US3740125A - Motion picture sound processing apparatus - Google Patents

Abstract

Apparatus is described for processing motion picture film and audio sound data recorded on standard sprocketless magnetic tape. A tape synchronizing system is used in which the film is driven by a stepper motor which, in turn, is controlled by synchronizing pulses recorded on tracks of the audio tape. The film can be driven in forward and reverse directions at various speeds, with exact synchronization being maintained between the film and tape during editing. After the sound tracks have been recorded and assembled on their respective tapes, they can be mixed under the control of conductive strips placed on the film which, through a special programming unit, control the starting and stopping of the various tapes.

Description

United States Patent 1 Harris MOTION PICTURE SOUND PROCESSING APPARATUS [76] Inventor: Hilary Harris, 49-A Eighth Avenue,

New York, N.Y. 10014 [22] Filed: Sept. 8, 1971 [21] Appl. No.: 178,630

[52] US. Cl. 352/17, 352/129 [51] Int. Cl. G03b 31/04 [58] Field of Search 352/12, 15,16, 17,

[56] References Cited UNITED STATES PATENTS 2,606,476 8/1952 Waller-ct a1. 352/17 2,854,526 9/1958 Morgan 352/17 UX 2,878,321 3/1959 Davis 352/17 X 3,441,342 4/1969 Ball et a1.... 353/17 3,492,068 1/1970 Baron 352/17 X 1 June 19, 1973 Primary Examiner-Samuel S. Matthews Assistant ExaminerMichael L. Gellner Attorney-Darby & Darby [57] ABSTRACT Apparatus is described for processing motion picture film and audio sound data recorded on standard sprocketless magnetic tape. A tape synchronizing system is used in which the film is driven by a stepper motor which, in turn, is controlled by synchronizing pulses recorded on tracks of the audio tape. The film can be driven in forward and reverse directions at various speeds, with exact synchronization being maintained between the film and tape during editing.

After the sound tracks have been recorded and assembled on their respective tapes, they can be mixed under the control of conductive strips placed on the film which, through a special programming unit, control the starting and stopping of the various tapes.

2 Claims, 3 Drawing Figures GHIIIII Illlll minnow elm FIG.

FIG. 2

FILTER INVENTOR. HILARY HARRIS ATTORNEYS MOTION PICTURE SOUND PROCESSING APPARATUS This invention relates to apparatus for processing motion picture film in conjunction with sound. More particularly, the present invention relates to apparatus is driven in either direction, an image is projected and for editing motion picture film and for mixing a plurality of sound tracks to yield a final mix.

In the production of motion pictures, it is standard practice to use a number of different sprocketed sound tracks. For example, such sound tracks may contain audio corresponding to dialogue, music, sound effects, etc. In producing the final sound track, it is necessary to combine these multiple sources into a single track which, of course, must correlate with corresponding frames of the film. In some cases'(for example, the dialogue) the recorded audio must be accurately synchronized with the film images. In other cases (such as background music) precise synchronization is not required.

In practice, the production of a motion picture wherein multiple sound tracks must be mixed in a cumbersome and expensive undertaking. The present invention provides apparatus which is convenient to use and relatively inexpensive,'which produces high quality results in a relatively short time, and which, most importantly, gives the film editor greater feel for the final effect of the picture. It permits production of sound tracks on convenient sprocketless magnetic tape while maintaining exact synchronization (where required) between the soundtrack and film during editing for tape movement in forward or reverse directions.

The processing unit, in the preferred embodiment,

also includes a means for mixingor combining all of the various sound tracks, including those produced pursuant to the foregoing. According to this feature of the invention. The various sound tracks are recorded on individual magnetic tapes. A special programmer operates each of these tapes only when it is desired to add the sound recorded on that tape to the final mix.

Briefly, the invention comprises an editing table on which a film-viewing mechanism and a magnetic tape deck are supported. The film is driven by a stepper motor either under control of the line voltage or synchronization pulses recorded in special tracks on the magnetic tape. The film includes conductive strips at preselected positions which cause a special programmer unit to actuate one or more of a plurality of additional tape decks to add the sound recorded on their associated tapes to the final mix when desired;

The invention is described in further detail below with reference to the annexed drawings wherein:

FIG. 1 is a diagrammatic illustration of the physical layout of a system embodying the invention;

FIG. 2 is a block diagram of the system used by the invention to synchronize the tapes and film with respect to each other and also to synchronize the tapes and films with the line frequencyyand FIG. 3 is a semidiagrammatic illustration of the programmer used in the preferred embodiment of the invention.

