Demo/sgi/video/README

This directory contains Python and C code for video stuff.

History:

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.

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
library to Python (sv) and Guido wrote makemovie.py (based upon a
still frame grabber by Sjoerd) to record a movie using it.

	--Guido, Jack and Sjoerd


cam.py		network real-time tv broadcast; see tv.py
		usage: cam [packfactor [host]]
		specifying 'all' for host broadcasts

camcorder.py	record video movies or make snapshots (in movie format)
		usage: camcorder [-c] [-a audiohost [-s]] [-p pf] [moviefile]
		-c		color (equivalent to -p 0)
		-a audiohost	syncaudio is running on audiohost
		-s		start syncaudio (on audiohost)
		-p packfactor	packfactor (default 2; 0 records color)
		moviefile	(default film.video)
		keyboard commands:
		s	stop grabbing (single step if already stopped)
		c	continuous grabbing
		r	start recording
		p	pause recording (record single frame if paused)
		ESC	quit

colorsys.py	color conversions, used by video

makemovie.py	record video movies using the Indigo video library and
		board

statit.py	various statistics operations on movie files

syncaudio.py	record audio synchronized with camcorder -a
		usage: syncaudio videohost soundfile
		soundfile format: 16 bits/sample, 16000 samples/sec, 1 channel
		(actually, you'd better set the sampling rate to 16000
		with the audio panel)

tv.py		receiver for transmissions from cam.py

vcopy.py	selectively write frames from one movie file to another
		usage: vcopy infile outfile
		commands: 'n' gets next frame; 'w' writes current frame

video.py	player for movies recorded by camcorder.py
		usage: video [-l] [-p pf] [-m mag] [-F]
					[moviefile [soundfile [skipbytes]]]
		-p pf		override packfactor (to zoom)
		-l		looping -- restart movie when done
		-m mag		magnification
		-F		run at max speed
		moviefile	default is film.video
		soundfile	default is none (no sound)
		skipbytes	byte offset in soundfile where sound starts

Vplay.py	same but 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

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.

squash.c	make a movie smaller by averaging pixels
		usage: squash factor [bits] <moviefile >newmoviefile
		factor		x and y compression factor
		bits		#bits left per sample in result (default 8)

squash2.c	make a movie smaller by dropping pixels
		usage: squash2 factor <moviefile >newmoviefile
		factor		x and y compression factor

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