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• Android - 360 video metadata

  11 mai 2017, par Xys

  So with ffmpeg I’ve concatenated two 360 videos into one. The problem is that I lost all the 360 video metadata in the final video (so it’s not recognized as a 360 video anymore). If I use exiftool on the final video, I lack those metadatas :

  • Spherical : true
  • Stitched : true
  • Stitching Software : Spherical Metadata Tool
  • Projection Type : equirectangular

  I’ve tried to inject those metadatas with ffmpeg, like this for example :

  ffmpeg -i  -metadata Spherical="true" -codec copy 

  I don’t get any errors doing that, but exiftool still doesn’t show the metadatas.

  I know Google has a Python script that does this well, here .

  But I would like to inject metadatas in my app as well, any help would be much appreciated,

  thanks !

• Using ffmpeg to remove green screen from video

  27 mai 2024, par CYAD

  I have a video : https://drive.google.com/file/d/1tiP2fX0Xfc6YjIymcHyEXP8-JqEJrlgG/view

  


  I'm trying to use ffmpeg to remove the green screen but none of the commands I use work. I saved a frame as a png and was able to remove the green from it :

  


  ffmpeg -i green.png -vf chromakey=green:0.1 out.png

  


  but the video edit does nothing.

  


  ffmpeg -i video.mp4 -vf chromakey=DarkGreen:similarity=0.2:blend=0.3 output4.mov

  


  I'm on a windows machine and need to output a format iOS and Android can use, though multiple formats are fine. Any thoughts ?

  


• 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 ?