CODEWITHSUNDEEP
pythonopencvvideocolors
Gulzar
Gulzar

Reputation: 27956

How to know how many color channels in cv2 VideoCapture object?

I have the following method:

def _create_capture_object(self):
    self._cap = cv2.VideoCapture(self._path_to_video)
    self._width = self._cap.get(cv2.CAP_PROP_FRAME_WIDTH)
    self._height = self._cap.get(cv2.CAP_PROP_FRAME_HEIGHT)
    self._frame_rate = self._cap.get(cv2.CAP_PROP_FPS)
    self._frame_count = self._cap.get(cv2.CAP_PROP_FRAME_COUNT)
    self._n_channels = self._cap.get(cv2.CAP_PROP_CHANNEL)

Everything works as expected, except 

    self._n_channels = self._cap.get(cv2.CAP_PROP_CHANNEL)

Which always returns 0.0

How can I get 1 in case of a gray-scale video, or 3 in case of a color video?

Upvotes: 0

Views: 1748

Answers (1)

Meto
Meto

Reputation: 658

cv2.CAP_PROP_CHANNEL attribute seems to

return 0 when querying a property that is not supported by the backend used by the VideoWriter instance.

Quoted from up to date documentation of opencv 4.3.

I believe the only way you can get the channel value is by capturing a frame then retriving the shape information of it.

EDIT #1: Thanks to @Dan Mašek I updated my answer corresponding to new documentation.

Upvotes: 3

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