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• Obtaining frames from IP Camera with low latency

  5 février 2023, par Russ1337

  I am currently using this command to get frames from my RTSP stream and reading frames from stdout :

  


  ffmpeg -nostdin -rtsp_transport tcp -i  -pix_fmt bgr24 -an -vcodec rawvideo -f rawvideo -


  


  However, I would like to get the same latency as when I see it via ffplay :

  


  ffplay -fflags nobuffer -flags low_delay -tune zerolatency -framedrop -rtsp_transport tcp 


  


  or when I play it via VLC Media > Open Network Stream with :network_caching=300ms.

  


  I would like to know what other parameters I can use with my ffmpeg command to get an equivalent (or better) result compared to the ffplay command.

  


  I have made references from : How to dump raw RTSP stream to file ?, Open CV RTSP camera buffer lag, How to pipe output from ffmpeg using python ?, bad ffmpeg performace compared to ffplay and VLC, How to minimize the delay in a live streaming with ffmpeg

  


  My current implmentation :

  


  FFMPEG_CMD = "ffmpeg -nostdin -rtsp_transport tcp -i  -pix_fmt bgr24 -an -vcodec rawvideo -f rawvideo -".split(" ")&#xA;WIDTH = 2560&#xA;HEIGHT = 1440&#xA;&#xA;process = subprocess.Popen(FFMPEG_CMD, stdout=subprocess.PIPE, stderr=subprocess.DEVNULL)&#xA;&#xA;while True:&#xA;    raw_frame = process.stdout.read(WIDTH*HEIGHT*3)&#xA;    frame = np.frombuffer(raw_frame, np.uint8) &#xA;    frame = frame.reshape((HEIGHT, WIDTH, 3))&#xA;&#xA;    <do stuff="stuff" with="with" frame="frame"></do> show frame etc.>&#xA;

  


  Thanks for reading.

  


  ---

  


  ffmpeg command I am now using for < 1s latency.

  &#xA;

  ffmpeg -nostdin -flags low_delay -rtsp_transport tcp -i  -pix_fmt bgr24 -an -vcodec rawvideo -f rawvideo -


  &#xA;

  ---

  &#xA;

  Implementation with suggestion(s) from Answers :

  &#xA;

  import subprocess&#xA;import numpy as np&#xA;&#xA;FFMPEG_CMD = "ffmpeg -nostdin -flags low_delay -rtsp_transport tcp -i  -pix_fmt bgr24 -an -vcodec rawvideo -f rawvideo -".split(" ")&#xA;WIDTH = 2560&#xA;HEIGHT = 1440&#xA;&#xA;process = subprocess.Popen(FFMPEG_CMD, stdout=subprocess.PIPE, stderr=subprocess.DEVNULL)&#xA;&#xA;raw_frame = np.empty((HEIGHT, WIDTH, 3), np.uint8) &#xA;frame_bytes = memoryview(raw_frame).cast("B")&#xA;&#xA;while process.poll() is None:&#xA;    process.stdout.readinto(frame_bytes)&#xA;    frame = raw_frame.reshape((HEIGHT, WIDTH, 3))&#xA;&#xA;    <do stuff="stuff" with="with" frame="frame"></do> show frame etc.>&#xA;

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• avformat/avisynth : fix fallbacks for four frameprops

  27 février 2022, par Stephen Hutchinson

  avformat/avisynth : fix fallbacks for four frameprops
  If _FieldBased, _Matrix, _ColorRange, or _ChromaLocation haven't
  
  been set, that absence would be interpreted as 0, leading to those
  
  being set to case 0 instead of default. There is no case 0 for
  
  _Primaries and _Transfer, so those were correctly falling back
  
  to the default case.
  Signed-off-by : Stephen Hutchinson <qyot27@gmail.com>
  

  • [DH] libavformat/avisynth.c

• avformat/avisynth : remove unused variable 'frameprop'

  19 février 2022, par Stephen Hutchinson

  avformat/avisynth : remove unused variable 'frameprop'
  Since the check got simplified and stdbool was no longer necessary
  
  to include, neither is that variable.  Silences a warning.
  Signed-off-by : Stephen Hutchinson <qyot27@gmail.com>
  

  • [DH] libavformat/avisynth.c