diff --git a/Demo/sgi/video/cam.py b/Demo/sgi/video/cam.py
index f30e1e0..fa8966f 100755
--- a/Demo/sgi/video/cam.py
+++ b/Demo/sgi/video/cam.py
@@ -23,7 +23,7 @@
 
 if sys.argv[2:]:
 	HOST = sys.argv[2]
-	if HOST = 'all':
+	if HOST == 'all':
 		HOST = '<broadcast>'
 		MAX = 1400
 
@@ -47,7 +47,7 @@
 	readsource(SRC_FRAMEGRABBER)
 
 	s = socket(AF_INET, SOCK_DGRAM)
-	if HOST = '<broadcast>':
+	if HOST == '<broadcast>':
 		s.allowbroadcast(1)
 	addr = HOST, PORT
 
@@ -72,7 +72,7 @@
 	while 1:
 		while qtest():
 			dev, val = qread()
-			if dev = REDRAW:
+			if dev == REDRAW:
 				reshapeviewport()
 				w, h = getsize()
 				ortho2(0, w, 0, h)
@@ -93,7 +93,7 @@
 
 				fps = 0
 
-			elif dev = ESCKEY:
+			elif dev == ESCKEY:
 				winclose(wid)
 				return
 
diff --git a/Demo/sgi/video/camcorder.py b/Demo/sgi/video/camcorder.py
index 528ff29..9b7618c 100755
--- a/Demo/sgi/video/camcorder.py
+++ b/Demo/sgi/video/camcorder.py
@@ -93,7 +93,7 @@
     	f.write('CMIF video 1.0\n')
 	f.write(`w,h,pf` + '\n')
 	print 'width,height,pf:', w, h, pf,
-	if pf = 0: pf = 4
+	if pf == 0: pf = 4
 	print '(i.e.,', w*h*pf, 'bytes/frame)'
 
