KR0181084B1 - Dts coding apparatus of mpeg - Google Patents

Abstract

The present invention relates to an encoding apparatus capable of efficiently encoding and recording a DTS of information data in an MPEG system, and to solve this problem, an elementary stream encoder for encoding an audio / video signal based on an MPEG recommendation; A PES packetizer for PES packetizing the encoded output, transport packetizing the PES packet, and from the time when the transport packetized stream is first recorded in the transport buffer to the time when the first PCR is recorded in the transport buffer An apparatus for calculating an initial PCR by dividing a accumulated data amount by a transmission rate, and recording a DTS for matching a decoding time of a decoder in the transport packet based on the initial PCR and outputting the DTS to a transport channel, the elementary stream encoder ( The output of 510 indicates the start of the audio and video signal in the elementary stream. Flag generating means for providing a flag according to a detection result of the tart code or a flag generation means for providing a flag based on a comparison between a preset value and a count value counted from the time when the DTS indicating the decoding time is recorded and transmitted; and the PES packet tie A transmission packetizer for outputting a PES packet into a transmission packet, recording and outputting a flag of the flag generating means in the transmission packetized transmission packet, and the decoder based on the initial PCR value and a system clock. Record an encoder clock system for generating and outputting a DTS, which is a time to be decoded, and a DTS, which is an output of the encoder clock system, and read out the recorded DTS in response to a detection result of a flag in a transmission packet of the transport packetizer. Limiting the maximum transmission time of DTS data by including detection and recording means output to the transmission buffer There is an effect that can reduce decoding time while satisfying thing.

Description

DTS Coding System of MPEG System

1 is a block diagram schematically illustrating an encoder of a transport stream in an MPEG-2 (ISO / IEC 13818) system.

2 is a diagram illustrating a relationship between an elementary stream, a packetizer, and a PES packet.

3 to 5 are diagrams showing a packet configuration and a transport stream configuration.

6 shows a program constituting an audio / video elementary stream.

7 is a DTS encoding apparatus of an MPEG system according to the present invention.

* Explanation of symbols for main parts of the drawings

510: elementary stream encoder 520: PES packetizer

530: flag generation means 540: transmission packetizer

550: encoder clock system 560: detection and recording means

570: transmission buffer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an MPEG system. In particular, the DTS of the MPEG system is capable of efficiently encoding and recording a Decoding Time Stamp (DTS), which is decoding time information of an information data (video, audio, etc.). (DTS) encoding apparatus.

The MPEG-2 transport stream is a type of MPEG system stream. As the final technology for the MPEG system, the official name of MPEG-2 is known as ITU-T Rec. H.222.01 | SO / 1EC 13818.

MPEG-2 is largely divided into a first part system, a second part video, and a third part audio. The first part is a recommendation for the overall field of system layer coding.

Here, system layer coding (hereinafter referred to as system coding) is suitable for transmission or storage by multiplexing not only an audio / video stream compressed by a data compression method of MPEG-1 or MPEG-2, but also user data, etc. as necessary. It relates to a technique for formatting.

As described above, a process of receiving a plurality of bit streams and formatting them into a series of streams is called a system encoder, and a process of unpacking the formatted stream into the original input stream is called a system decoder.

The formatting rule is called syntax, and the semantics that define the meaning of each part in the process of creating this syntax are called semantics.

Since MPEG system IS prescribes formatting rules such as syntax and semantics, when encoding in a system encoder, a bitstream must be created according to such a rule, and the system decoder must be configured to decode a stream produced by this rule. .

The system encoding not only combines and combines each audio / video stream, but also includes a process of inserting some parameters for reproducing the buffer control and synchronizing each decoded stream in the system decoder in decoding the stream. Include.

In the system encoding method, there are two forms of transport stream encoding and program stream encoding, which program stream is mainly used for storage.

For reference, FIG. 1 schematically illustrates an encoder of a transport stream in an MPEG-2 system, which is a process of creating a transport stream from an audio / video stream through a packetizer.

As shown in the figure, audio and video encoders 11, 12 may assume MPEG-1 or MPEG-2, but MPEG-2 system encoding excludes streams encoded with encoders other than the MPEG family. Hence, it could be a H.261 video encoder, a CCITT G.721 audio encoder, or a unique audio / video encoder used only for specific limited users.

