Minor improvements, comments; fix Vinfo -d.

Demo/sgi/video/README

-This directory contains Python and C code for video stuff.
+CMIF video tools
+================
 
-History:
+This directory contains Python and C programs to manipulate files
+containing digitized video in the "CMIF video format".
 
-We started this in October 1991, when we had a large framegrabber
-board on loan from SGI for a few weeks.
 
-Later, when we started processing the recorded film fragments, the
-"CMIF video format" was revised several times, and we finally created
-an object-oriented interface for reading and writing various
-incarnations of these files, called VFile.
+History
+-------
 
-When we finally got our own Indigo entry-level video board (in June
-1992) and a version of the Irix video library that supported capturing
-PAL format (August 1992) Sjoerd added an interface to the video
+We started this in October 1991, when we had a large framegrabber
+board on loan from SGI for a few weeks: we developed a movie recording
+program (camcorder.py) and added numerous features, including still
+frame capture and synchronous sound recording using a second machine
+(the machine holding the framegrabber board didn't have audio).
+
+During the following months, when we started using and processing the
+recorded film fragments, the "CMIF video format" was revised several
+times, and we eventually created an object-oriented interface for
+reading and writing various incarnations of these files, called VFile.
+(This module is also used by our flagship application, the CMIF
+editor, not in this directory but in /ufs/guido/mm/.)
+
+When we got our own Indigo entry-level video board (in June 1992) and
+a version of the Irix video library that supported capturing PAL
+format (in August 1992), Sjoerd added an interface to the video
 library to Python (sv) and Guido wrote makemovie.py (based upon a
-still frame grabber by Sjoerd) to record a movie using it.
+still frame grabber by Sjoerd, in turn based upon SGI demo code in C)
+to record a movie using it.
 
-	--Guido, Jack and Sjoerd
+	Guido van Rossum
+	Jack Jansen
+	Sjoerd Mullender
 
 
+Overview of files
+-----------------
+
 cam.py		network real-time tv broadcast; see tv.py
 		usage: cam [packfactor [host]]
 		specifying 'all' for host broadcasts
@@ -67,21 +84,21 @@ video.py	player for movies recorded by camcorder.py
 		soundfile	default is none (no sound)
 		skipbytes	byte offset in soundfile where sound starts
 
-Vplay.py	same but using VFile.py
+Vplay.py	similar but more modern, using VFile.py
 
 vinfo.py	print summary of movie file(s)
 		usage: vinfo [-d] moviefile ...
 		-d		print delta times (default: print abs times)
 
-Vinfo.py	same but using VFile.py
+Vinfo.py	similar but more modern, using VFile.py
 
 vpregs.py	definition of VP registers
 
 vtime.py	virtual time module imported by syncaudio.py and camcorder.py
 
 
-These are C programs, either for efficiency or because they need to
-link with a C library.
+The following are C programs, either for efficiency or because they
+need to link with a C library:
 
 squash.c	make a movie smaller by averaging pixels
 		usage: squash factor [bits] <moviefile >newmoviefile
@@ -96,3 +113,6 @@ tomono.c	like squash2 but outputs a monochrome movie
 
 v2i.c		convert the first frame of a movie file to SGI .rgb format
 		link with -limage
+
+i2v.c		convert an rgb file to "lrectwrite" format (this was
+		used one time by the CMIF editor)

Demo/sgi/video/VFile.py

@@ -33,8 +33,9 @@ def conv_rgb8(rgb,d1,d2):
 # init(filename)
 # initfp(fp, filename)
 # rewind()
-# getframe()
-# skipframe()
+# getnextframe()
+# skipnextframe()
+# (and many more)
 #
 # The following read-only data members provide public information:
 # version

Demo/sgi/video/Vinfo.py

@@ -26,19 +26,19 @@ import getopt
 
 short = 0
 quick = 0
-diffs = 0
+delta = 0
 
 
 # Main program -- mostly command line parsing
 
 def main():
-	global short, quick, diffs
+	global short, quick, delta
 	opts, args = getopt.getopt(sys.argv[1:], 'dqs')
 	for opt, arg in opts:
 		if opt == '-q':
 			quick = 1
 		elif opt == '-d':
-			diffs = 1
+			delta = 1
 		elif opt == '-s':
 			short = 1
 	if not args:
@@ -50,7 +50,17 @@ def main():
 # Process one file
 
 def process(filename):
-	vin = VFile.VinFile().init(filename)
+	try:
+		vin = VFile.VinFile().init(filename)
+	except IOError, msg:
+		sys.stderr.write(filename + ': I/O error: ' + `msg` + '\n')
+		return
+	except VFile.Error, msg:
+		sys.stderr.write(msg + '\n')
+		return
+	except EOFError:
+		sys.stderr.write(filename + ': EOF in video file\n')
+		return
 	print 'File:    ', filename
 	print 'Version: ', vin.version
 	print 'Size:    ', vin.width, 'x', vin.height
@@ -62,7 +72,10 @@ def process(filename):
 		vin.close()
 		return
 	if not short:
-		print 'Frame times:',
+		if delta:
+			print 'Frame time deltas:',
+		else:
+			print 'Frame times:',
 	n = 0
 	t = 0
 	told = 0

Demo/sgi/video/makemovie.py

+#! /ufs/guido/bin/sgi/python
 #! /ufs/guido/src/video/py
-# XXX for now, you need this special version of Python
 
 # Capture a CMIF movie using the Indigo video library and board