KR940010144B1 - Method and device for operating data on videro tape - Google Patents

Abstract

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Description

Method and apparatus for manipulating information on videotape

1 is a schematic diagram of a videotape in which information is recorded in one relatively simple format,

2 is a functional block diagram of a vertical retrace period time code integration system according to the present invention, and

3 is a functional block diagram illustrating details of one component of the FIG. 2 system.

* Explanation of symbols for main parts of the drawings

0, 1, 2, 3: Track 10: Tape feeder

12: injection head 13: supply rail

14: Read Converter 15: Video Tape

16: take up reel 20, 28: guide

The present invention relates to a method and system for manipulating information on a videotape, and more particularly, to a method and system for reading and controllably recording data on a videotape, such as vertical interval time code information. This data is especially useful when editing videotapes.

In current video tape recording technology, it is common to edit video tapes over a wide range. In practice, the editing processes are usually described as either "insert" and "assembly" operations. In the insert operation, new information on the videotape is merged into the center of the existing information. In the assembly operation, new information on the video tape is added to the end of other information.

In both editing operations, the editing orientation information on the videotape is preferably consistent before and after the editing transitions.

The storage of editorial orientation information on the video tape can be provided at so-called "vertical blanking intervals". Normally, the vertical blanking intervals coincide with the time required by the cathode emitters to "return the scan" from the bottom to the top of the screen, i.e., the cathode ray syringes do not emit light on the screen during the return scanning periods. . Since the television signals are transmitted continuously but the operation of the cathode emitters is discontinuous, the return scan periods are described approximately with vertical blanking intervals. Currently, the vertical blanking intervals are 20 or more lines containing signal information, such as video subtitles for the hearing impaired, most importantly for this purpose, the vertical blanking time type code (VITC) information. It may also include.

Normally, VITC information is recorded in vertical blanking intervals so that after a frame is identified as "frame 0", it identifies the time at which a particular frame occurs (although not necessarily necessary, frame 0 often occurs concurrently with the start of recording). ). For example, the 2055th frame after frame 0 may be displayed as 00: 01: 08: 15, indicating that the tape follows frame 0 by 1 minute 8.5 seconds when played at the normal operating speed of 30 frames per second. . That is, the first two numbers in this code represent hours in decimal, the next two digits in minutes, the next two digits in seconds, and the last two digits in frames. Thus, providing VITO information is equivalent to identifying video frames with addresses that are sequential from frame to frame.

Indeed, VITO information is similar to known longitudinal time code information, except that the VITO information contains one "sign" bit that identifies which interlaced field of video information is extracted.

The precision code formats for VITC information were defined by standards such as ANSI / SMPTE 12M-1986, which was promoted by the American National Standards Institute (ANSI) (New York) and the Society of Cinematography and Television Engineers (SMPTE).

In this standard format, VITC information consists of 90 digital bits of 9 bytes with two synchronization bits between each byte encoded into the video information line. That is, two initial synchronization bits and eight cyclical re-dundancy check (CRC) codes at the tip are included in the 90 bits.

However, other standard code formats for VITC information are in addition to the American Standards Association. That is, for example, the European Broadcasters' Union specification displays the format for VITC code information somewhat differently. Typically under several specifications, VITC information is duplicated on only two non-adjacent lines in the vertical blanking interval and identified as VITC information by unique synchronization bit sets embedded in the information.

Although the specifications specify code formats for VITC information, the specifications provide substantial flexibility with respect to the location of the VITC information within the vertical blanking intervals. Thus, in videotape editing, the selection of VITC information position is a matter of the editor's choice, and the actual line position of the VITC information may vary from one device to another or from one editor to another.

For example, one editor may choose to record VITC information on the 13th and 15th lines in vertical blanking intervals, and another editor may choose to record VITC information on the 17th and 19th lines. have.

