Automated stereo synthesizer for audiovisual programs

Automated stereo synthesizer for audiovisual programs
UIllted States Patent [19]
[11] Patent Number:
Chace
[45]
[54]
Date of Patent:
AUTOMATED STEREO SYNTHESIZER FOR
4,593,324
AUDIOVISUAL PROGRAMS
4,706,287 11/1987
[76] Inventor:
Frederic I. Chace, 1746 N. Courtney,
Los Angeles, Calif_ 90046
507
Dec. 20, 1988
1/ 1986 Efron et a1. ................ .. 358/341
Blackmer et a]. ................... .. 381/17
Prima'? Examiner'forester
Isa“
_
Attorney, Agent, or Fzrm—Fulw1der, Patton, R1eber,
Lee 8: Utecht
[21] Appl. No.. 89,
[22] Elm’
4,792,974
[57]
Aug’ 26’ 1987
ABSTRACT
Surround stereo signals are synthesized from the com
[51]
Int. Cl.‘ .............................................. .. H048 1/00
posite or DME monaural sound tracks of audiovisual
[52]
US. Cl. ...................................... .. 381/ 1; 358/341;
programs by use of multi-channel, computer-controlled
[58]
358/343; 360/ 19.1; 369/87; 381/17
digital circuitry and operator-programmed sound cues,
Field of Search ..................... .. 358/341, 342, 343;
the latter matching video time codes with audio control
[56]
360/ 19.1, 14.1; 369/ 87, 89, 92; 381/1, l7, l8
signals. The stereo signals have out-of-phase delay com
_
ponents, resulting in compatibility with conventional
References Clted
U.S. PATENT DOCUMENTS
monaural audio equipment, and steerable pan compo
nents, resulting in selective sound placement capacility.
3 217 080 11/1965 Clark JR I
Variable time delays and variable ratios of dry and
3:670:106 6/1972 Orbar; _
delay are used in conjunction with panning movements
4,067,049
l/1978 Kelly et a1. ...................... .. 360/14.1
to achieve a Wide variety Of acoustical effects, Such as
4,188,504 2/1980 Kasuga et a1. .
4,329,544 5/1982 Yamada ............................... .. 381/86
resonance, spread and cutting, which correlate the
audio portion of the program with the video portion of
4,388,654 6/1983 Mehrotra .......................... .. 358/343
the program. An operator selects and programs sound
4,394,536 7/ 1933 Shima at al- '
cues and stores them for playback by using a plurality of
4399329 8/1983 wh'fmon """"" "
4’433’347 2/1984 Suglyama et a1‘
4,489,439
12/1984
Scholze et al.
358/341
“ 358/342
. ..... .
. . . ..
4,503,471 3/1985 Hanajima et a1‘ _
4,523,236 6/1985 HayaShi et a1‘
4,564,867
l/l986 Nakajima ........ ..
audio controls and a computer interface which are pro
vided on an operator console Subroutines are used for
381/63
.
360/65
358/341
'
.
.
automated cue recording and for editing. Stereo sound
tracks are created from monaural source material.
358/343
4,583,132 4/1986 Nakano et al.
.. 358/341
41 Claims, 4 Drawing Sheets
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Delay-type synthesizers also had a tendency to pro
duce an echo in the audio program when the synthe
sizer channels were mixed together This could be a
AUTOMATED STEREO SYNTHESIZER FOR
AUDIOVISUAL PROGRAMS
problem in applications such as television broadcasting
5 and home video where it is often desirable to restore the
BACKGROUND OF THE INVENTION
original monaural signal for playback through the mon
This invention relates generally to stereo synthesizers
aural sound system of a conventional television re
and, more particularly, has reference to a new and im
ceiver.
Stereo synthesizers and other types of devices which
proved method and apparatus for converting the mon
aural audio tracks of audiovisual programs into sur
round stereo signal which are mono-compatible and
steerable and which are synchronized with the video
portion of the program.
In early movies and television programs, all of the
sound elements in the audio portion of the program (i.e.,
dialogue, music and effects) were combined into a com
posite monaural signal which was recorded onto a sin
alter audio signals have been known for a number of
years, and by way of example, several forms of such
devices can be found in U.S. Pat. Nos. 4,489,439 (Scholz
15
et al.), 3,670,106 (Orban), 4,188,504 (Kasuga et al.),
4,394,536 (Schima et al.), 3,217,080 (Clark) and
4,329,544 (Yamada).
was scanned by a reader which recovered the compos
There was recently a proposal for a new type of
television sound system in which mono dialogue, mono
music and panned effects were used to simulate a stereo
ite monaural signal and fed the signal into the input of a
monaural sound system.
Later ?lms, taking advantage of magnetic tape re
sound ?eld where it belongs, but the system operated
gle optical sound track. On playback, the optical track
cording techniques, used magnetic sound tracks. These
tracks often had less surface noise (e. g., clicks and pops)
and less distortion than optical tracks, but they gener
ally continued to employ a composite monaural signal
which was designed to be played through a monaural
sound system.
sound. The system had some steering compatibility, i.e.,
the ability to move a sound around and place it in the
with a multitrack audio source having separate monau
ral tracks for dialogue, music and effects. This “DME”
source created problems of compatibility with the great
numbers of audio programs which used a composite
sound track. Moreover, the system left considerable
room for improvement in creating convincing stereo
like sound which the ear would perceive.
An audiovisual program with a monaural sound track
tends to lack realism. The sound remains stationary 30 When a stereo synthesizer is used with an audiovisual
program, it is obviously desirable to produce a stereo
despite the fact that the sound elements may be moving
sound which is well synchronized with the video pro
around in the visual ?eld. Stereo sound is generally
gram. The sound elements should change and move
regarded as more realistic and more pleasing to the ear
throughout the sound ?eld as the corresponding visual
because the sound can be moved around and placed in
the sound ?eld where it appears in the video picture. 35 elements change and move throughout the video ?eld.
For example, the sound of a siren can be moved from
left-to-right in the sound ?eld as a police car speeds
across the screen.
It would be highly desirable to produce movies and
Existing systems have not been entirely satisfactory in
this respect. Passive stereo synthesizers derive sound
?elds from monaural audio signals which contain little
or no video information. Certain active stereo synthe
other audiovisual programs with true stereo sound
sizers have accepted user input of video information but
tracks. Unfortunately, many early attempts to record
stereo movies were not entirely satisfactory. The micro
they operated manually. The user had to turn dials or
the like to effect changes in the audio signals while the
phone array used for recording was often heavy and
video program was being run in real time. With such a
caused shadows. Post-production and dialogue replace
system, it was dif?cult to accurately synchronize the
ment was often difficult. The process tended to be ex 45 audio signal with the video program, particularly where
pensive and there were certain technical dif?culties in
producing consistent stereo scene-to-scene.
The continuing desire for stereo sound led to the
development of so-called stereo synthesizers. These
devices were passive “boxes” which received the out
put from a monaural audio source and purported to
convert the composite monaura signal into a pseudo
stereo signal.
Conventional synthesizers fell into three general cate
the video program required rapid or complex changes
in the sounds.
Accordingly, a need exists for a stereo synthesizer
which can produce a steerable surround stereo signal
from a composite or separate monaural sound tracks
used in audiovisual programs, which can automatically
maneuver the sound signal left-to-right or front-to-back
in the sound ?eld in a manner which is well-synchro
nized with the movement of the corresponding visual
gories. The ?rst used a comb ?lter to separate the mon 55 elements in the program, and which can restore the
aural signal into alternating frequency bands and then
placed the alternate bands into respective left and right
channels. The second category used a time delay in
which the monaural signal was separated into two chan
nels with one of the channels being delayed by some 60
time period. The third category combined a time delay
and a comb ?lter.
These types of stereo synthesizers produced a station
ary sound ?eld in which the monaural sound was simply
program’s original monaural signal for broadcast or
playback through a conventional monaural sound sys
tem. The present invention ful?lls all of these needs.
SUMMARY OF THE INVENTION
Brie?y, and in general terms, the present invention
provides a new and improved method and apparatus for
creating a mono-compatible and steerable surround
stereo signal from a single track or multiple track mon
spread out in some ?xed manner. The listener became 65 aural audiovisual program by using computer-con
accustomed to this ?xed ?eld and did not perceive any
trolled digital circuitry, video time codes and operator
of the left-to-right or front-to-back movement of a
sound which is characteristic of a stereo system.
programmed sound cues. The result is realistic post-pro
duction stereo sound which is well synchronized with
3
4,792,974
4
the video program and which obviates the expense and
technical dif?culties of stereo recording.