The data encoded by these video and audio encoders 11 and 12 are called elementary streams, which are primarily packetized through respective audio and video packetizers 13 and 14.

The data that has undergone this process is called a packetized elementary stream (PES), and a packetizer that makes this PES packet is called a PES packetizer.

That is, each of the audio PES packet and the video PES packet, which are made through the audio packetizer 13 and the video packetizer 14, is input to the multiplexer 15 with the transport stream (or program stream). ) Creates and outputs a program stream and a transport stream.

In the end, system encoding corresponds to a process of creating an PES packetizing and transport stream by receiving an elimtree stream. In other words, the system coding process can be divided into two functions: PES packet and TS / PS multiplexing.

The PES packetizer makes elementary streams into PES packets, and the TS / PS multiplexing process corresponds to making TS / PS packets from PES packets.

As such, the MPEG-2 system recommendation does not specifically specify the process for encoding, and there are no separate provisions for application systems that may occur from time to time.

Therefore, in encoding systems, the output stream needs to provide an accurate stream that meets the decoder specification specified by the MPEG-2 stream IS. In this encoding process, the method of configuring an encoder and the technology for making an efficient decoder are not standardized. not.

2 illustrates a process of PES packetization of an input elementary stream with reference to a system coding recommendation, in which all information encoded in a system encoder is formatted in a packet unit. 3 shows a configuration of a PES packet, in which a PES packet includes a header and a payload.

The payload 32 part cuts the elementary stream into a predetermined length and inserts other useful information (eg, time information, address, tag, etc.) into the header 31 part. Here, a device for generating a PES packet is called a packetizer, and a device for receiving an elementary stream and generating a packet is called a PES packetizer (reference numeral 22 in FIG. 2).

In the present system encoder, an elementary stream means an input stream for performing packetizing (packet making process), and in a broader sense, a stream in which a coded stream is input to the system encoder in some form. do.

The system encoding process can be understood as a process of generating a PES packet by receiving an elementary stream and then generating a transport stream packet or a program stream packet by receiving a PES packet.

4 shows an example of transport streams based on audio PES streams, video PES streams, and transport header information. Since the length of a transport packet is always equally short as 188 bytes, multiplexing, re-multiplexing, demultiplexing, and receiver It is easy to manufacture and has the advantage of low loss in transmission error such as cell loss.

Overall, a transport stream composed of transport packets is suitable for broadcasting that transmits a program using a channel having a large transmission error.

As such, since the transport stream is composed of short packets of fixed length, it is easy to convert to another stream and minimize the effects of loss such as cellulose.

FIG. 5 schematically illustrates a relationship between a transport packet described above with reference to FIGS. 3 to 4, a PES packet, a compressed video and an audio stream, and it can be seen that the compressed video and audio signal includes a start code.

6 shows a concept of time in addition to the encoder shown in FIG. 1 and shows a program composed of an audio / video elementary stream. Each elementary stream in which audio and video signals are encoded by encoders 61 and 62 is input to audio and video signal PES packetizers 63 and 64.

The system clock stage 65 generates a time information clock (ESCR / PTS / DTS) to provide the PES packetizers 63 and 64, wherein the PES packetizers 63 and 64 The time information clock (ESCR / PTS / DTS) is inserted into the header portion of the PES packet, and the elementary stream is packetized and input to the TS / PS packetizer (or multiplexer) 66. Accordingly, the TS / PS packetizer 66 inserts another time information clock (PCR / SCR) from the system clock stage 65 into the header portion of the transmission packet, and packetizes the PES packet to TS / PS. Will output to the stream.

Here, the system clock corresponds to the system clock provided to all blocks constituting the system encoder, and the frequency of the system clock satisfies the following constraints.

