KR20140118059A - Method for reproducing contents - Google Patents

Abstract

The present invention relates to a content playback method. According to an embodiment of the present invention, in response to a reproduction request of a content received via a broadcast signal and stored in a storage medium, data of the content is read from the storage medium, and the content data to be read is interpreted, And a decoding step of decoding the video data and the subtitle data and outputting the decoded video data and the subtitle data, wherein when the subtitle data has no time information related to the output time, The buffering unit divides the filtered video data and the subtitle data into a buffer and buffers the buffered video data. When the buffered video data is decoded and output, a predetermined amount of the buffered subtitle data Subtitle day of It decodes the subtitle data since can be output together with the video data. Therefore, even when the content transmitted in the broadcast state without the time information in the subtitle data is recorded on the recording medium and then reproduced, the AV data and the subtitle data can be reproduced in synchronization with each other.

Description

Method for reproducing contents [0002]

The present invention relates to a method of reproducing a content, and more particularly to a method of reproducing A / V data and a subtitle of a content broadcasted without a time information in a subtitle and synchronized with a subtitle.

Various types of digital broadcasting services such as terrestrial broadcasting, satellite broadcasting, cable broadcasting, and the like are provided, and channels and contents that can be viewed through these various types of broadcasting are increasing, and a set-top box Broadcast receivers such as televisions and the like are becoming popular.

Also, a set-top box having a PVR (Personal Video Recording) function is widely popularized so that a user can record a desired broadcast program on a large-capacity storage medium such as a hard disk and watch it at a desired time.

The broadcasting station digitizes and broadcasts analog contents such as old movies and broadcasting programs to fill up the increased broadcasting channels and diversify the contents. The video data and the audio data are encoded so as to include time information in accordance with the MPEG-2 standard, (Transport Packet) is generated and transmitted. However, a subtitle, that is, Subtitle data, may be generated by transmitting a transport packet without inserting time information. At this time, a subtitle transport packet is inserted between the A / V transport packets so as to be synchronized with the A / V transport packet, and the transmission interval is adjusted so that the broadcasting receiver receives the A / V data and the subtitle So that data can be reproduced synchronously without any special operation.

However, when contents to be broadcast in a state in which time information is not embedded in the subtitle data is stored in the hard disk via the PVR function of the broadcast receiver and then reproduced, there arises a problem that the subtitle data and the AV data can not be synchronized with each other .

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and it is an object of the present invention to provide a method and apparatus for reproducing a content recorded on a recording medium without time information in subtitle data, Method.

According to another aspect of the present invention, there is provided a method for reproducing content, the method comprising the steps of: reading data of the content from the storage medium upon receipt of a broadcast signal and requesting reproduction of the content stored in the storage medium; And outputting the decoded video data and the subtitle data; and when there is no time information related to the output time in the subtitle data, Wherein the filtering operation is performed prior to reading the content data from the storage medium, the buffered video data and the subtitle data are separated and buffered in a buffer, and when the buffered video data is decoded and output, Of subtitle data Subtitle data after a predetermined amount of subtitle data is decoded and output together with the video data.

In one embodiment, the buffered subtitle data may not be output until the first video data to be outputted first among the buffered video data is output.

In one embodiment, the predetermined amount corresponds to the time interval when video data and subtitle data to be output at the same timing are transmitted at different times to the broadcasting signal in consideration of the processing speed of the video data and the subtitle data .

In one embodiment, the time interval may be measured and stored when a broadcast receiver receiving and storing the content receives a broadcast signal corresponding to the content, or may be stored in a nonvolatile memory when the broadcast receiver is manufactured.

In one embodiment, the content data stored in and read out from the storage medium is a transport stream, and the filtering operation may convert the transport stream into a packet element stream including a video packet and a subtitle packet.

In one embodiment, the presence or absence of the time information of the subtitle data may be determined by checking the header of the subtitle packet or by using information indicating the presence or absence of time information on the subtitle data in the header of the content file .

In one embodiment, the video data and the subtitle data may be buffered and output in payload units constituting packets of a packet elementary stream.

In an embodiment, the predetermined amount may be a value represented by the number of subtitle payloads and a value smaller than the total number of subtitle payloads buffered in the buffer.

In one embodiment, when the video packet and subtitle packet are output, the output video packet and the subtitle packet may be erased from the buffer.

In one embodiment, the predetermined amount of subtitle data, which is buffered before the output subtitle data when the subtitle data is output together with the original video data, may be erased from the buffer.

In one embodiment, if the fast, fast, or jump operation is requested in the course of playing back the content, all data stored in the buffer is erased, the data at the point in time when the playback is requested is read from the storage medium, And decodes and subtracts the subtitle data after the predetermined amount of subtitle data from the buffered subtitle data when decoding the first video data to be outputted first among the video data buffered in the buffer, And output it together with the initial video data.