In a presently preferred embodiment, by way of ex
POT RECORDING function is used to record a real
time pot movement exactly as it was done. A SOFT
KEY function is used to cause a prerecorded pot setting
ample and not necessarily by way of limitation, the
to be put into memory as a cue. An EDIT function
monaural signal from the audio track is fed into a com
puter-controlled audio processing unit where it is di
vided into three substantially identical monaural signals.
Two of the signals are processed similarly by digital
delay circuitry which adds a variable time delay to the
signal and by level control circuitry which varies the
amplitude of the delayed signal which is mixed with the
allows cues to be changed or deleted after they have
been stored in memory and also allows new cues to be
inserted directly into memory.
In the playback mode, the audiovisual program is run
in real time and the sound cues stored in memory are
automatically recalled when a time code match is
achieved. This time code automation process causes the
undelayed or “dry” monaural signal. The third signal is
processed by pan and pan width control circuitry which
uses voltage-controlled ampli?ers to produce pan left
and pan right signals. The delay signals and the pan
dance with the sequence of recalled sound cues. The
signals are combined with a mono summation signal in
a combining matrix circuit. The matrix output includes
ator are thss recreated in real time in a manner which is
left channel and right channel stereo output signals with
synchronized with the video program. The sound fol
encoded surround information.
The audio processing unit has three separate channels
lows the picture so that wherever a sound source ap
pears on the screen, the corresponding sound can be
for separately processing the dialogue track, the music
located there in the sound ?eld. The result is realistic
computer to produce a series of output control voltages
which regulate the audio processing circuits in accor
acoustical effects which were programmed by the oper
track and the effects track of a multitrack DME source.
stereo sound from a composite or multitrack monaural
In the case of a single track source, the monaural signal
is fed into the dialogue channel (which is then conve
audio source.
Additional ?exibility is provided by a WILD AD
niently called the composite mono channel) and the 25 JUST function which can be used to intercept a control
other two channels are not used. The mono summation
signal fed into the combining matrix is a summation of
the separate channel inputs.
Sound cues which are used to create the stereo output
voltage dictated by a recalled cue and to substitute a
new voltage dictated by the present manual setting of a
pot. In other words, WILD ADJUST can be used over
ride the programmed acoustical effects and substitute
signals are programmed into the memory of the pro 30
new acoustical effects which are dictated by the real
cessing unit computer by an operator who sits at a con
time pot settings.
sole and steps through the video program. The console
In addition to creating a conventional left/right ste
has a keyboard which is used to give commands to
reo
signal, the present invention is also capable of con
computer programs and subroutines which are stored in
verting a monaural audio signal into an encoded four
the computer. The console also has a plurality of dials
channel center and surround signal which is compatible
(called “pots”) which manually operate potentiometers
with the Dolby Surround playback equipment fre
that control the delay, level, pan and pan width circuits
quently found in theaters and consumer electronics
in the audio processing unit.
products. When the delay pots and level pots are set to
The delay pots affect the resonance of the sound. The
level pots affect the width or spread of the sound ?eld 40 produce long or intense delays and the resulting stereo
and the pan pots move the sound left and right in the
signal is fed into a standard Dolby decoder, the sound
sound ?eld. By turning individual pots or groups of pots
tends to be directed into the surround channel. This
in a prescribed manner, the operator can achieve a wide
feature can be used to provide full stereo and surround
for monaural programs which are released in theatres,
steering of the sound elements left-to-right or front-to 45 home video and broadcast media.
back in the sound ?eld, even with a composite monaural
The stereo signals produced by the present invention
source.
are also mono compatible. The combining matrix causes
The operator adjusts the pots until he obtains the
the delay signals which are added to the left channel to
acoustical effects which best match the sound to the
be 180° out-of-phase with the delay signals which are
scene under observation. For example, he can cause the
added to the right channel. When the two channels are
dialogue from a stationary actor to remain center screen
mixed back together as would happen in television
while the siren behind him moves left-to-right. When
variety of acoustical effects, including the selective
the appropriate pot settings are found, the operator
commands the computer to store the settings in memory
along with codes which identify the corresponding
video frames. In the preferred embodiment of the inven
tion, the code is the well-known SMPTE time code
broadcasting or home video, the delay signals cancel
each other out and the original mono signal is restored.
After the sound cues have been entered, the present
invention can be used as a playback system to provide
stereo sound from a monaural audiovisual program or it
can be used as a post-production technique to create a
recorded stereo sound track from a monaural program.
which is used with certain types of audiovisual source
material such as video cassette tapes. The SMPTE sys
tem assigns a separate code number to each video frame 60 Hence, the present invention is used to enhance an exist
to indicate the sequential position of the frame and the
ing monaural program by providing it with stereo
sound without the high cost and technical difficulties
associated with recording in stereo.
These and other objects and advantages of the inven
fashion by use of certain subroutine functions pro 65 tion will become apparent from the following more
grammed into the computer. A DYNAMIC function is
detailed description, when taken in conjunction with
used to automatically perform a linear move between
the accompanying drawings of illustrative embodi
time when the frame appears on the screen.
The sound cues can be recorded manually on a frame
by-frame basis or they can be recorded in an automated
the instant cue and a previous cue. A CONTINUOUS
ments.
5
4,792,974
DESCRIPTION OF THE DRAWINGS
FIG. 1 is an overall block diagram of an automated
stereo synthesizer embodying features of present inven
tion;
FIG. 2 is an electrical schematic diagram of one chan
nel in an audio processing unit suitable for use in the
synthesizer of FIG. 1;
FIG. 3 is an electrical schematic diagram of a com
bining matrix suitable for use in the synthesizer of FIG.
1; and
FIG. 4 is a functional block diagram for a cue control
processing system utilized by the synthesizer of FIG. 1.
DETAILED DESCRIPTION OF THE
PREFERRED EMBODIMENTS
As shown in the drawings for purposes of illustration,
the invention is embodied in an operator-programmed,
computer-controlled audio processing unit which pro
duces surround stereo signals from the monaural audio
track of an audiovisual program. The overall layout and
operation of the equipment used for a preferred embodi
6
The monaural audio signal produced by the VCR 10
is fed into the input of an audio processing unit. In
accordance with the present invention, the audio pro
cessing unit acts in concert with the system computer
16, the video time codes and the operator-programmed
sound cues to create mono-compatible and steerable
surround stereo signals from the monaural audio source
which are well synchronized with the video program. >
The result is enhanced audio quality for the monaural
audio program and a reduction in the expense and tech
nicl dif?culties associated with creating a stereo sound
track.
The preferred audio processing unit has three sub
stantially similar audio processing channels. For conve
nience, only one of these channels 18 is shown in FIG.
1.
For a composite monaural sound track, the audio
signal from the VCR 10 is fed into only one of the audio
processing channels (e.g., Audio Channel No. 1) which
20 is then conveniently referred to as the composite mono
channel. For a DME sound track, all three audio pro
cessing channels are used. The dialogue signal from the
VCR 10 is fed into one of the channels (e.g., Audio
ment of the invention is best understood by reference to
Channel No. 1) which is then conveniently called the
FIGS. 1-3.
25 dialogue channel. The effects signal and the music sig
nal are separately fed into the remaining two channels
A. Preferred Apparatus
Referring to FIG. 1, a conventional two channel,
VITC-compatible, video cassette deck (“VCR”) 10 is
(e.g., Audio Channels No. 2 and Audio Channel No. 3)
which are then conveniently referred to as the effects
When dealing with theater ?lm and other audiovisual
channel and the music channel, respectively.
Each audio processing channel 18 splits its respective
input signal into three branches 20, 22 and 24. One of
the branches 20 is processed by delay circuitry 26 and
level control circuitry 28. The delay circuits 26 add a
variable time delay to the signal while the level control
circuitry 28 varies the amplitude of the delayed signal.
source material which are originated in a non-VCR
The delay adds resonance to the sound. The amplitude
format, the audio and video programs are ?rst laid back
onto a working tape which typically is a video cassette
in a VCR format with SMPTE time code. A single
of the delay controls the spaciousness or spread of the
sound, i.e., it acoustically expands the sound to a wider
used to play a selected audiovisual program which has
a monaural sound track. The VCR 10 preferably has a
shuttle control which can be used to step through the
video program one frame at a time. A suitable VCR is
the JVC model CR850U.
audio channel of the working cassette is usually suf?
?eld when it is increased and contracts the sound into a
narrower ?eld when it is decreased. This control over
cient for a composite monaural sound track. For a
DME sound track which normally uses both audio
the spaciousness of the sound is achieved because the
delayed signals are ultimately combined with the origi
channels in the working cassette, the audio program is
nal or “dry” signals. The level control circuitry 26 thus
?rst conformed onto a multitrack audio tape matching
regulates the amplitude ratio of dry and delay signals
the video The conformed DME track is then laid back 45 which are mixed together.
onto the working cassette by placing the dialogue track
Another branch 22 of the audio processing channel
onto one channel, the effects track onto the other chan
18 also processes the input signal by delay circuitry 30
nel, and the music track on both channels out-of-phase
and level control circuitry 32. Thes circuits are substan
tially similar in structure and function to the ones used
with each other and at about 10 db below its mono
level.
