JPH1198472A - Field decision controller for closed caption decoder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve decision accuracy by deciding an even number or odd number field through software processing from a start command included in closed caption data. SOLUTION: A field decision section 20 decides an even number field or an odd number field based on a phase difference between a horizontal synchronizing signal S2 and a vertical synchronizing signal S3 outputted from a closed caption data information extract section 10. A decoding section 30 decodes a start command included in closed caption data S4 outputted from the closed caption data information extract section 10 to discriminate whether the start command is for an odd number field or an even number field. The decoding section 30 compares and evaluates the discrimination result from the field decision section 20 with the decision result obtained from the start command.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to program information, time,
The present invention relates to a closed caption decoder for displaying character information such as dialogue superimposed on image information, and to a control device for determining even or odd fields.

[0002]

2. Description of the Related Art As this kind of field judgment control device, for example, a device described in Japanese Patent Application Laid-Open No. H4-265085 is known. In this device, it is determined whether the field is an even field or an odd field based on the positional relationship (phase difference) between the horizontal synchronization signal and the vertical synchronization signal.

[0003]

However, only the positional relationship between the horizontal synchronizing signal and the vertical synchronizing signal is used to determine whether the field is an even field or an odd field, and the data fetched at the decoded timing without verifying the field determination result. When used as field data as a result of the determination, there is a possibility that data that should not originally be in the field is used without being canceled.

That is, erroneous field data is provided due to a typo on the side of the field data provider, or the positional relationship between the horizontal synchronizing signal and the vertical synchronizing signal is deviated due to deterioration of the field determination circuit or the like. If the field is erroneously determined, information in a different field may be erroneously displayed, or data existing only in even fields such as program information and time may be missed.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned conventional problems and to improve the accuracy of determination of an even or odd field in a closed caption decoder.

[0006]

According to the present invention, there is provided a field decision control device for a closed caption decoder, comprising: a video signal on which a closed caption signal is superimposed; a horizontal sync signal, a vertical sync signal, and a closed sync signal;
A closed caption data information extraction unit for extracting caption data, and a start field included in the closed caption data output from the closed caption data information extraction unit is decoded to determine whether the current field is an even field or an odd field. And a decryption unit for determining whether

According to the above configuration, the closed
It avoids providing incorrect field data information due to typographical errors on the side of the caption data provider, and enables closed caption decode data with high reliability without being affected by a malfunction of the field judgment unit. Decrypt and provide.

[0008] Preferably, the closed caption
The apparatus further includes a field determination unit that determines whether the field is an odd field or an even field from the phase difference between the horizontal synchronization signal and the vertical synchronization signal output from the data information extraction unit, and the decoding unit is obtained from a start command. The field determination result obtained and the field determination result output from the field determination unit are compared and evaluated. For example, when both match, the determination result is output as valid.

Further, the decoding unit in any one of the above configurations determines whether a plurality of consecutive start commands are for an odd field or an even field, and the start command for the same field continues for a set value continuously. sometimes,
It is preferable to be configured to determine the field determination.

According to the above configuration, when the start command is recognized at each timing of the vertical synchronizing signal, the start command is decoded, and the start command for the same field continues for the set value continuously. Is preferably used together with the determination result of (2) to determine whether the current field is an odd field or an even field. By handling only the data following this start command, the use of different field data in the wrong field is avoided.

[0011]

FIG. 1 is a block diagram of a field judgment control device according to the present invention. In FIG. 1, a closed caption data information extracting unit 10 extracts a horizontal synchronizing signal S2, a vertical synchronizing signal S3, and closed caption data S4 from a video signal (composite signal) S1, and outputs each.

The field determining section 20 determines whether the field is an even field or an odd field based on the phase difference between the horizontal synchronizing signal S2 and the vertical synchronizing signal S3 output from the closed caption data information extracting section 10, The field determination result S5 is output. Specifically, as shown in FIG. 2, if the period from the falling edge of the horizontal synchronizing signal S2 to the falling edge of the vertical synchronizing signal S3 is shorter than the half horizontal synchronizing cycle, it is determined that the field is an odd field, and the length is increased. If it is an even field.

In FIG. 1, a decoding unit 30 decodes a start command included in the closed caption data S4 output from the closed caption data information extracting unit 10, and determines whether the start command is for an odd field or an even field. Is determined.

Various start commands (Miscellaneous Contr.
ol Codes) is shown in Table 1.