FIG. 1 illustrates the components of a preferred embodiment of the system and is intended to illustrate the manner in which the invention is used for editing and mixing. In FIG. 1, a basic editing table is illustrated at 10. A standard sprocket-type projector mechanism (not numbered) is mounted on table 10 for driving the motion picture film 12. As the motion picture film 12 displayed by means of a viewing apparatus 16. A tape deck 13 containing conventional '74 inch magnetic tape 14 is also mounted within table 10.

A removable programmer 18 is inserted into a suitable opening in the front portion of table 10. Four (for example) separate tape decks 20a, 20b, 20c and 20d are mounted at a convenient distance from the table 10 and connected to the programmer circuitry by means of a cable 22. Programmer 18 contains the controls which determine the mode of operation of the system as explained below.

For purposes of explanation it is assumed that it is desired to prepare and mix two sound tracks containing, respectively, music and dialogue. These two tracks may be considered as the tracks which are stored on the tapes of decks 20a and 20b. As the first step in the editing process, it is necessary to synchronize exactly the dialogue on the tape of deck 20b with the appropriate frames of motion picture 12. As explained below, this tape will have been recorded with special synchronizing pulses (derived from line frequency) in two sync tracks on the tape. Thus, this dialogue tape will be placed on tape deck 13 within the editing table 10. A suitable switch (not shown) on the programmer control panel is then actuated to place the system in a TAPE- SYNC mode. In this mode, the synchronizing pulses on the magnetic tape are used to drive the motion picture film 12 so that exact synchronism is maintained between the sound track on tape deck 13 and film 12. During this process, the user can move this sound track in forward or reverse directions, either manually or under the control of the motor of tape deck 13, and the film 12 will follow the tape movement. After the film has been edited as desired, the tape bearing the dialogue is returned to the tape decks 20b so that it can be used as part of the final mix.

In compiling all of the sound tracks, programmer 18, as explained below, causes each of the tape decks 20a20d to operate its tape at appropriate intervals so 7 that the information on the various sound tracks can be combined and recorded on a new tape on deck 13 within table 10. After this mix has been completed, the sound track on tape 14 can be recorded at a later time on the motion picture film 12 by conversion to an optical sound track in the usual way.

FIG. 2 illustrates in block diagram form a preferred embodiment of the invention. As diagrammatically illustrated, tape 14 may be considered to include an audio channel 14A and two synchronization tracks 14B and 14C. The lines 30 in tracks 14B and 14C represent the synchronizing pulses recorded in the respective tracks and illustrate that the pulses recorded in the synchronizing tracks are slightly offset with respect to each other. The synchronizing pulses 30 are recorded as the information in channel 14a is recordedand can be derived directly from the 60-cycle line frequency which is fed to the tape-driving motor during recording. Alternatively, the synchronizing pulses may be added to a previously recorded tape.

Film 12 is driven in the usual fashion by means of a sprocket 34 which engages the standard sprocket holes within the film 12. According to this feature of the invention, the sprocket reel 34 is rotated by a stepper motor 36 which is controlled by a logic circuit 38 in response to the sync pulses 30 on tracks 14B and 14C of tape 14. The sync pulses 30 are detected by an oscillating transducer 40 and coupled through a filter 42 to the inputs of the logic circuit 38.

Logic circuit 38 may comprise a known device which is capable of driving stepper motor 36 in forward or reverse directions depending upon the sequence in which the sync pulses 30 from tracks 14B and 14C are received. For example, assuming that the forward direction of tape 14 is left to right, if the pulses in track 143 occur prior to the sync pulses in track 14C, logic circuit 38 will drive the stepper motor 36 in a forward direction. If the pulses in track 14B occur after those in track 14C, logic circuit 38 will drive the stepper motor 36 in a reverse direction.

