116 lines
2.1 KiB
Python
116 lines
2.1 KiB
Python
|
import sys
|
||
|
|
from time import millitimer
|
||
|
|
|
||
|
|
def main():
|
||
|
|
filename = 'film2.video'
|
||
|
|
if sys.argv[1:]: filename = sys.argv[1]
|
||
|
|
f = open(filename, 'r')
|
||
|
|
|
||
|
|
line = f.readline()
|
||
|
|
w, h = eval(line[:-1])
|
||
|
|
w2, h2 = w/2, h/2
|
||
|
|
size = w2 * h2
|
||
|
|
|
||
|
|
data = data2 = t = t0 = t1 = None
|
||
|
|
nframes = 0
|
||
|
|
t0 = millitimer()
|
||
|
|
while 1:
|
||
|
|
line = f.readline()
|
||
|
|
if not line: break
|
||
|
|
t = eval(line[:-1])
|
||
|
|
data = None
|
||
|
|
data = f.read(size)
|
||
|
|
if len(data) <> size:
|
||
|
|
raise EOFError
|
||
|
|
dostat(w2, h2, data)
|
||
|
|
nframes = nframes+1
|
||
|
|
t1 = millitimer()
|
||
|
|
|
||
|
|
t = 0.001 * (t1-t0)
|
||
|
|
fps = 0.1 * int(10*nframes/t)
|
||
|
|
print nframes, 'frames in', t, 'sec. =', fps, 'frames/sec.'
|
||
|
|
|
||
|
|
def dostat(w, h, data):
|
||
|
|
print
|
||
|
|
stat3(w, h, data)
|
||
|
|
|
||
|
|
# Statistic op 1: frequencies of byte values
|
||
|
|
def stat1(w, h, data):
|
||
|
|
bins = [0]*256
|
||
|
|
for c in data:
|
||
|
|
i = ord(c)
|
||
|
|
bins[i] = bins[i]+1
|
||
|
|
prbins(bins)
|
||
|
|
|
||
|
|
def prbins(bins):
|
||
|
|
import string
|
||
|
|
s = ''
|
||
|
|
tot = 0
|
||
|
|
for i in range(256):
|
||
|
|
tot = tot + bins[i]
|
||
|
|
s = s + string.rjust(`bins[i]`, 4)
|
||
|
|
if len(s) >= 4*16:
|
||
|
|
print s, string.rjust(`tot`, 7)
|
||
|
|
s = ''
|
||
|
|
tot = 0
|
||
|
|
|
||
|
|
# Statistic op 2: run lengths
|
||
|
|
def stat2(w, h, data):
|
||
|
|
runs = []
|
||
|
|
for y in range(h):
|
||
|
|
count, value = 0, ord(data[y*w])
|
||
|
|
for c in data[y*w : y*w+w]:
|
||
|
|
i = ord(c)
|
||
|
|
if i <> value:
|
||
|
|
runs.append(count, value)
|
||
|
|
count, value = 0, i
|
||
|
|
count = count+1
|
||
|
|
runs.append(count, value)
|
||
|
|
print len(runs), 'runs =', 0.1 * (10*w*h/len(runs)), 'bytes/run'
|
||
|
|
|
||
|
|
# Statistic op 3: frequencies of byte differences
|
||
|
|
def stat3(w, h, data):
|
||
|
|
bins = [0]*256
|
||
|
|
prev = 0
|
||
|
|
for c in data:
|
||
|
|
i = ord(c)
|
||
|
|
delta = divmod(i-prev, 256)[1]
|
||
|
|
prev = i
|
||
|
|
bins[delta] = bins[delta]+1
|
||
|
|
prbins(bins)
|
||
|
|
|
||
|
|
# Try packing
|
||
|
|
def packblock(w, h, data):
|
||
|
|
res = ''
|
||
|
|
for y in range(h):
|
||
|
|
res = res + packline(data[y*w : y*w+w])
|
||
|
|
return res
|
||
|
|
|
||
|
|
def packline(line):
|
||
|
|
bytes = []
|
||
|
|
for c in line:
|
||
|
|
bytes.append(ord(c))
|
||
|
|
prev = bytes[0]
|
||
|
|
i, n = 1, len(bytes)
|
||
|
|
while i < n:
|
||
|
|
for pack in (0, 2, 4, 8):
|
||
|
|
if pack = 0:
|
||
|
|
lo, hi = 0, 0
|
||
|
|
else:
|
||
|
|
hi = pow(2, pack-1)-1
|
||
|
|
lo = -hi-1
|
||
|
|
p = prev
|
||
|
|
j = i
|
||
|
|
count = 0
|
||
|
|
while j < n:
|
||
|
|
x = bytes[j]
|
||
|
|
delta = byte(x-p)
|
||
|
|
if not lo <= delta <= hi:
|
||
|
|
break
|
||
|
|
p = x
|
||
|
|
j = j+1
|
||
|
|
|
||
|
|
def byte(x): return divmod(x, 256)[1]
|
||
|
|
|
||
|
|
main()
|