KR100775169B1 - Method for playing broadcasting stream stored in digital broadcasting receiver - Google Patents

Abstract

The present invention relates to a method for reproducing a broadcast stream stored in a digital broadcast receiver having a storage unit. When an FF / RW command is input while reproducing a broadcast stream stored in the storage unit, the present invention provides a method for reproducing a broadcast stream stored in the storage unit. Extracts a TS packet from the storage unit, and determines whether 28 bytes of the extracted TS packet is a NAL start code; and if 28 bytes of the TS packet is a NAL start code, a day NAL ) Determining whether the type is an SPS, if the NAL type is an SPS, calculating a delta time, calculating an IDR number using the calculated delta time, and starting from a TS packet corresponding to the calculated IDR number. If the FF / RW command is input while the broadcast stream stored in the digital broadcast receiver such as digital multimedia broadcasting (DMB) is playing, the packet corresponding to the command can be played more quickly. All.

Digital Broadcast Receivers, DMB, Broadcast Stream, NAL, IDR

Description

Method for playing broadcasting stream stored in digital broadcasting receiver

1 is a flowchart illustrating a FF / RW method in a conventional digital multimedia broadcasting (DMB) system.

2 is a block diagram schematically showing the configuration of a digital multimedia broadcasting system according to the present invention;

3 is a flowchart illustrating a method of performing FF / RW in a digital multimedia broadcasting system according to the present invention.

<Explanation of symbols for the main parts of the drawings>

200: tuner 210: A / D conversion unit

220: demodulation unit 230: demultiplexer

240: control unit 250: key input unit

260: storage unit 270: audio / video decoder

280: audio processing unit 290: video processing unit

According to the present invention, when an FF / RW command is input while a broadcast stream stored in a digital broadcast receiver such as digital multimedia broadcasting (DMB) is being played, a digital broadcast can be played more quickly. The present invention relates to a broadcast stream reproduction method stored in a receiver.

The radio broadcasts currently in use are analogue and originally developed for fixed reception, so that the reception of sound while walking or driving a vehicle is considerably degraded and requires high power and a wide frequency band.

In order to solve this problem, standardization and commercialization of digital audio broadcasting is underway around the world.In Europe, which adopts Eureka-147 as the digital audio broadcasting standard, DAB (Digital Audio Broadcasting) in Europe, DAR in USA, Canada In the case of DRS and the International Telecommunication Union, DSB is used, and in Korea, it is used by the Ministry of Information and Communication as DMB (Digital Multimedia Broadcasting).

At this time, DAB developed for next generation broadcasting is able to receive CD level sound quality in a vehicle driving at high speed even though it transmits at low power because it is strong in urban environment and noise. In addition, the concept of radio broadcasting has been extended to see and listen to the concept of existing listening broadcasts, and in addition to music broadcasting, various multimedia information such as news, traffic information, weather information, geographic location information, and video information can be transmitted in text and graphics. .

Meanwhile, DMB, or digital multimedia broadcasting, named by the Ministry of Information and Communication of Korea, is digitalizing voice broadcasting, and it transfers 1.5Mbit / s of data to high quality CD level, text, graphics, and moving pictures beyond AM and FM radio. This is the next generation broadcast that offers a variety of possible data services, bidirectional and excellent mobile reception qualities.

The above-described DMB can be broadly classified into terrestrial DMB and satellite DMB according to the characteristics of a medium, which is a means of transmission. In the case of satellite DMB broadcasting, it can be divided into fixed service and mobile service.

Satellite DMB-related technologies are currently only available as specifications that are not commercially available. Some product functions have been developed, but many of them are not yet developed.

The concept of storing broadcast streams and replaying them regardless of time is also considered technically feasible because it is transmitted through satellite DMB, but it is not yet determined how to implement them. If the broadcast stream can be stored like this, FF and RW are also required when commercializing it. Technically, according to MPEG or various technical standards, it is necessary to follow a method of analyzing and implementing data according to a normal path.

1 is a flowchart illustrating an FF / RW method in a conventional digital multimedia broadcasting (DMB) system.

Referring to FIG. 1, when a digital multimedia broadcasting system is playing a broadcast stream stored in a storage unit (S100) and an FF / RW command is input by a user (S102), a time point at which the FF / RW command is input The N packets of N are collected to generate a PES packet (S104). That is, when the FF / RW command is input by the user, the digital multimedia broadcasting system collects N packets having a size of 188 bytes and generates an intact PES packet.

Then, the digital multimedia broadcasting system analyzes the header of the generated PES packet and extracts a playing time (S106). That is, the PES packet is composed of a header and a payload. In the header, a code for identifying an individual stream and a packet size, time information for synchronous reproduction such as PTS or DTS, and control information (with or without scramble and copyright) are described. Therefore, the digital multimedia broadcasting system can extract the playback time using the time information in the header of the PES packet configured as described above.

After performing step 106, the digital multimedia broadcasting system decodes the payload to analyze the corresponding video stream and determines what the NAL type is (S108).

