KR20010009393A - Channel selecting method at the digital television signal reproduce - Google Patents

Abstract

PURPOSE: A method for selecting a channel when reproducing a digital broadcasting signal is to selectively output only a desired channel even though PSI(Program Specific Information) or PSIP(Program and System Information Protocol) including information of various channels is stored along with information of the desired channel. CONSTITUTION: A method for selecting a channel when reproducing a digital broadcasting signal comprise the steps of: decoding PSI or PSIP in a reproducing mode; extracting all of PID(Packet Identification Data) lists contained in a signal using a PID table, and processing into a format showing to a user, and then displaying a selection image of A/V(Audio/Video) PID; setting up the A/V PID to a TP demultiplexer if the user selects one of the displayed PID lists, and reproducing an audio/video signal. Alternatively, the method comprises the steps of: decoding the PSI or PSIP in the reproducing mode and extracting a PMT PID from a PAT(Program Association Section) table; performing an A/V decoding operation to detect the A/V PID; setting the A/V PID to the TP demultiplexer; deciding frame synchronization output from an A/V decoder; reproducing the audio/video signal if the frame synchronization is detected; and resetting the A/V PID if the frame synchronization is not detected.

Description

CHCHANNEL SELECTING METHOD AT THE DIGITAL TELEVISION SIGNAL REPRODUCE}

The present invention relates to a channel selection method for reproducing a digital broadcast signal, and more particularly, to a channel selection method for reproducing a digital broadcast signal in which a user can select a desired channel when recording and reproducing a digital TV signal.

In general, since MPEG (Motion Picture Expert Group) 2 became an international standard in 1994, various countries and companies have been developing systems for transmitting and receiving digital images in various forms. The transmission and reception of digital images through broadcasting was widely held, and Korea opened the digital era in broadcasting after launching the Mugunghwa satellites 1,2.

In 1997, the US FCC adopted the ATSC (Advanced Television System Committee) standard, which opened a wide market for the 21st century digital video era, and various storage media have emerged as the digital broadcasting era entered. (Digital Video Disc) and the like are widely known to the general public, and the DVCR (Digital Video Cassette Record) is at some stage of realization.

Meanwhile, various methods of storing broadcasts desired by digital TVs have been considered. Among them, a method of storing in a DVCR using IEEE 1394 is the most popular method.

IEEE1394 can be regarded as the standard interface standard for digital devices. Applications include desktop and notebook computers, VOD set-top boxes, VRs, camcorders, digital TVs, multimedia equipment, printers, scanners, and hard disks. It can be used in many fields, such as CD-ROMs, optical discs, and DVDs.

In the case of storing broadcast signals in this manner, it is common to store data of a transport layer of MPEG-2.

In the current satellite broadcasting transmission / reception system or ATSC terrestrial broadcasting, it is possible to receive several program channels at one frequency. However, the channel selected by the user is one and the recording is made in two ways depending on the connection of the recording device. Is possible.

1 is a block diagram of a general digital broadcast signal recording and reproducing apparatus, and as shown therein, a DTV tuner unit 1 for receiving a digital broadcast signal; A VSB demodulator (2) for converting a signal into a transport stream through the DTV tuner (1); A TP demux (4) for extracting only one stream through a switch (3) from a bitstream having several programs outputted through the VSB demodulator (2); An A / V decoder (5) for decoding and outputting audio and video signals from one stream extracted from the TP demux (4) to an audio output device (9) and an image output device (10); A CPU for controlling the output of the VSB demodulator 2 or the TP demux 4 to be transferred to the respective data paths DATA PATH1 and DATA PATH3 and stored in the DVCR 8 through the IEEE1394 interface 6; 7), the conventional operation and operation of the device configured as described above are as follows.

In this case, the transport stream is composed of 188-byte packets, and since each packet has a packet ID (PID), for example, a packet of a table containing information about audio and video channels can be distinguished.

In the case of recording while receiving broadcasts, it is common to record signals in the digital broadcast receivers in general by receiving the output of the VSB demodulator 2 or the output of the TP demux 4.

Here, when recording the output of the VSB demodulator 2, the output of the VSB demodulator 2 is filtered as it is, regardless of whether multiple channel data enters one frequency or one channel data enters one frequency. It will be saved as DVCR (8) without it.

In this case, the content of the DVCR 8 can be shown to the user by allowing the user to select a channel when the user plays and watches the DVCR 8 in the future.

However, if the user wants to record the desired channel with the DVCR 8 while watching a certain broadcast, the channel selected through the switch 3 and the TP demux 4 will be recorded in the DVCR 8.