As illustrated in FIG. 2, the logic circuit 38 also receives an input on line 44 from a standard 60-cycle alternating current source. When the stepper motor 36 is operated from this 60-siXty-cycle source, the film 12 will be driven at a rate of 24 frames per second, as determined by the reduction gears of the motor. Determination of whether the motor 36 is to be driven by the line current on lines 44 or the sync pulses derived from transducer 40 is at the option of the user with such selection being made in an obvious fashion by appropriate switches on the control panel. Where the motor 36 is controlled by the sync pulses 30 the rate of film movement will, of course, be directly dependent upon the rate of movement of tape 14.

In some cases, during the editing process, it may be desirable to move the tape 14 at very low speeds. In such cases, a standard transducer may be unable to pick up the sync pulses because of the low induced magnetic flux. Hence, transducer 40 is caused to oscillate when the sync pulses reach a critically low voltage due to the low speed of the tape movement. A filter 42 may be used to reject signals above a predetermined frequency to block unwanted pulses.

The tape 14 is moved under the control of a DC motor 50 which drives a standard capstan 52 diagrammatically shown in FIG. 2. The speed of motor 50 and the direction of rotation of the capstan 52 is controlled by a standard SCR speed and direction control circuit 54 which, in turn, is responsive to the sixty-cycle line voltage applied to terminals 56. Control circuit 54 is conventional and gives the user the capability of moving tape 14 at a desired speed in forward or reverse directions during editing. Since the film follows the tape movement during the TAPE-SYNC mode, control circuit 54 is used as the system control during editing. The tape 14 may be moved manually for precise cueing or editing in which case the film will precisely follow the tape.

As described to this point, the system is capable of operating with both the film I2 and tape 14 driven by means of the sixty-cycle line current or with film l2 driven in synchronization with the tape 14. In addition, the system includes a further mode of operation, a tape self-resolving mode, in which tape movement is accurately synchronized with the line frequency.

For the tape self-resolving mode, a servo system employing an amplifier and wave shaper 60 and two small synchronous motors 62 and 64 is used. Amplifier and wave shaper 60 produces a sine wave from the synchronizing pulses 30 on tracksv 14B and 14C to drive motor 50. The motor 64 is driven from the line current. A small light 66, powered by a battery 65, is mounted on a lever 67 extending from the output shaft of motor 64 and thus rotates with an angular velocity dependent upon the frequency of the line current. A photocell 68 mounted on a lever 69 rotates with the output shaft of motor 62. A feedback path to the DC motor 50 is completed by deriving the voltage from photocell 68 by means of slip rings 70, and this voltage is coupled by line 72 to the SCR speed and direction control circuit 54.

The servo loop is such that the voltage on line 72 causes the control circuit 54 to drive motor 50 at a speed corresponding to the line frequency when photocell 68 is slightly in front of the bulb 66. With this arrangement, the light received by photocell 68 can be increased (if the bulb catches up with it) or decreased (if the photocell draws further ahead of bulb 66). Thus, if for any reason, the speed of tape 14 increases, photocell 68 will move ahead of the light bulb 66. This will result in a decrease in the light intensity reaching the photocell 68 resulting in a lower voltage on line 72 to the speed and direction control circuit 54. This lower voltage will reduce the speed of motor 50 until the tape is again synchronized with the line frequency. Similarly, if the tape 14 tends to lag, the bulb 66 will draw closer to photocell 68 resulting in an increased voltage on line 72 which will increase the speed of motor 50, and thus the tape speed.

In this tape self-resolving mode, the magnetic tape is maintained at precisely the same relationship to the line frequency as when the sync pulses 30 were originally recorded on the tape. When the system is used for mixing, all film and tape playback units are operated in the self-resolving mode with the common 60-cycle line being used as a reference. In the TAPE-SYNC mode the film is not driven by the line frequency but by the pulses previously recorded on the tape; hence, the film 12 is resolved to the particular tape being played and would not run in synchronization with additional selfresolved decks. This means that the tape deck 13 must be self-resolving during mixing if it is to be used as one of the synchronized sound sources in the mix. On the other hand, this deck may be used free running (nonresolving) if the sound material is non-synchronous, or it may be used (probably the most common case) as the means for recording the final mix in which case sync signals would be recorded simultaneously on the sync pulse half of the tape for subsequent synchronous playback.