In one embodiment, when the content is received and stored, the data at the time when the playback is requested is referred to as management information in which time information indicating the output time of the video data is associated with location information in which the video data is recorded Can be read out.

According to another aspect of the present invention, there is provided a broadcast receiver including: a broadcast receiver for receiving a broadcast signal of a content; A storage unit for storing content data received through the broadcast signal; A parser for analyzing the content data and performing a filtering operation to classify the content data according to types of video data and subtitle data; A buffer memory for buffering the video data and the subtitle data classified by the type; A decoder for decoding and outputting video data and subtitle data stored in the buffer memory; And a control unit for controlling each component to reproduce the content, wherein when the content stored in the storage unit is reproduced, if there is no time information related to the output time point in the subtitle data, Wherein the parser performs the filtering operation by controlling the parser before reading the content data, and when decoding and outputting the buffered video data, subtitle data after a predetermined amount of subtitle data among the buffered subtitle data And controls the decoder to output the video data together with the video data.

Therefore, even when the broadcast receiver records the content transmitted on the broadcast in the state in which there is no time information in the subtitle data, the AV data and the subtitle data can be reproduced in synchronization with each other.

1 shows a process of generating a transport stream (TS) transmitted from an elementary stream (ES) and a packetized elementary stream (PES)
FIG. 2 is a schematic view illustrating a process of analyzing a TS packet transmitted by a broadcast receiver in order to view a broadcast,
FIG. 3 shows a process of generating a PES packet using PAT and PMT,
FIG. 4 shows that the broadcast receiver reproduces the A / V data transmitted through broadcasting and the subtitle data without time information in synchronization with each other,
5 shows that the broadcast receiver fails to synchronize sub-title data when reproducing A / V data including time information and sub-title data not including time information stored in the recording medium,
6 shows a configuration of a broadcast receiver to which the present invention is applied,
FIG. 7 illustrates synchronizing playback of A / V data including time information stored on a recording medium and subtitle data not including time information according to an embodiment of the present invention.

Hereinafter, an embodiment of a content reproducing method according to the present invention will be described in detail with reference to the accompanying drawings.

Currently, digital broadcasting is provided using a TS packet in the MPEG-2 system. The TS packet has a fixed length of 188 bytes, a 4-byte TS header, and a payload ). Since digital broadcasting has a bad data transmission environment, the probability of errors occurring during transmission is high. Therefore, it is possible to minimize the influence of errors that may occur even if the data is transmitted in a short time. Also, TS is used for digital broadcasting because it has a structure capable of transmitting multi channels.

FIG. 1 illustrates a process of generating a transport stream (TS) transmitted from an elementary stream (ES) and a packetized elementary stream (PES) and a digital broadcast.

An elementary stream (ES) refers to an elementary stream of digital data, which is composed of video and audio, which is encoded and compressed by an MPEG-2 encoder, and has a single basic ES ES is a single stream in which the contents of the program are encoded and compressed. The generated ES is used to create a program stream or a transport stream that can be stored or transmitted through the packet-typing process and the multiplexing process. The PES is a packetized stream with header information added to transmit the ES, and the video PES is image information for one frame.

The PES packet is generated as shown in FIG. 1. Assuming that Ex is a video elementary stream (ES), E1, E2, and E3 may be the result of encoding each frame. PES packets are created by attaching a PES header to each ES thus created. In FIG. 1, P1, P2, and P3 are PES headers, and the length of each PES may not be the same.

To make the PES packets into a TS packet having a fixed length, the TS packet is generated by cutting it to a predetermined size (184 bytes) and attaching a 4-byte TS header. At this stage, the PES packet does not transmit the previous PES packet and the current PES packet in one TS packet while creating the TS. In FIG. 1, the first TS packet includes a part of the first PES packet, Because of this, you can load part of the second PES packet, but do not do so and instead fill the place with null data to make 184 bytes.

The TS packet can be classified as including a PES packet and a section having other additional table data. Section is the same as the process of generating the TS packet including the PES described above except that the process of filling the null data and adding the 1 byte pointer_field are different.

A TS packet containing a section can be transmitted with two consecutive sections included in one TS packet. Instead of inserting null data, a 1-byte pointer_field is added immediately after the TS header. Pointer_field indicates the start position of a section that is newly started in one TS packet. More precisely, Pointer_field indicates the length of the last data in a subsequent section. The reason for adding the Pointer_field is to allow the receiver to correctly separate the two sections if the consecutive section is transmitted in one TS packet.

The data included in the payload of the TS packet includes audio, video, subtitle and supplementary information. The supplementary information includes a program association table (PAT), a program map table (PMT) ), CAT (Conditional Access Table), and NIT (Network Information Table). In the receiving end, these tables must be obtained. Since the TS packet size is fixed, the tables are cut and transmitted. That is, the table is at the top level of the section and the N sections that have been transferred must be collected to complete a table.

