JP2001223994A - Device and method for recording image and video rate adjusting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a video recording device for faithfully recording character information as much as possible even when a video signal comprising character information is recorded via TBC. SOLUTION: The video recording device is the one for recording video information comprising character information in a recording medium and is provided with an ADC 100 for successively receiving video information, a character information extracting part 102 for extracting character information from video information, a video recording control part 101 for performing omission or superimposition as to partial video information of a received video information group and outputting it by fixed period, a character information recording control part 103 for outputting extracted character information by fixed period and a recording part 106 for respectively recording outputted video information and character information by correspondence to reception order. The part 103 judges whether the value of extracted character information is null or not under a prescribed condition, removes the character information from an output object in the case of the null value and permits the succeeding character information to be an object outputted from a character information output means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

2. Description of the Related Art Conventionally, analog video signals in video frame units output from a TV broadcast, a video recorder, and the like are sequentially received and converted into digital signals, and the digital video signal is converted into a digital signal.
As a device for recording on a recording medium such as D, there is a video recording device having a built-in time base collector (hereinafter, referred to as “TBC”).

Generally, when an analog video signal is converted into a digital video signal and recorded, a reception frequency of a video input signal and a clock frequency (hereinafter, referred to as a "standard frequency") that defines a timing at which the video signal is written to a recording medium. )
Does not strictly match, so that the video signal is written to a memory built in the video recording device in synchronization with the reception frequency of the video signal, and read out from this memory and recorded in synchronization with the standard frequency described above. Then, the data inflow / outflow amount in the memory becomes unbalanced, and the memory may underflow or overflow.

[0003] In order to avoid such a situation, TBC:
In order to enable continuous recording, the occurrence state of the underflow and the overflow in the above-mentioned memory is monitored, and the recording speed of the video signal specified by the standard frequency and the input of the video signal determined by the variable receiving frequency are monitored. A process for absorbing a difference from the speed, that is, a process of adding or thinning a video signal in video frame units, is performed to maintain the balance of the data amount in the memory.

More specifically, when the reception frequency of the video signal is higher than the standard frequency, the amount of data flowing into the memory exceeds the amount of outflow, so that the TBC stores the video signal for one frame contained in the video signal in the memory. Output from
Also, when the reception frequency of the video signal is lower than the standard frequency, the amount of data flowing into the memory is smaller than the amount of flowing data, so that 1
The video signal for one frame output once is output again.

FIG. 18 is a diagram showing a conventional process of adding or thinning such video signals in video frame units. Each frame in FIG. 18 indicates a video signal for one frame. The video signal in the figure includes video information for video display and text information for text display.

In FIG. 1, each frame of a video signal is provided with an alphabet for identifying the video signal in order to indicate the flow of each video signal in writing and reading the video signal to and from a memory. On the other hand, the alphabet attached to the character information described later indicates the character stored in each of the two types of character information included in the video signal for one frame. It is associated with information.

[0007] The upper side of each frame delimited by "/" is a video signal when the reception frequency of the video signal is higher than the standard frequency (t ₁ <t ₀ , t ₀ = 1 / standard frequency). The lower side separated by “/” indicates that the reception frequency of the video signal is lower than the standard frequency (t ₂ >
2 shows the flow of the video signal at t ₀ ). The left-right direction in the figure is a time axis, and time progresses from left to right, and a reference line corresponding to the time axis in each frame is the left end of each frame.

Here, the processing by the above-described TBC will be described. As long as the reception frequency of the video signal does not match the above-mentioned standard frequency, the data inflow / outflow in the memory eventually becomes unbalanced, and the memory overflows and underflows occur. Therefore, the TBC determines that the memory overflow is ₁ in X1 in the figure.
Frame of the video signal "D" skip read the next video signal "E" from the memory and, for underflow, in X ₂ in the figure, one frame of video signal "A", It is read from the memory twice to avoid overflow and underflow in the memory.

By the way, in recent years, a caption display technique called a closed caption has been developed in which actors' dialogue, narration, sound effects, and the like are displayed as captions so that a deaf person can enjoy a broadcast program or a video. By multiplexing character information for displaying subtitles with a video signal, subtitles synchronized with the video are displayed. In addition to such closed captions, a technology for displaying such information by multiplexing information such as weather forecast, time information and stock price information on a video signal has been developed, and has been put to practical use together with closed captions.

As described above, a case may occur in which a normal video signal including only video information further includes character information such as the closed caption described above.
This character information is multiplexed in the line 21 of the video signal, that is, in a vertical blanking period not used for displaying a video. In order to display such character information on the screen, a decoder for decoding the character information multiplexed in the video signal and displaying the character information on the screen is required. It is up to you to choose.

[0011]

However, the above prior art has the following problems. That is, video information for one frame is visual information of about 29.97 msec,
Even if one frame of video information is missing or duplicated, there is no visual discomfort, but the process of adding or thinning video signals in video frame units by TBC is also applied to character information. If implemented, the character information will be ASC
II (American Standard Code)
for Information Intercha
nge) and special character codes, as shown in FIG. 18, for example, characters “A, B”, “C, D”,
Even if character information indicating “E, F”, “G, H”, “I, J”,... Sequentially arrives, if the video signal reception frequency is higher than the standard frequency, “A, B” "," C, D ",
"E, F", "I, J" ... are recorded, and when the reception frequency of the video signal is lower than the standard frequency, "A,
B "," A, B "," C, D "," E, F ",..., There is a possibility that characters may be missing or duplicated, and it is likely to be recorded as meaningless information. There is a point.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has been made in consideration of the above-described problems. Even when a video signal including character information is recorded via a TBC, a video recording for recording character information as faithfully as possible It is another object of the present invention to provide a device and a video recording method, and to provide a video rate adjusting device for outputting a video signal for recording for achieving the recording by removing a recording medium from the above-described video recording device.

[0013]

According to another aspect of the present invention, there is provided a video recording apparatus for recording video information including character information on a recording medium. Receiving means, and extracting means for extracting the character information from the video information, and omitting or overlapping some of the video information of the received video information group, regardless of the reception frequency of the video information, a fixed period And a character information output means for outputting the extracted character information at the fixed period, and a recording for recording the output image information and the character information in the recording medium in association with the order in which they are received. Means, under predetermined conditions, determine whether or not the value of the extracted character information is a null value.If the value is a null value, the character information is excluded from the output target, and the next Sentence Characterized in that it comprises a negative means that the target of the output from the character information output unit information.

Further, the video recording method of the present invention is a video recording method for recording video information including character information on a recording medium, comprising: a receiving step of sequentially receiving the video information; A video output step of omitting or overlapping a portion of the video information of the received video information group, and outputting the video information at a constant cycle, regardless of the reception frequency of the video information, Outputting character information at the constant period,
A recording step of recording the output video information and the text information on the recording medium in association with the order in which the video information and the text information are received, and determining whether a value of the extracted text information is a null value under a predetermined condition. When the value is a null value, the character information is excluded from the output target.

Further, the video rate adjusting device of the present invention has an input receiving means for sequentially receiving character information and a video, and a video output for outputting some of the remaining video by omitting a part of the video from the received video group. Means, character information determining means for determining whether or not the received character information has a null value under predetermined conditions, and determining that the received character information is not a null value by the character information determining means in the received character information group Character information output means for outputting each of the obtained character information at a constant speed in a one-to-one correspondence with each video output by the video output means.

[0016]

Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a functional block diagram of a video recording device 1 according to an embodiment of the present invention. The video recording device 1 sequentially receives analog video signals in which text information such as closed captions and text information other than closed captions such as weather forecasts and video information for one video frame are multiplexed, and receives the video information and text information. Is continuously recorded based on an internal reference clock unique to a video recording apparatus without depending on an input clock generated from a video signal, and includes an ADC (Analog).
to Digital Converter) 100
A video recording control unit 101 for performing control for recording video information, a text information extraction unit 102 for extracting text information from a video signal, and a text information recording control for performing control for recording text information Unit 103 and a PLL (Pha
(se Locked Loop) 104, a clock generation unit 105 for generating a clock of a fixed frequency, a recording unit 106 for storing video information and character information, and an LPF
(Low Pass Filter) 107.