Although flexibility relative to the VITC information position within the vertical blanking intervals is highly desirable for some editing purposes, flexibility causes problems when video tapes are re-edited or played back. In part, such problems arise because conventional devices, usually referred to as "VITC readers", that read VITC information from a videotape do not provide identification of the addresses of the lines from which VITC information is read. In the absence of such address information, it is a common editing practice to record VITC information by arbitrarily selecting line addresses, regardless of pre-addresses that may have previously been recorded on the videotape to be edited. Thus, in conventional practice, the location of VITC information in sundresses is extremely unpredictable. One copying resulting from such a convention is that during editing VITC information may be overwritten with important non-VITC information in vertical blanking intervals. For example, an editor may inadvertently overwrite VITC information with closed caption information, causing subtitles to be lost or distorted during playback of the edited videotape.

In view of the foregoing, it may be understood that there may be cases where previously recorded VITC information coexists with newly recorded VITC information on the edited videotape. That is, for example, the previously recorded VITC information may appear on the 13th and 15th lines in the vertical blanking intervals of the edited video tape, and the newly recorded VITC information may appear on the 17th and 19th lines of the same tape. Can be recorded on. This can cause difficulties during editing, since a conventional VITC reading device is located only in the first valid line of VITC information in the vertical blanking intervals and ignores all subsequent lines. Thus, when re-editing a videotape, sometimes inconsistencies may occur if the VITC reader misses the newly recorded VITC information and reads the original recorded information instead. In other words, it is also possible that the VITC reader reads the newly recorded VITC information and the next recorded VITC information next time.

It should also be understood that in the description of this technique, conventional devices are to ensure that newly recorded VITC information is numerically sequential with previously recorded VITC information across edit transitions. Such devices simplify editing tasks because the sequential VITC information conveniently guides the editor up to a point on the edited videotape.

This invention substantially improves the current technical level of processing information stored on videotape, and is particularly useful for videotape editing. In particular, the present invention provides a system that ensures that data on a videotape, in particular aberrantly sequential VITC information, can be written on the same lines in vertical blanking intervals when the information is extracted.

Thus, the present invention can substantially enhance the convenience of videotape editing, and furthermore, can ensure that valuable information recorded on the videotape is not lost during editing. As a specific example, the present invention may exclude the possibility that VITC information is overwritten with information such as closed caption information in vertical blanking intervals, thus eliminating the loss or distortion of closed captions during playback of an edited videotape. can do. As another particular example with the advantages of this invention, this invention may prevent previously recorded VITC information from coexisting with newly recorded VITC information only on other lines after an edit transition. As another particular example, this invention allows convenient identification of particular lines in a video field, in particular particular lines in vertical blanking intervals, in which specific data such as VITC information is stored in those lines. This ability provides editors with improved control over the editing process and is useful in avoiding the difficulties encountered in conventional editing practices due to inconsistencies in locating VITC information.

In order to provide the above advantages and others, a preferred embodiment of the present invention comprises means for selecting a particular line within a video field, such as a vertical blanking interval, scanning means for scanning only a specially selected line, and the scanned line is vertical. A detector means for detecting whether or not interval time code information is contained is provided. Also, as is suitable for editing processes relating to the position of VITC information within vertical blanking intervals, a preferred embodiment of the present invention also provides time code information and numerically sequential time code information detected on the scanned line. Generator means for generating and writing means for writing numerically sequential time code information in vertical blanking intervals on detected lines to contain vertical blanking time code information.

In addition, certain embodiments of the invention that are particularly useful for videotape editing include scanning specially selected information lines in vertical blanking intervals, identifying a special line containing VITC information, generating time code information, and And writing the generated time code information in the vertical blanking intervals onto the selected lines.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

The field of the invention can be understood with reference to FIG. 1, which shows one section of the video tape 15, where the direction of movement of the video tape by the video recording-reproducing apparatus is parallel to the longitudinal centerline of the tape. Are indicated by horizontal arrows. Tracks (0, 1, 2) of magnetically recorded information on video tape 10 simulate images recorded including data on a cathode ray (CRT) screen. As such, the image display on the CRT screen may be regarded as a pattern consisting of sets of horizontal lines of ordered light emitting points that are controllably changed in accordance with information recorded on information tracks (0, 1, 2). However, for this invention, the special format in which the information is organized on the videotape is not important.

