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• Trim (remove frames from) live video from webcam using python

  10 septembre 2020, par Muhammad Usman

  I have a webcam that captures video stream. After 30 seconds I want to remove 1 sec of the video from the start and keep capturing the video stream and so on. In short, I only want to save the latest 30 seconds of the live video.

  


  OpenCV does not provide video processing

  


  ffmpeg trims the video but creates a new output file, I don't want to keep copies.

  


  #Create a video write before entering the loop
#Create a video write before entering the loop
video_writer = cv2.VideoWriter(
    video_file, video_codec, fps, (int(cap.get(3)), int(cap.get(4)))
)

#video_file is the file being saved

start = time.time()
i=0
seconds='1'
while cap.isOpened():


    ret, frame = cap.read()
    if ret == True:
        cv2.imshow("frame", frame)
        if time.time() - start > 10:
            print('video > 10 sec')
        
            subprocess.call(['ffmpeg', '-i', video_file, '-ss', seconds, 'output.avi'])
            break

    # Write the frame to the current video writer
    video_writer.write(frame)
    if i%24 == 0:
        cv2.imwrite('image'+str(i)+'.jpg',frame)
    i+=1
    if cv2.waitKey(1) & 0xFF == ord("q"):
        break
else:
    break
cap.release()
cv2.destroyAllWindows()


  


  What I am looking for is how we can trip a live video and keep saving future frames so that the video don't exceed 30 seconds and keeps the latest frames.

  


• ffmpeg NVENC Encoding with -flags:v +ildct shows "No NVENC capable devices found"

  29 mai 2020, par gaamaa

  So far I use NVENC with ffmpeg for all my encoding successfully. Today I got a new Zotac nVidia GEForce GTX 1660 6GB card.

  



  I get "No NVENC capable devices found" error from ffmpeg. Only if I use -flags:v +ildct flag. Without ildct flag no issues except the output is progressive.

  



  I 100% need Interlaced output and I tried most of the Interlaced flags like, -vf tinterlace=interleave_top,fieldorder=tff -x264opts tff=1 Nothing is giving me Interlaced output except -flags +ildct But with "Zotac nVidia GEForce GTX 1660" ffmpeg shows :

  



  No NVENC capable devices found


  



  I even tried all latest nVidia drivers. Nothing helped me.

  



  My pseudo ffmpeg command line is as below :

  



  ffmpeg -i SourceFile.mkv -codec:v h264_nvenc -preset:v slow -flags:v +ildct+cgop -s:v 1920x1080 -ac 2 -ar 48000 -codec:a mp2 -b:a 384k -r 25 -f mp4 -y NewFile.mp4


  



  Is it a bug with nVidia driver or ffmpeg ? Is latest nVidia Turing technology doesn't support Interlaced (very Bad) ?

  



  Could some one help me ?

  


• ffmpeg not working after update to Mavericks

  24 février 2024, par Hudson Buddy

  After recently updating to Mavericks 10.9.5, my installation of ffmpeg has been bugging out

  



  Error :

  



  dyld: Library not loaded: /usr/local/lib/libx264.142.dylib
  Referenced from: /usr/local/bin/ffmpeg
  Reason: image not found
Trace/BPT trap: 5


  



  Any thoughts ? I'm not very familar with manual compiling and I installed ffmpeg through Homebrew.

  



  I tried uninstalling and doing :

  



  brew install ffmpeg --HEAD
brew install ffmpeg --build-from-source


  



  but it spits back a ./configure error

  



  ==> ./configure --prefix=/usr/local/Cellar/ffmpeg/2.4.2 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-nonfree --enable-hardcoded-tables --enable-avresample
If you think configure made a mistake, make sure you are using the latest
version from Git.  If the latest version fails, report the problem to the
ffmpeg-user@ffmpeg.org mailing list or IRC #ffmpeg on irc.freenode.net.
Include the log file "config.log" produced by configure as this will help
solve the problem.

READ THIS: https://github.com/Homebrew/homebrew/wiki/troubleshooting

These open issues may also help:
gpac 0.5.0 doesn't build against ffmpeg 2.4.1 (https://github.com/Homebrew/homebrew/issues/32978)