Method and apparatus for recording a digital signal on motion picture film
First Claim
1. Apparatus for recording a continuous digital signal on motion picture film as it is being intermittently advanced a distance of one frame spacing by a motion picture camera, the precise times at which the intermittent frame advancement begins and ends being variable, the apparatus comprising:
- transducer means disposed adjacent the film; and
digital signal means for coupling a prescribed sequence of digital bits to the transducer means whenever the motion picture camera intermittently advances the film, to record the bit sequence on the film;
wherein the digital signal means adjusts the durations of the successive bits in each recording sequence such that the last bit recorded on the film during each sequence has a length longer than the nominal lengths of the remaining bits recorded in the sequence, thereby ensuring that the variability in the precise times at which the intermittent frame advancement begins and ends does not result in the recording of a bit that is shorter than a nominal bit duration.
0 Assignments
0 Petitions
Accused Products
Abstract
A method and apparatus for recording a digital signal such as a modified SMPTE time code on motion picture film as it is being intermittently advanced by a motion picture camera. The recorded time code includes a set of timing bits followed immediately by a set of synchronization bits. In one embodiment, the time code is recorded as a continuous signal with the last bit recorded for each frame having an extended length, to ensure that uncertainties in the specific times at which the camera begins and ends its advancement of the film don'"'"'t result in the recording of a bit that is shorter than a nominal bit duration. In a second embodiment, an addition set of synchronization bits is recorded at the beginning of each frame, so that a time code reader assumes it corresponds to the previous frame and properly decodes the following sets of timing bits and synchronization bits as corresponding to the current frame.
115 Citations
34 Claims
-
1. Apparatus for recording a continuous digital signal on motion picture film as it is being intermittently advanced a distance of one frame spacing by a motion picture camera, the precise times at which the intermittent frame advancement begins and ends being variable, the apparatus comprising:
-
transducer means disposed adjacent the film; and digital signal means for coupling a prescribed sequence of digital bits to the transducer means whenever the motion picture camera intermittently advances the film, to record the bit sequence on the film; wherein the digital signal means adjusts the durations of the successive bits in each recording sequence such that the last bit recorded on the film during each sequence has a length longer than the nominal lengths of the remaining bits recorded in the sequence, thereby ensuring that the variability in the precise times at which the intermittent frame advancement begins and ends does not result in the recording of a bit that is shorter than a nominal bit duration. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. Apparatus for recording a continuous diphase digital signal on motion picture film as it is being intermittently advanced a distance of one frame spacing by a motion picture camera, wherein the film includes a photosensitive region adjacent one of its edges, and wherein the precise times at which the intermittent frame advancement begins and ends are variable, the apparatus comprising:
-
a light source disposed adjacent the phtosensitive region of the film; modulating means for modulating the light source on and off; and digital signal means for coupling a prescribed sequence of digital bits to the modulating means for the duration of the intermittent times the motion picture camera advances the film, to expose the successive bit sequences in the photosensitive region of the film as a continuous signal; wherein the digital signal means couples the last bit in each recording sequence to the modulating means for a prescribed time duration at the end of each recording sequence, such that the resulting recorded bit has a nominal length approximately the same as the lengths of the preceding bits, and for a prescribed time duration at the beginning of the following recording sequence, such that the resulting recorded bit has a nominal length approximately one-half the lengths of the bits following it, whereby the composite bit normally appears to have a length about one and one-half times the nominal bit lengths; and wherein the digital signal means further couples the last bit in each recording sequence to the transducer means for a relatively short time duration after the nominal ending of the intermittent film advancement and for a relatively short duration before the nominal beginning of the intermittent film advancement, to ensure that the digital signal is recorded on the film as a continuous signal.