The ADC 100 is an A / D converter,
The video information, character information such as closed captions, and the N signal transmitted from a TV broadcast station or the like in which the synchronization signal is multiplexed.
TSC (National Television S)
An analog signal of the standard (Committees) method is received from the receiving device, converted into a digital signal, and output to the video recording control unit 101 and the character information extracting unit 102.

This character information is stored in line 2 in the video signal.
1, that is, multiplexed in the vertical flyback period. Each line 21 of the first field and the second field forming the frame stores character information of two characters.
It has a first area and a second area of bits.

FIG. 2 is a diagram showing a waveform of a line 21 of the first field in which character information is multiplexed. The character information report stored in the first area (hereinafter, referred to as “first character information”) includes a character code and a parity bit used only for closed captions, and is stored in the second area. (Hereinafter, referred to as “second character information”) is information other than closed captions, and is, for example, a video scene obtained from a character code and a parity bit for displaying a weather forecast in caption, or from video information. Is composed of a control character code and a parity bit for permitting viewing only for a certain age or more when violent ones are included.

The above-mentioned parity bits are bits for determining whether a character code stored in the same area is correct or not.
The first character information and the second character information constitute a part of a data transfer packet used in a system for displaying the character information on a screen. This packet includes a header, a payload, and a footer.

FIG. 3 shows the relationship between the video information in frame units and the first character information and the second character information, and the value of the character code constituting these character information, that is, the relationship between the character code and the above-mentioned packet. FIG. Here, a case where character information is multiplexed together with video information indicating a video cine which splits a balloon is exemplified. As this character information, one is for displaying “BANG! The first character information for closed caption and time information "10:
A situation in which the second character information such as “12:31” is included in the video signal is shown.

For example, the first character information indicating “N” of the character string “BANG!...” To be displayed in the closed caption, together with the first character information indicating “G” to be displayed later, together with the first character information indicating the video signal It is multiplexed in the first area of the second frame. For example, character information indicating "N" is
It is composed of 8-bit data, of which one bit is a bit used for parity check, and the other 7 bits indicate ASCII indicating "N", that is, "4e".

That is, the first area stored in the first area
The character information has a data amount corresponding to two characters as characters to be displayed, and an area for one character among them is AS AS.
It consists of a 7-bit area for storing characters according to CII and special character codes and a 1-bit area used for parity check. Then, for example, by concatenating the ASCII codes stored in the 7-bit area described above, one packet is formed, and the data indicating “N” is included in a part of the character data included in the payload of the packet. Equivalent to.

Similarly, the second area stored in the second area
The character information also has a size equivalent to two characters in terms of characters, and an area for one character is ASC.
The second area includes a 7-bit area for storing characters according to II and the like and a 1-bit area used for parity check. In some cases, a control character code for a chip or the like is stored.

The PLL 104 generates an input clock composed of a pulse train having a constant period based on a synchronizing signal multiplexed with the analog video signal.
The information is output to the character information recording control unit 103 and the clock generation unit 105. The clock generation unit 105 outputs the input clock
If the input clock received from L104 matches the frequency of the fixed frequency internal reference clock, an internal reference clock is generated by synchronizing the frequency and phase with the input clock, and the video recording control unit 101, the character information recording control Output to the unit 103, the clock generation unit 105, and the recording unit 106.

When the input clock and the fixed frequency internal reference clock do not match, the clock generation unit 105 generates an internal reference clock having a fixed frequency and no jitter asynchronously with the input clock, and performs video recording control. Part 10
1, character information recording control section 103, clock generation section 10
5. Output to the recording unit 106. Video recording control unit 101
Is composed of a memory for temporarily storing video information, and a plurality of control circuits for controlling the timing of data input / output and the selection of data to be input / output. The video information received from the ADC 100 is transferred to the PLL 104 in units of one video frame.
Is written to the memory in synchronization with the pulse of the input clock output from the memory.

On the other hand, when reading video information from the memory, the video recording control unit 101 synchronizes with the pulse of the internal reference clock while determining the number and timing of reading the video information from the memory. And read out the image in units of one frame, and
Output to The character information extraction unit 102 outputs the character information of the video information and the character information multiplexed on the digitized video signal output from the ADC 100, that is, the first character information and the first character information stored in the line 21. Only the second character information is extracted and output to the character information recording control unit 103.

The LPF 107 is a low-pass filter that separates low-frequency components such as a vertical synchronizing signal in a video signal. This signal is used by the video recording control unit 101 to determine that the head information of the video information for one frame has been received. The character information recording control unit 103 includes a recording medium such as a CPU, a DRAM, and a ROM. The character information recording control unit 103 synchronizes the character information received from the character information extraction unit 102 with a pulse of an input clock obtained from the PLL 104 and stores the character information in the DRAM. While writing, the character information is continuously recorded at the timing of the pulse input of the internal reference clock obtained from the clock generation unit 105.
6 is output.

FIG. 4 is a functional block diagram of the video recording control unit 101. The video recording control unit 101 includes a writing circuit 200, a memory 201, a reading circuit 202, a writing register 203, a count adding circuit 204,
07, the pointer comparison unit 205, and the read register 2
06. The writing circuit 200 includes the ADC 100
The received video information is written from the write register 203 to an address in the memory designated.

The memory 201 is a memory such as an SDRAM, and has a capacity of about 16 MB capable of storing video information of two frames. The video information for one frame is 1
This is information for displaying a still image for a screen for 29.97 msec. The readout circuit 202 reads out video information from an address inside the memory 201 specified by the readout register 206 and outputs the video information to the recording unit 106.

The write register 203 is
A register circuit for storing a write address of
Each time the stored value is updated, the stored value is output to the writing circuit 200 and the pointer comparison unit 205. The count addition circuit 204 is a circuit that adds 1 to the value stored in the write register 203 at the timing of inputting the pulse of the input clock received from the PLL 104 and updates the numerical value.

The read register 206 is provided in the memory 201
A register circuit for storing a read address of
Upon receiving an instruction from the pointer comparison unit 205, the stored value is output to the readout circuit 202 and the pointer comparison unit 205. The count addition circuit 207 is a circuit that adds 1 to the value stored in the read register 206 and updates the numerical value at the timing of the pulse input of the internal reference clock received from the clock generation unit 105.

The pointer comparison unit 205 controls writing and reading addresses to and from the memory 201 by rewriting the value of the read register 206 while comparing the value of the write register with the value of the read register 206. That is, a read address for using the memory 201 as a ring buffer is controlled.

More specifically, when the power of the video recording apparatus according to the present invention is turned on, first, the data in the memory 201 is cleared, and when the address value in the write register 203 is counted up, each address is stored. Data is stored sequentially. 1 in memory for the first time after power-on
When it is determined by the video signal from the LPF 107 that the data corresponding to the video information for the frame has been recorded, the reading register 206 starts counting up. At this time, writing has been completed in half the area of the memory, and the difference between the write address value and the read address value is １ ／ of the full address value.

Here, for example, with respect to the internal reference clock,
When the frequency of the input clock is high, the amount of data written to the memory 201 per unit time exceeds the amount of readout. Therefore, an address value indicating a write position in the memory at a certain time (hereinafter, referred to as a “write address”). And the address value indicating the read position in the memory (hereinafter, referred to as “read address”) gradually opens.

If this state continues, data that has not been read yet is overwritten with another data, so that a frame in which two frames of images are mixed is read, which causes inconvenience as a video. In order to avoid this, when it is determined by the video signal from the LPF 107 that the head data of the video information for one frame has been input, the difference between the write address value and the read address value is 70% of the full address value. If
When the value of the write address at this time is used later as the value of the read address, the read register 20
The half of the full address value of the memory 201 is added to the value of 6, and the video information for one frame is skipped (hereinafter referred to as "skipping").

[0037] For example, in X ₁ portion shown in FIG. 18,
The video information “D” is discarded without being read from the memory, and the above-described skipping is performed. Such skipping is repeated almost regularly unless the condition that the frequency of the input clock is higher than the frequency of the internal reference clock of the video recording apparatus is not eliminated. However, the skipped video information is a still image. This is information to be displayed for 97 msec, and there is no visual problem if it disappears.

On the other hand, with respect to the frequency of the internal reference clock,
When the frequency of the input clock is low, the amount of data written to the memory 201 per unit time is smaller than the amount of read, so that the difference between the write address value and the read address value gradually decreases. This causes reading and underflow.

