Recherche avancée

Sur d’autres sites (5332)

• OpenCV reading from live camera creates a short video that moves quickly

  17 novembre 2022, par user19019404

  I am reading in a live vide stream from a CCTV camera. The camera is set to 5 fps, another is set to 25fps and another to 30fps. Irrespective of the FPS that the camera is set, I can record 5 minutes but end up with a 30 second recorded clip where everyone is running around the scene.

  


  My code is the 'typical' read in video and write video code that you would find online such as (code below simplified for readability) :

  


  import cv2

video = cv2.VideoCapture(live RTSP address of camera)

if (video.isOpened() == False):
    print("Error reading video file")
else:
    frame_width = video.get(cv2.CAP_PROP_FRAME_WIDTH)
    frame_height = video.get(cv2.CAP_PROP_FRAME_HEIGHT)
    frame_fps = video.get(cv2.CAP_PROP_FPS)
    size = (frame_width, frame_height)
    result = cv2.VideoWriter('filename.avi',cv2.VideoWriter_fourcc(*'MJPG'),frame_fps , size)

    while(True):
        ret, frame = video.read()
        if ret == True:
            result.write(frame)
            cv2.imshow('Frame', frame)
        if cv2.waitKey(1) & 0xFF == ord('s'):
            break
        else:
            break
    video.release()
    result.release()
    cv2.destroyAllWindows()
print("The video was successfully saved with new fps")


  


  I have tried playing with the FPS by reading in the FPS from the live camera and using the same FPS in the video write, but all that results is a video that is a fraction of the real time and with people zooming around the scene. So watching a 5 minute smooth video results in a 20 second recorded video with everyone zooming around.

  


  Is this something that I need to fix in the writing of the video or do I need a second pass with ffmpeg to readjust the video ?

  


  Much appreciated

  


  Update, corrected the code above and :
When printing the frames read and the frame written the numbers are the same, showing that each frame that is read is being written (so I am not losing frames along the way thereby writing half the amount of frames).

  


• Webrtc streaming issue with Wowza and FFMPEG

  26 juin 2018, par Diego T

  I am trying to stream video and audio from a Camera in a browser using Webrtc and Wowza Media Server (4.7.3 version).

  The camera stream (h264/aac) is first of all transcoded by using FFMPEG (version N-89681-g2477bfe built with gcc 4.8.5, last available version on ffmpeg website) in VP8/OPUS and then pushed to the Wowza Server.
  By using the small Wowza webpage I ask for the Wowza stream to be displayed in the browser (Chrome Version 66.0.3336.5 Build officiel canary 32 bits).

  FFMPEG used command :

  ffmpeg -rtsp_transport tcp -i rtsp:// -vcodec libvpx -vb 600000 -crf 10 -qmin 0 -qmax 50 -acodec libopus -ab 32000 -ar 48000 -ac 2 -f rtsp rtsp://://test

  When I click on Play stream I have a very bad quality video and audio (jerky video and very bad audio).

  If I use this FFMPEG command :

  ffmpeg -rtsp_transport tcp -i rtsp:// -vcodec libvpx -vb 600000 -crf 10 -qmin 0 -qmax 50 -acodec copy -f rtsp rtsp://://test

  I will have a good video (flowing, smooth) but no audio (the camera micro is ON).

  If libopus is the problem (as this test first shows), I tried libvorbis but with Chrome console I have this error "Failed to set remote offer sdp : Session error code : ERROR_CONTENT". Weird, cause libvorbis is one of the available codecs for Webrtc.

  Is someone experiencing the same issue ? Did someone experience the same issue ?

  Thanks in advance.

• Package Hs-FFmpeg won't compile

  28 décembre 2014, par changeyourstrings

  I guess, I’m another victim of cabal hell.

  I am trying to install the Haskell FFmpeg Bindings via the according cabal query using GHC-7.8.3 on OS X 10.9 :

  cabal install hs-ffmpeg

  After getting all the necessary libraries (like libdc1394, libvorbis,..) and includes usable via pkg-config, I thought I would finally come to compiling the sources.

  The latest Hs-FFmpeg package from Hackage (v.0.3.4) has a upper bound concerning the version of the haskell base lib, demanding a version less than 4.
  I failed in trying to install two separate versions of base using cabal sandboxes.

  Then I read that patching the hs-ffmpeg’s cabal file might work. So I changed the upper bound for base from versions <4 to <5.

  After doing so, the cabal configure works nice and smooth, cause I silenced the base constraint part.

  I found another resource, that says a source patch would be necessary for a working hs-ffmpeg with Ghc 7. The patch seems to change some pointer types in a source file of the packing, nothing really exciting.

  After all that, I am trying to compile again, getting the following type errors :

  cabal install
  
  Resolving dependencies...
  
  Configuring hs-ffmpeg-0.3.4.1...
  
  Building hs-ffmpeg-0.3.4.1...
  
  Failed to install hs-ffmpeg-0.3.4.1
  
  Last 10 lines of the build log ( /Users/helgetur/.cabal/logs/hs-ffmpeg-0.3.4.1.log ):
  
  Codec.hsc:147:20: note: forward declaration of 'enum CodecID'
  
      hsc_type (enum CodecID);
  
                     ^
  
  /Library/Frameworks/GHC.framework/Versions/7.8.3-x86_64/usr/lib/ghc-7.8.3/template-hsc.h:60:10: note: expanded from macro 'hsc_type'
  
      if ((t)(int)(t)1.4 == (t)1.4)                          \

  Maybe one must strictly use the ffmpeg’s demanded base version ? How can I find the problem ?

  I am running out of ideas now, moreover there are almost no similar questions out there.