-
-
9. A method for recording a continuous digital signal on motion picture film as it is being intermittently advanced a distance of one frame spacing by a motion picture camera, the precise times at which the intermittent frame advancement begins and ends being variable, the method comprising steps of:
-
positioning a transducer means adjacent the film; and coupling a prescribed sequence of digital bits to the transducer means whenever the motion picture camera intermittently advances the film, to record the bit sequence on the film; wherein the step of coupling includes a step of adjusting the durations of the successive bits in each recording sequence such that the last bit recorded on the film during each sequence has a length longer than the nominal lengths of the remaining bits recorded in the sequence, thereby ensuring that the variability in the precise times at which the intermittent frame advancement begins and ends does not result in the recording of a bit that is shorter than a nominal bit duration. - View Dependent Claims (10, 11, 12, 13, 14, 15)
-
-
16. Apparatus for recording a digital signal on motion picture film as it is being intermittently advanced a distance of one frame spacing by a motion picture camera, the precise times at which the intermittent frame advancement begins and ends being variable, wherein the recorded signal is suitable for decoding by a playback device adapted to detect a continuous digital signal that for each film frame consists entirely of a single set of information bits followed immediately by a single set of synchronization bits, the apparatus comprising:
-
transducer means disposed adjacent the film; and digital signal means for coupling a prescribed sequence of digital bits to the transducer means whenever the motion picture camera intermittently advances the film, to record the bit sequence on the film, the bit sequence associated with each frame including a first set of synchronization bits, followed immediately by a set of information bits and in turn by a second set of synchronization bits identical to the first set, such that the playback device properly decodes the information bits for each frame even though there might be superfluous bits at the beginning and ending of the bit sequence for the frame. - View Dependent Claims (17, 18, 19, 20)
-
-
21. Apparatus for recording a continuous digital signal on motion picture film as it is being intermittently advanced a distance of one frame spacing by a motion picture camera, the precise times at which the intermittent frame advancement begins and ends being variable, wherein the film includes a photosensftive region adjacent one of its edges and wherein the recorded signal is suitable for decoding by a playback device adapted to detect a continuous digital signal that for each film frame consists entirely of a single set of information bits followed immediately by a single set of synchronization bits, the apparatus comprising:
-
a light source disposed adjacent the photosensitive region of the film; modulating means for modulating the light source on and off; and digital signal means for coupling a prescribed sequence of digital bits to the modulating means whenever the motion picture camera intermittently advances the film, to expose the successive bit sequences in the photosensitive region of the film; wherein the bit sequence associated with each frame including a first set of synchronization bits, followed immediately by a set of information bits and in turn by a second set of synchronization bits identical to the first set, such that the playback device properly decodes the information bits for each frame; and wherein each of the successive bit sequences coupled by the digital signal means further includes a prescribed number of additional bits at its beginning and ending, such that the successive bit sequences recorded on the film appear to be a continuous digital signal, without any dropouts between the bit sequences associated with successive film frames.
-
-
22. A method for recording a digital signal on motion picture film as it is being intermittently advanced a distance of one frame spacing by a motion picture camera, the precise times at which the intermittent frame advancement begins and ends being variable, wherein the recorded signal is suitable for decoding by a playback device adapted to detect a continuous digital signal that for each film frame consists entirely of a single set of information bits followed immediately by a single set of synchronization bits, the method comprising steps of:
-
positioning transducer means adjacent the film; and coupling a prescribed sequence of digital bits to the transducer means whenever the motion picture camera intermittently advances the film, to record the bit sequence on the film, the bit sequence associated with each frame including a first set of synchronization bits, followed immediately by a set of information bits and in turn by a second set of synchronization bits identical to the first set, such that the playback device properly decodes the information bits for each frame even though there might be superfluous bits at the beginning and ending of the bit sequence for the frame. - View Dependent Claims (23, 24, 25, 26)
-
-
27. Apparatus for recording a continuous digital signal on motion picture film as it is being intermittently advanced by a motion picture camera, with the precise time at which each intermittent film advancement starts being variable between an earliest start time and a latest start time, and with the precise time at which each intermittent film advancement stops being variable between an earliest stop time and a latest stop time, the apparatus comprising:
-
transducer means disposed adjacent to the film; and digital signal means for coupling a prescribed sequence of digital bits to the transducer means whenever the motion picture camera intermittently advances the film, to record the bit sequence on the film; wherein the digital signal means couples the last bit in each recording sequence for at least as long as the latest stop time and couples the first bit in each recording sequence beginning at least as early as the earliest start time, whereby the apparatus records the successive bit sequences as a continuous signal, without any intervening spaces. - View Dependent Claims (28, 29, 30)
-
-
31. A method for recording a continuous digital signal on motion picture film as it is being intermittently advanced by a motion picture camera, with the precise time at which each intermittent film advancement starts being variable between an earliest start time and a latest start time, and with the precise time at which each intermittent film advancement stops being variable between an earliest stop time and a latest stop time, the method comprising steps of:
- PG,35
positioning a transducer means adjacent to the film; and coupling a prescribed sequence of digital bits to the transducer means whenever the motion picture camera intermittently advances the film, to record the bit sequence on the film; wherein the step of coupling couples the last bit in each recording sequence for at least as long as the latest stop time and coupling the first bit in each recording sequence beginning at least as early as the earliest start time, whereby the method records the successive bit sequences as a continuous signal, without any intervening spaces. - View Dependent Claims (32, 33, 34)
- PG,35
Specification