2 shows the components of the system for conveniently recording and reproducing data on any predetermined lines within the vertical blanking interval, in particular numerically sequential VITC information. In FIG. 2, a typical video tape conveyer 10 includes a rotating drum guide and scan head 12, a video tape feed rail 13, and a video tape take up rail 16. As shown in FIG. The scan head 12 includes read converters 14 that selectively read or write information on the video tape 15, or serve both functions. Several guides 20-28 are provided to guide the video tape 15 through the head 12 from the feed rail 13 along its path of travel and then to the winding rail 16 for pulling.

In the system of FIG. 2, the tape feeder 10 is controlled by the tape feed control device 33, which in turn is controlled by the system control device 35. As shown in FIG. The tape feeder 10 is interpreted as a system controller 35 and operates in response to control input signals on a line 36 that is executed by the tape feed controller 33.

In practice, as the speed and direction of the capstan 26, feed rail 13 and take-up rail 14 are controlled, several tape speeds, either forward or reverse, drive the tape feeder 10 to the play mode, stop mode, or reciprocation. It is given to operate selectively as a mode. In the play mode, the direction of the tape is in the forward direction (as indicated by the arrows), and the tape speed is equal to the speed at which video information was originally recorded on the tape. In the still mode, the video tape speed is zero but the scan head 12 Can be operated to read video information from the tape 15. The reciprocating mode is used to accelerate the movement of the tape 15 in both directions, usually at a speed raised to about 50 times the normal fryer speed. The tape conveyance apparatus 10, the tape conveyance control apparatus 33, and the system control apparatus 35 are all common, and are well known to those skilled in this technique. Control input signals on line 36 may be initiated at the operator control panel or from the video editor.

Also, generally, the system of FIG. 2 includes subsystem components that control the apparatus 10 to read information on predetermined lines within the vertical blanking interval. The reading subsystem includes conventional components such as a reproduction signal processing device 41 connected to the readhead 14 to receive information written in the vertical blanking intervals. The reproduction signal processing device 41 operates in accordance with the signals read from the video tape to perform many conventional operations to prepare for demodulating the signals. Such processors are well known to those skilled in video signal processing techniques. The demodulation device 43 operates in accordance with the output signals of the processing device 41 to generate a standard video signal. Demodulation devices are well known to those skilled in video signal processing techniques.

The standard video signals provided by the demodulation device 43 are suitable for use with video utilizing devices 45 such as CRT monitors or video tape record-playback devices. In addition, the output signals of the demodulator 43 are provided to a conventional synchronizing device 47 which separates the synchronization information such as the vertical synchronization information and the horizontal synchronization signal described herein as Htape from the demodulated signals. .

Further, in the system of FIG. 2, the signals of the demodulator 43 are processed by the limit detector 49. In general, the limit detector 49 is of a conventional type and provides a first constant output if the input signal amplitude exceeds a certain reference level and a second constant output if the input signal amplitude is below a predetermined level. In practice, the reference level of the limit detector 49 is selected to distinguish VITC information from other information. Because the output of the limit detector 49 is a flow of binary data pulses that selectively indicate the amplitude of the output signals, the limit detector 49 can be described as equally as a 1-bit analog to digital converter.

The output of the limit detector 49 is provided to the input / output processing unit 51 which also receives the H tape signal. The input / output processing unit 51 includes a series of registers and other conventional digital storage devices and logic elements that process binary information in response to command signals of the central processing unit (CPU) 55, and the center thereof. The processing unit communicates with the input / output processing unit 51 via the two-way data bus 57. In practice, the CPU 55 is a conventional microprocessor that executes arithmetic logic operations on data in selected registers of the input / output processing unit 51 under software control.

Also, as shown in FIG. 2, the input / output processing apparatus 51 receives the reference signals Href, Vref, and 4fsc.