The programmer is shown in semidiagrammatic form in FIG. 3. It includes a movable cue sheet suitably mounted within a housing 82. The sheet 80 may comprise a paper strip which is movable under the control of a pair of rollers 84.

The cue sheet 80 includes a number of individual channels corresponding to the tape decks 20. These channels are shown as channels 80a, 80b, 80c and 80d and correspond respectively to the tape decks 20a, 20b, 20c and 20d. A fifth channel 80x is used as a control track as will become apparent in the following.

Each of the channels contains data which, for example, may comprise a conductive pencil mark as indicated by the lines 85. These marks may be contacted by feeler pairs 86a-86d each pair, in a known way, causing a voltage output when both feelers are contacting a mark and a lack of a voltage output when they are not contacting a mark. This information in the tracks 80a-80d is used to control the starting of the respective tape decks 20a-20d.

The information contained in the control track 80x is used to control the movement of the cue sheet 80. This is done in response to a conductive strip 90 (see FIG. 2) placed on the film 12 at each place where a different control operation is to occur. Strip 90 may be sensed by a feeler 92 and the output voltage coupled by lines 94 to the programmer shown in FIG. 3.

The feeler pairs 86a-86d are mounted on a vertically movable bar 95 so that they normally do not engage the cue sheet 80. Each time a pulse is generated by strip 90, bar 95 is moved downwardly by any suitable mechanism (not shown) to cause temporary engagement of the feeler pairs with cue sheet 80. If a feeler pair is shorted by a mark 85, its associated tape drive is energized. The tape drive may be de-energized by means of a conductive strip on the tape so that the tape turns it self off after a selectedsegment has played back. Rollers 94 continue to move the cue sheet 80 until the feeler pair 86x is shorted by a mark 85 at which point the cue sheet 80 is stopped. When the next strip 90 on the film is sensed, another cycle starts.

The foregoing programming arrangement controls the entire mixing operation. Thus the user can correlate each of the tapes on decks a with the film 12 by the suitable placement of these strips 90. Those tapes which require exact synchronization are made while the film and tape are synchronized by means of the sync pulses 30 on tracks 14B and 14C. Thereafter, during the final mix, all of the audio tapes are driven in the tape self-resolving mode while the film is driven directly by the line current on lines 44. Consequently, both the film and audio are accurately synchronized with the line frequency. The final mix provides the desired combination of all of the tapes in decks 20 with each tape running only during that period when its formation content is being transferred to the final tape.

What is claimed is:

1. Motion picture editing and processing apparatus, comprising means for driving a motion picture film medium in' preselected increments,

a tape deck containing a magnetic tape medium having audio data recorded thereon, said magnetic tape medium having a synchronizing track including trains of forward and reverse sync-driving pulses recorded therein,

variable speed drive means for driving said magnetic tape in forward and reverse directions,

means for viewing the frames of said motion picture film, and

means responsive to said sync-driving pulses for driving said film medium in forward and reverse directions depending upon the direction of movement of said magnetic tape, said film-driving means being responsive to the frequency of occurrence of said data pulses as determined by the rate of movement of said magnetic tape.

2. Apparatus according to claim 1, further including self-resolving means for synchronizing said tape medium with respect to a preselected line frequency, said self-resolving means including means for comparing the frequency of occurrence of said sync-driving pulses derived from said synchronizing track with said preselected line frequency.

Claims (2)

1. Motion picture editing and processing apparatus, comprising means for driving a motion picture film medium in preselected increments, a tape deck containing a magnetic tape medium having audio data recorded thereon, said magnetic tape medium having a synchronizing track including trains of forward and reverse sync-driving pulses recorded therein, variable speed drive means for driving said magnetic tape in forward and reverse directions, means for viewing the frames of said motion picture film, and means responsive to said sync-driving pulses for driving said film medium in forward and reverse directions depending upon the direction of movement of said magnetic tape, said filmdriving means being responsive to the frequency of occurrence of said data pulses as determined by the rate of movement of said magnetic tape.

2. Apparatus according to claim 1, further including self-resolving means for synchronizing said tape medium with respect to a preselected line frequency, said self-resolving means including means for comparing the frequency of occurrence of said sync-driving pulses derived from said synchronizing track with said preselected line frequency.

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