The PSI is data required for normally reproducing audio and video data, and is composed of PAT, PMT, CAS, NIT, and TSDT. In case of multi-channel transmission, the PSI is transmitted at a fixed time interval so that the decoder can receive the changed information of the program as quickly as possible. In MPEG, the PSI must be transmitted within 0.7 seconds at most. In order to receive a broadcast desired by a broadcast receiver, a necessary number of randomly transmitted packets, a packet from a transponder, a packet identifier (PID) through a packet identification (PID) And this information is provided by the PSI.

The PAT is the most basic packet among the packets. The PID is also assigned with 0x0000. The PAT includes the PID of the PMT including information on the channel and the PID of the NIT that contains the network information. The PMT includes information about which PID the audio, video, and data information for each channel for viewing broadcasts of, for example, KBS, MBC, and SBS are transmitted with.

FIG. 2 is a flowchart briefly illustrating a process of analyzing a TS packet transmitted by a broadcast receiver to view a broadcast, and FIG. 3 illustrates a process of generating a PES packet using PAT and PMT.

In the example of FIG. 3, information on four channels, for example, KBS, MBC, SBS, and EBS, and NIT, TSDT, and the like are stored in the PAT by searching for a PID having a PID of 0x0000. Is transmitted through the network.

When the user selects to watch a channel, for example, MBC, the broadcast receiver finds the PID of the PMT indicating the PID through which the actual data (audio, video, and subtitle data) of the MBC channel is transmitted from the PAT , And finds a packet whose PID is 0x0102 in the example of FIG. Thereafter, a packet having a corresponding PID (a packet including a PMT) is parsed to check which PID packet the audio data, the video data, the subtitle data, etc. are in, and the audio , Video, and subtitle data to generate a PES packet, and audio, video, and subtitles are separated from each other and decoded to reproduce the broadcast.

PES is a packet composed of an elementary stream (ES), and is divided into a video PES packet, an audio PES packet, and a subtitle PES packet. Since playback of a moving picture is an important factor for audio, video and subtitle synchronization, Most of the information is composed of PCR (Program Clock Reference), PTS (Presentation Time Stamp), and DTS (Decoding Time Stamp), which are information to be used in synchronizing synchronization for reproducing audio, video and subtitles in the receiver.

PCR is used as a reference time when audio and video are reproduced with a value obtained by sampling the time of the encoder system with a system clock of a predetermined frequency (for example, 27 Mhz), PTS indicates a time at which audio or video is actually reproduced, Indicates the time at which the received audio and video information should be decoded.

FIG. 4 shows that the broadcast receiver reproduces the A / V data transmitted through broadcasting and the subtitle data without time information in synchronization with each other.

The transport packet including the subtitle data but not including the time information is reproduced together with the reproduction time point indicated by the time information included in the PES packet in which the PES packet is generated from the transport packet of the received audio / video data So that a transport packet including audio data or video data is transmitted.

Even if the subtitle data that does not include the time information is generated as a subtitle PES packet, the decoder does not buffer the transport packet because it can not know the output time point. The decoder collects the transport packet including the subtitle and generates the PES packet It should be displayed on the screen.

In the broadcasting station, the processing method of the subtitle without time information and the processing time of the audio data and the video data (collecting transport packets, generating PES packets, separating audio PES packets and video PES packets and buffering them, The time interval during which the audio data and the video data are decoded and outputted in accordance with the time information included in the audio data and the audio data), the transmission interval of the transport packet including the audio data / video data and the transport packet including the subtitle data do.

4, for example, audio data and video data (Video PTS 3 / Audio PTS 3) to be reproduced at the reproduction time point 3 (TimeStamp 3) are reproduced together with the subtitle data (Subtitle 1) Or at a near and far time not far apart from each other), and Subtitle 1 is immediately reproduced at playback point 1 (TimeStamp 1). Here, Video PTS 3 and Audio PTS 3 correspond to a video PES packet and an audio PES packet having a PTS value corresponding to TimeStamp 3 in the header, Subtitle 3 corresponds to a subtitle PES packet, and a video PTS 3 (or Audio PTS 3) and the transport packet including the PES packet of Subtitle 3 can be transmitted in the vicinity of TimeStamp 1. Likewise, Video PTS 4 / Audio PTS 4 to be reproduced in TimeStamp 4 is transmitted together with Subtitle 2 to TimeStamp 2, and Subtitle 2 is immediately reproduced to TimeStamp 2.

Video PTS 5 / Audio PTS 5 to be reproduced in TimeStamp 5 is transmitted together with Subtitle 3 to TimeStamp 3, Video PTS 3 / Audio PTS 3 is reproduced to TimeStamp 3, Subtitle 3 is also reproduced to TimeStamp 3, Audio PTS 3 and Subtitle 3 are reproduced in synchronization with each other.

The transport packets including audio and video data transmitted in TimeStamp 1 to TimeStamp 3 are collected according to the type and converted into PES packets (Video PTS 1 to 3, Audio PTS 1 to 3) The time information is managed in a timer block for controlling the time or the time, the payload of the PES packet is buffered in the audio buffer and the video buffer, the buffered data is decoded in accordance with the time information managed in the timer block, It is output through the amplifier.