These reference signals differ from H tape in that they do not start with information on the video tape as the H tape signal does. The Href signal is periodic with a frequency that matches the subphase frequency of the horizontal synchronization signal contained in the color television signals (e.g., 15,734 hertz). Similarly, the Vref signal matches the outlier frequency of the vertical synchronization signals contained in the color television signals (eg 59.94 hertz). The 4fsc signals, here called "fast clock" signals, are four times the frequency of the color subcarrier signals of the color television signals.

In addition, the system of FIG. 2 includes components for recording the output signals of the input / output processing unit 51 on the video tape 15.

In the recording subsystem, output signals of the input / output processing unit 51 are provided to the filter 59. The filter 59 converts the digital output signals of the input / output processing unit 51 into an appropriate form as defined by the application standard.

The filter signal is then sent to the adder circuit 60 where the signals from the video source 61 are added to the filter signal. The synthesized signal is then sent to modulator 62 and signal processor 63, converted to an appropriate level, and equalized to be recorded on video tape 15 via read head 14, recording sub The components of the system are conventional and actually perform the opposite functions of the functions performed by the analog components of the read subsystem.

Now in FIG. 3, the input / output processing unit 51 is provided for detecting data such as VITC information encoded on identified lines of vertical blanking intervals. The reference signals Vref, Href and 4 fsc are used in the line number generator 64 to generate vertical blanking price VBI line numbers for use in the input / output processing unit 51. Generator 64 includes a digital counter 66 that employs to reset the Vref signal, delay the Href signal, and delay 4fsc via delay 65.

선씩 비디오 테이프에서 판독되는 선 도착 예정 시간을 앞서는 출력 계수를 발생시킨다. 선택

선 계수를 실제로 비디오 테이프에서 판독된 정보와 동기시키기 위해서, 발생기(64)로 발생된 VBI선 번호들이 래치(67)에서 H tape신호에 의해 래치된다. 특정 기능들을 제공하기 위해, 디지탈 계수기(66)와 래치(67)는 통상의 형태일 수 있다.In fact, the digital counter 66

The output coefficients are generated one by one ahead of the estimated time of arrival of the line which is read from the videotape. Selection

In order to synchronize the line coefficient with the information actually read from the video tape, the VBI line numbers generated by the generator 64 are latched by the H tape signal at the latch 67. In order to provide certain functions, the digital counter 66 and the latch 67 may be of a conventional type.

As also shown in FIG. 3, the comparator 75 receives the output signals of the line-number generator 64 and the input / output register array 71. The signal of the input / output register array 71 is named "selected line number" signal. Although the selected line number signal is shown as the output of the input / output register array 71, in practice it is determined by the CPU 55 under normal software control. (I.e., the CPU provides a sequence of video line numbers in a determined and ordered manner, and at a specified rate, under normal software control.) The thrust of the comparator 75 on line 76 is " read gate. enable) " and is generated by the comparator 75 only if the selected line number matches the line number provided by the generator 64. That is, comparator 75 compares two input line numbers and provides a read gate grant signal only when the input line numbers are the same.

Further, in the system of FIG. 3, the read gate permission signal is transmitted to the syringe 79 consisting of the memory register 81 and the pattern detector 83. As shown in FIG.

The other input signal sent to the syringe 79 is the 'data' signal, which is usually VITC information read from the video tape 15. In fact, the memory register 81 is a conventional 90-bit shift register that is permitted by the read gate permission signal on the line 76. That is, only when the register 81 receives the gate permission signal at the same time, the register 81 will store the 'input' signal. In the syringe 79, the pattern detector 83 is a conventional type of comparator connected to the register 81, and detects which synchronization information is kept in the register 81 and put into the information.

In practice, preferably, the pattern detector 83 determines whether the stored 'data' information contains unique synchronization information in the VITC information.

As such, the pattern detector 83 may be described as identifying valid data, and the output on line 82 may be said to be a "data ready" signal.

As will be clear from the following description, the data ready signal on line 82 indicates that the read operation has been completed successfully and that the data read out of the input / output register array 71 can begin. The data ready signal on the line 82 is provided to the input / output register array 71 to start the transfer of data from the storage register 81 via the line 84 to the output register of the array 71.