At this time, the stream stored in the DVCR 8 stores not only the selected audio and video packet but also the program specific information (PSI) or the program and system information protocol (PSIP). Should be.

This is because the audio and video information packetized in the transport layer is configured to be viewed only when the PSI and PSIP information is extracted.

However, the PSI or PSIP information is stored in a table with a plurality of information even when one signal is stored while passing through the TP demux 4.

Fig. 2 is a block diagram showing a simple structure of the PSI. As shown in (c), a packet stream of a transport layer is shown, and streams are constructed according to the frequency of components, and each 188 byte packet The PID can be used to distinguish between properties and types.

This PID classification is first extracted from the PAT (Program Association Section) table in (a), as shown in (b), and the PMT PID is set in the TP demux and the PMT table is extracted from the PMT table. By extracting the audio / video PID (A / V PID) and setting this PID back to the TP demux, the A / V signal can be finally extracted.

That is, only PSI or PSIP can be used to extract audio and video PIDs, so even if only one channel selected by the user is recorded, this information cannot be processed and stored.

This is because, in order to process this table, not only has to decode and encode, but it is also impossible to embed an encoder in the decoder.

For this reason, current storage media and receivers will store PSI or PSIP information without processing regardless of the number of recording channels. Therefore, PID for audio / video information has nothing to do with recording channels. An error may occur, and if you select an irrelevant PID, unwanted images may appear on the screen, and you may not meet the user's requirements.

As described above, in the conventional technology, even if only one channel selected by the user is recorded, the PSI or PSIP information is stored without processing. In order to process this table, decoding and encoding must be performed once again. In addition to the hassle, it is practically impossible to embed an encoder in the decoder, so an error may occur in selecting a PID for audio and video information that has nothing to do with the channel to be played. There was a problem that the unwanted image may appear on the screen.

Accordingly, the present invention has been created to solve the above-mentioned conventional problems, and when selecting and storing one of a plurality of channels, information of a PSI or PSIP including information on several channels is stored therewith. It is an object of the present invention to provide a channel selection method when reproducing a digital broadcast signal that allows a user to select and output only a desired channel without an error even if there is an error.

1 is a block diagram of a general digital broadcast signal recording and reproducing apparatus.

Fig. 2 is a block diagram showing a simple structure of a PSI in audio / video information of a transport packet.

3 is a general interface timing diagram for a TP demux.

4 is a signal flow diagram according to an embodiment of the present invention.

Fig. 5 is an embodiment showing the PID list extracted by Fig. 4;

6 is a flowchart illustrating a channel selection method when reproducing a digital broadcast signal according to another embodiment of the present invention.

Figure 7 is a flow chart showing another embodiment of the present invention.

In order to achieve the above object, the present invention includes a first step of extracting the PMT PID from the PAT table extracted by decoding the PSI or PSIP in the playback mode; A second step of detecting A / V PID by A / V decoding when the PMT PID is extracted in the step; A third step of setting the A / V PID in the TP demux when the A / V PID is detected in the step; A fourth step of determining a frame sync output from the A / V decoder; A fifth step of reproducing an audio / video signal when frame synchronization is detected in the fourth step; When the frame sync is not detected in the fourth step, the A / V PID of the third step is reset and the sixth step proceeds to the fifth step. When described in detail with reference to the accompanying drawings as follows.

3 shows a typical interface timing for TP demux.

When the signal is input, once the signal is input, the TP demux 3 is set to the default PID, and in the case of PSIP, the MGT (Master Guide Table: PID 0x1FFB) is also set to the default PID. Assuming that the PSI is decoded as shown in Fig. 2, after the PMT PID is found, the audio / video PID can be found. After the found audio / video PID is set back to the TP demux 3, the TP demux The output is normally output to the A / V decoder 4, whereby the A / V decoder 4 outputs a signal for each frame while decoding each part, and the CPU 7 receives and recognizes it.

Next, the process of detecting the normal signal by the CPU 7 will be described in more detail with reference to the flowcharts of FIGS. 4, 6, and 7.

First, FIG. 4 is a signal flow diagram according to an embodiment of the present invention. As shown in FIG. 4, when a user reproduces a signal recorded in the DVCR 8, when the reproduction signal is output from the DVCR 8, the signal is stored therewith. It decodes the PSI or PSIP, and extracts all the PIDs in the signal from the PID table extracted from them, and processes them into a form that can be shown to the user to display the selection screen of the A / V PID.

Accordingly, when the user selects one from the displayed PID list, the selected A / V PID is set to the TP demux to reproduce the final A / V signal.