27 MHz-810 Hz ≤ system_clock_frequency ≤ 27 MHz + 810 Hz

Time change rate of system clock frequency ≤75 × 10 ^-3 Hz / sec-(A)

In the sense of Equation (A), the system clock frequency allows an error of +,-810 Hz at 27 MHz, which is in the range of-,-0.003% based on 27 MHz. In addition, even when operating in the range of this error, the clock change should not occur suddenly. In other words, if a clock frequency of 27 MHz is allowed in one second, allowing a change of 0.075 Hz in one second, it means that one clock shifts from the 360 M clock. In summary, the formula (A) defines the operating frequency range of the system clock and the rate of change of the operating frequency.

Next, the DTS defined in the MPEG system is a frame that is decoded by a decoder for an elementary stream (a term referring to encoded audio, video, or other encoded stream, which is generally input to a system encoder). This value represents the point in time at which data is to be decoded, which is expressed in time in units of 1/300 of the system clock frequency.

DTS (j) = (System_Clock_Frequency × tDn (j) DIV300)% 2 ³³ --- (B)

(tDn (j) represents the time when the data of the jth frame should be decoded, and DIV is a truncation operation that makes the remainders 0 by an operation of integer division.% takes a remainder by a modulo operation. Operation.

Referring to Fig. 3, the DTS is recorded and transmitted in the PES packet header portion (reference numeral 31), and the DTS in the header portion (reference numeral 31) is a start in the PES packet payload portion (reference numeral 32), Alternatively, this is to inform the decoder system of time to decode audio data of one frame or picture data of one frame starting from the start (start) code.

The start or start (start) code means an audio frame sync signal in the case of audio data, and corresponds to a picture start code in the case of video data. If there are several start codes in one PES payload (reference number 32), the first start code appears.

The audio data or picture data is generally bundled and encoded in a predetermined size (i.e., audio is frame-by-frame and video is picture-by-frame). However, DTS is required for every frame or picture, but DTS is required for every frame or picture. When data is transmitted, it is not transmitted every frame or picture because the amount of transmitted data increases. Therefore, the value of DTS is defined to be transmitted within a maximum of 0.7 seconds. Next, the DTS data format is as follows.

The DTS data defined in MPEG has a length of 33 bits, and the DTS includes three marker_bits. The configuration is as follows.

DTS [32..30] 3 bits

marker_bit 1 bit

DTS [29..15] 15 bits

marker_bit 1 bit

DTS [14..0] 15 bits

marker_bit 1 bit

In the above, 33 bits of DTS data are transmitted from upper bits of data, and actual DTS data is recorded in the 32nd to 30th bits. The marker_bit inserts meaningless data to separate DTS data, and this value is set as 1.

The system decoder ignores the value of the marker_bit and uses only the values of DTS [32..30] and DTS [14..0].

The transmission timing of the DTS will be described with reference to the above. As recommended by MPEG, the DTS should be retransmitted within 0.7 seconds. If the retransmission time is set at any time within 0.7 seconds, the decoding time becomes long in the overall stream configuration.

In the process of starting the decoding operation in the decoder, it uses the PCR value that receives the setting of the decoder system clock, stabilizes all the clocks of the decoder system using the PCR value, and then starts the elementary stream. Decoding will be performed.

However, the elementary stream decoder cannot decode the elementary stream even if the DTS value is not received even if the stream is in the transport buffer.

Accordingly, the present invention has been made to solve the above-described problem, an object of the present invention is an MPEG (MPEG) that can record and transmit the DTS before the start point of the elementary stream on the basis of the start point of the elementary stream The present invention provides a DTS encoding apparatus of a system.

According to the present invention for achieving the above object, an elementary stream encoder for encoding an audio / video signal based on an MPEG recommendation, a PES packetizer for PES packetizing the encoded output, and transmitting the PES packet And the initial PCR is obtained by dividing the accumulated data amount by the transfer rate from the time when the transport packetized stream is first recorded in the transport buffer to the time when the PCR first received in the transport buffer is recorded. A device for recording a DTS for matching a decoding time of a decoder in a transport packet and outputting the same to a transport channel, wherein the start of an audio and video signal is announced in an elementary stream which is an output of the elementary stream encoder 510. Depending on the detection result of the code, a DTS is provided to provide a flag or to indicate the decoding time. Flag generating means (530) for providing a flag based on a comparison between a count value which has been counted from the point of time of transmission and a predetermined value; A transmission packetizer 540 for converting a PES packet which is an output of the PES packetizer 520 into a transmission packet, and recording and outputting a flag of the flag generating means 530 in the transmission packetized transmission packet; ; An encoder clock system 550 for generating and outputting a DTS which is a time to be decoded in the decoder based on the initial PCR value and a system clock; Record the DTS, which is the output of the encoder clock system 550, and read the recorded DTS in response to the detection result of the flag in the transport packet of the transport packetizer 540 and output the read DTS to the transport buffer 570. Detection and recording means 560.

