JP2007036396A - Television content recording device and program thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To freely change the presence or absence of the display of a character image obtained by decoding the closed caption signal of television content for recording on a recording medium. <P>SOLUTION: The closed caption signal superposed on a vertical blanking period in the carrier of the television content is extracted. Raster data of a character obtained from the extracted closed caption signal are compressed and coded, and a code row obtained by the coding is recorded on a DVD recording medium as the pack of subpicture streams. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technique for recording television content.

DVD recorders that record television content on a recording medium as a bit stream according to the DVD (Digital Versatile Disk) standard are widely used.
In the DVD standard, a bit stream obtained by individually compressing and encoding an image signal and an audio signal of television content is recorded on a recording medium for each group called a “pack”. Each pack contains various control codes for reproducing images and audio in synchronization, and the bit stream of each pack is decoded and output using this control code to be recorded on the recording medium. The television content being played back is realized (see Patent Document 1 for this type of technology).
JP-A-2005-27332

  By the way, most of the television content broadcast through each television broadcasting station is compatible with so-called character multiplex broadcasting. The text multiplex broadcasting is a broadcasting form in which a character image such as a caption is viewed together with a main image of the television content. The character image of the character multiplex broadcasting can be viewed by connecting a special equipment called a closed caption decoder to the television receiver. The closed caption decoder extracts a signal superimposed on a vertical blanking period of a carrier wave (hereinafter, this signal is referred to as a “closed caption signal”), and decodes the closed caption signal. Are superimposed on the main image.

  However, since the DVD recorders proposed so far did not have a function corresponding to this closed caption decoder, it is not possible to record even a character image of a television content corresponding to character multiplex broadcasting on a DVD recording medium. could not. Further, if a closed caption decoder is interposed between the broadcast signal input interface of the DVD recorder and the television receiving antenna, it is certainly possible to acquire a character image from the broadcast signal. Since the image and the video stream pack are recorded together, the recorded television content cannot be viewed as a reproduction mode without a character image.

  The present invention has been devised under such a background, and a character image obtained by decoding a closed caption signal of a television content is recorded on a recording medium while the display can be switched freely. The purpose is to realize such a mechanism.

  A television content recording apparatus according to a preferred aspect of the present invention includes a storage unit that stores each character code and character raster data indicated by each character code in association with each other, and a television content that supports character multiplex broadcasting. Receiving means for receiving a carrier wave, extracting means for extracting a closed caption signal superimposed in a vertical blanking period of the received carrier wave, and a character for obtaining a character code by decoding the extracted closed caption signal A code acquisition unit; a reading unit that reads out raster data stored in the storage unit in association with the acquired character code; and the read raster data is compression-encoded according to a predetermined standard, and obtained by the compression encoding. The recorded code string as a pack of sub-picture streams on a recording medium And a Bupikucha recording control means.

  In this aspect, a television image acquisition unit that demodulates the received carrier wave to acquire television image data, and the acquired television image data is compression-encoded according to a predetermined standard, and a code string obtained by the encoding Video stream recording control means for recording the video stream on the recording medium as a pack of video streams.

  Also, a television sound acquisition unit that demodulates the received carrier wave to acquire television sound data, and the acquired television sound data is compression-encoded according to a predetermined standard, and a code string obtained by the encoding is audio Audio stream recording control means for recording on a recording medium as a pack of streams may further be provided.

  According to another preferred aspect of the present invention, a program includes storage means for storing each character code and character raster data indicated by each character code in association with each other, and a television content carrier wave corresponding to character multiplex broadcasting. An extracting function for extracting a closed caption signal superimposed on a vertical blanking period of a carrier wave received by the receiving means, and a decoding of the extracted closed caption signal; A character decoding function for acquiring a character code, a read function for reading raster data stored in the storage means in association with the acquired character code, and compression encoding the read raster data in accordance with a predetermined standard. The code sequence obtained by the compression coding is recorded as a pack of sub-picture streams. To achieve a sub-picture recording control function for recording the medium.

  According to the present invention, characters obtained by decoding a closed caption signal of a television content can be recorded on a recording medium while allowing the display to be switched.

(Embodiment of the Invention)
The television content recording apparatus according to the embodiment of the present invention is characterized in that a television image, a television sound, and a character image acquired from a carrier wave of a television content compatible with character multiplex broadcasting are individually compressed and encoded. The compression encoding is performed, and the code string obtained by the compression encoding is recorded on the DVD recording medium as a bit stream in accordance with the DVD standard.

Here, the data format of the DVD, which is the premise of the operation of the present embodiment, will be outlined. In the DVD data format, the contents are divided into bitstreams called “packs” and managed. Each pack is recorded in one sector of the DVD recording medium.
As shown in FIG. 1, each pack includes a pack header 10 and one or a plurality of packets 20. The pack header 10 includes reference time information called SCR (System Clock Reference). The packet 20 includes a packet header 21 and packet data 22. The packet data 22 includes a bit stream that is a code string obtained by compression-coding video data, audio data, and sub-picture data. On the other hand, in the packet header 21, an identification code for identifying whether the bit stream of the packet data 22 that it follows indicates video, audio, or sub-picture, or a synchronization called PTS (Presentation Time Stamp). Playback support information is included.

