KR20010059825A - method for store and check of A/V and data stream in digital broadcasting - Google Patents

Abstract

PURPOSE: A method is provided to allow a user to efficiently utilize A/V and data streams by storing and retrieving the data stream, which is transmitted together with the A/V stream. Further, the method is provided to efficiently retrieve the A/V stream by synchronizing the data stream with the A/V stream and storing the same. CONSTITUTION: A broadcasting program to be stored out of received TS signals is selected. The selected broadcasting program is stored and a decision is made to determine whether or not a corresponding data stream is presented. When the corresponding data stream is presented, a storing position for a time which the broadcasting program and the corresponding data stream are transmitted is stored, or a storing position for the corresponding data stream only. The broadcasting program and the corresponding data stream are retrieved through the stored storing positions. When an additional data stream is presented, the data stream is stored. The additional data stream includes telephone number, shopping information, travel information and movie information.

Description

Method for store and check of A / V and data stream in digital broadcasting}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to digital broadcasting, and more particularly, to a storage and retrieval method according to synchronous and asynchronous synchronization of digital broadcast A / V and data streams.

The Personal Video Recorder (PVR), recently introduced by the US Tivo, Replay TV, etc., is applied to a TV or STB for up to 30 hours at the same time. The program was designed to be recordable, allowing viewers to have fun.

According to media analyst Josh Bernoff, who reported on the PVR earlier this year, "you will see it in more than 80% of homes in 10 years." have.

The time shifter is hardly patented in the related art, and it is known that a time shifter-related patent is pending in TiVo, Replay TV, and the like.

But it's still unknown what kind of thing it is.

Only, in the 1999 NAB proceedings, a "television home server for digital HDTV broadcasting" was published on how to store digital broadcast signals (called TS).

Looking at the contents of the above paper, the storage capacity of the disk is improved through the TS processing of the input and output during the storage of the TS and the play of the stored TS, respectively.

That is, a partial TS signal is generated through a desired stream selection process based on a PID (Packet IDentifier) as a previous step of a transport stream (TS) input during an input TP processing process.

In order for the TS signal generated as described above to be correctly decoded, the ratio of the encoder and the ratio of the decoder must be the same. To this end, time-related information is exchanged between the encoder and the decoder, and they must be synchronized with each other.

The method proposed in MPEG is a method using a system time clock (STC).

That is, a time stream is generated based on the system time clock (STC) for correct presentation and decoding time of audio and video.

At this time, the generated time streams include presentation time stamps (PTS) for designating a display time of audio and video, and decoding time stamps (DTS) for designating a decoding time.

The PTS and the DTS are used to make the correct decoding by equalizing the time intervals of the encoded audio and video at the encoder side and the time intervals of the decoded audio and video.

That is, the system clock reference (SCR) for the program stream and the program clock reference (PCR) for the transport stream are used to synchronize the system time clock (STC) in the encoding with the system time clock (STC) in the decoder. The system time clock (STC) value of the encoder is loaded into the SCR or PCR at regular intervals to set the system time clock (STC) value of the decoder.

Therefore, audio and video are decoded based on PTS and DTS at the time intended by the encoder.

As described above, in order to correctly decode PTSs and DTSs generated on the basis of the system time clock (STC) at the encoder side, when the system time clock (STC) of the decoder is equal to the system time clock (STC) at the encoder side, Video and audio encoded based on DTS are decoded correctly.

The SCR (for program stream) or PCR (for transport stream) described above are used to synchronize the system time clock (STC) period of the encoder and decoder.

In addition, the PCR value of the TS is transmitted by being combined with the transport stream by sampling the system time value calculated by its system time clock at a constant period in the transport encoder.

The transport decoder then uses this value to restore the decoder's system clock and use it as the decoder's system clock.

In this way, accurate clock recovery must be performed to prevent underflow / overflow of the buffer inside the decoder, and to accurately decode and synchronize the lip of audio / video.

In general, the time passed through the channel encoder and the channel decoder is called a constant delay module because it is regarded as the same by a constant constant difference.

However, when the TS is selectively stored in the HDD, which is a storage device, the delay of the constant multiple is changed irregularly, and if the TS is selectively decoded, a serious problem occurs in synchronizing the PCR values.

In other words, in general, the PCR value in the ATSC is coupled to the adaptation field of the video transport stream PID. In the case of SD, when a virtual channel of one of four virtual channels is selectively stored, the PCR in the original stream is selected. When the second signal, which is stream information selectively stored by the value period and the PID, is transmitted to the decoder and decoded, the period of the PCR value may not be constantly combined, and thus normal decoding cannot be performed.

Therefore, normal decoding is performed by adding and decoding a NULL packet by a predetermined value between the second signals so as to be equal to the PCR value period to the header generated in the second signal.

However, the digital broadcasting using the time shift according to the related art described above has the following problems.

First, TV programs can be searched and recorded using only MPEG-2 streams transmitted from broadcasting stations and program guide information. Currently, data services such as HTML pages or java applets are not provided.

