RU2088962C1 - Sound track film, sound system for movie on film, process for production of analog phonogram and digital identifier of position on film, process for generation of sound signal of movie film and method of reading the consistent digital data from digital storage - Google Patents

Abstract

FIELD: invention refers to systems and processes of recording and reproduction of phonograms on movie films. SUBSTANCE: time code is printed in digital form in area of movie film between analog optical phonogram and gate masks which is exposed together with phonogram when printing is performed. This area is partially developed anew and is usually reserved for separation of analog phonogram from gate masks. Sound in digital form for movie film is kept in storage of archives digital data having large capacity and density. Time codes corresponding to known positions on film are read as film is reproduced and sound signals in digital form for these gate masks are transmitted under waiting mode into buffer storage of data of quick access where these data are stored for time being before they are converted to analog format for reproduction in movie theater. Time code is read with the aid of light which is absorbed by pigments of film produced during its processing. Temporary keeping of sound signal in digital form in buffer storage is used during rupture of film, change of projector and in various circuits acknowledging authenticity of time code. EFFECT: invention makes it possible to keep sound data in digital form and to be aid for reliable storage of data of relatively slow access, for instance, magnetic tape with information in digital form. 10 cl, 7 dwg

Description

 The invention relates to systems and methods for recording in the playback of phonograms on film.

Standard films use analog audio technology. Most films use an analog optical phonogram, which is printed on the film with the image and scanned optically for sound reproduction [1] Using another technology, sound is recorded on magnetic strips deposited along the edges of the film [2]
Optical phonograms may become clogged and produce noise. Phonograms are subject to the same noise problems encountered when using other tapes for sound recording. It is highly desirable to improve the sound quality of a movie to a level comparable to the sound level achieved on CDs.

 Previously, it was proposed to replace a conventional optical analog phonogram with a phonogram in digital form in which digital encoding of sound was performed [1, 3] Although theoretically this could be used to obtain higher quality sound reproduction, it is too expensive in terms of recording many bits of digital data reading them, and the high compactness of the data can become a source of their own noise problems. In addition, such digital tracks will be difficult to reliably print using film processing methods [4]. In addition, there will be a limit on the number of phonograms that can be encoded on the film. Since the digital track is reserved, you will have to make and distribute two types of fingerprints of the analog optical phonogram, one with the phonogram in digital form and the other in the analog. If a digital fingerprint is sent to the theater without the possibility of digital playback, it cannot be displayed. In addition, a theater showing digital films will not have backup facilities in the event of a digital reader failure.

 The objective of the invention is to create a digital audio encoding technology for movies, which is compatible with analog optical phonograms in the same film, less susceptible to noise than other technologies, relatively inexpensive to implement, can be used with a large number of sound tracks, provides analog redundancy in in case of any failure in the digital system and can be printed using standard laboratory processing methods.

 The presented problem is solved in that both the analog phonogram and the time code in digital form are formed on a sound film. The time code in digital form is placed next to the frame frames in the area of the film, which is not occupied by any frame frames, on an analog phonogram and provides digital identification of the position of the code on the film. The audio data itself is stored in a high-capacity and high reliability archive memory rather than on tape. When the time code of the corresponding position is read from the film, digital data, digital data of the buffer memory, to which digital data are digitally transferred from the large main archive storage device in anticipation of their need for a “virtual” memory circuit, are received from the quick access. Sound data is selected from the buffer memory, converted into analog form and synchronized during the design with frame frames. For this purpose, the time code in digital form of the position of the film is read from the film and used by a microprocessor-controlled system to transfer data from the buffer memory for quick access to computer registers and to transfer data in standby mode from a storage device (memory) of digital data of a larger capacity to the buffer ( Memory) quick access before it should be used. In this “virtual” mode of operation, digital sound for a special position on the film can be instantly allowed from the buffer memory. This allows for fast synchronization with jumps in the film due to the loss of frames or “replacement” of the projector without the need for instant physical changes in the read position in a large archived sound memory in digital form.