Hereinafter, the present invention will be described in detail with reference to the illustrated drawings.

7 is a DTS encoding apparatus diagram of an MPEG system according to the present invention.

Referring to FIG. 7, the DTS encoding apparatus of the MPEG system according to the present invention includes an elementary stream encoder 510, a PES packetizer 520, a flag generating means 530, and a transport packet tie. Low 540, encoder clock system 550, detection and recording means 560, and transmission buffer 570.

The elementary stream encoder 510 encodes a video and audio signal based on the MPEG standard, and forms an elementary stream into an elementary stream to describe a PES packetizer 520 and a start code detector (described below). 531).

The PES packetizer 520 is configured to PES the elementary stream from the elementary stream encoder 510 and provide it to the transport packetizer 540 described later.

The flag generating means 520 is composed of a start code detector 531, a time-lapse irradiator 532, and a flag processor 533.

The start code detector 531 is provided to a flag processor 533 which describes a flag request signal later in response to a detection result of a start code (start code, start code) in an elementary stream output from the elementary stream encoder 510. It is composed.

The time-lapse irradiation unit 532 is a flag processing unit 533 which describes the flag request signal at a time point when the value counted from the time point at which the DTS described below is recorded and transmitted coincides with the preset value (count value corresponding to 0.7 second). It is configured to be provided.

The flag processor 533 provides a flag in response to the flag request signal from the start code detector 531 to the transport packetizer 540 described later, and also a flag in response to the flag request signal from the time-lapse irradiation unit 532. It is configured to provide to the transport packetizer 540 to be described later.

The transport packetizer 540 transports the PES recorded with the flag of the flag processing unit 533 in the header portion of the PES packet output from the PES packetizer 520 to detect and record the means 560 which will be described later. And a transmission buffer 570.

The encoder clock system 550 includes an initial PCR detector 551, a system clock 552, a first counter 553, a comparator 554, a second counter 555, and a combination processor 556.

The initial PCR detection unit 551 accumulates the transport packet stream output from the transport packetizer 540 from the time when the transport packet stream is first recorded in the transport buffer 570 to the time when the PCR first received in the transport buffer 570 is recorded. The initial PCR value obtained by dividing the amount of data obtained by the transfer rate is detected, and the initial PCR value is provided to the first and second counters 553 and 555 described later.

The system clock unit 552 is configured to generate a system clock and provide it to a first counter 553, etc., which will be described later, wherein the clock is 27 MHz-810 Hz ≤ system_clock_frequency ≤ 27 MHz + 810 Hz; The rate of time-varying ≤ 75 x 10 ^-3 Hz / sec of the system clock frequency is satisfied. For reference, the internal configuration feeds back the output of the voltage controlled oscillator to the appropriate voltage output in the clock control system and inputs it to the voltage controlled oscillator again to use a phase locked loop (PLL) method.

The first counter 553 may reset the initial value to 0 based on the initial PCR detected by the initial PCR detection unit 551, and may be configured to receive a reference value other than 0, and the first counter 553 may be provided. The counter 553 is incremented by one 9-bit counter for each clock of the system clock unit 552, and this value is provided to the comparator 554 for each system clock, and the first counter 553 is a module 300 9-bit. It consists of a counter. Herein, when the module 300 9-bit counter reaches a value of 0 to 299, it means that the period is 300 by setting it back to 0 at the next clock.

The comparator 554 compares the value counted by the first counter 553 with the reference value (9-bit binary value of 299), generates a carry at the matching time point, and outputs it to the second counter 555 described later. It is configured to be.

The second counter 555 is configured to count the carry provided from the comparator 554, and to be provided to the combination processing unit 556 which describes the counted value, and the second count 555 is composed of a 33-bit counter. . Here, the 33 bit counter is calculated to increment once every 300 of the system clock.