A conventional television monitor 12 receives the
in the aforementioned delay branch 20, the primary
difference residing in the length of the time delay which
video signals from the VCR 10 and displays the video
is added to the signal. For the dialogue and the effects
program on the monitor display screen (not shown).
channels (in the case of a DME source), one of the delay
The video time code is also displayed in a code display
circuits 26 preferably introduces a short duration delay
region 14 of the monitor screen. A suitable monitor is 55 which is selectively variable between about 2-8 ms. The
the Profeel video monitor manufactured by Sony.
other delay circuit 30 preferably introduces a medium
The working cassette is played by the VCR 10 in
duration delay which is selectively variable between
order to program the sound cues. The exact nature of
about 8-32 ms. The delay circuits for the music channel
these sound cues and of the programming process will
introduce ?xed delays of medium duration (preferably
be described in detail later in this speci?cation. Suf?ce 60 about 16 ms) and long duration (preferably about 64
it to say at this stage that the sound cues are a series of
commands which are selected and programmed into a
ms), respectively. The composite mono channel prefer
ably-uses a short duration delay which is selectively
variable between about 2~8 ms and a long duration
system computer 16 by an operator who watches the
delay which is selectively variable between about
video program being displayed on the monitor 12. The
preferred computer is the Apple II GS. These sound 65 32-128 ms.
The remaining branch 24 of the audio processing
cues are used during a playback mode of operation to
channel 18 is processed by pan and pan width control
alter the signals which are produced by a monaural
circuitry 34 and 36. Pan control 34 is used to selectively
sound track and thus create stereo sound signals.
7
4,792,974
8
adjust the left and right placement of the sound in the
The Model VCA 505 manufactured by Aphex is an
sound ?eld. Pan width control 36 is used to selectively
adjust the width of the pans, i.e., the maximum range of
left and right panning movement.
The processed signals from each of the three
branches 20, 22 and 24 of each audio processing channel
example of an ampli?er which is suitable for use as the
master gain ampli?er 52 or for use as any of the other
ampli?ers which are used in the audio processing unit.
The output of the master gain ampli?er 52 feeds a ?rst
line 54 which contributes the channel input signal to the
18 are combined and mixed together with a mono sum
mono summation signal 38. It also feeds a second line 56
mation signal 38 in a combining matrix 40. The mono
which passes the channel input signal to the three
branches 20, 22 and 24 of the audio processing channel
18. By selectively varying the gains of the master gain
summation signal 38 is formed by summing together all
of the respective input signals which are fed into the
,. . 0
three channels of the audio processing unit. In the case
ampli?ers 52 in each of the audio channels 18, the re
of a composite monaural source, the mono summation
spective channel input signals for dialogue, music and
effects can be mixed together in varying proportions to
form the mono summation signal 38. The gains of the
master gain ampli?ers 52 are controlled by channel
master control voltages 58 which are supplied by the
system computer 16.
The delay circuits 26 and 30 are provided by a pair of
signal is identical to the input signal which is fed into
the composite mono channel. The mixing which takes
place. in the combining matrix 40 produces left channel
and right stereo output signals 42 and 44 which are
mono compatible. In a preferred embodiment of the
invention, the combining matrix 40 is provided with a
5
mono test switch (not shown) which can be used to
voltage-controlled time line digital delay units 59 and
selectively combine the left and right channels 42 and 20 60, such as the model PCM 41 manufactured by Lexi
44 for periodically checking the integrity of the recon
con, which are arranged to receive the input signals
stituted mono signal and for test and alignment pur
applied to the respective delay branches 20 and 22 of
poses.
the audio processing channel 18. The delay units 59 and
The stereo output signals 42 and 44 produced by the
60 are provided with range switches (not shown) which
combining matrix 40 are capable of carrying Dolby 25 are used to manually set the range of delay which can be
Surround information. Hence, in a preferred embodi
produced by the unit. Selection of a speci?c duration of
ment of the invention, the stereo signals 42 and 44 are
delay within the set range is accomplished by varying
fed into the input of a conventinnal Dolby Surround
delay time control voltages 62 and 64 which are applied
decoder (not shown), such as the Fosgate 360'’ Space
to the respective units 59 and 60. The control voltages
Matix, which is set up to drive center and surround
for the delay units are 59 and 60 are supplied by the
speakers (not shown). When the delay circuits 26 and 30
computer 16.
and level control circuits 28 and 32 are set to produce
long or intense delays, the Dolby four-channel surround
information which is encoded onto the stereo signals 42
and 44 tends to cause the sound to be directed into the
surround channel. In an alternative embodiment of the
invention, the stereo signals 42 and 44 are fed directly
The level control circuits 28 and 32 are provided by
a pair of voltage-controlled ampli?ers 66 and 68 which
are arranged in series with the respective delay units 59
and 60 to receive the output signals therefrom. Delay
amplitude control voltages 70 and 72 which regulate the
gains of the level control ampli?ers 66 and 68 are sup
into the input of a conventional stereo amplifier (not
plied by the computer 16. The outputs of the level con
shown) which drives conventional stereo speakers (not
trol ampli?ers 66 and 68 are fed over respective channel
shown). A conventional stereo headphone amplifer 46 40 output lines 71 and 73 to provide delay signals to the
is built into the combining matrix 40 and is used to drive
combining matrix 40.
conventional stereo headphones (not shown) which
The pan and pan width control circuits 34 and 36 are
may be worn by the operator to monitor the stereo
provided by a pair of voltage-controlled ampli?ers 74
signals 42 and 44.
and 76 which are arranged to receive the input signals
In a preferred embodiment of the invention, the ste 45 applied to the pan branch 24 of the audio processing
reo signals 42 and 44 are also applied to the input of a
channel 18. The gains of these ampli?ers 74 and 76 are
conventional XY oscilloscope (not shown), such as the
regulated by respective pan left and pan right control
Kenwood CS 1575A. The left channel signal 42 is pref
voltages 78 and 80 which are supplied by the computer
erably applied to the vertical de?ection input of the
16. The output of one of the ampli?ers 74 is fed over a
oscilloscope while the right channel signal 44 is prefera
channel output line 81 to provide pan left signals to the
bly applied to the horizontal deflection input of the
combining matrix 40, while the output of the other
oscilloscope. The scope thus provides a two-dimen
ampli?er 76 is fed over another channel output line 82
sional visual image of the contour and placement of the
to provide pan right signals to the combining matrix 40.
stereo sound. This can be useful to the operator when he
Pan left is accomplished by increasing the pan right
is selecting and adjusting the sound cues.
55 control voltage 80 to decrease the gain of the pan right
The preferred embodiment of the invention also in
ampli?er 76. Pan right is accomplished in an opposite
cludes a 400 Hz test oscillator 48 which is built into the
manner, i.e., by increasing the pan left control voltage
combining matrix 40. The oscillator can be selectively
activated to produce a +4 dbm test signal on both the
left and right channel stereo outputs 42 and 44.
78 to decrease the gain of the pan left ampli?er 74. Pan
Details of the circuitry for the audio processing chan
width is adjusted by making simultaneous and substan
tially identical adjustments in both of the pan control
voltages 78 and 80. A simultaneous increase in the pan
control voltages 78 and 80 decreases the ratio of pan
signals mixed with mono summation signals in the com
Referring to FIG. 2, which illustrates circuitry for
bining matrix 40 and thus decreases the width of the
one of the audio processing channels 18, the monaural 65 pans. A simultaneous decrease in the pan control volt
input signal from the VCR 10 which is to be processed
ages 78 and 80 increases the width of the pans.
by that audio channel 18 is ?rst fed over a line 50 into
The channel output lines 54, 71, 73, 81 and 82 for each
the input of a voltage-control master gain ampli?er 52.
channel of the audio processing unit feed their respec
nel 18 and the combining matrix 40 are best understood
by reference to FIGS. 2 and 3.
4,792,974
10
tive signals into input terminals of the combining matrix
90. The resulting ampli?er output signals (which have
40. Referring to FIGS. 2 and 3, the output lines 71
which carry the shorter duration delay signals for each
channel and the output lines 81 which carry the pan left
signals for each channel are connected to respective
summed with the mono summation signal 38 in the third
and fourth banks of resistors 92 and 96 and are then fed
matrix input terminals D, E, F, and G, H, I which lead
94 and 98. The stereo output signals 42 and 44 produced
by these second stage ampli?ers 94 and 98 thus contain
both delay components and dry pan components) are
into the inputs of the respective second stage ampli?ers
through a ?rst bank of resistors 84 (typically about 10k
ohms each) arranged as an active combining network
into the inverting input of a ?rst stage operational am
pli?er 86. The output lines 73 which carry the longer
delay components, dry pan components, and dry mono
summation components.
