gstTestCV3.py

# copied from https://gist.github.com/jampekka/ec4a3f3a3748fd2a281d/

import numpy as np

import gi
import sys
sys.path.insert(1, '/usr/local/lib/python2.7/site-packages')
import cv2
print cv2.__version__

gi.require_version('Gst', '1.0')
from gi.repository import GObject, Gst


def gst_to_opencv(gst_buffer):
    return np.ndarray((480,640,3), buffer=gst_buffer.extract_dup(0, gst_buffer.get_size()), dtype=np.uint8)

Gst.init(None)

pipe = Gst.parse_launch("""v4l2src device=/dev/video1 ! video/x-raw, width=640, height=480,format=(string)BGR ! appsink sync=false max-buffers=2 drop=true name=sink emit-signals=true""")
#pipe2 = Gst.parse_launch("""v4l2src device=/dev/video2 ! video/x-raw, width=640, height=480,format=(string)BGR ! appsink sync=false max-buffers=2 drop=true name=sink emit-signals=true""")#

sink = pipe.get_by_name('sink')
#sink2 = pipe2.get_by_name('sink')
pipe.set_state(Gst.State.PLAYING)
#pipe2.set_state(Gst.State.PLAYING)

while True:
    sample = sink.emit('pull-sample')
    #   sample2 = sink2.emit('pull-sample')
    img = gst_to_opencv(sample.get_buffer())
    blk = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
    edges = cv2.Canny(blk,100,200)
    edges = cv2.cvtColor(edges, cv2.COLOR_GRAY2BGR)
    #  img2 = gst_to_opencv(sample2.get_buffer())
    cv2.imshow('frame',img)
    cv2.imshow('edges',edges)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

cv2.destroyAllWindows()