JP2014068102A - Time code synchronization device, and time code synchronization method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a time code synchronization device ensuring normal time code synchronization.SOLUTION: A time code synchronization device comprises: a time code reading section 101 for reading an externally supplied time code at a plurality of timings synchronized with a video signal to be recorded; a time code determining section 102 for employing the value of a time code employed immediately before if the value of at least one time code, out of a plurality of time codes read in the time code reading section, has been increased by a predetermined number from the value of a time code employed immediately before, otherwise employing the value of any time code other than one time code; and a time code setting section 103 for adding the value of a time code employed in the time code determining section to the video signal to be recorded.

Description

  The present invention relates to a time code synchronization apparatus and a time code synchronization method for synchronizing time codes added to video signals recorded simultaneously on a plurality of video recording apparatuses.

When recording a video signal on a recording medium, it is generally performed to add a time code to the video signal in order to specify a temporal position of the recorded video signal. The time code is represented by “hour: minute: second: frame”. Since the frame rate is usually 30 frames / second, the frame digits are counted up in a range from 0 to 29. For example, “02: 14: 36: 19”
Is 2: 14: 36.19 frames. This time code is normally generated by a time code signal generator built in the video recording apparatus.

  By the way, there is an application in which the same subject is imaged and recorded using a plurality of cameras and video recording devices, and editing is performed later using a time code. In this case, any one of the plurality of video recording apparatuses is set as a master, and the video synchronization signal and the time code are supplied from the master video signal recording apparatus to another slave video recording apparatus. The slave-side video recording device synchronizes the video signal to be recorded on its own device with the video synchronization signal supplied from the master video recording device, and the synchronized video signal is also supplied from the master video recording device. Record with the added time code. As a result, the video signals recorded in the respective video recording devices are synchronized with each other, and the time code is also synchronized. Accordingly, since the recorded video signals have the same time axis, the subsequent editing work is facilitated.

  However, it is expensive to install a function (external video synchronization function) for synchronizing a video signal to be recorded on the device with a video synchronization signal supplied from the outside. Video signal synchronization and time code synchronization are often operated in a pair. However, even if only the time code is synchronized without synchronizing the video signal, the subsequent editing work is easy. This is effective and meaningful. For example, Patent Document 1 discloses a technique for omitting the external video synchronization function and synchronizing only the time code in order to reduce the cost.

JP 2006-4575

  However, the technique described in Patent Document 1 is based on the premise that the time code can be read correctly at the time of starting the time code synchronization. Also, when an error such as a disturbance occurs when reading the time code, and the update value of the time code value is out of the range of 0 to 2, the normal value cannot be acquired and the time code is synchronized correctly The problem of being unable to take was left.

  The present invention has been made in view of such a situation, and its purpose is to eliminate the external video synchronization function, and to synchronize only the time code, it is possible to achieve time code synchronization normally. A code synchronization apparatus and a time code synchronization method are provided.

In order to solve the above problems, the present invention provides the following apparatus and method.
(1) a time code reading unit (101) for reading a time code supplied from outside at a plurality of timings synchronized with a video signal to be recorded;
When the value of at least one time code among the plurality of time codes read by the time code reading unit is increased by a predetermined number from the value of the time code adopted immediately before, the value of the one time code is On the other hand, if the predetermined number has not increased, a time code determination unit (102) that adopts any time code value other than the one time code;
A time code setting unit (103) for adding the value of the time code adopted by the time code determination unit to the video signal to be recorded;
A time code synchronization device comprising:
(2) a time code reading unit that reads a time code supplied from the outside at a first timing synchronized with a video signal to be recorded;
When the time code value read by the time code reading unit has increased by a predetermined number from the value of the time code adopted immediately before, the value of the one time code is used, but the predetermined number has not increased. A time code determination unit that causes the time code reading unit to read the time code at a second timing different from the first timing, and adopts a value of the time code read at the second timing; ,
A time code setting unit that adds the value of the time code adopted by the time code determination unit to the video signal to be recorded;
A time code synchronization device comprising:
(3) After the time code setting unit has performed the process of adding the time code value adopted by the time code determination unit to the video signal to be recorded a predetermined number of times, the time code setting unit itself The time code synchronizer according to (1) or (2), wherein the code value is increased by a predetermined number and added to the video signal to be recorded.
(4) a time code reading step for reading a time code supplied from the outside at a plurality of timings synchronized with a video signal to be recorded;
When the value of at least one time code among the plurality of time codes read in the time code reading step is increased by a predetermined number from the value of the time code adopted immediately before, the value of the one time code is set. On the other hand, if the predetermined number has not increased, a time code determination step that employs any time code value other than the one time code;
A time code setting step of adding the value of the time code adopted in the time code determination step to the video signal to be recorded;
Including a time code synchronization method.
(5) a time code reading step of reading a time code supplied from the outside at a first timing synchronized with a video signal to be recorded;
When the time code value read in the time code reading step is increased by a predetermined number from the value of the time code adopted immediately before, the value of the one time code is adopted, but the predetermined number is not increased. A time code determination step of causing the time code reading step to read the time code at a second timing different from the first timing, and adopting a value of the time code read at the second timing; ,
A time code setting step of adding the value of the time code adopted in the time code determination step to the video signal to be recorded;
Including a time code synchronization method.