It will be appreciated that the left/right panning of
sound which is acheived by the circuitry described
duration delay signals for each channel and the output
above results in part from the fact that some portion of
lines 82 which carry the pan right signals for each chan
nel are connected to respective matrix input terminals J,
K, L and M, N, O which lead through a second bank of
resistors 88 (typically about 10k ohms each) arranged as
an active combining network into the inverting input of
the dry pan components is selectively shifted between
the left channel stereo output 42 and the right channel
output 44. These pan components are essentially the
same as the individual mono input signals which are fed
another ?rst stage operational ampli?er 90. The output
into the respective channels of audio processing unit.
lines 54 which carry the channel input signals that are
used to generate the mono summation signal 38 are
cessing channels regulate the magnitudes of the dry
connected to respective matrix input terminals A, B, C
which lead through a third bank of resistors 92 (typi
cally about 10k ohms each) arranged as an active com
bining network into the inverting input of a second
stage operational ampli?er 94 and through a fourth
bank of resistors 96 (typically about ‘10K ohms each)
The pan control ampli?ers 74 and 76 in the audio pro
monaural signals which are fed into the inputs of the
respective ?rst stage ampli?ers 86 and 90 of the combin
ing matrix 40. These magnitudes in turn determine the
magnitudes of the dry components of the signals which
are fed into the inputs of the second stage ampli?ers 94
25 and 98. By adjusting the gains of the pan control ampli
?ers 74 and 76 in an appropriate manner, the dry com
arranged as an active combining network into them
ponents of the input signals can be selectively shifted in
varying proportions between the left channel second
?er 98. The output line 100 which carries the signal
stage amplifer 94 and the right channel second stage
generated by the test oscillator 48 is connected to an
other matrix terminal ? which also leads through the 30 ampli?er 98, thereby affecting a change in the left/right
spatial location of the sound produced by the stereo
third and fourth banks of resistors 92 and 96 to the
output signals 42 and 44 generated at the outputs of the
inverting inputs of the second stage operational ampli?
second stage ampli?ers 94 and 98.
ers 94 and 98. The second stage operational ampli?ers
It will be further appreciated that mono-compati
94 and 98 act as the left channel output and the right
35 blility of the stereo output signals 42 and 44 is achieved
channel output ampli?er, respectively.
in part by the fact that the delay components which are
The non-inverting outputs of the ?rst stage ampli?ers
present in the left channel stereo output signal 42 are
86 and 90 lead through respective ones of the third and
180° out-of-phase with the delay components which are
fourth banks of resistors 92 and 96 to the inverting input
present in the right channel stereo output signal 44. The
inputs of respective ones of the second stage operational
ampli?ers 94 and 98. The inverting outputs of the ?rst 40 delay signals fed into the inputs of the ?rst stage ampli?
ers 86 and 90 in the combining matrix 40 are distributed
stage ampli?ers 86 and 90 lead through respective oppo
to the inputs of the respective second stage ampli?ers 94
site ones of the third and fourth banks of resistors 92 and
and 98 in equal magnitudes but in opposite phases. The
96 to the inverting inputs of respective opposite ones of
stereo output signals 42 and 44 which are produced by
the second stage ampli?ers 94 and 98. The non-invert
ing and inverting outputs of these second stage ampli? 45 these second stage ampli?ers 94 and 98 thus possess
verting input of another second stage operational ampli
ers 94 and 98 terminate in conventional XLR connec
similar out-of-phase relationships between their delay
tors (not shown) which provide balanced output lines
102 and 104 (i.e., lines with ground, inverted and in
phase terminals) for the left channel and right channel
components. When these output signals 42 and 44 are
summed together to produce a monaural signal, the
stereo output signals 42 and 44.
The inverting outputs of the second stage ampli?ers
94 and 98 are also connected to the non-inverting inputs
of the headphone ampli?ers 106 and 108. The non
50
out-of-phase delay components cancel each other out.
The dry components of the output signals which remain
after summation are substantially identical in nature to
the original mono signals which were fed into the audio
processing unit.
Referring again to FIG. 1, the sound cues used to
108 feed the ampli?ed in-phase stereo signals to respec 55 create the left and right channel signals 42 and 44 are
selected and programmed into the system computer 16
tive left and right headphone speakers 110 and 112.
by an operator who sits at an operator console 118.
A potentiometer 114 in the output line 100 of the test
The operator console 118 includes a plurality o dials,
oscillator 48 permits adjustment in the level of the test
toggle switches and push buttons (all not shown) which
signal which is passed into the combining matrix 40. A
are mounted on the face of the console 118 and which
switch 116 in series with the potentiometer 114 is used
are manually controlled by the operator. In a preferred
to selectively connect the test signal to the input termi
embodiment of the invention, the console 118 has one
nal P of the matrix 40 or to disconnect the test signal
pan control dial and two level control dials for each
and connect the input terminal P to ground.
channel of the audio processing unit, two delay control
The banks of resistors 84, 88, 92 and 96 in the combin
ing matrix 40 perform a summing function. The delay 65 dials for each of the dialogue and music channels, one
pan width control dial for the dialogue channel, one pan
signals and the pan signals are summed by the ?rst and
width control dial for both the effects and music chan
second banks of resistors 84 and 88 and are then fed into
nels, and one timing dial which controls the length of
the inputs of the respective ?rst stage ampli?ers 86 and
inverting outputs of these headphone ampli?ers 106 and
11
4,792,974
time the computer waits before sensing a stoppage of
dial movement during a CONTINUOUS POT RE
CORDING function.
The preferred console 118 also includes two toggle
12
cessed and stored by the computer 16 and allows the
operator to achieve one-hand control over both left and
right pan movements.
The settings of the two level pots for each channel of
switches for each channel which can be used to selec
the audio processing unit produce computer input sig
tively activate and deactivate the level control dials. By
nals which result in the delay amplitude control volt
using these switches, the operator can remove a delay
ages 70 and 72 which are applied to the level control
effect without losing the setting of the level control dial.
amplifiers 66 for the shorter duration delay units 59 and
the level control ampli?ers 68 for the longer duration
delay units 60, respectively. These pots thus control the
amplitude of the delayed signals which are mixed with
Two push buttons are also provided for each channel to
select the desired range of delay for the delay units in
that channel. Additional 'dials, switches and buttons
may be provided to control additional functions, if de
sired.
Each of the dials controls a potentiometer (not
shown) which is electrically connected to a voltage
source (not shown) housed within the operator console
118. The potentiometers, conveniently referred to as
“pots”, regulate the levels of signal voltage which are
passed from the the console 118 over an input line 120
to the input of the system computer 16. The toggle
switches are connected in series between the level pots
and their respective voltage sources to selectively open
and close the circuit therebetween. The push buttons
are the previously described range switches which are
part of the processor delay units 59 and 60.
In addition to being provided with a plurality of pots,
switches and push buttons, the operator console 118 is
also provided with a conventional computer keyboard
(not shown) which, in the preferred embodiment, is
supplied as a part of the computer. The keyboard is used
to send operator commands and input data over the
input line 120 to the computer 16. A conventional com
puter monitor 124, such as the Apple G09OH, receives
display information signals from the computer 16 over a
data line 126 and provides the operator with a visual
menu of programming options and subroutines and a
display of various processor variables and input data.
A detailed description of the manner in which the
the dry signals in the combining matrix 40, acoustically
expanding the sound to a wider ?eld or contracting it to
a narrower ?eld.
The settings of the two delay pots for the dialogue
channel and the two delay pots for the effects channel
produce computer input signals which result in the
delay time control voltages 62 and 64 for their respec
tive channels. One of the delay pots for each channel
regulates the control voltage 62 applied to the shorter
duration delay unit 59, while the other of the delay pots
for that channel regulates the control voltage 64 applied
to the longer duration unit 60. The delay pots thus con
trol the length of the delay which is mixed with the
mono in the combining matrix 40.
Like the dialogue channel pan pot, the settings of the
pan width control pot for the dialogue channel (conve
niently referred to as the “Wild” pot) produce com
puter input signals which result in both a pan left con
trol voltage 78 and a pan right control voltage 80 in the
dialogue channel. However, unlike the pan pot, a
change in the setting of the Wild pot produces substan
tially simultaneous and identical changes in the pan
control voltages 78 and 80. It thus controls the width of '
the dialogue pans.