The combination processing unit 556 includes additional bits in units of 3 bits, and includes a counted value (DTS represented by 33 bits) and the additional bits (reserved bits) provided from the second counter 555. In combination with the detection and recording means 560 described below.

The detection and recording means 560 is composed of a flag detector 561 and a DTS memory 562.

The flag detector 561 is configured to detect whether a flag exists in a transport stream output from the transport packetizer 540 and provide the same to a DTS memory 562 which will be described later.

The DTS memory 562 stores the DTS provided from the encoder clock system 550 to be described later, and reads the stored DTS in response to the flag detection of the flag detector 561 and outputs the stored DTS to the transmission buffer 570. And a signal indicating that the DTS is recorded and transmitted is provided to the time-lapse irradiation unit 532.

The transport buffer 570 is configured such that the output of the transport packetizer 540 records the DTS read out from the detection and recording means 560 in the transport packet stream and outputs it to the transport channel.

In particular, the transmission buffer 570 obtains an initial PCR by dividing the amount of data accumulated by the transmission rate from the time when the transport packetized stream is first recorded in the transport buffer to the time when the PCR first received in the transport buffer is recorded. The transmission packet is output along with the transmission packet.

As described above, the present invention configured will be described in detail with reference to preferred embodiments.

First, looking at the DTS data structure presented in the MPEG Recommendation, the DTS in the PES packet header appears first in the PES payload. The start code of the elementary stream (in the case of a video signal, corresponds to a picture start code, and in the case of an audio signal, corresponds to a frame sync code), starts with the first byte (j-th). Means the time to be decoded by the stream decoder.

The DTS is used to generate a start (initiation) signal for decoding the elimtree stream at the decoder. In Equation (2), DTS (j) represents tdn (j), which is the time to decode the elementary stream, at a frequency of system clock_frequency / 300, which has a time interval of 300 / system clock frequency. It is expressed as a binary number of 33 bits. Therefore, when the system decoder divides the value of DTS (j) by the system_clock_frequency / 300, it is possible to know the time to decode.

DTS (j) value is a relative time expressed based on DTS, which is a time here, and should be interpreted based on DTS.

According to the definition of the DTS value defined in MPEG, the DTS is a value of a counter driven by a system clock, and one of the lower 33 bits, which is DTS_base, has a clock frequency as in the DTS. The head of the DTS is sent for each elementary system, with a maximum of 0.7 seconds.

As described above, the DTS data is generated by using the encoder system clock as described above, and the data is composed by the appropriate formatting process and then recorded in the transport stream header to be transmitted.

In this process, the meaning of the DTS data value is that the DTS data is a system target decoder (the system target decoder is an ideal decoder model, which is different from the actual decoder. This decoder sets up a standard that is based on the MPEG standard. It is for.

Thus, such a decoder cannot exist in an actual decoder system. Therefore, the system designer should clearly recognize the difference between the system and the system target decoder that he or she wants to design, and correct the value prescribed by MPEG), which is the point of time when the data is decoded after being decoded by the elementary stream decoder. In this case, the encoder should make DTS data according to this meaning.

In addition, the first and second counters 553 and 555 are initialized and the reference value is set by initial PCR.

Referring to FIG. 7, the elementary stream encoder 510 encodes a video and audio signal based on an MPEG recommendation and converts the video and audio signals into an elementary stream. The start code detector 531 and the PES packetizer 520 convert the video and audio signals. To be provided.

The PES packetizer 520 PESs the elementary stream provided from the elementary stream encoder 510 and then provides the PES packet to the transport packetizer 540.

The transport packetizer 540 transmits the PES output from the PES packetizer 520 to the channel through the transport buffer 570 after transport streamization (see FIG. 4).

For reference, in recording DTS data, the transport packet structure is as follows.

Transport_Packet {Transport Packet Header (), Transport Packet Payload ()}

In the transport packet header, transport packet sync data and other information required by the system are recorded. PES packet data is recorded in the transport packet payload, and the configuration of the transport packet payload is as follows. Transport Packet Payload {PES Packet Header () PES Packet Payload ()}

The PES packet consists of a PES packet header and a PES packet payload portion, and the DTS is recorded in the PES packet header. This process is recorded as going through several more steps.