As shown in FIG. 4, audio / video / subtitle data to be reproduced at the same time is transmitted with a predetermined time interval (processing time of audio / video data), and subtitle data without time information is converted into a PES packet And the audio / video / subtitle data is synchronized.

5 illustrates that the broadcast receiver fails to synchronize sub-title data when reading and reproducing the A / V data including time information and the sub-title data not including time information stored in the recording medium.

A broadcast receiver having a recording function can receive broadcast data selected and received through a tuner in the form of a transport packet such as a storage medium such as a hard disk drive (HDD), a solid state drive (SSD), or a secure digital Can be written to flash memory card.

In reproducing a broadcast content recorded on a storage medium, a broadcast receiver reads a large amount of data (transport packet) at a time on a storage medium to filter, buffer, decode, and reproduce the broadcast content to prevent an underflow of the buffer Here, filtering refers to an operation of converting a transport packet read from a storage medium into a PES packet and classifying the transport packet according to the type of the PES packet.

The audio and video data of the payload of the PES packet collected in the transport packet and converted into the PES packet and buffered respectively are reproduced according to the time information included in the header of the PES packet. The subtitle data converted into the PES packet is time Since there is no information, they are not buffered and are all output at once, so that the audio and video data are not synchronized with each other.

(Video PTS 3, 4, 5, 6) and audio data (Audio PTS 3, 4, 5, 6) to be reproduced on a storage medium, for example, TimeStamp 3-6, And subtitle data (Subtitle 1, 2, 3, 4) to be reproduced in the TimeStamp 1-4 are read out. All the subtitle data converted into the PES packet are directly output to TimeStamp 1, and the video data and audio data are transmitted from TimeStamp 3 And the video / audio data and the subtitle data are not synchronized with each other.

Similarly, in TimeStamp 4, the video data (Video PTS 7, 8, 9, 10) and audio data (Audio PTS 7, 8, 9, 10) and TimeStamp 5-8 Subtitle data (Subtitle 5, 6, 7, 8) is read out and the subtitle data converted into the PES packet is immediately output to TimeStamp 4, and video data and audio data are sequentially reproduced starting from TimeStamp 5, The audio data and the subtitle data are not synchronized with each other.

In addition, when data read from the storage medium is filtered and buffered according to the type of data, data read from the storage medium before the filtering operation is performed on the data is not filtered and discarded. Since the audio data and the video data filtered by the PES packet include the time information in the PES packet, the number of already discarded PES packets can be confirmed. However, the subtitle data filtered by the PES packet does not include the time information in the PES packet Therefore, the number of already discarded subtitle PES packets can not be confirmed.

In addition, the PES packet may have a larger amount of subtitle PES packets discarded than the audio / video PES packet because the payloads are different in size and the amount of subtitle data is much smaller than audio / video data.

Accordingly, even if the subtitle PES packet is buffered and the audio / video PES packet is output at a time interval, the subtitle data may be outputted before the audio / video data by the subtitle PES packet already discarded.

In order to overcome this situation, in order to overcome such a situation, a filtering operation is first performed before an operation of reading recorded broadcast data from a storage medium to prevent data read from a storage medium from being discarded without being filtered, Video data and subtitle data by adjusting the output time of the subtitle data based on the output time of the audio / video data and the transmission interval of the video data and the subtitle data, by buffering the subtitle data in the subtitle buffer It adjusts.

6 shows a configuration of a broadcast receiver to which the present invention is applied. The broadcast receiver according to the present invention includes a set-top box or a television receiving digital broadcasts such as terrestrial broadcast, satellite broadcast, cable broadcast, .

A broadcast receiver 100 according to the present invention includes a tuner / demodulator 10 (hereinafter simply referred to as a tuner), a demultiplexer 20, a parser 30, a buffer memory 40, a storage 50, a decoder 60, an OSD generating unit 70, a mixer 75, a control unit 80, a system memory 85, a network unit 90, The tuner 10 and the demultiplexer 20 may be combined into one broadcasting receiver.

The tuner 10 tunes a signal band selected by a user from a broadcast signal (for example, a terrestrial wave, a cable or a satellite broadcast signal) received through a connected RF signal line, for example, a coaxial cable, Demodulates a digital signal modulated by Quadrature Phase Shift Keying (QPSK), Quadrature Amplitude Modulation (QAM), Vestigial Sideband (VSB), or Orthogonal Frequency Division Multiplexing (OFDM)

The demultiplexer 20 is a transport stream transporting video, audio, subtitle data, management information (for example, PSI), etc. belonging to a single selected program among the transport streams of the multiplexed program in the output digital stream The reason information for selecting and outputting only the transport stream corresponding to one program in the digital stream by the demultiplexer 20 is obtained from the tuning channel before the selective output of the transport stream, Is a transport packet ID, i.e., PID, which is confirmed from PSI (Program Specific Information) (PAT, PMT, etc.).

