast port ?

  17 janvier 2020, par xor31four

  I am trying to open a h.264 encoded stream from an IP camera, re-encode and stream it to a multicast address on my local subnet.

  Found a post that seems to describe what I’d like to achieve but I am running into several issues.

  I am using this command :

  ffmpeg -re -i rtsp://192.168.0.11/stream1.sdp mpegts udp://239.168.0.1:11000

  and I am receiving this output :

  [h264 @ 000001531da0ad40] SPS unavailable in decode_picture_timing
  
  [h264 @ 000001531da0ad40] non-existing PPS 0 referenced
  
  [h264 @ 000001531da0ad40] SPS unavailable in decode_picture_timing
  
  [h264 @ 000001531da0ad40] non-existing PPS 0 referenced
  
  [h264 @ 000001531da0ad40] decode_slice_header error
  
  [h264 @ 000001531da0ad40] no frame!
  
  [rtsp @ 000001531d9b9700] max delay reached. need to consume packet
  
  -- Above is repeated dozens of times
  
  [rtsp @ 000001531d9b9700] RTP: missed 8 packets
  
  [rtsp @ 000001531d9b9700] Could not find codec parameters for stream 1 (Unknown: none (meta / 0x6174656D)): unknown codec
  
  Consider increasing the value for the 'analyzeduration' and 'probesize' options
  
  [rtsp @ 000001531d9b9700] Could not find codec parameters for stream 2 (Unknown: none (bdat / 0x74616462)): unknown codec
  
  Consider increasing the value for the 'analyzeduration' and 'probesize' options
  
  Input #0, rtsp, from 'rtsp://192.168.0.11/stream1.sdp':
  
    Metadata:
  
      title           : DTC
  
      comment         : Pagos
  
    Duration: N/A, start: 1557.106222, bitrate: N/A
  
    Program 1
  
      Metadata:
  
        service_name    : Service #1
  
        service_provider: DTC
  
      Stream #0:0: Video: h264 (High) (vid1 / 0x31646976), yuv420p(progressive), 960x540 [SAR 1:1 DAR 16:9], 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc
  
      Stream #0:1: Unknown: none (meta / 0x6174656D)
  
      Stream #0:2: Unknown: none (bdat / 0x74616462)
  
    No Program
  
      Stream #0:3: Data: epg
  
  [NULL @ 000001531e5aa940] Unable to find a suitable output format for 'mpegts'
  
  mpegts: Invalid argument

  Where am I going wrong ? I am quite inexperienced in this field but determined to learn more.

  Thank you in advance for any pointers on how to go about this..