PES packet header () { _… PTS_DTS_flag 2 bit

_… if (PTS_DTS_flag = 11) { _…

33 bits of PTS data

33 bits of DTS data

If the value of the PTS_DTS_ flag in the PES packet header is 11, it means that there is PTS data and DTS data in the current PES header, and the DTS data format is as described above.

That is, it indicates whether DTS exists in the header of the PES packet.

This tells the decoder whether there is a DTS in the data that is currently being received using only the flag data.

When the DTS is recorded in the current PES packet header, the DTS_flag data is set to 11, and the record of the DTS is written on the transmission buffer 570.

For example, when the start code is detected in the elementary stream of the elementary stream encoder 510, the start code detector 531 provides a flag request signal to the flag processor 533.

Accordingly, the flag processing unit 533 provides the flag to the transport packetizer 540, and the transport packetizer 540 outputs the flag from the flag processor 533 to the header of the PES output from the PES packetizer 520. Record the flag provided.

In more detail, the flag is written as follows.

Send-packet () {

Information to record Value to record

Transport packet header () _...

Send packet payload () {

PTS DTS Flag 10

PTS data 000 _... 0

PES Packet Payload ()}}

The transport packetizer 540 converts the PES stream into a transport packet based on the MPEG standard, and then provides the transport packet to the transport buffer 570 and the flag detector 561.

Prior to this, the DTS memory 562 stores the DTS provided from the encoder clock system 550.

Therefore, if it is determined that the flag PTS_DTS_flag data 10 or 11 is present in the PES header of the transport packet provided from the transport packetizer 540, the flag detection unit 551 stores the read signal accordingly. The DTS memory 562.

For example, send_packet () {

Information to record Value to record

Transport packet header () _...

Send packet payload () {

PTS_DTS_Flag 10

PTS data

PTSS data 1010 _... 10011

PES Packet Payload ()}}

In other words, the underlined part receives and records data in the part making the actual DTS. Transport stream the flagged PES.

This means that a flag is recorded in a transport packet payload portion of a transport stream including a transport packet header portion and a transport packet payload portion.

This means that only the flag is recorded but the DTS, which is the decoding time information, is not recorded, and only a place to be recorded later is secured.

The flagged and transport packetized transport stream is provided to the transport buffer 570 and the flag detector 561.

The flag detector 561 checks whether a flag has been recorded in the transport stream of the transport packetizer 540. When the flag is detected, the DTS recorded in the DTS memory 562 is read, and the read DTS is stored in the transfer buffer 570.

Therefore, the transmission buffer 570 records the DTS in the transmission packet payload portion of the transmission packetizer 540 and then outputs it to the transmission channel.

At the same time, the time-lapse irradiation unit 532 initializes at the time when the DTS is recorded and transmitted, and then counts from this. The flag request signal is supplied to the flag processor 533 at a time point when the count value (for example, 0.7 second) is compared with the counted value.

Accordingly, the flag processor 533 provides the flag to the transport packetizer 540 and records the flag in the header of the PES packet, which is the output of the PES packetizer 520, to transmit the packetizer 540 as described above. And through the transmission buffer 570.

Thereafter, the DTS stored in the DTS memory 562 is obtained as follows.

The initial PCR detection unit 551 accumulates from the time when the transport packet stream output from the transport packetizer 540 is first recorded in the transport buffer 570 to the time when the PCR first received in the transport buffer 570 is recorded. After the initial PCR obtained by dividing the data amount by the transfer rate is loaded into the first and second counters 553 and 555, this value is increased according to the operation of the system encoder clock unit 552.

The system clock unit 552 is a clock that satisfies the above-described 27 MHz-810 Hz ≤ system_clock_frequency ≤ 27 MHz + 810 Hz, and the time change rate of the system_clock_frequency ≤ 75 x 10 ^-3 Hz / sec. Occurs.

Accordingly, the first counter 553 and the second counter 555 perform initial and operation, and the system clock unit 552 generates a stable clock (27 MHz) within the range of the above-described conditions, thereby generating the first counter. It provides a counter 553.