  When playing back a recorded DVD recording medium, a plurality of packs containing the same SCR in the header are collected and sequentially transferred to the decoder. The decoder decodes and outputs the bit stream included in the pack in accordance with the timing indicated by the PTS (Presentation Time Stamp). Thereby, synchronized reproduction of video, audio, and sub-picture is realized.

  FIG. 2 is a block diagram showing a hardware configuration of the television content recording apparatus 1 according to the present embodiment. This apparatus includes a system timer 101, a carrier wave receiver 102, an image demodulator 103, an image encoder 104, an audio demodulator 105, an audio encoder 106, a signal extractor 107, a character code decoder 108, and a character image storage unit. 109, a character image reading unit 110, a character encoding unit 111, a recording control unit 112, and a disk drive 113. The function of each part is outlined.

The system timer 101 generates a clock signal for each unit to measure synchronization.
The carrier receiving unit 102 receives a video carrier and an audio carrier of the television content.
The image demodulating unit 103 supplies television image data obtained by demodulating the video carrier received by the carrier receiving unit 102 to the image encoding unit 104. The image coding unit 104 performs compression coding processing according to the MPEG (Moving Picture Coding Experts Group) standard on the television image data supplied from the image demodulation unit 103, and obtains a code obtained by the compression coding. The column is supplied to the recording control unit 112.

  The audio demodulator 105 supplies the television audio data obtained by demodulating the audio carrier received by the carrier receiver 102 to the audio encoder 106. The audio encoding unit 106 compresses the television audio data supplied from the audio demodulating unit 105 according to a standard such as AC-3 (Audio Code number 3) standard, LPCM (Linear Pulse Code Modulation) standard, or the like. The code sequence obtained by the compression encoding is supplied to the recording control unit 112.

The signal extraction unit 107 extracts a closed caption signal superimposed in the vertical blanking period of the video carrier supplied to the image demodulation unit 103 and supplies the closed caption signal to the character code decoding unit 108.
The character code decoding unit 108 decodes the closed caption signal supplied from the signal extraction unit 107 to obtain a character code of character multiplex broadcasting.

The character image storage unit 109 stores character codes of various characters used in character multiplex broadcasting and raster data representing these characters as a bitmap in association with each other. Then, the character image reading unit 110 reads raster data corresponding to the character code acquired by the character code decoding unit 108 from the character image storage unit 109 and supplies the read raster data to the character encoding unit 111.
The character encoding unit 111 performs a run-length compression encoding process on the raster data supplied from the character image reading unit 110 and supplies a code string obtained by the compression encoding to the recording control unit 112.

  The recording control unit 112 individually packs the code strings supplied from the image encoding unit 104, the audio encoding unit 106, and the character encoding unit 111, and transfers them to the disk drive 113. Specifically, the following processing is performed. First, the packet data 22 is formed by collecting the code strings supplied from the image encoding unit 104, the audio encoding unit 106, and the character encoding unit 111 by a predetermined bit length. Subsequently, a PTS and an identification code are generated and connected to the packet data 22 as the packet header 21. Here, the PTS is generated according to the clock signal of the system timer 101, and the identification code is “video” indicating that the video stream is a video stream if the source of the code string is the image encoding unit 104, and the audio If it is the encoding part 106, it will be set as the "audio" which shows that it is an audio stream. Furthermore, if the source of the code string is the character encoding unit 111, it is set as “sub picture” indicating that it is a sub picture stream. After the packet header 21 is connected, the packet processing is completed by further connecting the packet header 21 including the SCR.

  A writing device (not shown) of the disk drive 113 sequentially writes each pack transferred from the recording control unit 112 to each sector of the DVD recording medium 20.

  FIG. 3 is a conceptual diagram of a system stream recorded on the DVD recording medium 20. As shown in the figure, the system stream is formed by connecting a pack of video streams, a pack of audio streams, and a pack of sub-picture streams in multiple stages. As shown in the figure, according to the television content recording apparatus 1 of the present embodiment, a video stream pack is obtained from a code sequence of television image data, and an audio stream pack is obtained from a code sequence of television audio data. A pack of picture streams is generated from a code string of character raster data.

  Many commercially available DVD players are equipped with a sub-picture display switching function for switching whether or not to display a sub-picture as standard. Therefore, if a DVD recording medium on which television content is recorded by this recording apparatus is reproduced using a commercially available DVD player, and the sub-picture display switching function is appropriately used at that time, recording is performed separately from the television image. The display of the displayed character image can be switched freely.

  According to the present embodiment described above, a code string obtained by compression-encoding a character image obtained from a closed caption signal of a television content carrier is recorded on a DVD recording medium as a pack of sub-picture streams. Therefore, the character image of the television content corresponding to the character multiplex broadcasting can be recorded on the DVD recording medium while the presence / absence of the display can be freely switched.

