[Numpy-discussion] Reading 12bits numbers ?

Nadav Horesh nadavh@visionsense....
Tue Jun 8 07:28:16 CDT 2010


You can. If each number occupies 2 bytes (16 bits) it is straight forward. If it is a continues 12 bits stream you have to unpack by your self:
data = np.fromstring(str12bits, dtype=np.uint8)
data1 = data.astype(no.uint16)
data1[::3] = data1[::3]*256 + data1[1::3] // 16
data1[1::3] = (data[1::3] & 0x0f)*16 + data[2::3]

If you have even number of 12 bits you can continue as the follows:

result = np.ravel(data1.reshape(-1,3)[:,:2])

I might have mistakes, but I hope you grasped the idea.

  Nadav



-----Original Message-----
From: numpy-discussion-bounces@scipy.org on behalf of Martin Raspaud
Sent: Tue 08-Jun-10 15:04
To: Discussion of Numerical Python
Subject: [Numpy-discussion] Reading 12bits numbers ?
 
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Hi,

Is it possible to read an array of 12bit encoded numbers from file (or string)
using numpy ?



Thanks,
Martin
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