In such a case, when it is determined by the video signal from the LPF 107 that the leading data of the video information for one frame has been input, the difference between the write address value and the read address value is larger than the full address value. 20
If the value is less than%, when the value of the write address at this time is used as the value of the read address, half the value of the full address value of the memory 201 is subtracted from the value of the read register 206, and the latest read is performed. The video information for one frame is read out again (hereinafter referred to as “double reading”).

[0040] For example, in the X ₂ portion shown in FIG. 18, supra, the video information "A", after being read from a time memory is read again, read twice the above have been made. Such double reading of video information is repeated almost regularly unless the state in which the frequency of the input clock is lower than the frequency of the internal reference clock is eliminated, but the video information read twice is obtained by converting a still image. This is information for display for 29.97 msec, and there is no visual problem if it is duplicated.

FIG. 5 is a functional block diagram of the character information recording control unit 103. The character information recording control unit 103 includes a writing unit 300, a memory 301, and a reading control unit 30.
2, a reading unit 303, an information checking unit 304,
It comprises an information processing unit 305, a NULL generation unit 306, and a recording output unit 307. The writing unit 300 includes the PLL 1
The character information obtained from the character information extracting unit 102 is written into the memory 301 at the timing of the pulse input of the input clock received from the input clock 04, and the writing is output to the read control unit 302.

The memory 301 is a DRAM that is registered in a queue and temporarily stores data in a first-in first-out manner.
And a storage area for temporarily storing the first character information having a 40-byte capacity capable of storing 10 frames of character information multiplexed in one frame. Storage area) and a storage area for temporarily storing the second character information (hereinafter, referred to as “second storage area”).

The memory 301 has a read control unit 3
In response to the inquiry from 02, the memory usage in each of the first storage area and the second storage area at that time is output to the read control unit 302. The reading unit 303
At the timing instructed by the read control unit 302, the first character information and the second character information for one frame are read from the memory 301 in 16-bit units, that is, in units of one frame of character information. Output to

The read control unit 302 has a CPU and RA
It is configured by a recording medium such as an M and a ROM, and executes control for reading out character information from the memory 301 and continuously recording it in the recording unit 106. More specifically, the read control unit 302 uses the timing of the pulse input of the internal reference clock obtained from the clock
Of the first storage area and the second storage area, and obtains one frame (1
It is determined whether or not the data amount is 6-bit) character information (hereinafter referred to as “reference data amount”).
If the memory usage of the memory 301 is the same as the reference data amount, the normal processing described later is performed. If the memory usage of the memory 301 is less than the reference data amount, the anti-underflow control described later is performed. If the memory usage of 301 exceeds the reference data amount, anti-overflow control described later is performed.

Normal processing performed on character information,
The anti-underflow control and the anti-overflow control are hereinafter collectively referred to as TBC character information control. Next, the TBC character information control will be described. The read control unit 302 inquires of the memory 301 about the memory usage, and when the memory usage is equal to the reference data amount, performs the normal processing.

More specifically, the read control unit 302
Inquires the memory 301 of the usage amount of each of the first storage area and the second storage area of the memory 301 at the timing of the input pulse obtained from the clock generation unit 105.
When the memory usage is equal to the reference data amount, the read control unit 302 instructs the read unit 303 to read the character information stored in the area and registered in the queue in the earliest order. Then, the recording output unit 307 outputs character information read from the memory 301 and passed to the recording output unit 307 via the information check unit 304 when 15 msec elapses from the input of the pulse. To instruct.

That is, the read control unit 302 performs the TBC character information control on each of the first character information and the second character information. Also, as a result of the inquiry to the memory 301, when the memory usage is less than the reference data amount, the read control unit 302 determines the character information to be stored in the area, for example, the usage of the memory in the first storage area. If the amount is less than the reference data amount, the read control unit 302 performs anti-underflow control on the first character information.

More specifically, read control unit 302
When the usage amount of the memory 301 is less than the reference data amount, the null generation unit 306 is informed of an invalid character code having no meaning in data processing, that is, a character including a character code indicating a null value. An instruction to generate information is issued, and as a result, the generated character information (hereinafter, referred to as “generated character information”) is transmitted to the recording output unit 307 at a point in time when 15 msec elapses from the input of the pulse. 106 is instructed to output.

FIG. 6 is a diagram for explaining the normal processing and the anti-underflow control, focusing only on the first character information. When the read control unit 302 inquires of the memory 301 about the memory usage of the first storage area at the timing of the input pulse obtained from the clock generation unit 105, in the first inquiry of the memory usage in FIG. Since the used amount of the memory is equal to the reference data amount, the reading unit 30
In the memory 3, character information indicating the characters "A" and "B" is stored.
01, and instructs the recording output unit 307 to output these character information when 15 msec elapses from the input of the pulse.

The second read control unit 302
In the second inquiry about the memory usage, the memory usage is 0, that is, less than the reference data amount, and the characters “C” and “D” to arrive next are not stored in the memory 301. Therefore, the read control unit 302 performs anti-underflow control, and the NULL generation unit 30
6 generates generated character information for one frame, and outputs the generated character information to the recording unit 106 when 15 msec elapses from the input of the pulse.
Instruct 7.

For the character information indicating “C” and “D” that arrive next, and the character information that indicates “E” and “F” that arrive next, the read control unit 302 uses the memory usage as a reference. Since the data amount is equal, the above-described normal processing is performed. As a situation in which such anti-underflow control is frequently performed, there may be a case where character information is not multiplexed in a video signal.

Next, the anti-overflow control will be described. When the memory usage exceeds the reference data amount as a result of the inquiry to the memory 301, the character information to be stored in the area, for example, the memory usage of the first storage area is reduced to the reference data amount. Is exceeded, the read control unit 3
02 implements anti-overflow control.

More specifically, the read control unit 302
Confirms that the used amount of the memory 301 exceeds the reference data amount, instructs the reading unit 303 to read the character information. As a result, the character information is read from the memory 301 by the reading unit 303 and output to the information checking unit 304.

When the information check unit 304 notifies that the value of the character code constituting the character information is not a null value, the read control unit 302 converts the character information into a signal for 15 msec from the input of the next pulse. The recording output unit 307 is instructed to output the data when the time has elapsed. On the other hand, when the information check unit 304 notifies that the value of the character code constituting the character information is a null value, the read control unit 302 instructs the information check unit 304 to discard the character information, Immediately, the memory 301 is inquired about the amount of memory used, and normal processing or the above-described anti-overflow control is performed.

That is, the read control unit 302 replaces the character information consisting of a null-valued character code with the memory 301.
, Character information registered in the queue next to this character information is set as an output target from the recording output unit 307. However, the value of the character code constituting the above-described character information registered next in the queue in the memory 301 is a null value, and immediately before reading this character information, the memory usage of the memory 301 is still the reference data amount. If the number exceeds the limit, the read control unit 302 further sets the next character information registered in the queue as an output target from the recording output unit 307.

FIG. 7 is a diagram for explaining the anti-overflow control by focusing only on the first character information. When the read control unit 302 inquires the memory 301 about the amount of memory used in the first storage area at the timing of the pulse obtained from the clock generation unit 105, the read control unit 302 performs the first inquiry about the amount of memory used in FIG. Is equal to the reference data amount, the above-described normal processing is performed, and the reading unit 303 reads character information indicating the characters “a” and “b” from the memory 301, and 15 from the pulse input
The recording output unit 3 outputs the data at the time when msec elapses.
07.

In the second inquiry about the memory usage, since the memory usage is larger than the reference data amount, the read control unit 302 instructs the read unit 303 by anti-overflow control. Then, the first character information is read from the memory 301.
As a result, the read character information is stored in the information check unit 3
04 is output.

Since the value of the character code constituting the character information is a null value, the information check unit 304 notifies the information check unit 304 that the character code is a null value. Therefore, the read control unit 302 discards the character information to the information check unit 304. When the memory 301 is immediately queried for the amount of memory used, normal processing is performed because the amount of memory used is equal to the reference data amount, and characters indicating "c" and "d" are used. Information from the memory 301,
The recording output unit 307 is instructed to output to the recording unit 106 when 15 msec elapses from the input of the pulse.

For the character information “NULL” and “NULL”, “e” and “f” stored in the memory 301 later, when the memory 301 is inquired about the memory usage of the first storage area, the memory usage is reduced. Since the amount is equal to the reference data amount, the above-described normal processing is performed. That is, when the memory usage is equal to the reference data amount, even if character information including a null-value character code arrives, the character information is output to the recording output unit 307 without being discarded in the normal processing. You.