(Other embodiments)
The present invention can be modified in various ways.
In the above embodiment, the television content is recorded on the DVD recording medium almost in real time together with the broadcast. On the other hand, the television image data demodulated by the image demodulator 103, the television audio data demodulated by the audio demodulator 105, and the character raster data read from the character image storage unit 109 are independent files. May be stored in a memory, and compression encoding and recording on a recording medium may be performed together after the television content broadcast ends. In this case, in order to synchronize the time axis when recording each data file, the control data indicating the character code and the display timing thereof is extracted from the closed caption signal, and the raster data of the character indicated by the control data and the character code Must be stored in the memory in pairs. Further, the stored character code file may be edited to generate a caption script for the television content.

The presence or absence of driving of the signal extraction unit 107 of the DVD recording apparatus shown in the above embodiment may be linked to an EPG (Electronic Program Guide) system. FIG. 4 is a block diagram showing a hardware configuration of the modified example. The television content recording apparatus 1 shown in the figure includes a system timer 101, a carrier wave receiver 102, an image demodulator 103, a character encoder 111, an audio demodulator 105, an audio encoder 106, a signal extractor 107, and a character code decoder. In addition to the unit 108, the character image storage unit 109, the character image reading unit 110, the image encoding unit 104, the recording control unit 112, and the disk drive 113, an EPG receiving unit 114 and a drive control unit 15 are provided.
The EPG receiving unit 114 is connected to the Internet network, and supplies the EPG provided through the network to the drive control unit 15. Based on the EPG supplied from the EPG receiving unit 114, the drive control unit 15 specifies the broadcast time of the television content corresponding to the text multiplex broadcasting. Then, when the broadcast time of the television content corresponding to the text multiplex broadcast arrives, the signal extraction unit 107 is driven, and when the broadcast time ends, the drive is stopped. According to the present modification, since the sub-picture stream is generated only while the television content corresponding to the text multiplex broadcast is being broadcast, the resources of the recording medium can be used efficiently. The EPG receiving unit 114 may acquire the EPG from a television carrier instead of from the Internet network.

  In the above embodiment, each stream obtained from a television content carrier wave is recorded on a DVD recording medium. However, the stream may be recorded on another recording medium such as a large-capacity hard disk.

It is a figure which shows the data format of DVD. It is a hardware block diagram of a television content recording device. It is a conceptual diagram of the system stream recorded on a DVD recording medium. It is a hardware block diagram of a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Pack header, 20 ... Packet, 21 ... Packet header, 22 ... Packet data, 101 ... System timer, 102 ... Carrier wave receiver, 103 ... Image demodulator, 104 ... Image encoder, 105 ... Audio demodulator, 106 DESCRIPTION OF SYMBOLS ... Voice encoding part, 107 ... Signal extraction part, 108 ... Character code decoding part, 109 ... Character image storage part, 110 ... Character image reading part, 111 ... Character encoding part, 112 ... Recording control part, 113 ... Disk drive , 114 ... EPG receiver, 115 ... Drive controller

Claims (4)

Storage means for storing each character code and raster data of the character indicated by each character code in association with each other;
Receiving means for receiving a carrier wave of television content corresponding to the text multiplex broadcasting;
Extracting means for extracting a closed caption signal superimposed in a vertical blanking period of the received carrier;
Character code acquisition means for acquiring a character code by decoding the extracted closed caption signal;
Reading means for reading raster data stored in the storage means in association with the acquired character code;
A television content recording apparatus comprising: sub-picture recording control means for compressing and encoding the read raster data in accordance with a predetermined standard, and recording a code string obtained by the compression encoding on a recording medium as a pack of sub-picture streams. The television content recording device according to claim 1,
Television image acquisition means for demodulating the received carrier wave to acquire television image data;
A television content recording apparatus, further comprising: a video stream recording control unit that compresses and encodes the acquired television image data in accordance with a predetermined standard, and records a code string obtained by the encoding as a video stream pack on a recording medium. . In the television content recording device according to claim 1 or 2,
Television sound acquisition means for demodulating the received carrier wave to acquire television sound data;
A television content recording apparatus further comprising: audio stream recording control means for compressing and encoding the acquired television audio data according to a predetermined standard, and recording a code string obtained by the encoding on the recording medium as an audio stream pack . A computer apparatus comprising storage means for storing each character code and character raster data indicated by each character code in association with each other, and receiving means for receiving a carrier wave of television content compatible with character multiplex broadcasting.
An extraction function for extracting a closed caption signal superimposed on a vertical blanking period of a carrier wave received by the receiving means;
A character decoding function for acquiring a character code by decoding the extracted closed caption signal;
A read function for reading raster data stored in the storage means in association with the acquired character code;
A program for realizing a sub-picture recording control function for compressing and encoding the read raster data in accordance with a predetermined standard and recording a code string obtained by the compression encoding on a recording medium as a pack of sub-picture streams.

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