 The time code in digital form is preferred to be placed between the frame frames and the analog phonogram in a partially re-developed region of the film, which also includes dyes of the color film. In contrast to an analog phonogram, which is read only by infrared radiation, the time code is digitally read by light, which is absorbed by color dyes, for example, light from light-emitting diodes. The area of the time code is effectively separated from the frame by the re-developed analog phonogram.

 Various "fail-safe" standard programs can ensure that reliable time codes are read, for example, programs requiring time codes for at least two consecutive frames in a new series of frames before a jump to a new series can be made. This prevents simple errors in reading the time code. An analogue phonogram can be used in theaters that have only analogue sound-reproducing equipment, and can also serve as a reserve in the event of a digital system failure.

 In FIG. 1 shows an enlarged partial image of a fragment of a filmstrip that includes both a conventional analog phonogram and a digital time code in accordance with the present invention; in FIG. 2 shows a time code in digital form that can be used to identify positions on a film; in FIG. 3 is a simplified drawing of a device showing a film recording system of both a time code in digital form and an analog phonogram; in FIG. 4 shows a simplified fragmentary perspective invention showing a system for reading a time code from a film in digital form; in FIG. 5 is a block diagram illustrating a dual digital-to-analog reading system of a time code in digital form and an analog phonogram; in FIG. 6 is a flowchart for processing time codes read from a film into an audio signal; in FIG. 7a and 7c with a flowchart illustrating the operation of the real memory when a jump is detected between successive words of the time code.

 The invention provides a method for producing digitally produced sound in film, in addition to a conventional analog optical phonogram.

 This is achieved by providing on the film tracks of the time code, which synchronizes the external sound source in digital form with the image. The time code, located on the film so as not to interfere with the usual optical phonogram or image in any way, is highly reliable, easy to read, can be printed on ordinary laboratory equipment and within processing standards.

 The time code is located in the area on the print between the usual optical phonogram and the frame. This area usually serves to separate the portion of the optical phonogram from the frame and is usually deliberately excluded when printing phonograms. It lies within the area of the phonogram print head exposed by the laboratory head, but outside the area of the usual frame print head exposed. It is far enough from the area scanned by a conventional optical sound reproduction head in a projector so as not to interfere with a conventional optical phonogram.

 In FIG. 1 shows a fragment of a 35 mm film strip having a new time code in digital form. A series of perforation holes 1 is located between the edge 2 of the film and the region 3 of the optical phonogram. Frame frames are printed using the frame print head in area 4, which is offset inward from the phonogram area. Intermediate region 5 is used for the time code in digital form of the invention. This area is exposed by a conventional phonogram print head, but not a frame print head.

 A color film, such as that shown in FIG. 1 typically contains three photosensitive layers of silver halide corresponding to red, green, and blue light. The color light of the negative exposes these layers, which then manifest. In the process of manifestation, dyes corresponding to yellow, purple, and blue-green colors are released in the layers. However, the theater lamps used to reproduce the optical phonogram are incandescent lamps emitting infrared radiation for which these colors on the film are transparent. Accordingly, after the usual color processing, but before the final fixation, the phonogram region is re-developed using the silver conversion process. The developer of the second manifestation is either rolled or sprayed onto the phonogram area. This process is not precisely regulated, but it is important that the developer of the second manifestation does not fall into the field of personnel, since this would lead to their blackening. Accordingly, region 5 is usually left free as a buffer zone for separating the optical phonogram from the frame frames.

 In the film industry, an agreement has been concluded to divide 35 mm film into its various functional areas. The edge of the frame frame region 4, which is exposed to the frame aperture, extends 7.7 ± 0.005 mm from the edge 2 of the film. In demonstration projectors, the slit shown by dashed line 6 limits the scanning width of the optical phonogram to prevent reading light from passing through the perforation holes 1 or the frame region 4. Since image analyzers in projectors are sensitive to infrared radiation, the released printed phonograms are re-developed, as described above, to obtain an optical phonogram whose dark region is opaque to infrared radiation. The slot of the projector extends from the edge of the film to 7.3 ± 0.025 mm to avoid exposure to neighboring areas, and the optical phonogram is limited by the slot, respectively, to the reading area. Thus, for recording the time code in digital form of the invention, there is a region located at a distance of 7.29 to 7.67 mm from the edge of the film. This area is usually considered unacceptable for printing frames or phonograms, since an unpredictable part of it undergoes re-development, and the rest is not.

