Convert str to numpy.ndarray

Question

I'm creating a system to share video with opencv but I've got a problem. I've a server and a client but when I send informations to the server, the must be bytes. I send 2 things:

 ret, frame = cap.read()

ret is a booland frame is the data video, a numpy.ndarray ret is not a problem but frame: I convert it in string and then in bytes:

frame = str(frame).encode()
connexion_avec_serveur.send(frame)

I'd like now to convert again frame in a numpy.ndarray.

Why not use frame.tobytes and then np.frombuffer to recover? — Paul Panzer
– Paul Panzer, Commented Dec 26, 2017 at 11:01

Kinght 金 · Accepted Answer · 2017-12-26 14:10:59Z

1

Your str(frame).encode() is wrong. If you print it to terminal, then you will find it is not the data of the frame.

An alternative method is to use tobytes() and frombuffer().

## read
ret, frame = cap.read()
sz = frame.shape

## tobytes 
frame_bytes = frame.tobytes()
print(type(frame_bytes))
# <class 'bytes'>

## frombuffer and reshape 
frame_frombytes = np.frombuffer(frame_bytes, dtype=np.uint8).reshape(sz)
print(type(frame_frombytes))
## <class 'numpy.ndarray'>

## test whether they equal or not 
print(np.array_equal(frame, frame_frombytes))

edited Dec 26, 2017 at 14:10

answered Dec 26, 2017 at 11:12

Kinght 金

18.4k5 gold badges63 silver badges77 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Convert str to numpy.ndarray

1 Answer 1

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related