If it is determined in step 108 that the NAL type is an Instantaneous Decoder Refresh (IDR) frame (S110), the digital multimedia broadcasting system plays a series of streams starting from the file stream position where the TS packet is located (S112). In the digital multimedia broadcasting system, even if the time value is correct, it is impossible to reproduce the P frame once it is given to the codec, so it is important to determine the I frame. Thus, the digital multimedia broadcasting system determines whether the NAL type is an IDR frame.

After analyzing the video stream as described above and determining what the day type is, if all of these conditions are met, normal playback is possible by sending a series of streams to the codec starting from the file stream location where the TS packet is located.

If it is determined in step 110 that the NAL type is not an IDR frame, the digital multimedia broadcasting system extracts the packet from the storage unit again and generates a packetized elementarty stream (PES) packet (S114). The digital multimedia broadcasting system then performs again from step 106.

However, since the PES header information is decoded to calculate a value in the related art, it takes a long time to perform a desired reproduction.

Accordingly, an object of the present invention is that if an FF / RW command is input while a broadcast stream stored in a digital broadcast receiver such as a DMB is being played back, the broadcast stream stored in the digital broadcast receiver can speed up playback of a packet corresponding to the command. It is to provide a reproduction method.

According to an aspect of the present invention to achieve the above object, in the method for reproducing a broadcast stream stored in a digital broadcast receiver provided with a storage unit, when an FF / RW command is input while reproducing the broadcast stream stored in the storage unit And extracting, from the storage, a TS packet at the time when the FF / RW command is input, determining whether 28 bytes of the extracted TS packet is a NAL start code, and starting from 28 bytes of the TS packet. If is the NAL start code, it is determined whether the NAL type is SPS, if the NAL type is SPS, the delta time is calculated, and the IDR number is calculated using the calculated delta time. The present invention provides a method for reproducing a broadcast stream stored in a digital broadcast receiver, characterized by reproducing the TS packet corresponding to the calculated IDR number.

Extracting the TS packet at the time when the FF / RW command is input from the storage unit extracts a 188-byte TS packet because the TS packet is a fixed packet of 188 bytes.

The delta time is a difference between an FF / RW start time and a time value of a current stream point. The FF / RW start time and a time of a current stream point respectively indicate playback time information in header information of a corresponding TS packet. Obtain by using

The IDR number of times is calculated using a delta time / IDR period value, and the IDR period value has a constant period for the same stream.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram schematically showing the configuration of a digital multimedia broadcasting system according to the present invention.

2, the digital multimedia broadcasting system includes a tuner 200, an A / D converter 210, a demodulator 220, a demultiplexer 230, a controller 240, a key input unit 250, and a storage unit ( 260, an audio / video decoder 270, an audio processor 280, and a video processor 290.

The tuner 200 tunes a broadcast signal.

The A / D converter 210 converts an analog signal received through the tuner 200 into a digital form.

The demodulator 220 demodulates the digital signal converted by the A / D converter 210 to correct an error and converts the digital signal into a transport stream.

The demultiplexer 230 demultiplexes a time multiplexed transport stream, i.e., separates video, audio, and additional information signal sequences.

The audio / video decoder 270 extends / restores the audio and video signal sequences separated by the demultiplexer 230.

The audio processor 280 converts the audio signal output from the audio / video decoder 270 into an analog audio signal to be output through a speaker.

The video processor 290 converts the video signal output from the audio / video decoder 270 into luminance and color signals so as to be displayed on a screen.

The storage unit 260 stores program guide related information, detailed information, and a recorded program.

The controller 240 controls the operation of each part of the digital multimedia broadcasting system.

When the FF / RW command is input through the key input unit 250 while the program stored in the storage unit 260 is playing back, the controller 240 is 28 bytes based on a 188-byte TS packet at the start of the FF / RW. Determines if is a NAL start code.

If the start result code is 28 bytes from the determination result, the control unit 240 accesses the day type field after the corresponding day start code, and if the type is a sequence parameter set (SPS), the Instantaneous Decoder Refresh (IDR) frame from the current TS packet. Is started and it is determined that the point of the stream that can be locally played back from the TS packet is controlled to be played back from the TS packet.

A method of performing FF / RW when a user inputs an FF / RW command while playing a broadcast stream stored in a storage unit in the digital multimedia broadcasting system configured as described above will be described with reference to FIG. 3.

3 is a flowchart illustrating a method of performing FF / RW in a digital multimedia broadcasting (DMB) system according to the present invention.

Referring to FIG. 3, the digital multimedia broadcasting (DMB) system determines whether an FF / RW command is input from a user while playing a broadcast stream stored in a storage unit (S300). That is, since the digital multimedia broadcasting (DMB) system can store and reproduce the broadcast stream regardless of time, the user can select and play any broadcast stream stored in the storage unit. The user may select an FF / RW command using the key input unit while the corresponding broadcast stream is being played.