The setting of the single pan width control for the
effects channel and the music channel produces com
puter input signals which result in both a pan left con
computer 16 utilize the input signal voltages, the opera
trol voltage 78 and a pan right control voltage 80 in
tor commands and the input data to regulate the opera 40 both channels. Like the Wild pot, any change in the
tion of the audio processing unit will be provided later.
setting of this pan width control pot produces substan
Suf?ce it to say at this stage that the signals, data, add
tially simultaneous and identical changes in the pan
commands are utilized by the computer in conjunction
control voltages 78 and 80 for each channel. It thus has
with data and subroutines which are stored in the mem
the same effect on the pan widths of the effects and
ory of the computer to produce a plurality of output 45 music channels as the Wild pot has on the pan width of
control voltages (typically O-SV analog voltages)
the dialogue channel.
which are fed over data lines 122 into the audio process
The setting of the timing pot has no direct effect on
ing unit. In the audio processing unit, the voltages be
come the various control voltages 58, 62, 64, 70, 72, 78
the audio signal. The computer input signal produced
and 80 which were previously described and which are
applied to the delay units 59 and 60 and the voltage-con
trolled ampli?ers 52, 66, 68, 74, and 76 to regulate the
perforaance of the audio processing channels.
As previously noted, the preferred embodiment of
the invention utilizes only one pan pot for each channel
by the settings of this pot establish a waiting time value
which is used by the computer during a CONTINU
OUS POT RECORDING function. The details of that
funtion will be described later.
In the recording mode of operation, the operator
plays the working cassette on the VCR 10 and watches
of the audio processing unit. The computer input signals
the video program which is displayed on the television
monitor 12. He uses the shuttle control to step through
which are produced by the settings of these pots result
in both a pan left control voltage 78 and a pan right
the program as desired.
As he watches the program, he manually adjusts the
control voltage 80. Any change in the setting of the pan
controls on the operator console 18 in order to obtain
pot produces an increase in the control voltage which is 60 acoustical effects which best match the scene he is
applied to one of the pan ampli?ers 74 and 76. This
watching. In the recording mode, any change in the
results in a well focused, symmetrical and highly direc
settings of the pots or switches have an immediate effect
tional left/right movement of the sound due to the fact
on the control voltages which are applied to the audio
that the combining matrix 40 sends to the left and right
processing unit. The audio portion of the program being
channels of the stereo output 42 and 44 equal magni 65 played by the VCR 10 is thus processed in real time by
tudes but opposite polarities of the mono signal to be
the audio processing unit in a manner which re?ects the
recombined with the original mono signal. It also re
instantaneous settings of the console controls. The oper
duces the amount of information which must be pro
ator adjusts the console controls until he obtains the
13
4,792,974
desired sounds from speakers which are driven by the
stereo output signals 42 and 44.
When the appropriate settings are obtained, the oper
ator uses the keyboard to command the computer 16 to
formulate and store appropriate sound cues. In simple
terms, a sound cue is a data entry stored in the memory
of the computer 16 which matches the input signals
produced by the settings on the operator console 118
with the corresponding video time codes being dis
played in the code display region 14 of the television
monitor 12. A time code reader 128 is used to read the
time codes rrom the working cassette and send a corre
sponding time code signal over an input line 130 to the
computer 16. The sound cues thus synchronize the
appropriate portions of the video program with the
acoustical effects which were selected by the operator.
In the playback mode of operation, the working cas
sette is replaced by the master videotape element and by
the conformed original sound elements 132, 134 and
136. A synchronizer 138 communicates with the time
code reader 128 and a playback device for the sound
elements 132, 134 and 136 over sync lines 140-146 in
14
In a RECORD CUES mode of operation 204, the
computer utilizes the amps signals received over a line
206 and the digital time code signals received over a line
208 to formulate the sound cues which represent the
acoustical effects selected by the operator. Each sound
cue generally consists of the amps signals for the desired
acoustical effects matched with the time code signal for
the corresponding scene in the video program. The
sound cues are recorded and stored in a cue memory
10 210. A cue counter (not shown) assigns a different cue
number to each stored cue in order to keep the cues in
their proper sequence. There are four speci?c types of
sound cues which can be selected by the operator.
A STATIC cue is used for frame-by-frame cuing or
to make instantaneous cuts from one cue to another cue.
When played back, a STATIC cue cuts immediately to
the stored cue value when the time code signal reaches
or exceeds the associated time code stored for that cue.
A DYNAMIC cue subroutine is used to perform a
dynamic cut, i.e., a smooth, linear move to the stored
cue from a previous que. To make a DYNAMIC, a
STATIC cue is recorded where the dynamic is to start.
The pots and the video tape are then moved and a DY
order to synchronize the videotape with the sound ele
NAMIC cue is recorded where the dynamic is to stop.
ments 132, 134 and 136.
25 An advantage of the dynamic one is that it obviates the
While the VCR 10 plays the videotape in real time,
need for the operator to record a separate cue for each
the corresponding time codes are sent to the computer
video frame covered by the dynamic cut. DYNAMIC
16 over the input line 130. The computer 16 continu
cues can be stacked for continuous movement.
ously compares these time codes with the time codes for
When recording either a STATIC cue or a DY
the sound cues which are stored in memory, and when 30 NAMIC cue, a computer subroutine determines the
a time code match'is obtained, the computer 16 auto
differences in the pot settings and the differences in the
matically generates on the data lines 122 the control
time codes between the new one and the previous cue
voltages which correspond to that sound cue. These
and calculates the stepping increment which is needed
control voltages regulate the audio processing unit in a
to move the pots from the previous cues settings to the
manner which achieves real-time processing of the 35 new cue settings in the time period covered by the
monaural input signals received from the sound ele
corresponding video program. Two values called the
ments 132436. The stereo output signals 42 and 44
from the audio processing unit thus produce real-time
stereo sound which is synchronized with the videotape
and which recreates the acoustical effects programmed
by the operator.
After the sound cues have been entered, the audio
processing unit can be used as a playback device to
Step and the Remainder are computed to indicate the
amount which the pots settings must change at each
successive video frame and the amount of change re
maining to be made before the new pot settings are
reached. For each cue, the Step and Remainder values
are stored in the cue memory 210 along with the ?nal
amps values and the ?nal time code value for the cue. A
provide stereo sound from the original monaural sound
static or dynamic flag (“8” or “D”) is also stored with
elements or it can be used as a post-production device to
create a recorded stereo sound track. To record a stereo
the cue to differentiate between STATIC cues and
DYNAMIC cues in the playback mode of operation.
sound track, the stereo output signals 42 and 44 which
A CONTINUOUS POT RECORDING subroutine
are produced by the audio processing unit during the
is used for making a real-time pot movement and re
playback mode of operation are recorded onto a digital
cording it substantially the same as it was done. The
two track audiotape (not shown) and the tracks are then 50 computer monitors the real-time movement of the pots
subsequently laid back on to the videotape master.
and records a cue each time movement stops. The in
The operation of the programmed computer 16 is best
understood by reference to FIG. 4.
stantaneous amp value at each stoppage is automatically
matched with the corresponding time code to produce
The sixteen analog input signal voltages produced by
a continuous sequence of cues which are stored in the
the settings of the sixteen console pots are fed into the 55 one memory 210. On playback, the cues are automati
computer 16 over the input line 120. A POT INPUT
cally recalled in sequence when the corresponding time
function 200 utilizes a plurality of conventional analog
code values are reached, thereby recreating the audio
to-ditigal converters (not shown) to convert the analog
effect of continuous pot movements in real time. This
voltages into respective digital signals (denominated
type of cue recording is generally faster than STATIC
“amps”). The corresponding video time codes which
or DYNAMIC cue recording and is particularly useful
are read by the time code reader 128 are fed into the
where the scene being recorded calls for relatively slow
computer 16 over the input line 130 where they are
audio changes.
converted into digital time code signals by a READ
The setting of the timing pot is not recorded during
TIME CODE function 202. In a preferred embodiment
CONTINUOUS PO RECORDING but is used to de
of the invention, an Apple Super Serial Card is used in 65 termine how long the computer waits after the pots stop
moving before recognizing that a stoppage has oc
an extension slot of the preferred Apple II GS computer
curred. The shorter the delay, the faster the computer
to convert the serial data from the time code reader 128
into parallel data used by the computer.
reacts, leading to more ones being recorded in a given
15
4,792,974
time period and resulting in increased accuracy of
tracking during CONTINUOUS POT RECORDING.
A SOFTKEY subroutine automatically puts into the
16
which is stored with the cue. This approach is generally
sufficient for changing a DYNAMIC cue to a STATIC
cue, but an additional step is often used when changing
cue memory 210 a cue which represents a pre-recorded
a STATIC cue to a DYNAMIC cue. The videotape is
setting (called a “softkey”) for each of the sixteen pots.
placed several frames earlier than the time code of the
The one counter is automatically incremented by one
each time a softkey is placed into the cue memory 210.
instant stored cue and several frames later than the time
code of the previous stored cue. A new STATIC cue is
then placed into the cue memory 210 between the in
Softkeys are programmed by a RECORD SOFT
KEYS function 212 which takes input amps values over
stant stored one and the previous stored cue. The new
a line 214 and stores them in a softkey memory (not
cue is given the time code of the current position of the
shown). The stored amps values represent a snapshot of
the instantaneous settings of each of the sixteen pots. Up
videotape and is given amps values which are copied
from the previous stored cue. This technique softens the
abrupt change to the instant stored one by providing a
to nine such snapshots can be stored in the softkey mem
ory.