 The preferred area used for the time code in digital form extends from 7.52 to 7.65 mm from the edge of the film, providing a time code track of 0.125 mm width. Removing the track of the time code at a distance of 0.254 mm from the area scanned by the slot of the optical phonogram in the projector eliminates any possibility of interference with the usual phonogram. Since the time code track occupies an area that sometimes undergoes re-development, it sometimes does not re-appear, and sometimes only partially re-appears when it is clearly visible on another opaque track, but cannot be reliably read with a light source (incandescent lamp without a filter), which, for example, is used to read an optical phonogram. Instead, the time code should be read using a light source that emits energy absorbed by the dyes of the color film. A light emitting diode or an incandescent lamp with a filter can be used for this purpose.

 The time code is a narrow strip of digital data that perfectly identifies the position along the film. The code preferably contains a 24-bit digital word, wherein the time-code word begins with a synchronizing series of bits.

 In FIG. 2 shows an example of one data block of the corresponding time code. This is a time code word for frame number 478 on coil 7. A clock signal 8 for frame is provided at the beginning of the time code word. The frame number is identified by a 16-bit binary word 9 with the low-order bit shown by the number 10 and the high-order bit shown by the number 11. This is followed by a 4-bit word 12 that identifies the coil number, and then a sync word 13 for the next frame. The encoding type shown is known as two-phase marking encoding and is auto-synchronizing. The constant level (“high” or “low”) during this bit is shown by the number “0”, while the transition between two levels (either from high to low or from low to high) is the number “1”. There can be a direct correspondence between time code data blocks and frame frames, i.e. each time code data block is located at the corresponding frame frame. This is not a required or truly optimal location. The interval of time code data blocks can be chosen partly arbitrarily, since its function is to indicate the position along the film at any given time. While 35 mm film is usually reproduced at a speed of 24 frames per second, it is advantageous to use 30 blocks of time code data per second, since this speed is easier to “synchronize” with conventional digital sound reproducing equipment when using phonograms.

 In FIG. Figure 3 shows a system for recording both a time code in digital form and an analog phonogram on film negative phonogram. On its way to the inertial sound drum 14, the negative film 15 passes through the tension roller 16. The usual analog phonogram is exposed on the negative through the lens 17. The time code is digitally exposed on the negative optical sound track, while the negative phonogram is recorded. A light source 18 located at one end of the housing 19 generates radiation that is focused by a lens 20 at the other end of the housing at a portion of the film’s time code. The light source is preferably a high efficiency green light emitting diode. The light emitting diode creates an image directly on the sound track of the film negative using a lens, preferably in the form of a spot with a diameter of 0.127 mm. The light emitting diode turns on and off the response to the recorded time signal from the corresponding source 21 of the time code signal in digital form. The time code is exposed on the film in an area that is close to the corresponding frame on the film print. When the film passes under the recording head 17, an analog optical phonogram is recorded for this part of the film. For normal re-development, the film is guided through the tension roller 22.

 In FIG. 4 illustrates a time code reproducing system. The issued print of the film 23 passes under the read head before moving forward to the projector aperture. The read head illuminates the area of the time code in digital form with light that is absorbed by the developed dyes of the film, for this purpose it is preferable to use a high-performance red light-emitting diode 24. The light-emitting diode creates an image on the track of the time code using a lens 25, preferably in the form of a rectangular spot 0.127 x 0.254 in size mm, while the light-emitting diode and lens 48 are placed in a common housing 26. For the standard 35 mm film described above, this allows the time code to be read out when lit a film instability of 0.127 mm. For film moving in the direction of arrow 27, the time code track is indicated by number 28.