FIG. 5 is an exemplary diagram showing the PID list extracted by FIG. 4, which allows a user to select a PID.

That is, when the user checks the selection area of FIG. 5 (1), it can be seen that the PID is selected by the user. Based on this, the PID is selected for the TP demux to decode the A / V.

Next, Fig. 6 is a signal flow diagram of another embodiment of the present invention, which is different from the embodiment of Fig. 4, and is performed automatically. Once the reproduction mode is entered, the signal input from the data path 2 or the switch 2 is applied. The PMT PID is extracted from the PAT table in the PSI or PSIP decoding block. When the PMT PID is extracted, the A / V decoder detects the audio / video PID.

Next, after the A / V PID is detected and the PID is set in the TP demux, the CPU checks the frame sync output from the A / V decoder and does not enter the required time (about 50 msec). No signal is determined and the count is increased.

Then, the time limit (Limit) for the count is determined to be 3 as the current reference, that is, the time for the total no signal discrimination is determined in 10 msec or less.

That is, in the case of No Sync, when the count value exceeds the limit, the next A / V PID found by the PMT PID is set to the TP demux to go through the process previously performed.

In this process, when a user requests playback of a broadcast signal from a DVCR and a signal is input to a TP demux, the time difference may be different depending on the location of a program selected by the user, but the time for searching for a signal is within 100 msec. The user can watch automatically without reselecting the recorded signal.

Next, FIG. 7 is a signal flow diagram of another embodiment of the present invention. As shown therein, PSI or PSIP decoding extracts a PMT PID from a PAT table in a playback mode, and when the PMT PID is extracted, A / V decoding is performed. After detecting the audio / video PID (A / V PID), the data in the TP memory is read to detect how many packets contain the video PID.

Next, if there are three or more packets with video PIDs, set the PID to the TP demux and when the A / V PID is detected, set the detected A / V PID to the TP demux and output it from the A / V decoder. The frame sync is checked, and if the frame sync does not come in for a predetermined time (about 50 msec), it determines the no sync and increases the count.

Next, when the count value exceeds the limit, the A / V PID of the third step is set again to the TP demux, and the previous process is performed again. When the frame sync is detected, the audio / video signal is detected. Will play.

However, if the signal containing several PIDs recognizes that the storage media plays back the signals, it extracts the VID PID from the PSI or PSIP and reads the data from the TP memory before outputting the stream from the TP demux. If it detects that a packet contains a video PID and there are three or more packets with a video PID, the PID may be set to the TP demux to determine a signal.

As described above, the channel selection method of the digital TV receiver according to the present invention stores a digital broadcast signal including DVCR, and then, in a state in which it is difficult to modify information of a PSI or PSIP table, a user can quickly and easily watch a desired program. It can be applied to any device that stores and reproduces digital broadcast signals in real time as well as to enable effects and DVCR, so it is easy to use any interface (e.g. IEEE1394, QAM modulation, VSB modulation, etc.) between the receiver and the storage medium. There is an effect that can be applied.

Claims (3)

Decoding the PSI or the PSIP in the reproduction mode; A second step of displaying a selection screen of the A / V PID by extracting all the PID lists included in the signal from the PID table extracted from the first step and processing them in a form that can be shown to the user; And a third step of reproducing the audio / video signal by setting the selected A / V PID to the TP demux when the user selects one from the displayed PID list. Extracting the PMT PID from the PAT table obtained by decoding the PSI or PSIP in the reproduction mode; A second step of detecting A / V PID by A / V decoding when the PMT PID is extracted in the step; A third step of setting the A / V PID in the TP demux when the A / V PID is detected in the step; A fourth step of determining a frame sync output from the A / V decoder; A fifth step of reproducing an audio / video signal when frame synchronization is detected in the fourth step; If the frame sync is not detected in the fourth step, the channel selection is performed when the digital broadcast signal is reproduced, wherein the A / V PID of the third step is reset and the sixth step proceeds to the fifth step. Way. Extracting the PMT PID from the PAT table by PSI or PSIP decoding in the reproduction mode; A second step of detecting A / V PID by A / V decoding when the PMT PID is extracted in the step; A third step of reading data of the TP memory and detecting how many packets contain the video PIDs; A fourth step of determining a signal by setting the PID to the TP demux when there are three or more packets having the video PID; A fifth step of setting a PID in the TP demux when the A / V PID is detected in the step; A sixth step of determining a frame sync output from the A / V decoder; A seventh step of performing a process previously performed by setting the A / V PID of the third step to the TP demux again when frame synchronization is not detected in the sixth step; And an eighth step of reproducing the audio / video signal when the frame sync is detected in the sixth step.