For SOFTKEY cue recording, a PLAYBACK
SOFTKEYS function 216 is used to selectively recall
one of the stored snapshots from the softkey memory
and pass the corresponding softkey amps values over a
line 218 to a WILD ADJUST function 220. If the
DYNAMIC ramp to that cue.
A DISK I/O function 228 is used to save cues loaded
in the one memory 210 by storing them onto a ?oppy
disk (not shown) and to retrieve cues saved on floppy
disk and load them into the cue memory 210. Softkeys
can be loaded from and saved to floppy disk by using
WILD ADJUST function 220 has been activated by the
operator, the softkey amps values will be intercepted
the DISK I/O function 228 in a similar manner.
In the playback mode of operation, the cues which
and an amps value indicative of a live pot setting will be
have been stored in the cue memory cue 10 are automat
substituted. WILD ADJUST 220 can be used to over
ically recalled at the appropriate time during the video
ride all or only selected ones of the SOFTKEY amps
program and are used to regulate the audio processing
unit as previously described.
values. The latter feature is useful where, for example,
the softkey setting is desired for a single pan position but
live control is desired for the other positions. The soft
A PLAYBACK CUES function 230 recalls a cue
from the cue memory 210 over a line 232 when the
key amps values as modi?ed by the WILD ADJUST
220 are then passed over a line 222 to the RECORD
corresponding time code for that cue is received from
instantaneous time code value and stored as a cue in the
cue memory 210.
Cues stored in the cue memory 210 can be modi?ed
by use of an EDIT function 224.
cues and DYNAMIC cues.
The recalled cue is directed over a line 236 to an
CUES function 204 where they are matched with the 30 the READ TIME CODE function 202 over a line 234.
The PLAYBACK CUES function 230 reads the flag
stored with the cue to differentiate between STATIC
OUTPUT function 238 which includes a plurality of
In the editing mode, any of the stored pot amps val
conventional digital-to-analog converters (not shown).
ues can be selected for change. Once a value is selected,
it is temporarly pulled from memory over a line 226 and
the corresponding pot becomes live. Turning the pot
changes the amps value. The changed amps value is
then stored in the cue memory 210 in place of the origi
The OUTPUT function 238 converts the digital amps
signals for each of the pot settings stored in the cue to a
corresponding analog output signal. The analog signals
40 are passed over the data line 122 where they are used as
the control voltages which regulate the various voltage
controlled ampli?ers and delay units in the audio pro
nal amps value.
Stored time codes can also be pulled from memory
and changed in the editing mode. The time code for a
cessing unit.
selected cue can be incremented or decremented frame
by-frame or second-by-second.
A new cue can be inserted prior to a stored cue. The
videotape is moved to the position where the new one is
45
The progression of time codes which is read by the
READ TIME CODE function 202 during playback
causes the PLAYBACK CUES function 230 to recall
the stored cues in the desired sequence and at the de
sired time during the video program. This produces a
sequence of changes in the control voltages which simu
cue and greater than the time code value for the cue 50 lates the sequence of changes in pot settings which were
programmed by the operator during recording. The
previous to the stored cue) is then matched with the
audio processing unit responds to these changes in con
amps values for the one previous to the stored cue to
trol voltages to alter the monaural audio input signal in
create a new one which is stored in the one memory 210
desired. The time code value for the position (which
preferably is less than the time code value for the stored
real time in a manner which produces the desired acous
at the cue count immediately preceding the count of the
original stored cue.
55 tical effects.
A stored cue can be deleted from the one memory
210. In the preferred embodiment of the invention, the
time code and amps values for a cue pulled from mem
ory are temporarily stored in a buffer (not shown) so
It will be appreciated that the pots do not physically
turn when the control voltages are changed by the
sequence of recalled cues during playback. However,
the resulting acoustical effects produced by the control
that they may be selectively placed back into the cue 60 voltages are substantially the same as if the pots were
memory 210 at a different cue count position. The new
being physically turned by an operator acting in real
position is preferably selected so that the time code of
time.
the relocated cue is between the time code of the previ
The WILD ADJUST function 220 discussed earlier
ous cue and the time code of the next cue at the new
location.
can be used to cause selected pots to be “live” during
65 playback. Any one or more of the pots can be selected,
A stored cue can also be changed from a STATIC
while any unselected pots will remain automated from
type cue to a DYNAMIC type cue, or visa versa. A
the cue memory 210. Acting over a line 240, WILD
simple way to change the cue type is change the ?ag
ADJUST 220 will intercept the amps values for the
17
4,792,974
System testing is accomplished by a UTILITY func
tion which reads all of the live pot settings and outputs
them directly to the audio processing unit for listening,
testing and alignment. UTILITY is the default routine
which is entered automatically upon start-up of the
interior of a car. Longer duration delays in the range
about 8-32 ms can simulate medium rooms to large
balls.
The level pots can be used to make the room size
more pronounced. An increased level setting can create
the effect of a hard walled room with many reflective
surfaces while a decreased level setting can create the
effect of a soft padded room.
Dialogue movement can be achieved by any of sev
eral cut or slide techniques.
system.
In UTILITY, the amps values on the line 206 which
represent the live pot settings are passed directly to the
OUTPUT function 238 over a line 242. The control
voltages thus represent the instantaneous pot settings
and any adjustment in a pot setting will produce an
immediate and corresponding change in the control
voltage and in the acoustical effects produced by the
audio processing unit. Similar testing of the softkeys is
accomplished in UTILITY by passing the selected soft
18
simulate a small to medium size room. For example, a
delay of about 8 ms. can create the effect of a medium
size room whereas a delay of about 2 ms. can create the
effect of a room the size of a telephone booth or the
selected pots and will substitute the amps values which
are dictated by the live settings by the selected pots.
15
There are at least three ways to move an envelope to
an actor when he speaks. The ?rst is to cut to the actor
on the frame where he starts speaking. The second is to
key snapshots over a line 244 directly to the OUTPUT
start panning to him as soon as the previous actor fin
function 238.
ishes. The third is to insert a dynamic start about seven
A sample of a computer program (in object code) 20 to ten frames before the actor starts speaking in a new
which can be used with the preferred apparatus for
carrying out the features of the present invention is
attached hereto as an appendix and the entirety of that
program is incorporated herein by reference.
B. Preferred Methods Of Use
In addition to providing apparatus which converts a
monaural audio signal into a stereo surround signal, the
present invention is also concerned with various tech
position.
The choice among the three methods depends on
background ambience. If ambience is low and the actor
25
speaks loud and clear, cuts work well. If cuts are too
noticeable, the panning technique can be used. The
disadvantage of panning is in short pans. If the pan is
only a second or two, the audience may hear the back
ground panning. Longer pans are more effective. The
dynamic start tecnnique provides an effective compro
niques for creating desired acoustica effects. While the 30 mise. It is essentially a soft cut to the actor a few frames
techniques will be described wtth reference to the pre
before he speaks.
ferred apparatus of the present invention, it will be
Problems may arise when an actor talks while his
appreciated that the techniques can be carried out using
screen image cuts abruptly. It may be difficult to main
any suitable equipment.
tain the integrity of the positioning while avoiding a
With a multi-track DME source, dialogue panning is 35
break in the narrative flow. Two techniques for ap
proaching the problem are to reduce the pan width so
' nel of the audio processing unit. With a composite mon
that the cuts become less abrupt or to out between two
aural source, the same pan pot controls the left and right
achieved by adjusting the pan pot for the dialogue chan
placement of the composite monaural sound. The Wild
words near the visual cut rather than on the visual out
pot is used to control the pan width, i.e. the maximum 40 if the cut falls mid-word.
Dialogue overlaps can be handled with the pan pot
range of left and right movement.
and the level pots. If one actor interrupts another, there
When there are background sounds behind the dia
will be a point where the new actor (the interrupter) is
logue as is often the case with composite tracks, mere
dialogue panning may produce undesirable results. The
background sounds will tend to move with the panned
dialogue. This problem can be minimized by increasing
the settings of the dialogue level pots to spread the
dialogue out over a wider sound ?eld.
talking louder then the old actor (the interruptee).
When the new actor starts the interrupt, begin a pan to
him. When he is fully dominant or the old actor stops
talking, ?nish the pan. Once the audience has identified
with the new actor’s dialogue, the sound should be fully
positioned on that actor. If the actors are engaged in
Dialogue proximity is controlled by the delay pots
and the level pots. As a speaking actor moves toward 50 non-stop simultaneous talking, slightly favor the loudest
one. If none of these techniques produce satisfactory
the camera, a sense of approach can be created by de
results, center the envelope and increase the spread by
upwardly adjusting the level pots.
creates a doppler effect which enhances the approach
Effects panning is achieved by adjusting the pan pot
proximity information already recorded on the sound
track when the actor moved forward. The effect works 55 in the effects channel of the audio processing unit. The
pan width control pot controls the width of effects pans.
equally well in reverse for the case of an actor moving
creasing the settings of the dialogue delay pots. This
away from the camera. It may desirable to avoid this
effect when there are background sounds on the track
Effects on the dialogue track of a DME source are
often “doubled” on the effects track. A door slam
which appears on the dialogue track may not have
because the movement of the background may produce
enough impact when recorded with the dialogue so an
undesirable results.
emphasized door slam is recorded on the effects track.
As the actor moves forward, an increase in the set
Likewise, there may be foley work which adds to the
tings of the dialogue level pots will emphasize the ef
normal sounds on the dialogue track. In both of these
fect. As he recedes, the level pots should be decreased.
cases, the dialogue track should be moved with the
Simultaneous use of the delay and the level pots is an
effective technique for achieving realistic near/ far 65 effects track.
Good stereo opportunities arise when the effects on
placement.
the effects track are not doubled on the dialogue track.
Dialogue ambience is also controlled by the delay
Dog barks, traffic noise, crowds, and the like can be
pots and the level pots. A short duration delay is used to
19
4,792,974
appropriately placed while the dialogue is placed some
20
be separated from the mono in time. Accordingly, tran
sient sounds will be decoded as surround if given suffi
cient level and delay. Steady sounds, such as sirens, will
where else.
Effects spreading can be achieved with the level pots
and the delay pots in the effects channel.
not be in the surround as much as the transients. As a
Spread on the effects gives them liveliness. The level 5 general rule, surround can be triggered by turning the
pot for short duration delay can be used to spread the
medium delay level pot and the medium delay pot to
effects a little wider than the dialogue. The level pot for
their maximum settings.
medium duration delay is increased to obtain a long
Music panning is achieved by adjusting the pan pot in
spread for helicopters, distance, gun battle ambience,
the music channel of audio processing unit. Music pan
and general shock value. A simultaneous increase in the
ning is used to pan the music from a radio, television or
duration of the medium delay will often cause the ef
live band to the appropriate location on the screen. It is
fects to show up in the surround channel. This can be
also useful for placing lead instruments or vocalists in an
used for overwhelming effects like car crashes, wars,
on-screen performance. The pan width control pot
bombs, and the like.
controls the width of music pans.
The level pots and the delay pots can also be used to
Where dialogue or effects are present on the music
create proximity effects. For example, in a drag racing
track, the music pan pot can be used to place the sound
scene where two cars are starting up (revving engines,
appropriately, but the music level pot for long delays is
squealing tires, etc.) just behind the camera point of
preferably reduced to prevent unnatural doubling of the
view, the level may be increased to spread the sound
sound.
while the delay is decreased to create the sense of close 20
The techniques described above for dialogue _and
proximity. As the cars speed off to the vanishing point
effects are generally applicable to a composite mono
(i.e., center screen in the distance), the desired effect of
signal if proper cue placements are used.
cars heading off into the distance can be achieved by
The pot setup for using the dialogue channel with a
dynamically decreasing the level while increasing the
composite mono source is generally the same as when it
delay for doppler. Helicopters can bene?t from a simil 25 is used with a DME source except that.longer duration
iar sound treatment. Short duration delay and high level
delay is generally given a higher range (e.g., a range of
will create the desired noisy wide sound when the heli
about 32-128 ms). These longer delays are used mostly
copter is close up, while a receding effect is obtained by
for music and effects and will be turned off most of the
decreasing the level and increasing the duration of the
delay.
Left-right positioning and panning of effects is
time.
A consideration with composite mono is how to
move one sound without perceptibly moving another,
achieved by using the pan pot as described above.
especially if the other sound is background ambience.
Movement on an axis toward or away from the camera
To pan convincingly with high background ambience,
is achieved by use of the level pots and the delay pots.
the setting of the short delay level pot is turned up until
For example, when a vehicle approaches the camera, a 35 the scope trace approximates the shape of a fat cigar.
dynamic increaee in the level accompanied by a dy
This causes the pans to be somewhat hidden by the
namic decrease in the duration of the delay will create
spread so that there will be little or no perception of
the sound of approaching doppler. As the vehicle re
movement in the background ambience. The short du
cedes, an increase in the duration of the delay along
ration delay pot setting should be kept low enough so
with a decrease in the level will create a receding dop 40 that no dialogue doubling is perceived.
pler and a narrowing of the sound appropriate to the
Psychoacoustically, the ear senses the pan only on the
visual narrowing of the vehicle as it recedes.
loudest sound in the track. For example, the lead instru
In the case of a vehicle which approaches from
ment or vocalist in a band usually can be panned with
screen left in the distance, gets closer at about mid
out perceptibly moving the whole band. If a pan causes
screen, and then moves off to the right, a simple pan can 45 undesirable background movement, the problem can be
be used to follow the car from its start to its end posi
solved by panning less or by turning up the spread
tion. However, a more accurate way to follow the ac
through adjustment of the short delay level pot.
tion would be to initially set the pan pot to the proper
When the track contains music only, the long delay
start position, set the short duration delay pot to the
level pot can be turned up to let the music spread out. If
longest duration and set the short delay level pot to 50 dialogue or a solo vocal comes on while at a high setting
slightly less the maximum. As the car moves, make a
of the long delay level pot, a dynamic can be used to
track of its movements by connecting dots. When it
bring down the level and avoid the effect of having the
comes straight forward, decrease the delay and increase
dialogue or vocal sound as if it was coming from within
the level. When it turns to the right and continues to
a chamber.
approach, adjust the pan, the delay and the level simul 55
taneously.
For a gun battle, each shot can be placed at the gun
barrel when it is ?red. The sound can then be moved
across the sound ?eld to the locations where the bullet
hits and ricochets.
Effects which are not location speci?c should be
balanced off-screen left and off-screen right. Balancing
the effects around the center-screen over time enhances
A cut to wide music spread on a down beat is an
effective technique. When the music ends, the long
delay level can be brought down as the applause (if any)
dies. An increase in the long delay level can be used to
put transients like cymbals and drum rimshots into the
surround channel.
A common dif?cultly with a composite mono source
is achieving a proper balance between accurate place
ment of sound and compromise. For example, if there is
the impact of a quick placement of an effect off to the
a war background and two actors in the foreround are
side.
65 speaking on different sides of the screen, it is not always
Surround is generally perceivable when the level
practical to move the dialogue without also moving the
setting equals or exceeds the mono amplitude. More
center of the war. Similarly, if the long delay level pot
surround is perceived when the delay is long enough to
setting has been turned up to make the war exciting, it
4,792,974 '
21
22
2. Apparatus as set forth in claim 1,
audio processing means distributes said
signals among plural audio channels and
prises pan control means responsive to
can not always be decreased enough to make an actor
sound natural. The usual solution is to compromise the
level of the war and accept a slight unnaturalness in the
voices. This allows the war to remain spread out some
wherein said
stereo audio
further com
said control
what, yet also allows the level to be brought down less
signals for distributing said monaural audio signals
drastically when the actors speak.
Various editing problems can also arise when dealing
with composite mono tracks.
among said audio channels in a selectively variable
manner.
3. Apparatus as set forth in claim 1, wherein said
audio processing means comprises delay control means
responsive to said control signals for introducing time
delay into said monaural audio signals and thereby gen
As a general rule, if the sound to be located is long
enough and loud enough, it can be placed by cuts with
out causing noticeable movement in background
sounds. For example, where two people are talking
loudly across a table while a band is playing softly in the
background, it is possible to cut back-and-forth and
follow the dialogue with no perceptible shifting in the
4. Apparatus as set forth in claim 3, wherein said
audio processing means further comprises level control
means responsive to said control signals for regulating
location of the background music.
the amplitude of said delayed audio signals.
erating delayed audio signals.
When an actor is talking with only ?lm noise for
5. Apparatus as set forth in claim 4, wherein said
ambience (as often happens with optical sound tracks)
audio processing means further comprises combining
matrix means for combining said delayed audio signals
and a cut is made to the side of the screen to pick up an
effect, it is usually better to remain at that position and
cut back only when the actor starts talking again. Hear
with said monaual audio signals in a ratio determined by
said level control means.