 def main():
@@ -103,14 +103,14 @@
     austart = 0
     optlist, args = getopt.getopt(sys.argv[1:],'ca:sp:')
     for opt, arg in optlist:
-	if opt = '-c':
+	if opt == '-c':
 	    pf = 0
-	elif opt = '-a':
+	elif opt == '-a':
 	    ausync = 1
 	    aumachine = arg
-	elif opt = '-s':
+	elif opt == '-s':
 	    austart = 1
-	elif opt = '-p':
+	elif opt == '-p':
 	    pf = int(eval(arg))
 	else:
 	    usage()
@@ -184,13 +184,13 @@
 	    if qtest() or \
 	    not (mousing or inrunning or insingle or outrunning or outsingle):
 		ev, val = qread()
-		if ev = LEFTMOUSE and val = 1:
+		if ev == LEFTMOUSE and val == 1:
 		    drawframe(x,y,w,h,0)
 		    mousing = 1
 		    ox, oy = getorigin()
 		    x = getvaluator(MOUSEX)-ox
 		    y = getvaluator(MOUSEY)-oy
-		elif ev = LEFTMOUSE and val = 0:
+		elif ev == LEFTMOUSE and val == 0:
 		    if h < 0:
 		    	y, h = y+h, -h
 		    if w < 0:
@@ -200,7 +200,7 @@
 		    	wrheader(f, w, h, pf)
 			sizewritten = 1
 			prealloc(w, h)
-		elif ev = RKEY and val = 1:
+		elif ev == RKEY and val == 1:
 		    if not inrunning:
 			ringbell()
 		    else:
@@ -211,7 +211,7 @@
 			starttime = time.millitimer()
 			if ausync:
 			    ctl.sendto(`(1,starttime)`, aua)
-		elif ev = PKEY and val = 1 and outrunning:
+		elif ev == PKEY and val == 1 and outrunning:
 		    outrunning = 0
 		    stoptime = time.millitimer()
 		    if ausync:
@@ -222,11 +222,11 @@
 		    print 'Saving...'
 		    saveframes(f, w, h, pf)
 		    print 'Done.'
-		elif ev = PKEY and val = 1 and not outrunning:
+		elif ev == PKEY and val == 1 and not outrunning:
 			outsingle = 1
-		elif ev = CKEY and val = 1:
+		elif ev == CKEY and val == 1:
 			inrunning = 1
-		elif ev = SKEY and val = 1:
+		elif ev == SKEY and val == 1:
 			if outrunning:
 			    ringbell()
 			elif inrunning:
@@ -237,7 +237,7 @@
 		    if ausync:
 			ctl.sendto(`(2,time.millitimer())`, aua)
 		    raise stop
-		elif ev = REDRAW:
+		elif ev == REDRAW:
 			drawframe(x,y,w,h,0)
 			reshapeviewport()
 			drawframe(x,y,w,h,1)
diff --git a/Demo/sgi/video/colorsys.py b/Demo/sgi/video/colorsys.py
index 6735b35..dd3a033 100755
--- a/Demo/sgi/video/colorsys.py
+++ b/Demo/sgi/video/colorsys.py
@@ -96,11 +96,11 @@
     q = v*(1.0-s*f)
     t = v*(1.0-s*(1.0-f))
     if i in (0,6): return v,t,p
-    if i = 1: return q,v,p
-    if i = 2: return p,v,t
-    if i = 3: return p,q,v
-    if i = 4: return t,p,v
-    if i = 5: return v,p,q
+    if i == 1: return q,v,p
+    if i == 2: return p,v,t
+    if i == 3: return p,q,v
+    if i == 4: return t,p,v
+    if i == 5: return v,p,q
     print i, h, f
     print h, s, v
     raise 'Bad color'
diff --git a/Demo/sgi/video/statit.py b/Demo/sgi/video/statit.py
index 360e49e..b0c1782 100755
--- a/Demo/sgi/video/statit.py
+++ b/Demo/sgi/video/statit.py
@@ -94,7 +94,7 @@
 	i, n = 1, len(bytes)
 	while i < n:
 		for pack in (0, 2, 4, 8):
-			if pack = 0:
+			if pack == 0:
 				lo, hi = 0, 0
 			else:
 				hi = pow(2, pack-1)-1
diff --git a/Demo/sgi/video/syncaudio.py b/Demo/sgi/video/syncaudio.py
index 742a433..fd09d28 100755
--- a/Demo/sgi/video/syncaudio.py
+++ b/Demo/sgi/video/syncaudio.py
@@ -70,8 +70,8 @@
     # buffer. Discard all buffered data upto his starttime
     #
     startstop,histime = eval(ctl.recv(100))
-    if (ofile = None and startstop = 0) or \
-			   (ofile <> None and startstop = 1):
+    if (ofile == None and startstop == 0) or \
+			   (ofile <> None and startstop == 1):
 	print 'Sync error: saving=',save,' request=',startstop
 	sys.exit(1)
     filllevel = inp.getfilled()
@@ -89,6 +89,6 @@
     print 'Time: ', time.millitimer()-starttime, ', Bytes: ', totbytes, ', Samples: ', totsamps
     if ofile <> None:
 	ofile.write(data)
-    return (startstop = 2)
+    return (startstop == 2)
 
 main()
diff --git a/Demo/sgi/video/tv.py b/Demo/sgi/video/tv.py
index 621740c..da4bacb 100755
--- a/Demo/sgi/video/tv.py
+++ b/Demo/sgi/video/tv.py
@@ -44,10 +44,10 @@
 	while 1:
 		if qtest():
 			dev, val = qread()
-			if dev = ESCKEY:
+			if dev == ESCKEY:
 				winclose(wid)
 				return
-			elif dev = REDRAW:
+			elif dev == REDRAW:
 				oldw, oldh = reshape()
 		elif s.avail():
 			data = s.recv(17000)
diff --git a/Demo/sgi/video/vcopy.py b/Demo/sgi/video/vcopy.py
index a492073..3afe119 100755
--- a/Demo/sgi/video/vcopy.py
+++ b/Demo/sgi/video/vcopy.py
@@ -7,10 +7,10 @@
 