 Light passing through the time code track is incident on a photocell 29, the output of which is amplified by an amplifier 30 to provide a digital time code signal used to control sound reproduction. With the preferred film sizes described above, the analog phonogram 31 does not affect the reading of the time code.

 In FIG. 5 shows the sequence in which the imprint of the film 23, which is recorded as shown in FIG. 4 is read using a theater projector. Suppose the film moves through the projection device in the direction of the arrow 32. It first passes the time code reading head in digital form in the housing 26, which reads the time code with a color beam 33 that falls on the demodulator 34 on the opposite side of the film. Then the film moves forward to the projection lamp 35. The beam 36 from the lamp projects the frame frames to the theater screen 37. Then the film moves to the third source 38, whose beam 39 passes through the slot 40 into the region of the optical phonogram 31 and to the demodulator 41, which produces a conventional analog sound signal.

 In normal operation, either a time code in digital form 28 or an analog phonogram 31 can be read. In FIG. 5 shows the independence of these two audio devices and the fact that they do not interfere with each other. In the event of a failure somewhere in the digital system, an analog phonogram can be used as a backup. In theaters where there is no digital reading equipment, only analog phonogram will be used.

 It should be noted that the frame frames are illuminated by the projection lamp 35 for a predetermined period of time after their respective time codes have been read, as the gaps between the read lamp housing 26 and the projector 35 are determined and the film speed. (This gives time to process the signal of the time code, to control its reliability and to access the corresponding sound data in digital form in the fast random access of the "virtual" buffer memory). Therefore, the processing of the time code signal and the production of sound are synchronized with the illumination of the frame frames so that the frames are displayed on the screen while sound originating from their respective time codes in digital form is reproduced in the theater.

 In FIG. 6 shows a system that can be used to reproduce sound in a theater sensitive to a recorded time code in digital form. The digital sound data of the entire movie is stored in a highly reliable archival source 42 of high-capacity digital data. Sound data in digital form is preferably stored in compressed form. This compaction allows you to increase the volume and number of channels of recorded information. The digital data source may be one or more magnetic disk drives, or preferably a more economical and portable means, such as a digital audio tape drive (DAT). A multi-track sound source recorded on magnetic tape can be reproduced on multi-track digital or analog sound reproducing equipment. In the case of a digital tape recorder, digital data can be transmitted directly to the DAT. If an analog sound source is used, the analog data is converted to a digital signal using a conventional analog-to-digital converter (ADC). To ensure synchronous recording, the sampling clock in this converter has phase synchronization with the original phonogram tape. The sampling frequency can be standard 44.1 kHz or 48 kHz, which provides a frequency response of 20-20 kHz.

 The entire recording process is controlled using an IBM-compatible computer. Digital data is transmitted from the ADC through the data system in the computer. Digital data is transmitted to a DAT tape or other storage medium and addressed in blocks that are consistent with the time code words of the time codes in digital form recorded on the film print. Finished DAT tapes can be copied by the usual method of copying digit by digit. DAT drives are preferred to use for sound reproduction, and each of them contains data for three sound channels with a total capacity of six channels. Instead of DAT or magnetic storage media, a compact disc or any other suitable source with digital information can be used, for example magneto-optical disks, 8 mm digital information tapes or optical tapes.

 Returning to FIG. 6, note that the microprocessor controller 43 receives the time code data for the time code reader 44 (shown in more detail in FIG. 4). The time from the position of the head of the time code reader to the aperture of the projector is set in the controller so that the time to convert the digital audio data stored in the data source 42 into an analog signal is known exactly.