Note that there are two 8-bit data as character information of one frame, but when character information consisting of a null-valued character code arrives, most of the character information for one frame is used. That is, a null-valued character code is stored in each of two pieces of character information having a data amount of 8 bits. For this reason, discarding of the character information by the anti-overflow control is based on a data amount of one frame unit,
That is, the operation is performed in units of 16 bits.

If the used amount of the memory 301 exceeds the reference data amount and the character codes constituting the character information registered in the queue in the memory 301 continue to have non-null values, the read control unit As a result of performing the above-described control by 302, the amount of memory used increases,
Eventually, an overflow occurs, and part of the character information registered in the queue in the memory 301 disappears due to overwriting.

Before such a situation occurs, a description will be given of a header discarding process which complements the above-described anti-overflow control. FIG. 8 is a diagram illustrating a packet including a plurality of pieces of first character information, that is, character information for closed captions. For example, if the character information lost due to the overwriting described above is a footer of a packet, a packet having only a header and a payload is generated. If the packet is recorded in the recording unit 106 as it is, a closed caption is displayed. Decoder cannot decode this packet during playback, and an error occurs.
Normal operation may not be performed.

However, if the lost character information is a packet header, a packet containing only a payload and a footer is generated. There is a property that packets can be ignored. That is, other than the loss of the data of the packet, there is no problem in decoding the character information.

Therefore, when the usage of the memory 301 exceeds a certain threshold, the read control unit 302 according to the present embodiment determines whether the character information read from the memory 301 by the read unit 303 is a packet header. Is checked, and if it is a header, the data of the subsequent 48 bits including the data indicating the head of the packet, that is, data of three frames, is read out.
To perform a process of reading from the memory 301 and discarding, that is, a header discarding process.

The above-mentioned threshold value is determined based on the amount of memory used for five frames for the first character information and the second character information,
That is, it is set to 80 bits. Note that even when the memory usage exceeds the above-described threshold, the character information read from the memory 301 by the reading unit 303 is converted by the information check unit 304 into a character code of the character code constituting the character information. If it is determined that the value is a null value, the process of discarding the character information is performed with priority.

As described above, the reading control unit 302 instructs each functional unit in the character information recording control unit 103 to read out the character information from the memory 301 and continuously record it in the recording unit 106. Implement information control. The information check unit 304 includes a recording medium such as a CPU and a ROM. The information check unit 304 refers to the value of the character code constituting the character information received from the reading unit 303 according to the above-described anti-overflow control, and sets this value to a null value. And if it is a null value, read that fact
2 and the information processing unit 305.

The information checking unit 304 refers to the value of the character code constituting the character information received from the reading unit 303 along with the above-mentioned header discarding process, and this value indicates the value indicating the head of the packet. It is determined whether the value indicates the beginning of the packet, and if so, the read control unit 302 is notified and the character information is discarded. Referring to the value of the character code constituting such character information, a process of determining whether or not a null value or a value indicating the beginning of the packet,
Hereinafter, this is referred to as parsing.

By the way, in the DVD standard, it is prohibited to directly record data in which an error has occurred due to noise or the like, and it is necessary to correct and record the data in which the error has occurred. Therefore, the information check unit 304
Performs a parity check on the character information output from the recording output unit 307 as a result of normal processing and anti-overflow control.

More specifically, information check section 304
Is the character information for one frame from the reading unit 303,
That is, character information having a data amount of two characters in a 16-bit screen display is received, and is output to the recording output unit 307 without being discarded by normal processing and anti-overflow control performed by the read control unit 302. The above-described parity check is performed on the character information in units of 8-bit data, that is, in units of one character.

The character information for one character has the configuration shown in the center diagram of FIG. 3, and is composed of 1-bit parity bits and 7-bit data (such as ASCII). If the number of bits indicating “1” among these 8 bits is not an odd number, the information check unit 304 determines that an error has occurred in the 7-bit data and determines that the character information has an error. The information processing unit 3 outputs a signal to the character information recording control unit 103 and the information processing unit 305, and outputs the erroneous character information (hereinafter referred to as “character information requiring correction”).
Output to 05.

When the parity check of the character information is performed and no error is detected, the information check unit 3
04 outputs the character information (hereinafter referred to as “normal character information”) to the recording output unit 307. Information processing unit 30
5 corrects the value of the character code and the parity bit constituting the character information based on the character information received from the information check unit 304 and the result of the parity check, and corrects the corrected character information (hereinafter referred to as “corrected character information”). ")
Is output to the recording output unit 307.

More specifically, the value of the character code constituting the character information is replaced with an ASCII value “7f” indicating a black square (hereinafter referred to as “solid block”) to indicate normality. Parity bits. The process for correcting the parity bit performed according to the DVD recording standard performed by the information check unit 304 and the information processing unit 305 as described above is hereinafter referred to as a parity normalization process.

The NULL generating unit 306 generates character information including a null-valued character code for one frame in accordance with a generation instruction from the read control unit 302, and outputs the generated character information to the recording output unit 307 as generated character information. More specifically, the NULL generating unit 306 sets the character code value to a character code indicating a null value, that is, an ASCII (7-bit) value “00” as generated character information for one frame. And two 8-bit data to which a parity bit (1 bit) is added.

The recording output unit 307 includes the read control unit 30
The character information of any one of the normal character information, the corrected character information, and the generated character information designated by the second character information is continuously transmitted to the recording unit 106 at the pulse input timing of the internal reference clock obtained from the clock generation unit 105. Output. FIG.
4 is a functional block diagram of the recording unit 106.

The recording section 106 includes an encoding / multiplexing section 800, a writing section 801 and a recording medium 802. The encoding and multiplexing unit 800 receives character information from the character information recording control unit 103, receives video information from the video recording control unit 101, and divides the received character information and video information into D.
According to the VD recording standard, the encoded and multiplexed data (hereinafter referred to as “DVD data”) is output to the writing unit 801.

The writing unit 801 writes the above-mentioned DVD data on a DVD. FIG.
FIG. 6 is a diagram showing a logical configuration of data output from the terminal. D
VOB (Video) in the VD recording standard
Object) is a recording unit of video information and audio data of one TV program or the like, and a video information and audio data unit corresponding to 0.4 to 1 second is VOBU (Vi).
Deo Object Unit).

The VOBU stores information such as a buffer size and a transfer rate to be secured during reproduction.
A set of one navigation pack having a data amount of kilobytes, a plurality of video packs storing video information, and a plurality of audio packs storing audio data not described because it is not related to the present invention is provided. Is stored.

One VOBU is composed of one or two GOPs.
(Group Of Picture)
This GOP is a GOP storing time code and the like.
It consists of a header, an extended & user data area in which user data can be freely set, an I picture, a P picture, and a B picture. These pictures correspond to image data for 15 frames.

The encoding and multiplexing unit 800 stores the first character information and the second character information for 15 frames in the above-mentioned extended & user data area in the GOP. By the way, DVD
In the recording standard, one recording unit, VOB
, The change of the flag indicating the presence or absence of character information is prohibited. For example, a main program of a program corresponding to closed caption, which is one of character information, and a CM not supporting closed caption are mixed. However, if these are to be recorded on a DVD as one VOB, a flag is set as having character information in all of the main part and the CM, or the main part and the C
In all of M, the DVD recording standard can be satisfied only by flagging that there is no character information.

For this reason, the encoding and multiplexing unit 800
VOB is divided at the change of the flag indicating the character information.
It is conceivable to perform control for recording video information and character information, but in the DVD recording standard,
Since the number of VOBs is limited to 99 per disk, the number of VOBs cannot be easily increased. Therefore, the coding and multiplexing unit 800 sets the line 21 in the video signal
Even if the signal indicates that character information does not exist, the DVD data is output with the flag indicating the presence or absence of character information in the DVD recording standard, that is, the line 21 switch always enabled.

FIG. 11 is a diagram for explaining processing for recording with the line 21 switch always enabled in the above-mentioned DVD recording standard. Here, the presence / absence of character information, that is, the flag indicating the presence / absence of data in the line 21, that is, the line 21 switch of the DVD recording standard is always “1” indicating the presence of character information regardless of the presence / absence of character information. Has become.