Other components of the input / output processing unit 51 include a multiplexer 85 connected to the output of the input / output register array 71, a parallel-to-serial converter 89, and a generator 91 for generating CRC and sink butts.

These components work together upon the output of the input / output register array 71 to generate a signal suitable for processing with the filter 59 and other components of the write subsystem of FIG. The final processed signal is then suitable for being written onto the video tape by the components of FIG.

Now, the overall operation of the second and third degree systems will be described. Initially, it is assumed that the tape conveying apparatus 10 is installed and operated by the control apparatus 33 so that the video tape is being conveyed in the rewinding direction. Thus, if the operation begins in an edit transition, the device 10 will back up in the transition and then read the videotape prior to the transition. (This operation is often referred to as "pre-rell"). As the video tape 15 is read during the preliminary roll operation, the information in the vertical blanking intervals is read by the read heads 14, and the signal processor 41, the demodulator 43, the limit detector 49 ) And sink separator 47. The synthesized signals are provided to the input / output processing unit 51.

과 같은 기간만큼 오프(off)-테이프 선 번호들의 예정 도착 시간에 앞서 VBI선 번호들을 발생시킨다. 그 다음, 발생된 VBI선 번호들은 선 번호 발생기(64)의 출력을 비디오 테이프에서 판독된 Htape신호와 래치하므로써 실제로 비디오 테이프에서 판독되는 정보와 시간에 있어서 동기된다.In addition, when the recording-reproducing apparatus 10 is in the spare roll reproduction mode, the Htape signal is read out from the video tape 15. The Htape signal is used at the latch 67 connected to the output of the line number generator 64. In generator 64, line counter 66 uses the reference signals Vref, Href and 4fsc to approximate the horizontal line period.

VBI line numbers are generated prior to the scheduled arrival time of off-tape line numbers by a period such as. The generated VBI line numbers are then synchronized in time with the information actually read from the video tape by latching the output of the line number generator 64 with the Htape signal read from the video tape.

The synchronized VBI line number is then compared with the line number selected in comparator 75 to provide a permission signal on line 76 to storage register 81 of syringe 79. (As described above, the permission signal is provided only when the generated line number matches the selected line number). As such, when register 81 is enabled and the 'data' signal is stored therein, the 'data' signal information is compared with the information stored in detector 83 to determine whether there is unique synchronization information. Normally, the pattern detector 83 determines whether the synchronization bits indicating valid VITC information is contained in the 'data' stored in the register 81.

At this time, it can be understood that the register 81 in the syringe 79 is only allowed to read one selected line of the vertical blanking interval at any one time. As such, the syringe 79 may be said to provide a “window”, which is one long line that is controlled by the comparator 75 to examine a specially selected line within the at least one sequential vertical blanking intervals. . In practice, the selected line numbers are determined in order by the command of the CPU 55 under normal software control.

In normal operation of the syringe 79 to identify VITC information, several iterations are always required before the VITC information is placed at the selected line number. In other words, it is always necessary for the CPU 55 to select some line numbers to find extra two lines in which VITC information is actually stored. Also in normal operation, because of the tape feed rate, at most only one line is always examined at each vertical blanking interval to determine whether the line contains valid VITC information. That is, when containing valid VITC information, it may be traversed to some vertical blanking interval, etc., before a particular line is detected in the interval.

When the syringe 79 identifies valid 'data' information on the selected line within the vertical blanking interval, the data ready signal transmits the identified information via line 84 to the output registers of the input / output register array 71. Function The data ready signal also identifies the presence of the line number selected for the input / output register array 71 and the CPU 55 via line 82. The CPU 35 then operates in the usual manner to retain the identified line number in its internal storage. When these steps are taken for each of the two extra lines of VITC information within the vertical blanking interval, the process of reading the VITC information is essentially completed. As such, it is understood that the systems of Figures 2 and 3 differ from conventional systems in that they not only identify valid 'data' (ie VITC (information)), but also identify a special diagram within the vertical intervals where such information is written. The process of writing VITC information is conventional and need not be described in detail except that the lines in the vertical blanking intervals into which the 'data' information is written are selected by the CPU 55.