When the FF / RW command is input from the user as a result of the determination of step 302, the digital multimedia broadcasting (DMB) system extracts a 188-byte TS packet at the time when the FF / RW command is input (S304). The TS packet is a fixed packet of 188 bytes and consists of a packet header and a payload. Accordingly, when the FF / RW command is input by the user, the digital multimedia broadcasting (DMB) system extracts a TS packet from the storage unit when the FF / RW command is input.

After performing step 304, the digital multimedia broadcasting (DMB) system determines whether the starting TS is the NAL start code from 28 bytes for the extracted TS packet (S306). The day (NAL) is to provide header information carried by the transport layer or transport media or to specify the data format.

In streams complying with the satellite DMB specification currently in service, the NAL start code always starts at 28 bytes when an IDR frame comes out based on a 188-byte TS packet.

If it is determined in step 306 that the start TS is 28 bytes for the extracted TS packet, the digital multimedia broadcasting (DMB) system determines whether the day type behind the start code is SPS (S308). That is, the digital multimedia broadcasting (DMB) system determines that the day type is an SPS because the code type cannot be coded if the day type after the day start code is not an SPS but a Picture Parameter Set (PPS).

If it is determined in step 308 that the day type behind the day start code is SPS, the digital multimedia broadcasting (DMB) system determines that an IDR frame starts from a current TS packet (S310), and calculates a delta time at that time ( S312). That is, in the digital multimedia broadcasting (DMB) system, even if the time value is accurate, it is impossible to reproduce the P frame once given to the codec, so it is important to determine the I frame. Thus, the digital multimedia broadcasting (DMB) system determines whether the day type is an SPS.

The delta time refers to a difference value between the FF / RW start time and the time value of the current stream point. That is, since the header information of the TS packet includes the reproduction time information, the digital multimedia broadcasting (DMB) system can obtain the delta time using the header information.

After performing step 312, the digital multimedia broadcasting (DMB) system calculates the number of IDRs using the obtained delta time and IDR period value (S314). Since the IDR frame has a constant period in the same stream, the IDR period value can be known.

The number of IDRs can be obtained by using Equation 1.

IDR Count = Delta Time / IDR Period Value

After performing step 314, the digital multimedia broadcasting (DMB) system plays back TS packets corresponding to the calculated number of IDRs (S318).

For example, if the IDR cycle value appears once every 0.5 seconds and you want to view the video after 40 seconds through FF, the IDR frequency is 40 / 0.5 = 80.

Therefore, in the digital multimedia broadcasting (DMB) system, if the SPS is issued as a raw type, the local reproduction may be started from the corresponding TS packet when the TS packet is 80th.

When the FF / RW command is input by the user, it is correct to decode the header information of the PES packet to calculate the value. However, considering the various performance loads for decoding, the value estimated in the above-described manner is simple. The error is in the range of approximately +/- 15 ms, which is almost impossible for a human to discern.

The present invention is not limited to the above embodiments, and many variations are possible by those skilled in the art within the spirit of the present invention.

As described above, according to the present invention, if an FF / RW command is input while a broadcast stream stored in a digital broadcast receiver such as a digital multimedia broadcasting (DMB) is being played, the packet corresponding to the command can be played more quickly. A broadcast stream reproduction method stored in a digital broadcast receiver may be provided.

In addition, according to the present invention, when performing the FF / RW for the broadcast stream stored in the digital broadcast receiver, a lot of operations can be reduced, digital broadcasting capable of securing a certain degree of accuracy within the range that the human eye does not feel A broadcast stream reproduction method stored in a receiver may be provided.

In addition, according to the present invention, it is possible to provide a method for reproducing a broadcast stream stored in a digital broadcast receiver, which can be processed with faster and less inferior accuracy than the conventional method in storing and reproducing satellite DMB content.

Claims (8)

In the method of playing a broadcast stream stored in the digital broadcast receiver provided with a storage, If an FF / RW command is input while playing the broadcast stream stored in the storage unit, extracting a TS packet at the time when the FF / RW command is input from the storage unit; Determining whether a predetermined start area of the extracted TS packet is a NAL start code; Determining whether a day (NAL) type is an SPS if a starting point of a predetermined area of the TS packet is a NAL start code; If the NAL type is SPS, calculating a delta time that is a difference between an FF / RW start time and a time value of a current stream point; Calculating an IDR number using the calculated delta time; and Playing from the TS packet corresponding to the calculated IDR number Broadcast stream playback method stored in the digital broadcast receiver comprising a. The method of claim 1, Extracting the TS packet at the time when the FF / RW command is input from the storage unit extracts a 188-byte TS packet because the TS packet is a fixed packet of 188 bytes. . The method of claim 1, And a predetermined predetermined region of the TS packet is 28 bytes of the TS packet. delete The method of claim 1, And the time of the FF / RW start time point and the time of the current stream point are respectively calculated using the play time information in the header information of the corresponding TS packet. The method of claim 1, And the IDR frequency is calculated using a delta time / IDR period value. The method of claim 6, And the IDR period value has a constant period for the same stream. The method of claim 1, If the NAL type is SPS, it is determined that the IDR frame starts from the current TS packet and calculates a delta time.

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