Note that there is no character information in the video signal,
Even if the line 21 switch is always enabled as described above,
Since the generated character information is generated by the anti-underflow control by the read control unit 302, no problem occurs in the encoding and multiplexing unit 800 because null-value character information always exists. The description of each unit in the video recording device 1 configured as described above is finished, and next, processing performed in the video recording device 1 will be described.

FIG. 12 is a flowchart showing TBC character information control in a case where attention is paid only to the first character information. The read control unit 302 includes the clock generation unit 10
5 to determine whether there is a pulse input (step S50).
0), the process waits until there is a pulse input, and at the timing of the pulse input, the memory 301 is inquired of the memory usage of the first storage area, the memory usage is acquired (step S501), and the memory of the first storage area is obtained. It is determined whether or not the used amount is equal to or more than the amount of the character information for one frame, that is, the data amount of 16 bits (step S502), and if the used amount of the memory in the first storage area is less than the amount of the character information for one frame. Then, anti-underflow control described later is performed (step S503), and the process returns to step S500 for determining whether or not a pulse is input from the clock generation unit 105.

On the other hand, if the memory usage of the first storage area is 1
If the amount is equal to or greater than the amount of character information for a frame, the read control unit 302 instructs the read unit 303 to read one frame, that is, 16-bit first character information from the memory (step S504). In response to this instruction, the reading unit 303 reads the first character information from the memory 301 and outputs it to the information check unit 304.

The information check unit 304 checks the received first
Reference is made to the value of the character code constituting the character information, and syntax analysis is performed to recognize whether the value is a null value, a value indicating the head of the packet, or any other value (step S50).
5) The result is notified to the read control unit 302 and the information processing unit 305. Subsequently, the read control unit 302
It is determined whether or not the memory usage of the first storage area is equal to the amount of character information for one frame, that is, the data amount of 16 bits (step S506). If it is equal to the amount of character information, a parity normalization process described below is performed (step S507), and the process returns to step S500 where it is determined whether a pulse is input from the clock generation unit 105.

On the other hand, if the amount of memory used in the first storage area is not equal to the amount of character information for one frame,
If the memory usage of the storage area is equal to or more than the amount of character information for one frame, the read control unit 302 performs anti-overflow control, and the information check unit 304
With reference to the result of the syntax analysis notified from the user, it is determined whether the value of the character code constituting the first character information is a null value (step S508), and the value of the character code constituting the first character information is null. If it is a value, the information check unit 304
Is instructed to discard the first character information.

The information check unit 304 receives the instruction.
Discards the first character information (step S50).
9). Then, the read control unit 302 immediately inquires of the memory 301 about the memory usage of the first storage area, and returns to step S501 of acquiring the memory usage.
The processing based on the subsequent steps is repeated.

On the other hand, the notified result of the syntax analysis is the first
When the value of the character code constituting the character information indicates that the value is other than the null value, the read control unit 302 determines that the memory usage of the first storage area is the amount of the character information for five frames, that is, the 80-bit data. It is determined whether the amount exceeds the amount (step S510). If the amount of memory used in the first storage area does not exceed the amount of character information for five frames, a parity normalization process described later is performed (step S507), and the clock is reset. The process returns to step S500 for determining whether a pulse is input from the generation unit 105.

On the other hand, if the memory usage of the first storage area exceeds the amount of character information for five frames, the read control unit 302 makes the notified result of the syntax analysis constitute the first character information. It is determined whether or not the value of the character code indicates that it is the head of the packet (step S51).
1) When the value of the character code constituting the first character information indicates a value other than the beginning of the packet, a parity normalization process described below is performed (step S507), and a determination is made as to whether or not a pulse is input from the clock generation unit 105. It returns to S500.

Further, the notified result of the syntax analysis is the first
If the value of the character code constituting the character information indicates that the value is at the beginning of the packet, the read control unit 302
It instructs the information check unit 304 to discard the first character information, and reads out the first character information for two frames registered in the queue immediately after the first character information in the memory 301 to the reading unit 303. As a result, the information check unit 304 is instructed to discard the first character information information for two frames passed from the memory 301 to the read unit 303 and from the read unit 303 to the information check unit 304. Perform (step S512).

That is, the header discarding process is performed, and in the information check unit 304, the first character information of three consecutive frames including the first character information including the character code of the value indicating the beginning of the packet Will be discarded. The above processing describes the TBC character information control when focusing only on the first character information. However, the same processing is performed on the second character information.
In this case, the first character information is replaced with the second character information, and the first storage area is replaced with the second storage area.

FIG. 13 is a flowchart showing the processing in the anti-underflow control. The read control unit 302 instructs the NULL generation unit 306 to generate character information including a null-value character code, that is, generation character information (step S525).

As a result, the generated character information is generated by the NULL generating unit 306 and output to the recording output unit 307. The read control unit 302 controls the recording output unit 3
07, an instruction is issued to output the generated character information (step S526). Then, the recording output unit 307 receives one pulse from the input of the pulse whose presence or absence has been determined in step S500.
When 5 msec has elapsed, the output is output to the recording unit 106 (step S527), and the process returns to step S500 where it is determined whether or not a pulse has been input from the clock generation unit 105.

FIG. 14 is a flowchart showing a parity normalization process when attention is paid only to the first character information. The read control unit 302 includes the information check unit 30
4 is instructed to perform a parity check of the first character information acquired by the information check unit 304 (step S530).

According to this instruction, the information check unit 304
Performs a parity check of the first character information, determines whether the parity indicates that the value of the character code constituting the first character information indicates normal, and notifies the read control unit 302 of the result. The read control unit 302 recognizes whether the value of the character code constituting the first character information is normal based on the notified parity check result (step S531). That is, the output of the normal character information is instructed to the recording output unit 307 (step S532).

Thus, the recording output unit 307 records the first character information, that is, the normal character information, received from the information checking unit 304 when 15 msec has elapsed from the input of the pulse whose presence or absence has been determined in step S500. The signal is output to the unit 106 (step S533), and the process returns to step S500 to determine whether a pulse is input from the clock generation unit 105.

On the other hand, when it is determined that the value of the character code constituting the first character information is not normal, the first character information subject to this determination has already been output from the information check unit 304 as character information requiring correction. Passed to the processing unit 305,
Since the information processing unit 305 corrects the value of the character code and the parity bit constituting the character information requiring correction to obtain corrected character information, and outputs the corrected character information to the recording output unit 307, the read control unit 302 Instructs the recording output unit 307 to output the corrected character information (step S534).

Then, the recording output unit 307 converts the first character information received from the information check unit 304 from the input of the pulse, the presence or absence of which has been determined in step S500, by one.
After the elapse of 5 msec, step S533 for outputting to the recording unit 106 is executed, and the process returns to step S500 for determining whether a pulse is input from the clock generation unit 105.

The above processing describes the parity normalization processing when attention is paid only to the first character information. However, the same processing is performed for the second character information. In this case, the first character information is , The second character information, and the first
The storage area will be read as the second storage area. FIG. 15 is a diagram showing an example in which such parity normalization processing is performed, and the character information recorded in the recording unit 106 is reproduced and displayed together with the video.

For example, originally, "Good morning"
g ”should be displayed in the information check unit 304
When an error is found in the character information indicating the character 1702 to be displayed as "r", the value of the character code constituting this character information is replaced with a black square, that is, a character code indicating a solid block. Therefore, the display is displayed as "Good mo @ ning".

FIG. 16 is an example of an external view when the video recording apparatus 1 of the present invention is applied to a product. The DVD recorder 1801 incorporates the video recording device 1 of the present invention, and further has a receiving unit for receiving TV broadcast radio waves, and a reproducing unit for reproducing video and character information based on information recorded on DVD. .

An antenna 1802 is an NTSC TV
An antenna tuned to broadcast waves. Display unit 1803
Is a TV receiver that receives and displays NTSC video signals. As described above, according to the present embodiment, in the video recording device 1, character information is recorded together with video information recorded via the TBC based on a video signal in which character information and video information are multiplexed. Even in this case, it is possible to realize a video recording device that records character information as faithfully as possible.