The digital stream selected and output by the demultiplexer 20 is also stored in the storage 50 in the case of a specific mode, for example, a time-shift mode or a recording mode, The digital stream is read out in a first-in first-out (FIFO) manner and applied to the parser 30.

The parser 30 removes the transport packets of each transport stream applied from the demultiplexer 20 or read from the storage 50 under the control of the controller 80 to remove only the payload data And outputs them to the buffer memory 40 in the form of a PES packet by dividing them by type of video, audio, subtitle or the like.

The buffer memory 40 separates the type-specific PES packets or the like output by the parser 30 by type (e.g., video, audio, or subtitle) by referring to the header information of the PES packet And stores it temporarily.

The storage 50 stores a large amount of data such as a hard disk, a solid state drive (SSD), and an SD memory. The storage 50 stores an output stream of the demultiplexer 20 under the control of the controller 80, The scrambled transport stream outputted from the tuner 10 may be directly stored, or may be stored in an external server connected to the network or via an interface such as USB or IEEE1394.

The decoder 60 applies the PES packets stored in the buffer memory 40 to the corresponding internal decoding module according to the PES packets, and decodes the PES packets to restore the original A / V (audio / video) do. The content file stored in the storage 50 is divided into small units and is buffered in the buffer memory 40. The decoder 60 decodes the data to be fed from the buffer memory 40 to reproduce the content have.

The OSD generating unit 70 generates a message to guide a response according to a user's request and superimposes and outputs the generated message and the image output from the decoder 60 through the mixer 75 have.

The control unit 80 controls the TV screen to output a broadcasting signal or a reproduction signal of the content according to a user's request and / or a set condition, and has a space for storing data necessary for a control operation, environment setting, And an operating system (not shown) for executing hardware resources of the broadcast receiver 100 and performing an appropriate signal and / or information exchange with the corresponding resources by executing instruction codes such as firmware, (Not shown).

The operation of the control unit 80 or the operation of an application executed thereby may be performed by an appropriate intermediary operation of the operating system (e.g., the components of FIG. 6 and the particular functions provided by the operating system, , Communication with the outside, confirmation of the hardware status, and operation by requesting a timer, etc.), and a description of the intermediary operation is omitted.

The configuration of the broadcast receiver 100 illustrated in FIG. 6 may be integrated with the TV, or may be configured in the form of a computer or a device added to the notebook computer. The controller 80 receives a request from a user through a normal user interface, for example, a key pad, a remote controller, a touch pad, etc., and controls the OSD generator 70, if necessary, A video signal for guiding a response can be outputted. The output video signal is visually expressed through an electronic device having a normal screen output function, for example, a TV, a monitor, or the like.

The configuration of the broadcast receiver 100 illustrated in FIG. 6 is merely an example for showing a specific and illustrative description of the present invention, and may further include various functional elements not shown. However, a broadcasting receiver that embodies the concepts and subject matter of the present invention by embodying the concepts and subject matter of the present invention, which is illustratively described below, even if it further includes unillustrated components, or by executing separate applications, It is to be understood that they fall within the scope of the present invention unless they are excluded from the interpretation.

The control unit 80 transmits a transport stream for a broadcast program of a channel selected through the tuner 10 and the demultiplexer 20 to the storage 50, And controls the parser 30 to generate a PES packet for each type from the transport packet of the transport stream recorded in the storage 50 and analyze the header of the PES packet to generate a PES packet And stores the storage location of the transport packet, which is collected for the generation of the PES packet and is recorded in the storage 50, in association with the confirmed time information, and manages it as management information .

The management information associates time information of a broadcast program recorded in the storage 50 with a storage location (address in a hard disk), and time information may be stored in the management information at predetermined time intervals together with a storage location . When the recording of the broadcast program ends, the management information may be recorded in the storage 50 as a separate management file for the recorded program, or may be recorded in the header of the data file of the broadcast program.

When recording a broadcast program received in the storage 50, the controller 80 generates a PES packet by type from the transport packet input by the parser 30, and transmits header information of the PES packet to the controller 80 If the time information is not included in the subtitle PES packet, it may be recorded in the header of the data file of the broadcast program.

In addition, the control unit 80 determines whether or not a transport packet containing audio and video data is transmitted from a time point when a transport packet containing audio and video data is applied to the parser 30 to some packets of a transport stream selected by the demultiplexer The time from the parser 30 to the PES packet and the payload of the PES packet is stored in the buffer memory 40 for each type and decoded by the decoder 60 and outputted, Or an audio PES packet, is buffered and decoded, and stores the measured time as management information.