 The controller allows the source 42 of data in digital form via access line 44 and forces the transmission of audio data in digital form in anticipation of the fact that they are requested through data channel 45 in the buffer memory 46 random random access. In the buffer memory, digital data is stored by the controller. In an IBM AT-based system, several megabytes of random access memory (RAM) can be provided for this purpose. The use of such a large intermediate memory with quick access is an important feature of the invention. The large buffer memory for quick access allows you to instantly jump inside it to maintain synchronous sound when parts of the film are lost during editing or when the projector is "replaced". The microprocessor system expects data that is likely to be requested, and transfers it to the block from an archive source with slow involuntary access; in this case dat sources. Sound data in digital form is transmitted from a digital data source 42 to a memory 46, where it is stored for several seconds before being selected and transmitted to a series of digital-to-analog converters (DACs) 47. This allows the system to coordinate projector replacements and unexpected jumps in the film, which may to occur if some frames of the film strip are destroyed during design and subsequently deleted. In this case, the controller has quick access to the buffer memory to obtain the necessary audio data in digital form for transmission to the DAC. Due to the buffering action of the memory 46, the digital data source 42 may have a relatively slow random access property, making it possible to use devices such as, for example, DAT as a digital data source.

 In FIG. 7a and 7c, the ability of the system to accommodate jumps in the usual sequence of a block of time code data is illustrated. At any given time, the buffer memory 46 will store audio data for the reproduced block of time code data, audio data for the required number of subsequent consecutive blocks of time code data for which there is enough space in the buffer memory, and also previously read blocks of time code data, if required jumpback ability. In FIG. 7a, a buffer memory is illustrated containing audio data of a time code data block and an additional amount of audio data for all subsequent time code data blocks up to a buffer memory capacity. For example, for a six-channel system operating at a sampling rate of 48 kHz and a digital data recovery method, an RAM of 16 megabytes will provide approximately one minute of buffer memory. The data moves from left to right through the buffer device 46. The current audio data is read by the DAC 47 after the built-in delay due to the time the film moves between the head of the time code reader and the aperture of the projector for use in the theater sound system 48, with the same average speeds, as expected future data, are fed into the buffer memory from DAT 42 or another source of digital data. Since the data is transferred from the magnetic tape to the buffer memory at a faster rate than the data is read from the buffer memory, the magnetic tape stops periodically while the data is read from the buffer memory and starts moving again to fill the buffer memory again.

 In FIG. 7, the time code device tends to wedge itself into the time code sequence with a jump from the data block of one time code into the last data block, skipping a series of intermediate data blocks. The buffer reading system responds with a similar jump, passing virtually instantly to the audio data that corresponds to the new data block outside the time code sequence. In this instant data, still read from the buffer memory, data is written to the buffer memory from DAT 42 at the same average speed.

 In FIG. 7c, the subsequent accommodation of the jump system is illustrated. The maximum output speed of the DAT data is greater than the output speed of the buffer memory data, so that new expected data is entered into the buffer device faster than the current data is read. For example, for a sampling rate of 44,100 samples per second, the sampling rate of the buffer data may be 264.6 kbytes per second, and the maximum data sampling rate is DAT 366 kbytes per second. The difference in the data flow rate continues until the buffer memory again regains its full waiting capacity, from then on the average data output speed DAT returns to the data output speed from the buffer memory to digital-to-analog converters.

 Referring again to FIG. 6, it can be seen that the DACs 47 convert digital audio data into analog output signals, preferably in the form of outputs from six full frequency ranges of 20-20 kHz. The analog output signals pass directly to the audio inputs of the theater sound system 48, which powers the speaker system 49.

 The buffer time provided by the memory 46 and the fact that the time code is read to the aperture of the projector also allows various software to guarantee the reliability of the read time codes and to correct possible errors of the system or film. For example, an internal timer in the system stores the track speed at which time codes of consecutive data blocks are read. If the time code signal is not received for the expected time, the internal timer can be used to play an audio signal corresponding to the next time code. Buffer time can also be used to validate new time codes when there is a jump in the time code sequence. For example, suppose codes 35, 36, and 37 are initially read, followed by a jump to time codes 265, 266, and 267 due to overlapping film bonding. Using standard software, it may be possible to prevent the reproduction of sound signals for the second series of data blocks until at least two consecutive valid data blocks in the new series are read.

