Time information generator

Abstract: In a time information generator (25, 26, 27) for generating time information with respect to an arbitrary frame of video information varying with time on the basis of time information delivered at predetermined time intervals from video information forming device (10) for forming video information as mentioned above, there is employed a scheme to discriminate between operational modes of the video information forming device (10) to form, by an interpolative operation, time information in said arbitrary frame of video information from time information delivered from the video information forming device every n ( n = 2, 3, 4, ...) frames of video information on the basis of the result indicative of the discriminated operational mode.

Description: This invention relates to a time information generator for generating time information with respect to an arbitrary frame of video information varying with changes in time, and more particularly to a time information generator for generating time information by interpolative processing. Generally, in video equipment systems, where equipment such as a video tape recorder, etc, is controlled by an editing machine, a time code signal as described in, eg, US-A- 4159480, is used as time information indicating the recording position of a video signal dealt with by that equipment. In such a video editing system, so called mark processing, etc, is conducted to read, for example, the time code value from a video tape and display it on a visual display screen, or for time reference purposes, eg, to cause the video tape machine to record or replay a video signal from a given time code value, starting at some arbitrary point of time, in the course of setting up or carrying out an edit on the editing machine. In the above mentioned video editing system, it is desirable to determine the time code as frequently as possible with respect to equipment such as a video tape recorder, etc, in order to provide precise time information at an arbitrary time point at the editing machine side. Since video information, ie, video signals dealt by the above mentioned video tape recorder, etc, are constructed on a per-frame basis, the activity of sensing the time code is conventionally conducted every frame on the editing machine side. Further, also in a digital video effector which is used to add a video effect to a video signal output from a video tape recorder, etc, some video editing systems use time codes as position information for providing a special effect. Some equipment such as video tape recorders, or digital video effects device, etc, controlled by an editing machine in the video editing system are constructed to suppress their response processing ability with respect to external devices in order to ensure the processing capacity for the original video processing on the equipment body side or the system control. In such equipment, there are instances where it is not possible to carry out the work necessary to sense time codes for every frame from the editing machine, and so accordingly, it is necessary to carry out the work for sensing the time codes only once every several frames to widen the sensing interval, so as to reduce the overhead involved in updating the time code information. However, if the sensing interval is widened, the updating interval of time information displayed on the display screen becomes coarse, resulting in a bad impression and/or reduced accuracy of control of the video tape recorder, etc. With the actual circumstances in the above described video editing system in view, this invention contemplates providing a time information generator capable of generating a time code at an arbitrary time point even if the sensing interval is widened with respect to equipment having a lower response processing ability. In GB-A-2,198,873 a system is described whereby digital data is read from a magnetic tape in blocks. The first of these blocks being for synchronisation. A synchronisation block detector serves to produce a synchronisation pulse when it detects the appropriate digital data corresponding to a synchronisation block. The apparatus also includes means for predicting when the synchronisation pulse should be received and produces a 'window' around that time so that erroneous synchronisation pulses cannot disrupt the system. However, if a synchronisation pulse is not detected due to drop-out etc., the window remains open and processing of data is suspended until a sync pulse is received. An object of this invention is thus to provide a time information generator for generating time information delivered every n ( n = 2, 3, 4, ...) frames from video information forming means for forming video information varying with changes in time and time information in an arbitrary frame of video information on the basis of the operational mode of the video information forming means. According to one aspect of the present invention there is provided a time information generator for generating time information with respect to an arbitrary frame of video information varying with time on the basis of time information delivered, at predetermined intervals, from video information forming means for forming said video information, comprising: a) discrimination means for discriminating between operational modes of said video information forming means; b) time information sense means for receiving time information from said video information forming means every n frames of said video information, where n is a positive integer greater than 1; and c) interpolative operation means adapted to be supplied with an output signal from said discrimination means and an output signal from said time information sense means to perform an interpolative operation corresponding to said discriminated operational mode to generate time information with respect to said arbitrary frame of said video information. According to a further aspect of the present invention there is provided a time information generator for generating time information with respect to an arbitrary frame of video information on the basis of time information delivered at predetermined time intervals from a playback device for playing back video information from a magnetic tape, comprising: a) discrimination means for discriminating between operational modes of said playback device; b) time information sense means for receiving time information from said playback device every n frames of said video information where n is a positive integer greater than 1; and c) interpolative operation means adapted to be supplied with an output signal from said discrimination means and an output signal from said time information sense means to perform an interpolative operation corresponding to said discriminated operational mode to generate time information with respect to said arbitrary frame of said video information. According to a yet further aspect of the present invention there is provided a time information generator for generating time information with respect to an arbitrary frame of video information indicative of an input image on the basis of time information delivered, at predetermined time intervals, from a digital video effects device for transforming the input image to form an output image, comprising: a) discrimination means for discriminating between operational modes of said digital video effects device; b) time information sense means for receiving time information from said digital video effects device every n frames of said video information where n = 2, 3, 4, ...; and c) interpolative operation means adapted to be supplied with an output signal from said discrimination means and an output from said time information sense means to perform an interpolative operation corresponding to the discriminated operational mode to generate time information in said arbitrary frame of said video information. The invention will be further described by way of non-limitative example with reference to the accompanying drawings, in which:- Figure 1 is a block diagram showing an embodiment in which a time information generator of this invention is applied to a video tape editing system. Figure 2 is a flowchart showing the procedure for generating time information in the time information generator of this invention. An embodiment of a time information device according to this invention will now be described in detail with reference to the accompanying drawings. In the embodiment shown in Figure 1 as a block diagram, this invention is applied to an editing machine (20) for controlling a video information forming device (10) such as a video tape recorder or a digital video effector for transforming an input image to form an output image, etc, in the video editing system. The video information forming device or unit (10) comprises an image information forming section (11), e.g., corresponding to a video playback or reproducing processing system, etc. in a video tape recorder for recording a video signal on a magnetic tape or playing back it therefrom. This video information forming section (11) forms video information varying with changes in time every frame. Further, the image information forming device (10) further comprises a control section (12) for controlling the operation of the image information forming section (11), etc. This control section (12) becomes operative in response to an operating control command transmitted as a remote signal from a command transmitting section (21) of the editing machine (20). Further, this video information forming device (10) comprises a time code reading section (13) for reading, from a magnetic tape, a time code as time information indicating a current position of an image information formed at the image information forming section (11), and a status transmitting section (14) for transmitting, to the editing machine (20), a status signal indicating the time code or an operational mode, etc. of the image information forming section (11). With respect to the time information, the status transmitting section (14) transmits it as a status signal only once every N frames. Where the video information forming unit (10) is a digital video effector, the time code reading section (13) reads time codes inputted along with an input image signal to deliver them to the status transmitting section (14). The editing machine (20) comprises a control section (24) to which operation data is inputted from an operation data input section (22) in which a key board, etc. is used. This control section (24) carries out such an operating control to take operation data, etc. from the operation data input section (22) into a memory (23), and/or to allow the command transmitting unit (21) to transmit an operating control command as a remote signal from the command transmitting section (21) in response to the operation data, control data stored in advance in the memory (23), or the like. The editing machine (20) further comprises a mode discriminative section (25) and a time information sense section (26). The mode discriminative section (25) discriminates between operational modes of the image information forming section (11) on the basis of an operating control command transmitted from the command transmitting section (21) or a status signal transmitted from the status transmitting section (14) of the image information forming unit (10). Further, the time information sense section (26) senses, once every N frames, time information indicative of a current position of image information formed at the image information forming section (11) on the basis of the status signal. The editing machine (20) comprises an interpolative operation processing section (27) for implementing interpolative operation to time information in an arbitrary frame of video information formed at the image information forming section (11) on the basis of the operational mode discriminated at the mode discrimination section (25) and time information sensed once every N frames at the time information sense unit (26) to allow a display section (29) to display, at a display control section (28), the time information, etc. obtained by the interpolative operation processing section (27). In this embodiment, the interpolative operation processing section (27) constitutes a time information generator according to this invention along with the mode discriminative section (25) and the time information sense section (26). This interpolative operation processing section (27) carries out, by the algorithm as indicated