6. Apparatus as set forth in claim 5, wherein said
ing a hiss envelope move over and then cut back while
waiting for the actor is an unnatural effect. A slow pan
audio processing means further comprises pan control
back to the actor is often preferable. Most pans of ?lm
means responsive to said control signals for producing
noise which last longer than about three seconds can be 25 pan control signals, said combining matrix means com
hidden fairly well psychoacoustically.
bining said pan control signals with said delayed audio
signals and said monaural audio signals to generate said
If a recorded cut sounds too abrupt when repeated on
playback, the EDIT function can be used to insert a
stereo audio signals which are distributed among plural
dynamic and soften the cut.
audio channels in a manner responsive to said pan con
From the foregoing it will be appreciated that the 30
trol signals.
automated stereo synthesizer method and apparatus of
7. Apparatus as set forth in claim 6, wherein said
the present invention produces realistic stereo with
combining
matrix distributes said delayed audio signals
surround from the monaural audio tracks of audiovisual
among
said
plural audio channels in an out-of-phase
programs, resulting in enhanced audio quality for older relationship
whereby
said delayed audio signals cancel
35
movies and television programs and reducing the ex
each other out upon summation of said audio channels.
pense and technical dif?culty of creating surround ste
8. Apparatus as set forth in claim 6, wherein said
reo sound tracks. The stereo signals are steerable and
delay control means comprise voltage-controlled digital
compatible with existing monaural audio equipment. A
wide variety of acoustical effects and sound placements
delay units and said pan control mean and said level
can be achieved and these are utilized to create an audio 40
program which matches the video program. Time
codes and sound cues are used to synchronize the pro
grams and to achieve operator control over the result
ing stereo sound.
While particular forms of the invention have been
illustrated and described, it will be apparent that various
modi?cations can be made without departing from the
spirit and scope of the invention. Accordingly, it is not
intended that the invention be limited, except as by the
appended claims.
What is claimed is:
1. Automated stereo syntheziser apparatus for use
with monaural audiovisual programs, comprising:
audio playback means for producing monaural audio
signals from an audio portion of a monaural audio
visual program;
audio processing means for converting said monaural
audio signals into stereo audio signals in response
to control signals;
‘
control means comprise voltage-controlled ampli?ers.
9. Apparatus as set forth in claim 6, wherein said
combining matrix means comprises ?rst stage ampli?ers
having inverting and non-inverting outputs and second
stage ampli?ers having identical inputs, said inverting
outputs from each of said ?rst stage ampli?ers being in
communication with said inputs of respective ones of
said second stage ampli?ers and said non-inverting out
puts from each of said ?rst stage ampli?ers being in
communication with said inputs of different respective
50 ones of said second stage ampli?ers.
10. Apparatus as set forth in claim 1, further compris
ing operator input means in communication with said
control means for generating user selected input signals
which regulate said control signals.
11. Apparatus as set forth in claim 2, further compris
ing operator input means for generating user selected
pan input signals which regulate said control signals in
a manner whereby the amplitudes of said monaural
audio signals distributed among said audio channels are
video code means for generating video code signals 60 simultaneously varied by substantially equal magnitudes
but opposite polarities.
correlated with a video portion of said audiovisual
program; and
12. Apparatus as set forth in claim 10, wherein said
control means responsive to said video code signals
operator input means comprise dynamic input means
for generating said control signals which regulate
the audio processing unit, whereby said stereo
audio signals produced by said audio processing
65 produce a continuous linear transition between a ?rst
means are synchronized with said video portion of
said audiovisual program.
selected one of said user input signals during a period
between selected video code signals.
for generating dynamic signals which automatically
selected one of said user input signals and a second
23
4,792,974
13. Apparatus as set forth in claim 10, wherein said
24
processing said monaural audio signals with a stereo
synthesizer responsive to said video codes to gen
erate stereo audio signals from said synthesizer
which are synchronized with said video portion of
said audiovisual program.
operator input means comprises continuous recording
means for automatically generating said user selected
input signals in response to changes in movement of a
control device
14. Apparatus as set forth in claim 10, wherein said
operator input means comprise means for selecting said
user input signals from a plurality of predetermined user
28. A method as set forth in claim 27, further com
prising distributing said stereo audio signals among
input signals.
plural audio channels in a selectively variable manner.
29. A method as set forth in claim 27, further com
15. Apparatus as set forth in claim 10, wherein said
control means comprise storage means for storing said
delayed audio signals.
user selected input signals over time.
16. Apparatus as set forth in claim 15, wherein said
prising regulating the amplitude of said delayed audio
operator input means comprise edit means for selec
signals.
tively altering said user selected input signals stored in
said storage means.
17. Apparatus as set forth in claim 15, wherein said
control means further comprise playback means for
prising delaying said monaural audio signals to produce
30. A method as set forth in claim 29, further com
15
from said storage means in response to said video code
20
33. A method is set forth in claim 27, further compris
operator input means comprise intercept means for
intercepting said user selected input signals recalled
ing regulating said processing of said monaural audio
signals in response to user selected inputs.
from said storage means and substituting therefor an
19. Apparatus as set forth in claim 1, wherein said
audio processing means comprise delay means for intro
ducing time delay into said stereo audio signals and
prising distributing said delayed audio signals among
plural audio channels and altering the phases of said
delayed audio signals whereby they cancel each other
out upon summation of said audio channels.
18. Apparatus as set forth in claim 17, wherein said
other of said user selected input signals generated by
said operator input means.
prising combining said delayed audio signals with said
monaural audio signals.
32. A method as set forth in claim 29, further com
automatically recalling said user selected input signals
signals.
'
31. A method as set forth in claim 29, further com
25
34. A method as set forth in claim 33, further com
prising forming sound cues which correlate said user
selected inputs with said video codes.
35. A method as set forth in claim 34, further com
prising processing said monaural audio signals in accor
matrix means for distributing said stereo audio signals 30 dance with said user selected inputs when said video
codes from said video portion of said audiovisual pro
among a plurality of audio channels in a manner
gram match said video codes correlated with said user
selected inputs.
respective ones of said audio channels are out-of-phase
36. A method for generating stereo sound from a
with each other.
20. Apparatus as set forth in claim 1, wherein said 35 monaural audiovisual program, comprising:
playing a monaural sound track from a monaural
audiovisual program has a composite monaural sound
audiovisual program;
track.
assigning video codes correlated with a video portion
21. Apparatus as set forth in claim 1, wherein said
of said audiovisual program; and
audiovisual program has multiple monaural sound
processing
said monaural sound with a stereo synthe
tracks.
sizer responsive to said video codes in order to
22. Apparatus as set forth in claim 10, wherein said
generate stereo sound which is synchronized with
operator input means comprise one forming means for
said video portion of said audiovisual program.
correlating said user selected input signals with said
37. A method as set forth in claim 36, wherein said
video code signals.
whereby said time delay in said stereo audio signals in
processing comprises spreading said monaural sound
23. Apparatus as set forth in claim 22, wherein said 45 over a relatively wide audio field and panning said
control means comprise storage means for storing said
spread sound across said ?eld to track movements by
user selected input signals and further comprises play
elements in said video portion of said audiovisual pro
back means for automatically recalling said user se
gram which correspond to said monaural sounds.
lected input signals from said storage means in response
38. A method as set forth in claim 36, wherein said
to said video code means generating said correlated
processing
comprises altering resonance and spread in
50
video code signals.
said monaural sound to track proximity movements by
24. Apparatus as set forth in claim 1, further compris
elements in said video portion of said audiovisual pro
ing stereo recording means for recording said stereo
gram which correspond to said monaural sound.
audio signals onto an audio track for an audiovisual
39. A method as set forth in claim 36, wherein said
program.
processing comprises altering resonance and spread in
55
25. Apparatus as set forth in claim 3, wherein said
said monaural sound to correlate said sound with ambi
delay means comprises first delay means for introducing
ence depicted in said video portion of said audiovisual
a delay of ?rst duration into said monaural audio signals
program.
and second delay means for introducing a delay of sec
40. A method as set forth in claim 36, wherein said
ond duration into said monaural audio signals.
processing comprises panning said monaural sound
26. Apparatus as set forth in claim 1, wherein said
across a sound ?eld in a gradual manner to track abrupt
video code signals comprise SMPTE time code.
changes in said video portion of said audiovisual pro
27. Method for generating stereo sound from a mon~
gram which correspond to said monaural sound.
aural audiovisual program, comprising:
41. A method as set forth in claim 36, wherein said
reading a monaural sound track from a monaural
processing comprises altering spread in said monaural
audiovisual program to generate monaural sound 65 sound in a gradual manner to track abrupt changes in
signals;
said video portion of said audiovisual program which
assigning video codes correlated with a video portion
correspond to said monaural sound.
*
*
Ill
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of said audiovisual program; and
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