Second, if the DTV and STB support the data service by the method suggested by ATVEF, DASE, etc., how to store and retrieve the A / V stream is an important issue.

Accordingly, an object of the present invention is to provide a method for storing and retrieving a data stream transmitted together with an A / V stream so that a user can efficiently use the same.

Another object of the present invention is to store the data stream in synchronization with the A / V stream to efficiently retrieve the A / V stream through data retrieval.

Yet another object of the present invention is to efficiently store a data stream when it is not directly related to an A / V stream or when data is to be stored separately.

1 is an overall system configuration diagram of a PVR for storing and retrieving A / V and data streams.

2 is a flowchart illustrating a method of storing and retrieving an A / V stream and a data stream according to the present invention.

* Explanation of symbols for main parts of the drawings

10: tuner 20: demodulator

30: PID filter portion 40: time stamp header portion

50: stamp control unit 60: storage control unit

70: mux part 80: storage part

90: decoder

A feature of the method for storing and retrieving A / V and data streams of digital broadcasting according to the present invention for achieving the above object is selecting a broadcast program to be stored from among received TS signals, and storing the selected broadcast program. Searching whether the data stream exists, and if the data stream exists as a result of the search, storing a storage location for the transmission point of the broadcast program and the data stream, or storing only a storage location of the data stream. And retrieving a broadcast program or data stream through the stored storage location.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments taken in conjunction with the accompanying drawings.

A preferred embodiment of the A / V and data stream storage and retrieval method of digital broadcasting according to the present invention will be described with reference to the accompanying drawings.

1 shows an overall system configuration of a PVR for storing and retrieving A / V and data streams.

Referring to FIG. 1, a tuner 10 for tuning a received broadcast signal, a demodulator 20 for demodulating a signal output from the tuner 10 to output a live stream, and a live stream output from the demodulator 20. The data other than the detected TS stream is regarded as a NULL packet between the data PID filter unit 30 for detecting only the TS stream to be filtered and stored, and the signal detected by the data PID filter unit 30, The header is counted to form a number, and the TS stamp generated by the time stamp header 40 is stored, and a time stamp header 40 for inserting the configured header between the partial TS signals. The storage unit 80, the stamp control unit 50 for controlling the search of the stream stored in the storage unit 80, the storage control unit 60 for managing the stream stored in the storage unit 80, and the stamp The mux unit 70 selects and outputs one of the signals output from the controller 50 and the demodulator 20, and the decoder unit 90 decodes the signal selected by the mux unit 70.

At this time, the method of storing and retrieving the A / V stream and the data stream by the stamp controller 50 can be largely divided into two types, a synchronization method and an asynchronous method.

The synchronization method is used when the contents of the data stream are browsed in synchronization with the A / V stream.

That is, the synchronization method stores information on at which point in the A / V stream the data stream is transmitted, and when searching the data stream with a keyword, it is possible to search through the corresponding position of the A / V stream. This is how you do it.

The asynchronous method is used to store data streams irrelevant to the contents of the A / V stream or to store important information in a memo format.

That is, the asynchronous method is a method used when storing and retrieving information (telephone number, shopping information, tourist information, movie information, etc.) to be referred to later.

Therefore, the asynchronous method is irrelevant to the position of the A / V stream, and only the data stream can be searched later when searching by keyword.

The operation of the A / V and data stream storage and retrieval method for digital broadcasting according to the present invention configured as described above will be described in detail with reference to the accompanying drawings.

2 is a flowchart illustrating a method of storing and retrieving an A / V stream and a data stream according to the present invention.

Referring to FIG. 2, first, an SD program to be stored among TS signals output from the demodulator 20 is selected through the PID filter unit 30 (S10).

The selected SD program is reproduced and stored in the storage unit 80 (S20).

At this time, if the corresponding data stream exists in the SD program to be reproduced (S30) by using the synchronization method is connected to the SD program to store the data stream (S40).

Alternatively, when storing the data stream separately, only the data stream except the SD stream is stored using an asynchronous method (S50).

If the transmitted data stream is information separate from the currently reproduced SD program, the data stream is stored using an asynchronous method (S50).

When the synchronous storage is selected as described above, the positions of the data stream and the A / V stream are stored together. When the synchronous storage is selected, only the data stream is stored.

As described above, the method for storing and retrieving the A / V and data stream of digital broadcasting according to the present invention has the following effects.

First, by storing and retrieving the data service provided by the digital TV in conjunction with the A / V stream, it is possible to provide a variety of search to the user.

Second, you can save only the data stream separately, so you can maximize the usefulness of data such as HTML pages or Java applets.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

Claims (3)

Selecting a broadcast program to be stored among the received TS signals; Storing the selected broadcast program and searching whether a corresponding data stream exists; Storing a storage location for the transmission point of the broadcast program and the data stream when the data stream exists as a result of the search, or storing a storage location of only the data stream; And retrieving a broadcast program or data stream through the stored storage location. The method of claim 1, And storing the data stream if there is a separate data stream as a result of the search. The method of claim 2, The separate data streams are telephone numbers, shopping information, tourism information, and movie information.