Since the subtitle data has a small amount of data to be contained in one PES packet, the time required for filtering (the time required for generating the subtitle PES packet from the transport packet) is very small and the decoding time is small, Video data may generate a single video PES packet from a large number of transport packets, which takes time for filtering, and complicated calculation for decoding such as decoding and inverse quantization, which takes a lot of time.

When the measured time is determined in the transmission position, the video transport packet and the subtitle transport packet to be output on the screen at the same timing are transmitted at different times in consideration of the difference in the processing speed of the video and the subtitle The audio packet is transmitted before the subtitle packet) corresponds to the time interval.

Alternatively, the controller 80 may store the number of subtitle PES packets generated by the parser 30 during the measured time as management information. The number of the subtitle PES packets may be the number of audio, (Without video output) or output (without outputting both video and subtitles) until the audio and / or video PES packet is decoded and output when the PES packet is generated from the video, subtitle transport packets by type Or the number of subtitle PES packets to be output together when the first video PES packet is output (the number starting from the first buffered subtitle PES packet).

Information on the transmission time difference information between the video data and the subtitle data or the amount of data to be discarded when the first video data is output from the subtitle data stored in the buffer memory 40 is measured in advance and the broadcast receiver 100 May be stored in the system memory 85 of the control unit 80 in advance.

The control unit 80 controls the storage 50 to store a large amount of transport packets of the transport stream recorded in the storage 50 if there is a request to reproduce the broadcast program recorded in the storage 50 And controls the parser 30 to analyze the transport packet to generate PES packets for each type and store the payloads of the generated PES packets in the buffer memory 40 according to types, Audio and subtitle data classified and stored in the buffer memory 40 by controlling the decoder 60 and extracts the time information from the header of the PES packet generated by the parser 30, The decoder 60 decides a point of time at which the decoder 60 decodes the payload of each PES packet and a point at which audio and video signals are output, And performs an output operation.

If the time information is not included in the subtitle data of the broadcast program recorded in the storage 50, the data firstly read out from the storage 50 before the filtering operation of the parser 30 is not filtered and lost And it is difficult to confirm how much data is lost, so that subtitle data and audio / video data can not be reproduced in synchronization with each other.

Therefore, if there is a playback request for the broadcast program recorded in the storage 50, the controller 80 performs a filtering operation before the parser 30 reads the data recorded in the storage 50 After the preparation of the parser 30 is completed, the storage 50 is controlled to sequentially read the transport packets of the transport stream recorded in the storage 50, The parser 30 analyzes the provided transport packet, generates PES packets for each type, stores payloads of the generated PES packets in the buffer memory 40 for each type, The decoder 60 performs a decoding operation and an output operation based on the time information extracted from the header of the PES packet generated by the decoder 30.

If the time information is not included in the header of the subtitle PES packet among the PES packets generated by the parser 30 or the time information of the subtitle data is included in the header of the program data file recorded in the storage 50 The subtitle PES packet is output through the decoder 60 without being stored in the space for the subtitle data of the buffer memory 40. However, in the present invention, the buffer memory 40 50), a payload of a video PES packet to be output according to time information extracted from a header of a video PES packet, and outputting a subtitle PES packet at a predetermined time interval, That is, a portion of the buffered subtitle PES packet is discarded and the subtitle PES packet Since it is possible to sequentially output.

The control unit 80 refers to the management information recorded when the broadcast program is recorded and outputs the payload of the video PES packet first outputted from among the subtitle PES packets stored in the buffer memory 40 As described above, the management information includes a time at which the video data is processed, a time interval at which the video data to be reproduced and the subtitle data are transmitted, or a time at which the sub- The number of packets to be ignored until video data is output from the title PES packet, and the like.

FIG. 7 illustrates synchronizing playback of A / V data including time information stored on a recording medium and subtitle data not including time information according to an embodiment of the present invention.

The controller 80 reads a large amount of data from the storage 50 to prevent underrun of the buffer memory 40 and enable trick play. The filtering operation of the parser 30 is prepared in advance.

The control unit 80 generates video PES packets (Video PTS 3, 4, 5, 6), audio PES packets (Audio PTS 3, 4, 5, 6) to be output to Time Stamps 3, 4, 5, The transport packets to form the PES packets (Subtitle 1, 2, 3 and 4) are read out from the storage 50 in the vicinity of TimeStamp 1 (exactly before TimeStamp), and the transport packets read out through the parser 30 Audio PES packet, and subtitle PES packet, reads time information from the header of the video / audio PES packet, and stores the generated PES packets into the buffer memory 40 In FIG. 7, PES packet conversion, buffering, and decoding of video / audio data are performed by PTS 1, PES 2, and PES 3 after decoding the data. The PES packet and the video PES packet are decoded by the decoder 60 according to the read time information. It takes 2 hours There.

The time information read from the header of the video / audio PES packet indicates that the output time of the first video and audio PES packet is TimeStamp 3, and the decoder 60 decodes the video PTS 3 and the audio PTS 3, The control unit 80 determines whether or not the management information recorded in the storage 50 in association with the broadcast program to be played back (or in the header of the file) among the subtitle PES packets stored in the buffer memory 40 The third subtitle PES packet (Subtitle 3) to be decoded by the decoder 60 and output the decoded subtitle PES packet to the screen together with the video PES packet (Video PTS 3).