by the flowchart in FIG. 2, interpolative operation for determining or deciding time information in an arbitrary frame of video information formed by the image information forming section (11). Namely, the interpolative operation processing section (27) first waits elapse of one frame from the last interpolative operation at the first step S₁ in the algorithm indicated by the flowchart of FIG. 2. At second step S₂, a flag (Flstart) indicating start of the interpolative processing is set to zero. The value (Frmctr) of the frame counter indicative of the number of frames being subjected to interpolative processing undergoes incremental operation, and the value (Snsctr) of the sense counter for sensing time information of a current position once every N frames undergoes incremental operation. At third step S₃, judgment processing as to whether the value (Snsctr) of the sense counter becomes equal to N is made. Where a judged result at the third step S₃ is YES, i.e., the value (Snsctr) of the sense counter is N, the operation shifts to the fourth step S₄ to sense, at the time information sense section (26), time information indicative of a current position of image information formed at the image information forming section (11) of the image information forming device (10) on the basis of the status signal. Then, at the fifth step S₅, a flag (Flstart) indicative of start of the interpolative processing is set to 1 and the value (Snsctr) of the sense counter for sensing time information of a current position once every N frames is set to zero. Then, the operation shifts to the sixth step S₆. It is to be noted that where a judged result at the third step S₃ is NO, i.e., the value (Snsctr) of the sense counter is not N, the operation shifts to the tenth step S₁₀ which will be described later to carry out discriminative processing of the operational mode of the image information forming unit (10). At the sixth step S₆, judgment processing as to whether or not sending command is present is made. Where a judged result in the sixth step S₆ is NO, i.e., transmit command is absent, the operation shifts to the seventh step S₇. In contrast, where a judged result at the sixth step S₆ is YES, i.e., the transmit command is present, the operation shifts to the fifteenth step S₁₅ which will be described later. At the seventh step S₇, judgment processing as to whether or not the flag (Flstart) indicative of start of interpolative processing is equal to 1 is made. Where a judged result at the seventh step S₇ is YES, i.e., the above-mentioned flag (Flstart) is equal to 1, the value (Curtim) of the register indicative of time information of a current position is set as the value (Starttim) of the register indicative of time information at the time of start of interpolation at eighth step. The value (Stepctr) of the step counter indicative of a sum of the number of steps by the JOG command is set to zero. Further, the value (Frmctr) of the frame counter indicative of the number of frames being subjected to interpolative processing is set to zero. The operation then shifts to the ninth step S₉. By repeatedly executing the first to ninth steps S₁ to S₉, time information once every N frames is established at the ninth step S₉ on the basis of time information sensed once every N frames at the time information sense section (26). Further, where a judged result at the third step S₃ is NO, i.e., the value (Snsctr) of the sense counter does not reach N, the operation shifts to the tenth step S₁₀ to carry out a discriminative processing of the operational mode at the mode discriminative section (25). In this embodiment, four kinds of operational modes of STOP mode for stopping formation of image information, PLAY mode for forming image information at an ordinary speed, JOG mode for forming image information at a speed corresponding to the content of steps of n frames, and a VAR mode for forming image information at an arbitrary constant speed are assumed as the operation of the image information forming device (10). The mode discriminative section (25) analyzes an operating control command transmitted from the command transmitting section (21) and/or a status signal transmitted from the status transmitting section (14) of the image information forming device (10) to thereby discriminate the operational mode of the image information forming unit (10). Where a judged result of the operational mode at the tenth step S₁₀ indicates STOP mode, the value (Curtim) of the register indicative of time information at a current position is set to the value (Starttim) of the register indicative of time information at the time of start of interpolation. The operation then shifts to the sixth step S₆ to carry out the judgment processing as to whether or not the transmit command is present. Where a judged result of the operational mode at the tenth step S₁₀ is PLAY mode, the value (Curtim) of the register indicative of time information at a current position is changed to a value obtained by adding the value (Frmctr) of the frame counter indicative of the number of frames being subjected to interpolative processing to the value (Starttim) of the register indicative of time information at the time of start of interolation. The operation then shifts to the sixth step S₆ to carry out a judgment processing as to whether or not transmit command is present. Further, where judged result of the operational mode at the tenth step S₁₀ is JOG mode, at the thirteenth step S₁₃, the value (Stepctr) of the step counter indicative of a sum of the number of steps by JOG command after start of interpolation is changed to a value obtained by adding the value (Step) indicative of the number of frames of the image information forming unit (10) advanced by JOG command to the value (Stepctr) of the step counter. Moreover, the value (Curtim) of the register indicative of time information at a current position is changed to a value obtained by adding the value (Stepctr) of the step counter to the value (Starttim) of the register indicative of time information at the time of start of interpolation. After the value (Step) of the register is set to zero, the operation shifts to the sixth step S₆ to carry out a judgment processing as to whether or not transmit command is