In the editing process, it is often convenient to select the line number to be written so that the valid 'data' information matches the pre-located line numbers. In such a write operation for VITC information during editing, it is a preliminary step that the CPU 55 generates an incremented frame number so that numerically sequential VITC information is used for writing. Other steps of the writing process include transferring the contents of the selected output registers in the input / output register array 71 to the multiplexer 85 and then to the parallel-to-serial transformer 89.

In converter 89, the CRC and synchronization bit information are added to the transmitted information to generate a complete 'data' signal. The generated 'data' signal is processed by the filter 59, the adder circuit 60, the modulator 62, and the write signal processor 63, and then the video tape 15 by the read heads 14. When recorded on C2, other signal processing steps are achieved prior to recording.

Since the memory in the CPU 55 can hold the line number that was detected in the vertical blanking intervals in which VITC information was read in advance, the CPU 55 inputs and outputs to write subsequent VITC information on the detected same lines. May be directed to the register array 71. In addition, the system of FIGS. 2-3 may be operable to record numerically sequential VITC information on lines of vertical blanking intervals that are the same lines, if desired, where valid VITC information was detected. For ease of video recording, the process of writing VITC information on identified lines of vertical blanking intervals may be called a "jam slave" process.

Although the invention has been described with particular reference to the illustrated embodiments, the content is not to be construed as limiting. Various other changes and modifications will no doubt be apparent to those skilled in the art after reading the foregoing. For example, it should be apparent from the above description that the system of FIGS. 2-3 can be used to write selected information in such a way that, unlike VITC information of selected lines, the information appears on the same lines as the lines from which it was detected. . However, in view of the modifications and others, the appended claims should be construed to encompass all optional embodiments and equivalents falling within the spirit and scope of this invention.

Claims (9)

A videotape includes video information lines, some of the information lines having time toe information including an identifier for setting time code information presence, and a system for writing vertical retrace period time code information to a videotape. Scanning means 81 for scanning the information lines in the vertical blanking interval on the image, control means 55 and 75 for individually selecting the video information lines to be scanned, and the number of scanned information lines including time code information. Vertical retrace period time code information for writing vertical retrace period code information generated at vertical blanking intervals only to lines detected or identified as detecting means 83 for detecting and identifying and including predetermined time code information. And means arranged for generating the control and for controlling the recording means. The system according to claim 1, wherein said scanning means (81) is controlled so that one line forms an elongated window. The system according to claim 1, wherein the central processing unit (55) selects information lines to be individually scanned by the scanning means. 4. A system according to claim 3, comprising means (63) for generating vertical retrace period line numbers of lines arriving first from the videotape, and means for synchronizing the generated line numbers with information read from the videotape. . 5. A comparator (75) according to claim 4, comprising a comparator (75) which provides an output for enabling the scanning means to scan the selected information lines only when the vertical retrace period line number is the same as the line number selected by the central processing unit. System. 6. The system according to any one of claims 1 to 5, wherein said detecting means comprises a synchronization pattern detecting means for checking whether the information contained in the line scanned by said scanning means contains unique synchronization information. 12. A method of inserting vertical retrace period time code information into a videotape, wherein the videotape includes video information lines, some of which have time code information including an identification that sets the presence of the vertical retrace period time code information. Reading information lines in the vertical blanking interval, identifying the line number of the specific line in the vertical blanking interval comprising identifiers setting the presence of the vertical blanking period time code information, generating time code information, and video And recording the time code information generated only on the identified specific lines on the tape. 8. The method of claim 7, wherein time code information is recorded in the information after the edit transition that occurs continuously before the edit transition and in the identified lines of vertical blanking intervals. 8. The method of claim 7, comprising selecting lines at vertical intervals for recording time code information via the central processing unit, and reading the individually selected lines within the vertical blanking interval generating line numbers. And reading the selected line only when the generated line number is the same as the line number selected by the central processing unit.

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