dear hoover & CVNet
there's now a VideoToolbox web site:
http://rajsky.psych.nyu.edu/VideoToolbox/
it has a new, June '96, release of the software.
there are now 190 VideoToolbox subscribers, who are notified by email of
software updates. Let me know if you want to join or quit the list.
best
denis
Denis Pelli
Psychology Dept.
NYU
ps. (I will be out of town 6/18-6/23; any server problems will await my
return.)
ABOUT THE VIDEOTOOLBOX
The VideoToolbox is a collection of two hundred C subroutines and several
demo
and utility programs that I and others have written to do visual
psychophysics
with Macintosh computers. It is fully compatible with 680x0 and PowerPC
Macs
and with Metrowerks CodeWarrior and Symantec C compilers. It's free and
may
not be sold without permission. It should be useful to anyone who wants to
present accurately specified visual stimuli or use the Mac for
psychometric
experiments. The "Video synch" page discusses all the ways of
synchronizing
programs to video displays and the many pitfalls to avoid. The TimeVideo
application checks out the timing of all video devices in anticipation of
their
use in critical real-time applications, e.g. movies or lookup table
animation.
"Video synch" reports all known bugs uncovered by TimeVideo's testing of
56
video cards and drivers. Low-level routines control video timing and
lookup
tables, display real-time movies, and implement the luminance-control
algorithms suggested by Pelli and Zhang (1991). In particular,
CopyWindows (or
CopyBitsQuickly) faithfully copies between on-screen and off-screen
windows
(or bit/pixmaps), WindowToEPS saves an image to disk as encapsulated
PostScript, for later printing or incorporation into a document, and
SetEntriesQuickly and GDSetEntries load the screen's color lookup table,
all
without any of QuickDraw's color translations. NoisePdfFill.c quickly
generates
visual noise images whose pixels are samples from a specified probability
density function. High-level routines help analyze psychophysical
experiments
(e.g. maximum-likelihood fitting and graphing of psychometric data).
Assign.c
is a runtime C interpreter for C assignment statements, which is useful
for
controlling experiments and sharing calibration data. This collection has
been
continually updated since 1991. More that one hundred colleagues
subscribe to
the email distribution (see below), and have indicated that they are
using the
software in their labs. Documentation is in the source files themselves.
Many
of the routines are Mac-specific, but some very useful routines, e.g. the
luminance-control, statistics, maximum-likelihood fitting algorithms, and
the
runtime interpreter are written in Standard C and will work on any
computer.
Those wishing to acknowledge use of the VideoToolbox software might cite:
Pelli, D. G. and Zhang, L. (1991) Accurate control of contrast on
microcomputer
displays. Vision Research, 31, 1337-1350. Reprints are available.