In the present embodiment, in the configuration of the character information extraction unit 102, when viewed from a viewpoint focusing on the flow of character information, the memory 301 includes the information check unit 304,
Although they are arranged upstream of the information processing unit 305 and the NULL generation unit 306, they may be arranged downstream of them. That is, before the character information is stored in the memory 301, the above-described normal processing, anti-underflow control, anti-overflow control, header discarding processing, and parity normalization processing can be performed.

FIG. 17 is a functional block diagram showing an example of the configuration of character information recording control section 390 corresponding to character information recording control section 103 in such a configuration. The character information recording control unit 390 includes an information check unit 400, a writing unit 401, a memory 402, and a writing control unit 4.
03, the information processing unit 404, and the NULL generating unit 405
And a reading unit 406.

The information check unit 400 includes a CPU and an RO.
M, and is a functional unit that basically performs the same function as the information check unit 304. The character information is obtained not from the readout unit 303 but from the character information extraction unit 1
02, and is different from the present embodiment in that the output destination of the character information is not the recording output unit 307 but the writing unit 401.

The writing section 401 is basically a functional section having the same function as the writing section 300. The character information is obtained not from the character information extracting section 102 but from the normal character information. Information check unit 400
The present embodiment is different from the present embodiment in that the information processing unit 404 obtains the corrected character information from the information processing unit 404.

The memory 402 is a recording medium such as a DRAM that performs the same function as the memory 301. Information processing unit 4
Reference numeral 04 denotes a functional unit that basically performs the same function as the information processing unit 305, and is different from the present embodiment in that the output destination of the corrected character information is not the recording output unit 307 but the writing unit 401. And different.

The NULL generation unit 405 basically generates N
This is a functional unit that performs the same function as the UL generation unit 306, and differs from the present embodiment in that the output destination of the generated character information is not the recording output unit 307 but the writing unit 401. The write control unit 403 is a functional unit that basically performs the same function as the read control unit 302, and differs from the present embodiment in the following points.

That is, the reference data amount is N frames (N
Is the data amount of character information of 2 or more natural numbers). In other words, the writing control unit 40 must be configured so that at least one of the normal character information, the corrected character information, and the generated character information is present in the memory 301.
Reference numeral 3 performs normal processing, anti-underflow control, anti-overflow control, header discarding processing, and parity normalization processing.

With the above configuration and function, the character information is recorded together with the video information recorded via the TBC based on the video signal in which the text information and the video information are multiplexed. However, it is possible to realize a video recording device that records character information as faithfully as possible. In the present embodiment, the ADC 100 is an A / D converter, which is widely used in the United States and transmitted from a TV broadcasting station or the like in which video information, character information such as closed captions, and a synchronization signal are multiplexed. Although the NTSC analog signal is received from the receiving device, when the video recording device 1 of the present invention is used in Europe, PAL (Phase Alternate) which is widely used in Europe is used.
(ionby Line) type analog signal may be received from the receiving device.

In this case, the video information for one frame is 4
It is considered that the text information is 0 msec, and instead of information such as closed captions which are widespread in the United States, teletext which is a teletext system widely used in Europe can be used as text information. Is also valid for this teletext. Further, in the present embodiment, the character information extracting unit 102 extracts only the character information of the video information and the character information multiplexed on the digitized video signal output from the ADC 100, and performs character information recording control. Output to the unit 103.
It is not a digitized video signal output from 0,
The analog video signal may be directly input, only character information may be extracted, and output to the character information recording control unit 103.

In this embodiment, the reference data amount is the data amount of one frame of character information.
It may be other than the data amount of the character information for the frame,
For example, as a realistic numerical value, the data amount of any one of two to four frames can be considered. Further, in the present embodiment, when an error is detected as a result of the parity check, the character code constituting the character information in which the error is detected is changed to a black square, ie, It is assumed that the parity code is replaced with the character code indicating the solid block and the parity normalization process is performed to record the parity so as to indicate that it is normal.However, from the character string indicated by the character code of the character information existing before and after the error character information, the error is For a certain character portion, the most appropriate word may be guessed and replaced.

In this case, the NULL generating unit 306 includes a recording medium such as a ROM in which a word dictionary is stored, detects a code indicating a space existing between each word, and converts a character string between the spaces. Characters which are recognized as one word and which are determined to be erroneous as a result of the parity check are replaced by searching the word dictionary for valid characters.

The parity normalization process is not limited to the above, and the character code of the erroneous character information is left as it is.
Only the parity may be replaced with a normal one, or a null value character code may be used instead of the solid block. In the parity normalization process, when the character code is replaced with a null-value character code, for example, “Good
When the information check unit 304 detects an error in the character information indicating the character to be displayed as “r”, the place where “d morning” should be displayed is changed to the character corresponding to “r” as described above. If the code takes a null value, the display will be displayed as "Good moning".

Further, the coding and multiplexing unit 80 of the present embodiment
0 receives character information and video information, encodes and multiplexes it, and records it on a DVD. However, in addition to these signals, it also receives an audio signal, and encodes and multiplexes it with the character information and video information to write to the writing unit 801. May be output.
In the present embodiment, recording of an analog video signal has been described. However, recording of a digital video signal using TBC may be performed.

In this case, the ADC 100 and the character information extracting unit 102 become unnecessary, but instead, a demultiplexing circuit for separating the video, video character information and synchronization information multiplexed in the video information is provided. Becomes Further, the video recording device 1 according to the present embodiment
1 and the recording medium 802, but these may not be included, and the data may be output from the encoding / multiplexing unit 800 to an external recording device.

Further, in the present embodiment, encoding and multiplexing section 800 performs the DVD multiplexing even if the signal of line 21 in the video signal indicates that no character information exists.
According to the recording standard, a flag indicating presence / absence of character information, that is, DVD data is output in a state where the line 21 switch is always enabled. May be generated, and if character information does not exist in the video signal at the start of recording, even if character information subsequently exists in the series of recordings, that is, in all corresponding VOBs, The line 21 switch may be left disabled.

In this case, no character information is recorded.

[0119]

As is clear from the above description, the video recording apparatus of the present invention is a video recording apparatus for recording video information including character information on a recording medium, and a receiving means for sequentially receiving the video information. Extracting means for extracting the character information from the video information, and omitting or overlapping some of the video information in the received video information group, and outputting the video information at a constant period regardless of the reception frequency of the video information. A video output unit, a character information output unit that outputs the extracted character information at the constant period, and a recording unit that records the output video information and the character information on the recording medium in association with the order in which they are received, Under predetermined conditions, it is determined whether or not the value of the extracted character information is a null value.If the value is a null value, the character information is excluded from the output target,
And an exclusion unit that sets the next character information as an object of the output from the character information output unit. The video recording method according to the present invention also includes a video recording method that records video information including character information on a recording medium. A recording method, a receiving step of sequentially receiving the video information, an extraction step of extracting the character information from the video information, and omitting or overlapping a part of the received video information group, Regardless of the reception frequency of the video information, a video output step of outputting the video information at a fixed cycle, a text information output step of outputting the extracted text information at the predetermined cycle, and receiving the output video information and the text information, respectively. A recording step of recording on the recording medium in association with the order in which the extracted character information is determined to be a null value under a predetermined condition. Case, characterized in that it comprises a negative step of excluding the character information from the target of the output.

If the predetermined condition is that buffering overflow is about to occur, invalid character information is excluded from the output target, and the next character information is output from the character information output means. Since the data is output, buffering overflow is reduced. The video recording apparatus further includes a buffer, a storage unit that stores the character information extracted by the extraction unit in the buffer, and a data amount detection unit that detects an amount of data in the buffer. The condition is that the amount of data in the buffer is equal to or greater than a first threshold, and the character information output unit performs the output after reading the character information in the order stored in the buffer, The exclusion unit may perform the exclusion on the character information read by the character information output unit.

Thus, when the amount of data in the buffer is equal to or larger than the first threshold value, character information that is invalid in data processing is excluded from output targets, and overflow of the buffer is reduced. Further, the video recording apparatus further includes null information generating means for generating null information whose value is a null value, wherein the character information output means includes a null information when the data amount of the buffer is equal to or less than a second threshold value. The output may be performed instead of the character information.

Thus, even when the data amount of the buffer is equal to or less than the second threshold value, character information having a null value is output from the output means, and the output of character information is prevented from being interrupted. In addition, the recording medium is a DVD, and the receiving unit sequentially receives video information not including character information in addition to the video information including text information, and further includes the video information further including text in the video information. The recording means includes inclusion information indicating whether or not information is included, wherein the recording information includes the character information according to the DVD recording standard in the video information, regardless of the content of the inclusion information. A flag indicating that the
(Video Object), the recording may be performed.

