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• Distorted frame when using rtsp stream from IP with opencv camera in python

  16 avril 2019, par Parth Kumar

  I am getting rtsp stream from IP camera and then passing the stream in opencv for getting frame, but i am getting distorted frame in that.
  But when i am using video file instead of rtsp stream frame is not distorted.

  import cv2
  
   video_capture = cv2.VideoCapture("rtsp://ip_address/onvif1")
  
   while True:
  
     ret, frame = video_capture.read()
  
     cv2.imshow('Video', frame)

  When streaming directly in vlc player and in ffmpeg frame is not distorting.

  

• How to encode a HEVC video from YUV420 Mat data (from a hardware triggered camera) via FFmpeg in Python

  4 juillet 2023, par QuantumRiver

  I am having problems encoding a HEVC video from a series of YUV420 Mat data via FFmpeg.

  


  

  1. I am using python in Ubuntu-20.04 ;

  


  2. I am retrieving frame data from a hardware triggered camera (BASLER), using pypylon ;

  


  3. I want to write a video from that camera in HEVC codec, using my GPU-NVENC ;

  


  4. I guess I have to use FFmpeg to achieve these ;

  


  


  What I have tried :

  


  

  1. I find that FFmpeg supports encoding from a camera, but it seems to only support webcams, not the camera I use (hardware triggered BASLER cameras with pypylon APIs) ;

  


  2. I find that FFmpeg supports transfering a video from one codec to another, which is not my case ;

  


  3. I find that FFmpeg supports encoding a video from a series of jpeg images. But in my case, it will be inefficient if I first save each frame into a picture and then encode them into a video ;

  


  4. The frame data retrieved from camera can be converted to YUV420 (directly from pypylon), which is suitable for HEVC encoding ;

  


  5. I learnt that the basic unit in FFmpeg to encode a video is AVFrame. I guess I have to first turn my YUV420 data into AVFrame, then encode AVFrames into HEVC ;

  


  6. But I do not know how to achieve that in python.

  


  


  My simplified and expected codes :

  


  camera = pylon.InstantCamera(tlf.CreateFirstDevice())
converter = pylon.ImageFormatConverter()
converter.OutputPixelFormat = pylon.PixelType_YUV420
video_handle = xxxxxx  # HEVC
while True:
    grabResult = camera.RetrieveResult(timeout, pylon.TimeoutHandling_ThrowException)
    image = converter.Convert(grabResult).GetArray()
    video_handle.write(frame)  # encode into a hevc video via ffmpeg in NVENC


  


• Connection to Tvt Camera with FFmpeg via RTSP

  29 avril 2014, par Deniz Beker

  I try to connect a TVT camera with FFmpeg via RTSP. However, I cannot obtain stream info by using avformat_find_stream_info() as it is based on POST commands of HTTP. I can only obtain the codec (H.264). I already tried to increase analyze duration & probesize parameters. How can I manually set these parameters ? Or how can I obtain codec parameters ?

  Edit : I can obtain these parameters from a specific port. How can I make FFmpeg to connect via this HTTP port to obtain the metadata ?