  According to the present invention, it is possible to properly synchronize the time code even when the external video synchronization function is omitted and only the time code is synchronized.

It is a system configuration diagram showing a state of time code synchronization. It is a timing chart which shows the mode of time code synchronization. It is a block diagram which shows the structure of the time code synchronizer of a present Example, and the video recording apparatus carrying this time code synchronizer. It is a timing chart which shows the mode of the time code synchronization of a present Example. It is a flowchart of the time code synchronization method of a present Example.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
<System configuration>
FIG. 1 is a system configuration diagram showing a state of time code synchronization among a plurality of video recording apparatuses. As shown in the figure, video signals are respectively input from the camera 5 to the plurality of video recording apparatuses 1. Also, any one of these video recording apparatuses 1 becomes a master, and a time code is supplied from the video recording apparatus 1 that has become the master to the video recording apparatus 1 that is another slave. The time code is transmitted / received as 80-bit serial data, for example, as LTC (Longitudinal Time Code). This does not include information such as error collection bits for error determination. Therefore, the slave video recording apparatus 1 on the receiving side needs to implement an error determination process.
<Time code synchronization>
FIG. 2 is a timing chart showing a state of time code synchronization in the video recording apparatus 1 which is a slave of the system. The time code (input time code) input from the master video recording device 1 is the timing of the trigger signal generated in synchronization with the frame of the video signal input from the camera 5 connected to the slave video recording device 1. Is read. Needless to say, the trigger signal need not be physically generated. For example, the time code may be read at a timing synchronized with the frame in terms of software by a program executed by the CPU. In order to show the read timing on the timing chart, a trigger signal is defined in this embodiment.

  At this time, the update timing of the input time code is synchronized with the video signal of the master video recording apparatus 1, and the generation timing of the trigger signal is synchronized with the video signal of the slave video recording apparatus 1. However, since the video signal is not synchronized between the master side and the slave side, the positional relationship between the update timing of the input time code and the generation timing of the trigger signal is indefinite. When the positional relationship between the update timing of the input time code and the generation timing of the trigger signal is as shown in FIG. 2A, for example, the input time code is read stably.

  However, if the positional relationship between the update timing of the input time code and the generation timing of the trigger signal is substantially the same as shown in FIG. 2B, the input time code is set to 2 due to subtle time fluctuation of the trigger signal. The problem of repeated reading or skipping occurs for a long time. The hatched portion of the read time code in FIG. 2B is the portion where the problem has occurred.

The object of the present invention is to solve the problem shown in FIG.
<Time code synchronization device>
FIG. 3 is an internal configuration diagram of the video recording apparatus 1 serving as a slave equipped with the time code synchronization apparatus 100 according to the present embodiment.

  The compression encoding unit 2 compresses and encodes the video signal supplied from the camera 5 using, for example, MPEG (Moving Picture Experts Group) -2, and generates an encoded video stream. The time code adding unit 3 adds a time code supplied from a time code synchronization apparatus 100 described later to a predetermined area of the generated encoded video stream. The video recording unit 4 records the encoded video stream to which the time code is added on a predetermined recording medium.

  The time code synchronization apparatus 100 is mounted, for example, inside the video recording apparatus 1 and includes a time code reading unit 101, a reading time code determination unit 102, and a writing time code setting unit 103.

  Based on the video synchronization signal separated from the video signal supplied from the camera 5, the time code reading unit 101 generates a trigger signal A at a first timing and a second timing that are shifted from each other by a predetermined period within one frame. And the trigger signal B are generated, and the time code supplied from the master video recording apparatus is read at two timings based on the trigger signals A and B. The time code value read based on the trigger signal A is set as time code A, and the time code value read based on the trigger signal B is set as time code B. These read time codes A and B are supplied to the read time code determination unit 10.

  The reading time code determination unit 102 determines the validity of the value of the time code A supplied from the time code reading unit 101. The validity of the value is determined by whether or not the value of the supplied time code A is a value that is increased by a predetermined value with respect to the value read immediately before. When the value is increased by a predetermined value, it is determined that the value of the time code A is valid, and when it is any other value, it is determined to be invalid. The predetermined value is normally 1 (frame).

  When the read time code determination unit 102 determines that the supplied time code A value is valid, the read time code determination unit 102 supplies the time code A value to the write time code setting unit 103.

  When the read time code determination unit 102 determines that the value of the supplied time code A is invalid, the relationship between the update timing of the input time code and the generation timing of the trigger signal is as shown in FIG. The value of the time code B supplied at the same time is supplied to the write time code setting unit 103.

  The write time code setting unit 103 supplies the value of the read time code A or B supplied from the read time code determination unit 102 to the time code adding unit 3 as a write time code.