 def loadframe(f, w, h, pf):
 	line = f.readline()
-	if not line or line = '\n':
+	if not line or line == '\n':
 		raise EOFError
 	x = eval(line[:-1])
-	if type(x) = type(0):
+	if type(x) == type(0):
 		if pf: size = w*h*4
 		else: size = w*h*pf
 	else:
@@ -47,10 +47,10 @@
 	ofp = open(ofile, 'w')
 	#
 	line = ifp.readline()
-	if line[:4] = 'CMIF':
+	if line[:4] == 'CMIF':
 		line = ifp.readline()
 	x = eval(line[:-1])
-	if len(x) = 3:
+	if len(x) == 3:
 		w, h, pf = x
 	else:
 		w, h = x
@@ -82,11 +82,11 @@
 		dev, val = qread()
 		if dev in (ESCKEY, WINQUIT, WINSHUT):
 			break
-		if dev = REDRAW:
+		if dev == REDRAW:
 			reshapeviewport()
-		elif dev = KEYBD:
+		elif dev == KEYBD:
 			c = chr(val)
-			if c = 'n':
+			if c == 'n':
 				try:
 					time, data = loadframe(ifp, w, h, pf)
 					iframe = iframe+1
@@ -94,13 +94,13 @@
 				except EOFError:
 					print 'EOF'
 					ringbell()
-			elif c = 'w':
+			elif c == 'w':
 				ofp.write(`time, len(data)` + '\n')
 				ofp.write(data)
 				print 'Frame', iframe, 'written.'
 			else:
 				print 'Character', `c`, 'ignored'
-		elif dev = INPUTCHANGE:
+		elif dev == INPUTCHANGE:
 			pass
 		else:
 			print '(dev, val) =', (dev, val)
diff --git a/Demo/sgi/video/video.py b/Demo/sgi/video/video.py
index da2d2c7..cf994a3 100755
--- a/Demo/sgi/video/video.py
+++ b/Demo/sgi/video/video.py
@@ -31,26 +31,26 @@
         sys.exit(1)
     line = f.readline()
     if not line: raise EndOfFile
-    if line[:4] = 'CMIF':
-	if line[:14] = 'CMIF video 2.0':
+    if line[:4] == 'CMIF':
+	if line[:14] == 'CMIF video 2.0':
 	    line = f.readline()
 	    colorinfo = eval(line[:-1])
 	else:
 	    colorinfo = (8,0,0,0)
 	line = f.readline()
     x = eval(line[:-1])
-    if len(x) = 3: w, h, pf = x
+    if len(x) == 3: w, h, pf = x
     else: w, h = x; pf = 2
     return f, w, h, pf, colorinfo
 