present. Furthermore, where a judged result of the operational mode at the tenth step S₁₀ is VAR mode, at the fourteenth step S₁₄, a value obtained by adding a value obtained by multiplying a value (Speed) of the register indicative of a speed by VAR command by the value (Frmctr) of the frame counter indicative of the number of frames being subjected to interpolative processing to the value (Starttim) of the register indicative of time information at the time of start of interpolation is set as the value (Curtim) indicative of time information at a current position. The operation then shifts to the sixth step S₆ to carry out a judgment processing as to whether or not transmit command is present. Where the judged result at the third step S₃ is NO, i.e., the value (Snsctr) of the sense counter does not reach N as stated above, the operation shifts to the tenth step S₁₀ to carry out processing at the eleventh to fourteenth steps S₁₁ to S₁₄ for altering, per each frame, the value (Curtim) of the register indicative of time information at a current position in dependency upon the operational mode of the image information forming device (10). In this case, since processings at the tenth to fourteenth steps S₁₀ to S₁₄ are carried out in place of the above-mentioned fourth and fifth steps S₄ and S₅, the flag (Flstart) indicative of start of the interpolation processing is held at a value of zero. Where a judged result at the seventh step S₇ is NO, i.e., the flag (Flstart) is zero, the operation shifts to the ninth step S₉ without carrying out the processing at the eighth step S₈ Thus, time information of that frame is established. Assuming now that a judged result at the sixth step S₆ is YES, i.e., an operating control command transmitted from the command transmitting section (21) is present, when that command designates JOG mode, the content of steps is set to the value (Step) of the register indicative of the number of frames of the image information forming device (10), which is advanced by JOG command at the fifteenth step S₁₅. The operation then shifts to the sixteenth step S₁₆ to carry out a judgment processing as to whether or not the processing for altering the operational mode is required. When a judged result at the sixteenth step S₁₆ is NO, ie., no processing for altering the operational mode is required, the operation returns to the seventh step S₇. In contrast, when that judged result is YES, i.e., the processing for altering the operational mode is required, the operation shifts to the seventeenth step S₁₇. At the seventeenth step S₁₇, discriminative processing for discriminating the kind of an operating control command transmitted from the command transmitting section (21) is carried out. When an operating control command transmitted is judged to be STOP command as a reuslt of the discriminative processing at the seventeenth step S₁₇, STOP mode is set at the eighteenth step S₁₈. The operation then shifts to the nineteenth step S₁₉ to set the flag (Flstart) indicative of start of interpolative processing to 1 to return to the seventh step S₇. When an operating control command transmitted is judged to be PLAY command as a result of the discriminative processing at the seventeenth step S₁₇, PLAY mode is set at the twentieth step S₂₀. The operation then shifts to the nineteenth step S₁₉ to set the flag (Flstart) to 1 to return to the seventh step S₇. Further, when an operating control command transmitted is judged to be JOG command as a result of the discriminative processing at the seventeenth step S₁₇, JOG mode is set at the twenty first step S₂₁. The operation then shifts to the nineteenth step S₁₉ to set the flag (Flstart) to 1 to return to the seventh step S₇. Furthermore, when an operating control command transmitted is judged to be VAR command as a result of the discriminative processing at the seventeenth step S₁₇, VAR mode is set at the twenty second step S₂₂, and speed data of the VAR command transmitted as a value (Speed) of the register indicative of a speed in the VAR mode is set at the twenty third step S₂₃. The operation then shifts to the nineteenth step S₁₉ to set the flag (Flstart) to 1 to return to the seventh step S₇. When an operating control command transmitted from the command transmitting section (21) is present as stated above, the processing for altering the operational mode is conducted in dependency upon that operating control command, thereby making it possible to carry out an interpolative operation processing corresponding to the operational mode to precisely interpolate, every frame, on the editing machine (20) side, time information indicative of a current position of image information formed in various operational modes at the image information forming device (10). Accordingly, this embodiment can update, every frame, on the editing machine (20) side, time information displayed on a display screen of the display section (29) to carry out time display with a good impression. Further, it is possible to make a marking at an arbitrary time point to take time information into the memory (23) with high accuracy. In accordance with time information generator according to this invention, an approach is employed to discriminate, at the discriminative processing means, the operational mode of the video information forming device for forming video information varying with changes in time every frame to carry out, at the interpolative operation processing means, interpolative operation processing corresponding to the operational mode of the video information forming device in dependency upon a discriminated output by the discriminative processing means, thereby making it possible to form time information in an arbitrary frame of video information formed in the video information forming device. Accordingly, when this invention is applied to, e.g., an editing machine of a video editing system, even if the sense interval of time codes is widened with respect to equipment having a low response processing ability, it is possible to generate time information with a high accuracy at an arbitrary time point on the editing machine side. Accordingly, this makes it possible to carry out a marking work with a high accuracy, and to display time information with a good impression.