[0015]

[Table 1]

As can be seen from Table 1, the codes for CH1 and CH2 of each start command are odd (O
A code for a DD) field and a code for an even (EVEN) field are prepared. Each code is composed of 2 bytes. By checking the upper 1 byte of the start command code, it is easy to determine whether the field is an odd field or an even field.

The decryption unit 30 determines the result of the determination for a plurality of activation commands by using an ODD field counter or EVE.
Counting is performed by an N-field counter, and when any of the counters reaches a set value, the field of that counter is determined to be the current field. The processing executed by the decryption unit 30 will be described with reference to a flowchart shown in FIG.

First, in step F101, it is determined whether or not the closed caption data S4 is a start command.
, It is determined whether or not the start command is for the ODD field. If the command is for the ODD field, the ODD field counter is updated (step F).
103), if it is not a command for the ODD field (that is, if it is a command for the EVEN field), the EVEN field counter is updated (step F106).

After updating the ODD field counter or the EVEN field counter, it is determined whether or not the counter has reached a set value (predetermined value) (step F10).
4 or Step F107). When the set value is reached, the (ODD or EVEN) field is determined,
Clear the other field counter. For example, if a command for an even field arrives for some reason before the command for the odd field reaches the set value and the command for the odd field continues, the odd field counter is cleared.

Therefore, it is determined whether not only one activation command but also a plurality of consecutive activation commands are for an odd field or an even field. The field is fixed only when it is the one. Such processing increases the reliability of the determination.

Further, the decryption unit 30 determines the field determination result obtained from the analysis of the start command as described above,
The field determination results obtained by the field determination unit 20 as described above are compared. If they match, the result is determined as the field determination final result S6 by odd / even (ODD / even).
EVEN) Output to the control unit. If the two field determination results are different, it is invalid and the field determination final result S6 is not output. Alternatively, information indicating that there is a determination error is output.

As described above, according to the present embodiment, the odd / even field determination result obtained from the positional relationship (phase difference) between the horizontal synchronization signal and the vertical synchronization signal is changed to the odd / even field determination obtained from each start command. Since the verification is performed based on the judgment result, for example, the closed caption data provider does not provide erroneous field data due to a typographical error or does not receive the influence of the malfunction of the field judgment unit. A high closed caption decoder can be provided.

In the above-described embodiment, the field determination result is valid only when the start command for the same field continues for the set value continuously. However, the present invention is not necessarily limited to this configuration, and is performed once or twice. The field determination result from the start command may be validated. Also, the odd / even field determination is determined based only on the determination result obtained from the start command without using the odd / even field determination result obtained from the positional relationship (phase difference) between the horizontal synchronization signal and the vertical synchronization signal. May be.

[0024]

As described above, the field determination control device of the closed caption decoder according to the present invention analyzes the activation code included in the closed caption data, thereby preparing the field information provider. Character information such as program information, time, dialogue,
Fields can be provided without errors or omissions.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a field decision control device of a closed caption decoder according to an embodiment of the present invention.

FIG. 2 is a diagram showing an odd number in the field determination control device of FIG.
Diagram showing phase relationship between even field and horizontal / vertical sync signal

FIG. 3 is a flowchart of a processing routine for determining an odd / even field from a start command in the field determination control device of FIG. 1;

[Explanation of symbols]

 Reference Signs List 10 Closed caption data information extraction unit 20 Field judgment unit 30 Decryption unit 40 ODD field counter 50 EVEN field counter

Claims (3)

[Claims] 1. A closed caption data information extraction unit for extracting a horizontal synchronizing signal, a vertical synchronizing signal, and closed caption data from a video signal on which a closed caption signal is superimposed, and the closed caption data information A field determination control device for a closed caption decoder, comprising: a decryption unit that decrypts a start command included in closed caption data output from an extraction unit and determines whether a current field is an even field or an odd field. 2. A field judging section for judging whether the field is an odd field or an even field based on a phase difference between a horizontal synchronizing signal and a vertical synchronizing signal output from the closed caption data information extracting section. Prepared,
The apparatus according to claim 1, wherein the decryption unit compares and evaluates a field determination result obtained from the start command with a field determination result output from the field determination unit. 3. The decoding section judges whether a plurality of consecutive start commands are for an odd field or an even field, and when a start command for the same field continues by a set value continuously, the field judgment is performed. 3. The field determination control device for a closed caption decoder according to claim 1, wherein: