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• How can i obtain raw frames with out writing them to disk using ffmpeg ?

  12 décembre 2018, par Abhijeet

  I have to use ffmpeg to detect shot change in a video, for which i need to monitor and each and every frame and save only the required ones. Writing all 30 frames to disk and then choosing takes a lot of time and is impractical, is there a way to get the decoded frames in a raw form before saving them to the disk ?

• How can I create a video from a list of JPEG files ?

  5 mars 2014, par Maged E William

  I did search and all I got is Windows Media Encoder Series 9 and I am not sure if DirectX can also do it, but I can't find any way to learn it. I even tried this tutorial but I can' t run the application, it gives me a bug (I did install Windows Media Encoder Series 9 and the SDK).

  My application is now running JPEG files in a PictureBox with a timer, but the size of one minute is about 20 MB and that is not good. I need to save the whole day every day !

  I found this software, it uses Windows Media Encoder and the video of one minute is about 1 MB which is great, now I know it's possible to record the desktop to a video file but how can I do it ? I need a step by step explanation or videos to teach me.

• running ffmpeg from Popen inside (twisted) timer.LoopingCall() stalls

  14 février 2014, par user1913115

  I have an RTSP stream which i need to re-stream as HLS. When RTSP stream goes down (e.g. camera disconnects) I put a blue screen to let the user know that the camera went offline. HLS segmenter is running separately, listening on port 22200 for incoming packets.

  in python the code essentially boils down to this :

  import psutil, subprocess as sb
  
  from twisted.internet import reactor, task
  
  from cameraControls import camStatus, camURL
  
  ffOn = False
  
  psRef = False
  
  def monitor():
  
   print "TIMER TICK"
  
   if camStatus()=='ON' and not ffOn: #camera just came online
  
    cmd = ["ffmpeg", "-i", camURL, "-codec", "copy", "-f", "mpegts", "udp://127.0.0.1:22200"]
  
    ps = sb.Popen(cmd,stderr=sb.PIPE)
  
    psRef=ps
  
   #check the stream:
  
   psmon = psutil.Process(psRef.pid)
  
   if psmon.status!=psutil.STATUS_RUNNING: 
  
    print "FFMPEG STOPPED"
  
  
  
  tmr = task.LoopingCall(monitor)
  
  tmr.start(2)
  
  reactor.run()

  it works fine for 5-6 minutes, then i see the video stall and if i check the cpu usage of the ffmpeg it shows 0, the ffmpeg output doesn't change, as if paused. however psmon.status shows as running, and the timer is still going (i see "TIMER TICK" message pop up every 2 seconds in the command line.

  if i simply run the ffmpeg command from the command line (not from python) then it works for hours no problem.

  does anybody know if the twisted reactor is stalling the process ? or is it the subprocess.Popen itself issue ? or the timer itself is glitching somehow(even though it gets to the 'monitor' function) ? i have other timers running also in the same reactor (same thread), could that be an issue ?