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• Making a ffmpeg screen capture on Mac OS X using YUV 4:2:0 Planar color model

  30 mai 2019, par Bass

  I make screen recordings with ffmpeg, using avfoundation on Mac OS X, x11grab on Linux and gdigrab on Windows.

  The resulting files should be compatible with modern web browsers (<video></video>), so I use H.264 codec and request YUV 4:2:0 Planar pixel format.

  On Mac OS X, however (unlike Linux and Windows), I receive the following logging :

  /usr/local/bin/ffmpeg -y -v error -f avfoundation -threads 0 -hide_banner -i 1:none -f mp4 -vcodec h264 -pix_fmt yuv420p -r 25/1 -qscale:v 1 -vf scale=-1:1080 target.mp4
  
  [avfoundation @ 0x7fdba2003a00] Selected pixel format (yuv420p) is not supported by the input device.
  
  [avfoundation @ 0x7fdba2003a00] Supported pixel formats:
  
  [avfoundation @ 0x7fdba2003a00]   uyvy422
  
  [avfoundation @ 0x7fdba2003a00]   yuyv422
  
  [avfoundation @ 0x7fdba2003a00]   nv12
  
  [avfoundation @ 0x7fdba2003a00]   0rgb
  
  [avfoundation @ 0x7fdba2003a00]   bgr0

  Still, according to mplayer, the resulting MP4 file seems to have YUV 4:2:0 Planar color model :

  [h264 @ 0x1048a8ac0]Format yuv420p chosen by get_format().
  
  [h264 @ 0x1048a8ac0]Reinit context to 1728x1088, pix_fmt: yuv420p
  
  [h264 @ 0x1048a8ac0]Format yuv420p chosen by get_format().
  
  [h264 @ 0x1048a8ac0]Reinit context to 1728x1088, pix_fmt: yuv420p
  
  [swscaler @ 0x1048c3cc0]bicubic scaler, from yuv420p to yuyv422 using MMXEXT
  
  *** [scale] Exporting mp_image_t, 1728x1080x12bpp YUV planar, 2799360 bytes
  
  *** [vo] Allocating mp_image_t, 1728x1080x16bpp YUV packed, 3732480 bytes

  the same confirmed by ffmpeg :

  $ ffmpeg -i target.mp4 -hide_banner
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'target.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf58.20.100
  
    Duration: 00:00:04.72, start: 0.000000, bitrate: 201 kb/s
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1728x1080, 197 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler

  Questions :

  1. Can someone explain the above ffmpeg logging ?
  2. If I still need to convert the avfoundation video stream to yuv420p, how do I make it on the fly (in a single ffmpeg pass) ?

• When I receive vlc file streaming using Python's video capture, error occured

  9 mai 2022, par 2tapgosu

  opencv version : 3.4.1

  


  ffmpeg version : 3.4.8-0ubuntu0.2

  


  os : ubuntu 18.04

  


  streaming code

  


  vlc -vvv /my/video/path.mp4 --play-and-exit :sout=#rtp{sdp=rtsp://127.0.0.1:8554/} :sout-keep


  


  python code(receiver)

  


  frame_buffer = None
def receiver(stream_uri):
    global frame_buffer
    while True:
        rtsp = cv2.VideoCapture(stream_uri, cv2.CAP_FFMPEG)
        if rtsp.isOpened():
            while True:
                connect, frame = rtsp.read()
                if not connect:
                    break
                frame_buffer = frame

def consumer():
    global frame_buffer
    while True:
        frame = frame_buffer

def main():
    os.environ["OPENCV_FFMPEG_CAPTURE_OPTIONS"] = "rtsp_transport;udp"

    receiver_thread = threading.Thread(target=receiver, args=(stream_uri,))
    consumer_thread = threading.Thread(target=consumer)

    receiver_thread.start()
    consumer_thread.start()

    receiver_thread.join()
    consumer_thread.join()

if __name__ == '__main__':
    main()
    


  


  console log(error)

  


  

  


  I've tried many things, but I keep getting errors.

  


• Cannot retrieve native file ffmpeg-amd64.exe

  26 septembre 2016, par Sagor Ahmed

  I am trying to convert video to audio . That is why , I am using the following code :

  File source = new File("E:\\Shunno - Khachar Bhitor Ochin Pakhi.mp4");
  
          File target = new File("E:\\output.mp3");
  
          AudioAttributes audio = new AudioAttributes();
  
      audio.setCodec("libmp3lame");
  
      audio.setBitRate(new Integer(128000));
  
      audio.setChannels(new Integer(2));
  
      audio.setSamplingRate(new Integer(44100));
  
      EncodingAttributes attrs = new EncodingAttributes();
  
      attrs.setFormat("mp3");
  
      attrs.setAudioAttributes(audio);
  
      Encoder encoder = new Encoder();
  
      try
  
      {
  
          encoder.encode(source, target, attrs); 
  
      }
  
      catch (IllegalArgumentException | EncoderException e)
  
      { 
  
      }

  But I am getting the following error :

  Sep 26, 2016 11:28:29 AM it.sauronsoftware.jave.DefaultFFMPEGLocator copyFile
  
  SEVERE: Could not get native library for ffmpeg-amd64.exe
  
  Exception in thread "main" java.lang.RuntimeException: Cannot retrieve native file ffmpeg-amd64.exe
  
      at it.sauronsoftware.jave.DefaultFFMPEGLocator.copyFile(DefaultFFMPEGLocator.java:139)
  
      at it.sauronsoftware.jave.DefaultFFMPEGLocator.<init>(DefaultFFMPEGLocator.java:80)
  
      at it.sauronsoftware.jave.Encoder.<init>(Encoder.java:105)
  
      at Convert.main(Convert.java:29)
  
  </init></init>

  How can I solve this error ? Please help me .