Claims: A time information generator for generating time information with respect to an arbitrary frame of video information, varying with time on the basis of time information, relating to the point in time of a given frame, received, at predetermined intervals, from video information forming means (10) for forming said video information, said predetermined interval corresponding to n frames of said video information, where n is a positive integer greater than 1, comprising: a) discrimination means (25) for discriminating between operational modes of said video information forming means; b) time information sense means (26) for receiving said time information from said video information forming means (10) every said predetermined interval, and c) interpolative operation means (27) adapted to be supplied with an output signal from said discrimination means (25) and an output signal from said time information sense means (26) to perform an interpolative operation corresponding to said discriminated operational mode to generate time information with respect to said arbitrary frame of said video information. A time information generator for generating time information with respect to an arbitrary frame of video information on the basis of time information, relating to the point in time of a given frame, received at predetermined time intervals, from a playback device for playing back video information from a magnetic tape, said predetermined interval corresponding to n frames of said video information, where n is a positive integer greater than 1, comprising: a) discrimination means (25) for discriminating between operational modes of said playback device; b) time information sense means (26) for receiving said time information from said playback device every said predetermined interval and c) interpolative operation means (27) adapted to be supplied with an output signal from said discrimination means (25) and an output signal from said time information sense means (26) to perform an interpolative operation corresponding to said discriminated operational mode to generate time information with respect to said arbitrary frame of said video information. A time information generator as set forth in claim 2, wherein said discrimination means (25) is operative to discriminate between STOP, PLAY, JOG and VARIABLE SPEED modes of said playback device. A time information generator as set forth in claim 2 or 3, wherein said interpolative operation means (27) is responsive to an output signal from said interpolative operation means to add a predetermined value to time information delivered from said playback device to thereby generate time information in said arbitrary frame. A time information generator as set forth in claim 4, wherein when the operational mode of said playback device is STOP mode, said interpolative operation means (27) outputs, as current time information, time information determined by the last interpolative operation; when the operational mode of said playback device is PLAY mode, said interpolative operation means (27) outputs, as current time information, a value obtained by adding a time corresponding to one frame of said video information to time information determined by the last interpolative operation; and when the operational mode of said playback device is JOG mode and VARIABLE SPEED mode, said interpolative operation means (27) outputs, as current time information, a value obtained by adding a time corresponding to a running speed of said magnetic tape to time information determined by the last interpolative operation. A time information generator as set forth in claim 2, 3, 4 or 5 wherein said time information is a time code signal. A time information generator for generating time information with respect to an arbitrary frame of video information indicative of an input image on the basis of time information relating to the point in time of a given frame, received at predetermined time intervals, from a digital video effects device for transforming the input image to form an output image, said predetermined time interval corresponding to n frames of said video information, where n is a positive integer greater than 1, comprising: a) discrimination means (25) for discriminating between operational modes of said digital video effects device; b) time information sense means (26) for receiving said time information from said digital video effects device every said predetermined period; and c) interpolative operation means (27) adapted to be supplied with an output signal from said discrimination means (25) and an output from said time information sense means (26) to perform an interpolative operation corresponding to the discriminated operational mode to generate time information in said arbitrary frame of said video information.

Inventors: SASHO HIDEHIKO C O SONY CORPOR, SASHO, HIDEHIKO, C/O SONY CORPORATION
Applicants: SONY CORP, SONY CORPORATION
Application year: 1990
Main classification: H04N5
IPC codes: H04N5, G11B27, H04N9