  FIG. 4 is a timing chart for explaining the state of time code synchronization by the time code synchronization device. The read time code A in FIG. 4 is a time code read by the trigger signal A (solid arrow), and the read time code B is a time code read by the trigger signal B (broken arrow). Even when the reading time code A is discontinuous (unauthorized) with the value 00, the reading time code B is continuous (valid) with the value 01. Therefore, at this time, the read time code determination unit 102 supplies the value of the read time code B to the write time code setting unit 103, so that the continuity of the write time code is maintained.

  It is not always necessary to read the time code. The write time code setting unit 103 supplies the time code supplied from the read time code determination unit 102 to the time code addition unit 3 a predetermined number of times (about four times), and then the time code of the time code from the read time code determination unit 102 is supplied. Instead of being supplied, the time code value may be counted up by itself and supplied to the time code adding unit 3.

  Further, the trigger signal is not limited to two types, and two or more types may be generated.

In the above description, an example of a configuration in which a plurality of time codes are read using a plurality of trigger signals has been described, but only one time code is read with one type of trigger signal, and the value of the read time code is invalid. If it is determined that the trigger signal timing is different, the trigger signal timing may be shifted. In this case, the trigger signal is generated by the reading time code determination unit 102 and supplied to the time code reading unit 101.
<Time code synchronization method>
The process flow of the time code synchronization method in the time code synchronization apparatus described above will be described with reference to the flowchart of FIG.

  When the time code synchronization is started, first, the time code reading unit 101 generates trigger signals A and B based on the video synchronization signal, and reads the input time code with the trigger signals A and B (step S1). At this time, the time code read by the trigger signal A is set as a read time code A, and the time code read by the trigger signal B is set as a read time code B.

  Next, the reading time code determination unit 102 determines whether or not the reading time code A read by the time code reading unit 101 is valid (step S2). If it is valid (step S2: Yes), the reading time code determination unit 102 adopts the reading time code A as a writing time code and supplies it to the writing time code setting unit 103 (step S3). On the other hand, if it is not valid (step S2: No), the reading time code determination unit 102 adopts the reading time code B as the writing time code and supplies it to the writing time code setting unit 103 (step S4). The write time code setting unit 103 supplies the supplied write time code to the time code adding unit 3 and adds it to a predetermined area of the video encoded stream (step S5).

  The present invention includes a program for causing a computer to realize the functions of the apparatus described above. These programs may be read from a recording medium and loaded into a computer, or may be transmitted via a communication network and loaded into a computer.

1: Video recording device 2: Compression encoding unit 3: Time code adding unit 4: Video recording unit 5: Camera 100: Time code synchronization device 101: Time code reading unit 102: Reading time code determination unit 103: Write time code setting Part

Claims (5)

A time code reading unit for reading a time code supplied from the outside at a plurality of timings synchronized with a video signal to be recorded;
When the value of at least one time code among the plurality of time codes read by the time code reading unit is increased by a predetermined number from the value of the time code adopted immediately before, the value of the one time code is On the other hand, if the predetermined number has not increased, a time code determination unit that adopts any time code value other than the one time code;
A time code setting unit that adds the value of the time code adopted by the time code determination unit to the video signal to be recorded;
A time code synchronization device comprising: A time code reading unit for reading a time code supplied from the outside at a first timing synchronized with a video signal to be recorded;
When the time code value read by the time code reading unit has increased by a predetermined number from the value of the time code adopted immediately before, the value of the one time code is used, but the predetermined number has not increased. A time code determination unit that causes the time code reading unit to read the time code at a second timing different from the first timing, and adopts a value of the time code read at the second timing; ,
A time code setting unit that adds the value of the time code adopted by the time code determination unit to the video signal to be recorded;
A time code synchronization device comprising:   After the time code setting unit has performed the process of adding the time code value adopted by the time code determination unit to the video signal to be recorded a predetermined number of times, the time code setting unit itself determines the time code value. 3. The time code synchronization apparatus according to claim 1, wherein a process of increasing a predetermined number and adding to the video signal to be recorded is repeated. A time code reading step for reading a time code supplied from the outside at a plurality of timings synchronized with a video signal to be recorded;
When the value of at least one time code among the plurality of time codes read in the time code reading step is increased by a predetermined number from the value of the time code adopted immediately before, the value of the one time code is set. On the other hand, if the predetermined number has not increased, a time code determination step that employs any time code value other than the one time code;
A time code setting step of adding the value of the time code adopted in the time code determination step to the video signal to be recorded;
Including a time code synchronization method. A time code reading step for reading a time code supplied from outside at a first timing synchronized with a video signal to be recorded;
When the time code value read in the time code reading step is increased by a predetermined number from the value of the time code adopted immediately before, the value of the one time code is adopted, but the predetermined number is not increased. A time code determination step of causing the time code reading step to read the time code at a second timing different from the first timing, and adopting a value of the time code read at the second timing; ,
A time code setting step of adding the value of the time code adopted in the time code determination step to the video signal to be recorded;
Including a time code synchronization method.

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