For example, assuming that a video PES packet corresponds to one frame in a PAL (Phase Alternation Line) scheme, which is a television system transmitting an image of 25 frames per second, receives video, audio, and subtitle data, (Or if the transport packet including the subtitle data is transmitted first with an interval of 800 milliseconds from the transport packet including the video or audio data), the control unit 80 controls the buffer 80, It is possible to discard the first 20 subtitle PES packets out of the subtitle PES packets stored in the memory 40 and to output the 21st subtitle PES packet at the time when the video data is output to synchronize with the video data.

7, Subtitle 3 is deleted from the buffer memory 40, and Video / Audio PTS 3 is also deleted from the buffer memory 40 although it is not shown in FIG. Subtitle 1 and Subtitle 2 may be deleted from the buffer memory 40 before or before TimeStamp 3 at which Subtitle 3 is output or before TimeStamp 3 at which the first video PES packet is output as shown in FIG. And may be deleted from the buffer memory 40 while being randomly output.

The control unit 80 stores video PES packets (Video PTS 7, 8, 9) to be output from the storage 50 at TimeStamps 7, 8, 9, 10 in the vicinity of TimeStamp 4 to prevent the buffer memory 40 from under- 9 and 10 and transport packets to form audio PES packets (Audio PTS 7, 8, 9 and 10) and subtitle PES packets (Subtitle 5, 6, 7 and 8) And generates audio, video, and subtitle PES packets by analyzing them, and stores them in the buffer memory 40. 5, 6, 7, 8, 9, 10) and five subtitle PES packets (Subtitle 4, 5, 6, 7, 8) are stored.

The control unit 80 decodes and outputs the Video PTS 4 and the Audio PTS 4 at the time point of TimeStamp 4 based on the time information read from the header of the video / audio PES packet, and records the decoded video PTS 4 and the Audio PTS 4 in the subtitle area of the buffer memory 40 Subtitle 4, which is the oldest PES packet among the subtitle PES packets, is decoded and output together with the video PTS 4 on the screen, and the video, audio, and subtitle PES packets output from the buffer memory 40 are removed.

The control unit 80 stores Video / Audio PTSs 5, 6, and 7 corresponding to TimeStamps 5, 6, and 7 on TimeStamps 5, 6, and 7 based on time information read from the header of the video / audio PES packet Subtitle 5, 6, and 7 are sequentially output in the order inputted from the buffer memory 40, and the output PES packet is deleted from the buffer memory 40.

The control unit 80 transmits video / audio PES packets (Video / Audio PTS 11, 12, 13, 14) and subtitles to be output from the storage 50 to TimeStamps 11, 12, 13, Transport packets to form PES packets (Subtitle 9, 10, 11, 12) and interprets them through the parser 30 to generate audio, video, and subtitle PES packets and store them in the buffer memory 40 And five subtitle PES packets (Subtitle 8, 9, 10, 11) are stored in the buffer memory 40.

Meanwhile, the controller 80 controls the video display time when a pause or a slow playback (Slow forward or Slow rewind) is performed during the playback of a broadcast program recorded in the storage 50, The PES packet is read from the buffer memory 40 in accordance with the progress of the time for reading and decoding the video / audio PES packet from the buffer memory 40 and outputting the decoded and output PES packet, The speed can be adjusted to synchronize.

When the fast forward, fast rewind, or jump jump operation is performed during the reproduction of the broadcast program recorded in the storage 50, It is necessary to synchronize the video / audio data with the subtitle data, so that all the data stored in the buffer memory 40 is erased and the data at the time of the reproduction is read from the storage 50 again for filtering A buffer corresponding to the transmission time interval between the video data and the subtitle data among the subtitle data newly stored in the buffer memory 40 at the time when the first video data is output, Ignores the title data and decodes and outputs the next subtitle data to synchronize with the video data .

The control unit 80 refers to the management information stored in association with the time information and the storage location (address) information with respect to the broadcast program recorded in the storage 50, Address, and control the storage 50 to read data from the hash address.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the appended claims. Addition or the like.