 def loadframe(f,w,h,pf,af,spkr, (ybits,ibits,qbits,chrompack),mf):
     line = f.readline()
-    if line = '':
+    if line == '':
 	raise EndOfFile
     x = eval(line[:-1])
-    if type(x) = type(0) or type(x) = type(0.0):
+    if type(x) == type(0) or type(x) == type(0.0):
     	tijd = x
-    	if pf = 0:
+    	if pf == 0:
     		size = w*h*4
     	else:
     		size = (w/pf) * (h/pf)
@@ -98,10 +98,10 @@
     for y in range(maxy):
       yv = float(y)/float(maxy-1)
       for i in range(maxi):
-      	if maxi = 1: iv = 0
+      	if maxi == 1: iv = 0
 	else: iv = (float(i)/float(maxi-1))-0.5
 	for q in range(maxq):
-	  if maxq = 1: qv = 0
+	  if maxq == 1: qv = 0
 	  else: qv = (float(q)/float(maxq-1))-0.5
 	  index = 2048 + y + (i << ybits) + (q << (ybits+ibits))
 	  rv,gv,bv = colorsys.yiq_to_rgb(yv,iv,qv)
@@ -125,13 +125,13 @@
 	'[-l] [-p pf] [-m mag] [-F] [moviefile [soundfile [skipbytes]]]\n')
 		sys.exit(2)
 	for opt, arg in opts:
-		if opt = '-m':
+		if opt == '-m':
 			magfactor = int(eval(arg))
-		elif opt = '-p':
+		elif opt == '-p':
 			packfactor = int(eval(arg))
-		elif opt = '-l':
+		elif opt == '-l':
 			looping = 1
-		elif opt = '-F':
+		elif opt == '-F':
 			epoch.correcttiming = 0
 	if args:
 		filename = args[0]
@@ -206,7 +206,7 @@
 		    dev, val = qread()
 		    if dev in (ESCKEY, WINSHUT, WINQUIT):
 			raise bye
-		    elif dev = REDRAW:
+		    elif dev == REDRAW:
 		    	reshapeviewport()
 	except bye:
 	    pass
diff --git a/Demo/sgi/video/vinfo.py b/Demo/sgi/video/vinfo.py
index e230c4f..6f8b543 100755
--- a/Demo/sgi/video/vinfo.py
+++ b/Demo/sgi/video/vinfo.py
@@ -14,20 +14,20 @@
     f = open(filename, 'r')
     line = f.readline()
     if not line: raise EndOfFile
-    if line[:4] = 'CMIF': line = f.readline()
+    if line[:4] == 'CMIF': line = f.readline()
     x = eval(line[:-1])
-    if len(x) = 3: w, h, pf = x
+    if len(x) == 3: w, h, pf = x
     else: w, h = x; pf = 2
     return f, w, h, pf
 
 def loadframe(f, w, h, pf):
     line = f.readline()
-    if line = '':
+    if line == '':
 	raise EndOfFile
     x = eval(line[:-1])
-    if type(x) = type(0) or type(x) = type(0.0):
+    if type(x) == type(0) or type(x) == type(0.0):
     	tijd = x
-    	if pf = 0:
+    	if pf == 0:
     		size = w*h*4
     	else:
     		size = (w/pf) * (h/pf)
@@ -47,8 +47,8 @@
 	delta = 0
 	opts, names = getopt.getopt(sys.argv[1:], 'd')
 	for opt, arg in opts:
-		if opt = '-d': delta = 1
-	if names = []:
+		if opt == '-d': delta = 1
+	if names == []:
 		names = ['film.video']
 	for name in names:
 	    try:
@@ -67,7 +67,7 @@
 			else: print '\t', tijd,
 			otijd = tijd
 			num = num + 1
-			if num % 8 = 0:
+			if num % 8 == 0:
 				print
 		    except EndOfFile:
 			raise bye
diff --git a/Demo/sgi/video/vtime.py b/Demo/sgi/video/vtime.py
index 00d821e..c333e57 100755
--- a/Demo/sgi/video/vtime.py
+++ b/Demo/sgi/video/vtime.py
@@ -59,7 +59,7 @@
 			    print 'Someone else syncing to us: ', other
 			    raise bad_connect
 			data = eval(data)
-			if data[:2] = (loopct+1,curtijd):
+			if data[:2] == (loopct+1,curtijd):
 			    break
 			if data[0] <> 2:
 			    print 'Illegal sync reply: ', data
@@ -83,7 +83,7 @@
 		if data[0] in (0,2):
 		    curtijd = time.millitimer()
 		    s.sendto(`(data[0]+1,data[1],curtijd)`,raddr)
-		elif data[0] = 4:
+		elif data[0] == 4:
 		    newtijd = time.millitimer()
 		    histime = data[1]
 		    mytime = timeavg(curtijd,newtijd)