Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
import subprocess as sp
import numpy as np
import signal
from PIL import Image
### TUKEY WINDOW
# https://leohart.wordpress.com/2006/01/29/hello-world/
def tukey_window(window_length, alpha=0.5):
# Special cases
if alpha <= 0:
return np.ones(window_length) #rectangular window
elif alpha >= 1:
return np.hanning(window_length)
# Normal case
x = np.linspace(0, 1, window_length)
w = np.ones(x.shape)
# first condition 0 <= x < alpha/2
first_condition = x<alpha/2
w[first_condition] = 0.5 * (1 + np.cos(2*np.pi/alpha * (x[first_condition] - alpha/2) ))
# second condition already taken care of
# third condition 1 - alpha / 2 <= x <= 1
third_condition = x>=(1 - alpha/2)
w[third_condition] = 0.5 * (1 + np.cos(2*np.pi/alpha * (x[third_condition] - 1 + alpha/2)))
return w
### END TUKEY WINDOW
# using ffmpeg, slick
# from http://zulko.github.io/blog/2013/09/27/read-and-write-video-frames-in-python-using-ffmpeg/
FFMPEG_BIN = "ffmpeg"
command = [ FFMPEG_BIN,
'-i', 'test.mov',
'-f', 'image2pipe',
'-pix_fmt', 'rgb24',
'-vcodec', 'rawvideo', '-']
cmd = 'ffmpeg -i test.mov -f image2pipe -pix_fmt rgb24 -vcodec rawvideo -'
pipe = sp.Popen(cmd, shell=True, stdout=sp.PIPE, bufsize=10**8)
x_res = 1080
y_res = 1920
fps = 24
duration = 5
num_frames = 100
print "num frames?", num_frames
frames = []
while True:
# x_res*y_res*3 bytes (= 1 frame)
raw_image = pipe.stdout.read(x_res*y_res*3)
if len(raw_image) < x_res*y_res*3:
print "No data!"
break
# transform the byte read into a numpy array
image = np.fromstring(raw_image, dtype='uint8')
image = image.reshape((y_res,x_res,3)) # those dims always backwards, dunno why!
# throw away the data in the pipe's buffer.
frames.append(image)
pipe.stdout.flush()
pipe.send_signal(signal.SIGINT)
print "got frames:", len(frames)
OVERLAP_FACTOR = 0.75
window_factor = 0.75
window_width = 128 # this is really what i'm going to be tuning, based on fps etc.
window_stride = int(window_width * (1-OVERLAP_FACTOR))
print "window width:", window_width
print "window stride:", window_stride
pano_width = len(frames)*window_stride
pano_img = Image.new("RGBA", (pano_width, y_res))
mask_array = np.ndarray(shape=(y_res, window_width), dtype="uint8")
tukey_template = tukey_window(window_width, window_factor) * 255
"""
import matplotlib.pyplot as plot
plot.plot(tukey_template)
axes = plot.gca()
margin = 10
axes.set_xlim([-margin,slice_x+margin])
axes.set_ylim([-margin,255+margin])
plot.show()
"""
for i in xrange(y_res):
mask_array[i, :] = tukey_template
mask = Image.fromarray(mask_array, "L")
for i in xrange(len(frames)):
begin_window_x = i*window_stride
end_window_x = begin_window_x+window_width
if end_window_x > pano_width:
break
frame_slice = Image.fromarray(frames[i][:,x_res/2-window_width/2:x_res/2+window_width/2,:])
pano_img.paste(frame_slice, (i*window_stride, 0), mask=mask)
pano_img.save("test-pano.jpg")
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.