10: tuner 20: demultiplexer
30: parser 40: buffer memory
50: Storage 60: Decoder
70: OSD generating section 75: Mixer
80: control unit 85: system memory
90: Network section 100: Broadcast receiver

Claims (21)

The content data is read from the storage medium in response to a request for reproduction of the content stored in the storage medium, and the content data is analyzed to classify the data into the video data and the subtitle data And decoding the video data and the subtitle data and outputting the decoded video data and the subtitle data,
Wherein the filtering operation is performed prior to reading the content data from the storage medium when the subtitle data does not include the time information related to the output time point, the buffered video data and the subtitle data are separated from each other, And decoding the subtitle data after a predetermined amount of subtitle data among the buffered subtitle data when decoding and outputting the buffered video data, and outputting the decoded subtitle data along with the video data. The method according to claim 1,
Wherein the buffered subtitle data is not output until the first video data to be outputted first among the buffered video data is output. The method according to claim 1,
Wherein the predetermined amount corresponds to a time interval when video data and subtitle data to be output at the same timing in consideration of a processing speed of the video data and subtitle data are transmitted at different times to the broadcasting signal / RTI > The method of claim 3,
Wherein the time interval is measured and stored when a broadcast receiver receiving and storing the content receives a broadcast signal corresponding to the content or is stored in a nonvolatile memory when the broadcast receiver is manufactured . The method according to claim 1,
Wherein the content data stored in and read from the storage medium is a transport stream, and the filtering operation converts the transport stream into a packet element stream including a video packet and a subtitle packet. 6. The method of claim 5,
Whether or not the subtitle data includes time information is determined by checking the header of the subtitle packet or by determining whether the subtitle data includes time information on the subtitle data in the header of the content file . 6. The method of claim 5,
Wherein the video data and the subtitle data are buffered and output in units of payloads constituting a packet of the packet elementary stream. 8. The method of claim 7,
Wherein the predetermined amount is a value represented by the number of subtitle payloads and smaller than the number of all subtitle payloads buffered in the buffer. 8. The method of claim 7,
And when the video packet and the subtitle packet are output, the output video packet and the subtitle packet are deleted from the buffer. The method according to claim 1,
And subtracting the predetermined amount of subtitle data buffered before the output subtitle data when the subtitle data is output together with the first video data to be output first among the buffered video data. / RTI > The method according to claim 1,
If the fast, fast, or jump operation is requested in the course of playing back the content, all the data stored in the buffer is erased, the data at the point in time when the playback is requested is read from the storage medium, and filtering, When decoding the first video data to be outputted first among the video data buffered in the buffer and outputting the decoded first video data, decoding the subtitle data after the predetermined amount of subtitle data among the buffered subtitle data, And outputting the content data. 12. The method of claim 11,
The data at the time when the content is requested to be reproduced is read out by referring to the management information in which the time information indicating the output time of the video data is associated with the location information in which the video data is recorded when the content is received and stored . A broadcast receiving unit for receiving a broadcast signal of contents;
A storage unit for storing content data received through the broadcast signal;
A parser for analyzing the content data and performing a filtering operation to classify the content data according to types of video data and subtitle data;
A buffer memory for buffering the video data and the subtitle data classified by the type;
A decoder for decoding and outputting video data and subtitle data stored in the buffer memory; And
And a control unit for controlling each component to reproduce the content,
When the content stored in the storage unit is reproduced, if there is no time information related to the output time in the subtitle data, the parser is controlled prior to reading the content data from the storage unit to perform the filtering operation first And controls the decoder to decode the subtitle data after a predetermined amount of subtitle data among the buffered subtitle data and to output the decoded subtitle data together with the video data when the buffered video data is decoded and output. Broadcasting receiver. 14. The method of claim 13,
The predetermined amount is a value obtained by subtracting the video data and the subtitle data to be output at the same timing in consideration of the speed at which the parser and the decoder process the video data and the subtitle data, Wherein the broadcast receiver is responsive to the broadcast signal. 15. The method of claim 14,
Wherein the controller measures the time interval when receiving a broadcast signal corresponding to the content and stores the time interval in a nonvolatile memory or is stored in a nonvolatile memory when the broadcast receiver is manufactured. 14. The method of claim 13,
When the subtitle data is output together with the first video data to be output first among the buffered video data, the control unit may store the predetermined amount of subtitle data before the output subtitle data in the buffer memory Wherein the broadcast receiver receives the broadcast signal. 14. The method of claim 13,
Wherein the content data stored in the storage unit is a transport stream and the parser converts the transport stream into a packet element stream including a video packet and a subtitle packet through the filtering operation. 18. The method of claim 17,
Wherein the buffer memory buffers the video data and the subtitle data in a payload unit constituting a packet of a packet elementary stream and outputs the buffered data. 19. The method of claim 18,
Wherein the controller erases the output video packet and the subtitle packet from the buffer memory when the video packet and the subtitle packet are outputted. 14. The method of claim 13,
Wherein the control unit deletes all data stored in the buffer memory and reads data from the storage unit at the time when the playback is requested from the storage unit when the content is rapidly, Wherein the first subtitle data after the predetermined amount of subtitle data among the buffered subtitle data is decoded when decoding the first video data to be outputted first among the video data buffered in the buffer memory, And outputs the decoded video data together with the initial video data. 21. The method of claim 20,
Wherein the control unit manages time information indicating the output time point of the video data when the received content is stored in the storage unit and location information in which the video data is recorded as management information, And reads the data at the requested time from the storage unit.

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