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• How to send continuous stream of frames to server most efficiently

  27 avril 2019, par Duthopi

  I am trying to send frames from a local camera (raspberry pi camera, but could also be my laptop’s webcam) to a Google cloud instance, on which I am running AI processing of the frames.

  I am managing to send frames captured through opencv via http (i.e. tcp ??) and receiving them on a flask server. When the flask server is running locally I can get good fps (50+ fps for image size 640x480), however once I send the frames to a flask app on the google instance the fps drop drastically to 5fps.

  How I currently send frames :

  while True:
  
          frame = vs.read() #Separate thread, using cv2 to get the frame
  
  
  
          ret, jpeg = cv2.imencode('.jpg', frame)
  
          imgdata = jpeg.tobytes()
  
          response = requests.post(
  
              url='http://<ip address="address" of="of" google="google" instance="instance">:<port>',
  
              data= imgdata,
  
              headers={'content-type':'image/jpeg'},
  
              )
  
  </port></ip>

  I see two problems with this :
  1 - using tcp means I am slower than udp protocol, however udp is limited in byte size. Correct me if I am wrong, but it seems very complex to send truncated frames and put them back together on the server..
  2 - Even if I had udp working, there is no compression of frames, so I will never reach an efficient transfer

  I expect the answer to be something like using ffmpeg, but so far I only figured out how to stream frames on a local port with ffmpeg, I do not know if it is possible to send frames to a remote server.

  Any recommendations on the best way forward ?

• recive klv data from a ffmpeg multicast

  5 avril 2019, par diego

  I am trying to get the klv data from a .mpeg.

  I tried this command and it works perfectly :

  ffmpeg -i video.mpg -map data-re -codec copy -f data data.klv

  (This first command has "data-re" which just works on linux, but it is the only way I found to get the .klv I need)

  Now I would like to open two CMD and transfer it by multicast, how could I do this ? i tried many comands like next ones, but I do not get the same .klv

  sender : ffmpeg -i video.mpeg -c copy -f mpegts udp://239.1.1.1:49410

  receiver : ffmpeg -i udp://239.1.1.1:49410 -map 0 -codec copy -f data data.klv

  I am new with ffmpeg and I do not know exactly what I need to change to get exactly whay I get in the first command.

  Thanks

• FFmpeg settings for encoding for 4K UHD Blu-ray Disc

  4 avril 2019, par Matt McManis

  What FFmpeg settings should I use for taking raw video and converting it to x265 for 4K UHD Disc ? This is a 1-Pass example.

  Are there more -x265-params needed ?

  For Audio, will DTS -c:a dca -strict -2 be compatible with 4K discs and palyers ? Also what is the Lossless command for dca ?

  ---

  Here is what I’ve got so far :

  ffmpeg -y 
  
  
  
  -i rawvideo 
  
  
  
  -c:v libx265 
  
  -preset slow -b:v 50M -maxrate 75M -bufsize 75M 
  
  -pix_fmt yuv420p10le 
  
  -r 60 
  
  -vf "scale=3840:-2" 
  
  -profile:v main10 -level 5.1 -sar 1:1 -x265-params "colorprim=bt2020:transfer=bt2020:colormatrix=bt2020" 
  
  -map 0:v:0?
  
  
  
  -c:s mov_text 
  
  -map 0:s? 
  
  
  
  -c:a dca -strict -2 
  
  -b:a 1509k 
  
  -map 0:a? 
  
  
  
  -f mp4 
  
  
  
  -threads 0 
  
  
  
  output.mp4