 Thus, a digital sound system allows for very flexible and reliable reproduction of film sound in digital form in the presence of a conventional analog optical phonogram on film.

Claims (10)

 1. An audio film containing sequences of image frames, an analog sound track and a digital time code for identifying positions on the film located near them, characterized in that the analog sound track is located in the re-development area of the film detected by infrared radiation, and the digital time code is located in areas of partial re-development of the film, including color dyes obtained by the development of the film, absorbing radiation when reading the time code.  2. A sound system for a film on a film containing a relatively large capacity digital storage device for storing information associated with successive image frames, a relatively quick access buffer memory, a time code reader for identifying positions on the film, a controller associated with the reader time code and buffer memory device, characterized in that a digital-to-analog converter is introduced, the inputs connected to the corresponding output a controller configured to access the digital storage device and transmit to the buffer memory digital audio data associated with positions on the film identified by the time code, as well as access to the buffer memory and transmit digital audio data to a digital-to-analog converter.  3. The system according to claim 2, characterized in that the controller is capable of transmitting digital audio data related to the positions on the film that follow the currently read position of the digital time code to the buffer memory to access the audio buffer memory data when a transition occurs in said digital time code.  4. The system according to claim 2, characterized in that a block for projecting image frames on a film is introduced, a time code reader is configured to generate a time code up to a predetermined period of time before projecting frames, and the controller is configured to control a digital storage device, a buffer memory device and digital-to-analog Converter when forming an analog audio signal synchronously with the projection of image frames on the film.  5. A method of obtaining an analog phonogram and a digital position identifier on a film, which consists in separately exposing the image frames and analog phonogram on separate parts of the film, developing the exposed film and its final fixing, characterized in that the region of the film with the digital code is separately exposed, and before the final by fixing, the region of the film exposed with the analog phonogram and the part of the region of the film exposed with the digital code can be repeatedly displayed, recording analog phonograms by infrared radiation, and the image frames and the re-development area separate the area with the digital code.  6. A method of obtaining an audio signal of a film film, which consists in storing in a digital storage device a relatively large capacity of information associated with successive image frames on the film, scanning the film and reading a digital time code identifying the position on the film, comparing the serial time codes read for sequential positions on the film, characterized in that when accessing the digital storage device, stored digital audio signals are output from it The s corresponding to the read temporary code temporarily store the transmitted digital audio signals in the buffer memory for relatively quick access, consider the temporarily stored digital audio signals synchronously with the scanning of the film and prohibit the transition from the first and second sequences of positions on the film in the digital memory to read at least at least two consecutive positions in the second sequences on the film.  7. A method of obtaining an audio signal of a film, which consists in storing in a digital storage device a relatively large capacity of information associated with successive frames of the image on the film and reading a digital time code identifying the position on the film, characterized in that the digital time code is formed in partially developed the area of the film, including color dyes obtained by the development of the film, the reading of the digital time code is performed when illuminating a partially developed region the light absorbed by the color dyes and the detection of the light transmitted through this region, and when accessing the digital storage device, digital audio signals corresponding to the read time code are output from it.  8. The method according to p. 7, characterized in that the analog phonogram is completely re-developed on the film, and the area of the digital time code is placed between the analog phonogram and image frames.  9. A method of reading serial digital data from a digital storage device, which consists in transmitting digital data sequentially following the current control signal from a digital storage device having a relatively large capacity with relatively slow access to a buffer storage device with relatively fast access and reading of digital data from the buffer storage device under the action of a control signal, characterized in that in the buffer storage device wound as digital data corresponding to the current control signal tuck transitions in the data sequence and the following sequence of digital data, and carry out the corresponding transition in the digital data at the transition of the control signal read out from the buffer memory.  10. The method according to claim 9, characterized in that after the jump in the digital data, the latter is transferred from the digital storage device to the buffer storage device at a significantly higher speed than such data is read from the buffer storage device.

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