Download video-toolbox.hqx (2,765,111 KB)
From: Denis Pelli
Subject: video-toolbox-00-06-22-c.sit
The VideoToolbox
two hundred C subroutines and several demo and utility programs that I
and others have written to do visual psychophysics with Macintosh
computers. It's fully compatible with 68K 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. Nearly two 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. (1997) The VideoToolbox software for visual psychophysics:
Transforming numbers into movies. Spatial Vision 10:437-442
Denis Pelli, Professor of Psycholoyg and Neural Science at NYU