Thus, even if there is no character information in the video information, a flag in the DVD recording standard indicating the presence or absence of character information in the video information is recorded in one VOB as being present, and the DVD recording standard is Be adhered to. Further, the flag may be a line 21 switch. Accordingly, even when there is no character information in the video information, the line 21 switch is output assuming that there is character information in the video information, recording is performed on one VOB, and the DVD recording standard complies. Is done.

Further, the value of the character information may be a character code used as a closed caption. As a result, if the predetermined condition is a situation where buffering overflow is about to occur, invalid closed caption data is excluded from the output target, and the character display during reproduction is not affected. Buffer overflow is reduced.

Further, the recording medium is a DVD, and the receiving means sequentially receives not only the video information including text information but also video information not including text information, and the video information further includes the video information. Information including inclusion information indicating whether or not character information is included in the information, wherein the extraction unit extracts the inclusion information from the video information, and the recording unit determines whether the inclusion information indicates inclusion of character information. A flag indicating that the video information to be recorded does not include the character information in the DVD recording standard, and if the inclusion information indicates no inclusion of the character information, A flag indicating that the character information is included in the video information, and a VOB for performing the recording before and after the flag changes.
May be another VOB.

Thus, when the flag in the DVD recording standard indicating the presence / absence of character information in the video information is changed, the recording is performed as another VOB, and the DVD recording standard is followed. Further, the flag may be a line 21 switch. Accordingly, when the value of the line 21 switch is changed, the recording is performed as another VOB, and the DV is recorded.
D recording standards are observed.

Further, the recording medium is a DVD, and the receiving means sequentially receives not only the video information including the text information but also the video information not including the text information. The information includes inclusion information indicating whether or not character information is included in the information, and the extraction unit extracts the inclusion information from the video information, and the recording unit, when the output starts, includes the inclusion information. When indicating the inclusion of character information, a flag indicating that the character information according to the DVD recording standard is not included in the image information is added to the video information to be recorded. When the information indicates no inclusion of character information, a flag indicating that the character information according to the DVD recording standard is included in the video information is added to the video information to be recorded. Performing the recording in the VOB, regardless of the contents indicated by the inclusion information after the output start may be to maintain the flag.

Thus, the inclusion information at the time of starting the output determines the flag of the DVD recording standard indicating the presence or absence of character information in the video information in all recordings, and the recording is performed in one VOB. D to be implemented
VD recording standards are adhered to. Further, the flag may be a line 21 switch.

As a result, the inclusion information at the time of starting the output determines the output of the line 21 switch in all recordings, and recording is performed on one VOB, so that the DVD recording standard is observed. . Further, the received string of character information constitutes packet data having a packet header, and the video recording device further comprises:
A determination unit configured to determine whether the value of the character information indicates the beginning of the packet; wherein the exclusion unit determines whether the amount of data stored in the buffer is larger than a first threshold value. If the value exceeds the threshold, if the value of the character information read by the character information output means indicates the beginning of the packet, the character information is included and buffered by a predetermined period after the character information. The column of the output character information may be excluded from the output target.

Thus, when the amount of data stored in the buffer exceeds the third threshold, a string of character information including the character information and buffered from the character information until a predetermined period later is output. , The buffering overflow is reduced.
Further, the character information includes defect information indicating the presence or absence of a defect in its own data, and the video recording device further obtains the defect information from the character information read by character information output means, The character information output means, when the defect information indicates that there is a defect, converts the defect information into defect information indicating that there is no defect, and outputs the output. It may be implemented.

Thus, even when the defect information included in the character information indicates that there is a defect, the character information including the defect information indicating that there is no defect at the time of output from the output means. Is output to comply with the DVD recording standard. In addition, when the defect information indicates that there is a defect, the character information output means converts the defect information indicating that there is a defect into defect information indicating that there is no defect, and The value of the character information including the information may be a predetermined value.

Thus, even when the defect information included in the character information indicates that there is a defect, the value of the character information is set to a predetermined value, and when the output from the output unit is performed, Then, character information including defect information indicating that there is no defect is output, and the DVD recording standard is complied with. Further, the predetermined value may be a value of a character code indicating a black square.

Accordingly, even when the defect information included in the character information indicates that there is a defect, the value of the character information is set to the value of the character code indicating a black square, and At the time of output from the means, character information including defect information indicating that there is no defect is output.
D recording standards are observed. Further, the character information includes a parity bit, the defect information is correct / incorrect information indicated by the parity bit, and the character information output unit outputs the character information determined to be defective by the defect determination unit. The output may be performed by setting the included parity bits to parity bits indicating normality.

Thus, even when the parity bit included in the character information indicates that there is a defect, the character information is converted into a normal parity bit when the character information is output from the output means. Is output. In addition, when the defect information indicates that there is a defect, the character information output means converts the defect information indicating that there is a defect into defect information indicating that there is no defect, and The output may be performed by changing the value of character information including information to a null value.

Accordingly, even when the defect information included in the character information indicates that there is a defect, the value of the character information is set to a null value, and when output from the output means, Character information including defect information indicating that there is no defect is output, and the DVD recording standard is observed. Further, the video recording device further includes a word storage unit storing a plurality of different words, and other character information received before and after the character information determined to be defective by the defect determination unit. Based on the characters obtained from the values, a character string that is considered to constitute one word is extracted, and a word corresponding to the character string is searched for from the words stored in the word storage unit. Character acquisition means for acquiring a character considered to be correct in the character portion indicated by the information value and converting it to a character code value, wherein the character information output means comprises a character information value determined to be defective. Is replaced by the value obtained by the character acquisition means,
The output may be performed.

Accordingly, when the defect information included in the character information indicates that there is a defect, the value of the character information is replaced with the value of the character code indicating the character considered to be correct, and it is determined that there is no defect. Character information including the indicated defect information is output from the output means, and the DVD recording standard is followed. In addition, the character obtaining means may determine that a character obtained from the values of other character information received before and after the character information determined to be defective has the same one word until immediately before a character other than the alphabet appears. The extraction of the character string may be performed as a range.

As a result, a word including an erroneous character is extracted, and a character considered to be correct for the erroneous character is obtained. Further, the video rate adjusting device of the present invention
Input receiving means for sequentially receiving text information and video, video output means for omitting a part of the video from the received video group, and outputting each of the remaining video, Character information determination means for determining whether or not the null value, and each of the character information determined as non-null by the character information determination means of the received character information group, is output by the video output means And character information output means for outputting each video at a constant speed in a one-to-one correspondence in the order received.

If the predetermined condition is that buffering overflow is about to occur, invalid character information is excluded from output targets, and the next character information is output from the character information output means. Since the data is output, buffering overflow is reduced.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of a video recording device 1 according to an embodiment of the present invention.

FIG. 2 is a diagram showing a waveform of a line 21 on which character information is multiplexed.

FIG. 3 is a diagram illustrating a relationship between a video signal in frame units, first character information, and second character information, a relationship between a character code and a parity bit constituting the character information, and a relationship between a character code string and a packet. FIG.

FIG. 4 is a functional block diagram of a video recording control unit.

FIG. 5 is a functional block diagram of a character information recording control unit.

FIG. 6 is a diagram illustrating normal processing and anti-underflow control, focusing on only first character information.

FIG. 7 is a diagram for explaining anti-overflow control by focusing on only first character information.

FIG. 8 is a diagram illustrating a packet including a plurality of pieces of first character information, that is, character information for closed captions.

FIG. 9 is a functional block diagram of a recording unit.

FIG. 10 is a diagram illustrating a logical configuration of data output from an encoding and multiplexing unit.

FIG. 11 is a diagram illustrating processing for recording with the line 21 switch always enabled in the DVD recording standard.

FIG. 12 shows a case where attention is paid only to first character information.
It is a flowchart which shows TBC character information control.

FIG. 13 is a flowchart showing processing in anti-underflow control.

FIG. 14 illustrates a case where attention is paid only to first character information.
15 is a flowchart illustrating a parity normalization process.

FIG. 15 is a diagram illustrating an example in which parity normalization processing is performed, and character information recorded in a recording unit is reproduced and displayed together with a video.

