Read a named pipe in opencv

asked 2017-07-07 03:49:20 -0500

Hi, I'm following this video guide (I'm using the last option presented in the video): https://www.youtube.com/watch?v=sYGdg...

Essentially my raspberry send a video stream with netcat, then a script on my pc receives this stream and redirects it in a pipe. I tried to access the pipe with this:

VideoCapture cap("path to pipe");

it works, but requires minutes of waiting. Is there a way to drastically reduce this waiting time?

Alternatively, I found a code (posted below) in openCV that works fine, but it's in python and I need it in C++ for my project. Is there a way to reach the same result in C++?

Thank you everybody.

import cv2
import subprocess as sp
import numpy

FFMPEG_BIN = "/home/gaspare/ffmpeg_sources/ffmpeg/ffmpeg"
command = [ FFMPEG_BIN,
    '-i', 'fifo264',             # fifo is the named pipe
    '-pix_fmt', 'bgr24',      # opencv requires bgr24 pixel format.
    '-vcodec', 'rawvideo',
    '-an','-sn',              # we want to disable audio processing (there is no audio)
    '-f', 'image2pipe', '-']    
    pipe = sp.Popen(command, stdout = sp.PIPE, bufsize=10**8)

    while True:
# Capture frame-by-frame
raw_image = pipe.stdout.read(1280*720*3)
# transform the byte read into a numpy array
image =  numpy.fromstring(raw_image, dtype='uint8')
image = image.reshape((720,1280,3))          # Notice how height is specified first and then width
if image is not None:
    cv2.imshow('Video', image)

if cv2.waitKey(1) & 0xFF == ord('q'):
    break
pipe.stdout.flush()

cv2.destroyAllWindows()
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