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• Running FFMPEG from Shell Script /bin/sh

  19 October 2015, by Chris James Champeau

  I am trying to setup a Shell Script to work within an automator watch folder...

  Everything works with the exception of the Run Shell Scrip portion...

  Essentially when a file shows up in the watch folder, it runs the shell scrip which calls FFMPEG and then will move the file to an archive folder for safe keeping. However right now automator is telling me everything worked but now file is being created.

  I have the Shell set to /bin/sh and Pass input set to as arguments

  Here is my script:

  for f in "$@"
  
  do
  
  name=$(basename "$f")
  
  dir=$(dirname "$f")
  
  ffmpeg -i "$f" -b 250k -strict experimental -deinterlace -vcodec h264 -acodec aac "$dir/mp4/${name%.*}.mp4"
  
  echo "$dir/mp4/${name%.*}.mp4"
  
  done

  it does echo the correct filename, but does not actually run ffmpeg

  I have tried adding -exec before it like I have seen in some scripts but still nothing...

• OpenCV is able to read the stream but VLC not

  25 April 2023, by Ahmet Çavdar

  I'm trying to stream my webcam frames to an UDP address. Here is my sender code.

  


  cmd = ['ffmpeg', '-y', '-f', 'rawvideo', '-pixel_format', 'bgr24', '-video_size', f'{width}x{height}', 
       '-i', '-', '-c:v', 'mpeg4','-preset', 'ultrafast', '-tune', 'zerolatency','-b:v', '1.5M',
       '-f', 'mpegts', f'udp://@{ip_address}:{port}']
p = subprocess.Popen(cmd, stdin=subprocess.PIPE)
camera = cv2.VideoCapture(0)
while True:
    ret, frame = camera.read()
    cv2.imshow("Sender",frame)
    if not ret:
        break
    p.stdin.write(frame.tobytes())
    p.stdin.flush()
    if cv2.waitKey(1) & 0xFF == ord('q'):
            break


  


  This Python code can make stream successfully. I can read the stream with this receiver code.

  


  q = queue.Queue()
def receive():
    cap = cv2.VideoCapture('udp://@xxx.x.xxx.xxx:5000')
    ret, frame = cap.read()
    q.put(frame)
    while ret:
        ret, frame = cap.read()
        q.put(frame)
def display():
    while True:
        if q.empty() != True:
            frame = q.get()
            cv2.imshow('Receiver', frame)
        k = cv2.waitKey(1) & 0xff
        if k == 27:  # press 'ESC' to quit
            break
tr = threading.Thread(target=receive, daemon=True)
td = threading.Thread(target=display)
tr.start()
td.start()
td.join()


  


  But I can not watch the stream from VLC. I'm going to Media->Open Network Stream->
udp://@xxx.x.xxx.xxx:5000 to watch stream. After some seconds, the timer that located bottom left of VLC starts to increase but there are no frames in screen, just VLC icon.

  


  I checked firewall rules, opened all ports to UDP connections. I am using my IP address to send frames and watch them.
Also, I tried other video codecs like h264, hvec, mpeg4, rawvideo.
Additionally, I tried to watch stream by using Windows Media Player but it didn't work.

  


  What should I do to fix this issue?

  


• How to extract orientation information from MOV videos created on the iPhone using ffmeg, ruby or objectivec?

  5 October 2014, by Sid

  After surfing through tons of documentation on the web it seems that the iPhone always shoots the video at a 480x360 aspect ratio and applies a transformation matrix on the video track. (480x360 may change but its always the same for a given device)

  Here is a way of modifying the ffmpeg source within a iOS project and accessing the matrix http://www.seqoy.com/correct-orientation-for-iphone-recorded-movies-with-ffmpeg/

  Here is a cleaner way of finding the transformation matrix in iOS-4
  how to detect (iphone sdk) if a video file was recorded in portrait orientation, or landscape

  How can the orientation of the video be extracted in either of the options below -
  
   iOS 3.2
  
   ffmpeg (through the command line server side)
  
   ruby
  

  Any help will be appreciated.