FIG. 16 is an example of an external view when the video recording device of the present invention is applied to a product.

FIG. 17 shows the configuration of a character information recording control unit in the case where the above-described normal processing, anti-underflow control, anti-overflow control, header discarding processing, and parity normalization processing are performed before character information is stored in the memory. FIG. 4 is a functional block diagram illustrating an example of the configuration.

FIG. 18 is a diagram illustrating a conventional process of adding or thinning a video signal by a TBC in video frame units.

[Explanation of symbols]

 1 Video Recording Device 100 ADC 101 Video Recording Control Unit 102 Character Information Extraction Unit 103 Character Information Recording Control Unit 104 PLL 105 Clock Generation Unit 106 Recording Unit 107 LPF 200 Circuit 201 Memory 202 Read Circuit 203 Register 204 Count Addition Circuit 205 Pointer Comparison Unit 206 register 207 count addition circuit 300 write unit 301 memory 302 read control unit 303 read unit 304 information check unit 305 information processing unit 306 NULL generation unit 307 record output unit 390 character information record control unit 400 information check unit 401 write unit 402 memory 403 Writing control unit 404 Information processing unit 405 NULL generating unit 406 Reading unit 800 Encoding and multiplexing unit 801 Writing unit 802 Recording medium 1801 DVD recorder 1802 Antenna 1803 Display

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yoshiyuki Watanabe 2-6-1, Sakae, Naka-ku, Nagoya-shi, Aichi Shirakawa Building Annex 5th Floor Matsushita Electric Information System Nagoya Research Laboratories

Claims (20)

[Claims] 1. A video recording apparatus for recording video information including text information on a recording medium, comprising: a receiving unit for sequentially receiving the video information; an extraction unit for extracting the text information from the video information; A video output means for omitting or overlapping a part of the video information of the video information group and outputting the video information at a constant cycle regardless of the reception frequency of the video information; and a character outputting the extracted character information at the predetermined cycle. An information output unit, a recording unit that records the output video information and the character information on the recording medium in association with the order in which they are received, and under a predetermined condition, a value of the extracted character information is a null value. It is determined whether or not the character information is excluded from the object of the output if the value is a null value, and the next character information is excluded from the object of the output from the character information output means. A video recording device, comprising: 2. The video recording apparatus further comprises: a buffer; storage means for storing the character information extracted by the extraction means in the buffer; and data amount detection means for detecting the data amount in the buffer. The predetermined condition is that the amount of data in the buffer is equal to or greater than a first threshold value, and the character information output unit reads the character information in the order stored in the buffer and then outputs the output. The video recording apparatus according to claim 1, wherein the exclusion unit performs the exclusion on the character information read by the character information output unit. 3. The video recording apparatus further comprises null information generating means for generating null information whose value is a null value, wherein the character information output means is configured to output data when the data amount of the buffer is equal to or less than a second threshold value. 3. The video recording apparatus according to claim 2, wherein the output is performed by replacing the null information with the character information. 4. The recording medium is a DVD, and the receiving means includes, in addition to the video information including character information,
Video information that does not include character information is also sequentially received, and the video information further includes inclusion information indicating whether or not the video information includes character information. Regardless, the video information to be recorded is provided with a flag indicating that the character information according to the DVD recording standard is included in the video information, and the recording is performed on one VOB (Video Object). The video recording device according to claim 3. 5. The video recording apparatus according to claim 4, wherein the flag is a line 21 switch. 6. The video recording apparatus according to claim 1, wherein the value of the character information is a character code used as a closed caption. 7. The recording medium is a DVD, and the receiving means includes, in addition to the video information including character information,
Video information that does not include character information is also sequentially received. The video information further includes inclusion information indicating whether or not the video information includes character information, and the extracting unit includes the inclusion information based on the video information. Extracting the information, and when the inclusion information indicates inclusion of character information, the recording unit attaches a flag indicating that the character information according to the DVD recording standard is not included in the video information to the video information to be recorded. When the inclusion information indicates that the text information is not included, a flag indicating that the text information is included in the video information is added to the recorded video information, and the flag changes. 2. The video recording apparatus according to claim 1, wherein a VOB (Video Object) for performing the recording is another VOB before and after. 8. The video recording apparatus according to claim 7, wherein the flag is a line 21 switch. 9. The recording medium is a DVD, and the receiving means includes, in addition to the video information including character information,
Video information that does not include character information is also sequentially received. The video information further includes inclusion information indicating whether or not the video information includes character information, and the extraction unit includes the inclusion information from the video information. If the inclusion information indicates inclusion of character information at the time of starting the output, the recording information includes the character information in the DVD recording standard in the video information. If the inclusion information indicates no inclusion of character information at the time when the output is started, a DV is added to the video information to be recorded.
A flag indicating that the character information in the D recording standard is included in the video information is attached to the VOB, and the recording is performed on one VOB, regardless of the content indicated by the inclusion information after the start of the output. 2. The video recording apparatus according to claim 1, wherein said flag is maintained. 10. The video recording apparatus according to claim 9, wherein the flag is a line 21 switch. 11. The received string of character information forms packet data having a packet header, and the video recording apparatus further determines whether the value of the character information indicates the beginning of the packet. The exclusion means includes: when the data amount stored in the buffer exceeds a third threshold value larger than the first threshold value, the character read by the character information output means. If the value of the information indicates the beginning of the packet, the character information is included, and a string of character information buffered up to a predetermined period after the character information is excluded from the output target. The video recording device according to claim 2. 12. The character information includes defect information indicating presence / absence of a defect in its own data. The video recording device further acquires the defect information from the character information read by character information output means. The character information output means, when the defect information indicates that there is a defect, the defect information is converted to defect information indicating that there is no defect, The video recording device according to claim 1, wherein the output is performed. 13. When the defect information indicates that there is a defect, the character information output means converts the defect information indicating that there is a defect into defect information indicating that there is no defect. 13. The video recording apparatus according to claim 12, wherein the value of the character information including the defect information is set to a predetermined value. 14. The video recording apparatus according to claim 13, wherein the predetermined value is a value of a character code indicating a black square. 15. The character information includes a parity bit, the defect information is correct / incorrect information indicated by the parity bit, and the character information output unit is determined to have a defect by the defect determination unit. 13. The video recording apparatus according to claim 12, wherein the output is performed by setting parity bits included in character information to parity bits indicating normality. 16. When the defect information indicates that there is a defect, the character information output means converts the defect information indicating that there is a defect into defect information indicating that there is no defect. 13. The video recording apparatus according to claim 12, wherein the output is performed by changing the value of the character information including the defect information to a null value. 17. The video recording apparatus further comprises: word storage means for storing a plurality of mutually different words; and other word information received before and after the character information judged to be defective by the defect judgment means. Based on the character obtained from the value of the character information, a character string that is considered to constitute one word is extracted, and a word corresponding to the character string is searched for from the words stored in the word storage means. Character acquisition means for acquiring a character considered to be correct in the character portion indicated by the value of the character information having the character information, and converting the character information into a character code value, wherein the character information output means comprises a character determined to be defective. 2. The output according to claim 1, wherein a value of the information is replaced with a value obtained by the character obtaining unit.
2. The video recording device according to item 2. 18. The character acquisition unit according to claim 1, wherein the characters obtained from the values of other character information received before and after the character information determined to be defective have the same value until immediately before a character other than the alphabet appears. As a range of two words,
The video recording apparatus according to claim 17, wherein the extraction of the character string is performed. 19. A video recording method for recording video information including text information on a recording medium, comprising: a reception step of sequentially receiving the video information; an extraction step of extracting the text information from the video information; A video output step of omitting or duplicating a part of the video information of the video information group and outputting the video information at a constant cycle regardless of the reception frequency of the video information; An information output step; a recording step of recording the output video information and the character information on the recording medium in association with the order in which they are received; under predetermined conditions, a value of the extracted character information is a null value Determining whether or not the character information is a null value, the character information is excluded from the output target. Method. 20. An input receiving means for sequentially receiving character information and a video, a video output means for omitting a part of the video from the received video group, and outputting each remaining video, Character information determining means for determining whether or not the received character information has a null value; and transmitting the character information determined to be non-null by the character information determining means in the received character information group to the image A video rate adjusting device comprising: a character information output unit that outputs a video at a constant speed in a one-to-one correspondence with each video output by an output unit in a received order.