The first counter 553 has a 9-bit counter incremented by one for each clock of the system clock unit 552, and this value is provided to the comparator 554 for every system clock.

Accordingly, the comparator 554 compares the counted value provided from the first counter 553 with the reference value 299, and generates a carry at the matching time point and is provided to the second count 555.

In addition, the second counter 555 counts the carry of the comparator 554, and provides the counted value to the combination processor 556.

That is, the comparator 554 generates a Kerry at the same time point as compared with the output of the 100101011 and the 9-bit counter (9-bit binary value of 299) and outputs the result to the combination processing unit 556.

The combination processor 556 provides the DTS memory 562 with a DTS that combines an additional bit of 3 bits unit and the count value of the second counter 555 in 36 bit units.

The DTS recorded in the DTS memory 562 is read by the flag detection signal of the flag detection unit 561 to be provided to the transmission buffer 570.

As a result, the transmission buffer 570 records the DTS in the header of the PES packet output from the packetizer 540 as a transmission, and then outputs the transmission channel.

Therefore, the system decoder can decode the PES packet based on the DTS input before the elementary stream (audio / video signal) in the transport packet.

As described above, the present invention operates in conjunction with the input of the DTS and the elementary stream for the PES stream during the initial operation of the system, so that the decoding can be stabilized based on the DTS received before the PES during decoding.

In addition, the decoding time can be shortened while satisfying the maximum transmission time constraint of the DTS specified in the MPEG system.

Claims (5)

An elementary stream encoder that encodes an audio / video signal based on an MPEG recommendation, a PES packetizer that PES packetizes the encoded output, transmit packetizes the PES packet, and the transport packetized stream first transmits The initial PCR is obtained by dividing the accumulated data amount by the transfer rate from the time when the data is written to the buffer to the time when the first PCR is received in the transmission buffer. A device for recording and outputting a DTS to a transmission channel, wherein a flag is provided or a decoding time indication is indicated according to a detection result of a start code indicating an start of an audio and video signal in an elementary stream which is an output of the elementary stream encoder 510 The count value and count that counted from the time when the DTS Flag generating means for providing a flag on the basis of the comparison between the measured value (530) and; A transmission packetizer 540 for converting the packetized PES packet, which is the output of the PES packetizer 520, and recording and outputting a flag of the flag generating means 530 in the transmission packetized transmission packet; ; An encoder clock system (550) for generating and outputting a DTS which is a time to be decoded in the decoder based on the initial PCR value and a system clock; A DTS that is an output of the encoder clock system 550, and a detection of reading the recorded DTS in response to a detection result of a flag in a transport packet of the transport packetizer 540 and outputting the recorded DTS to the transport buffer 570 And a recording means (560). A DTS encoding apparatus of an MPEG system. 2. The flag generating apparatus according to claim 1, wherein the flag generating means (530) comprises: a start code detector (531) for providing a flag request signal in response to a detection result of a start code in the elementary stream of the elementary stream encoder (510); A time-lapse irradiation unit 532 for providing a flag request signal based on a result of comparison between a value counted from a time point and a preset count value recorded and transmitted by the DTS; The flag is provided to the transport packetizer 540 in response to the flag request signal of the start code detector 531 or the flag is transmitted to the transport packetizer in response to the flag request signal of the time-lapse search unit 532. 540) A DTS encoding apparatus of an MPEG system, comprising: a flag processing unit 533 provided. The apparatus of claim 1, wherein the detection and recording unit 560 comprises: a flag detection unit 561 which detects whether a flag exists in a transport stream output from the transport packetizer 540 and provides a read signal accordingly; ; The DTS memory 562 which stores the DTS provided from the encoder clock system 550 and reads out the stored DTS in response to the flag detection of the flag detector 561 and outputs the stored DTS to the transmission buffer 579. DTS encoding apparatus of the MPEG system characterized by consisting of. 4. The apparatus of claim 3, wherein the flag is recorded in a header portion of a PES packet. 5. An initial PCR according to any one of claims 1 to 4, wherein an initial PCR from the encoder clock system 550 and the transmission buffer 570 is detected, and as a result of the detection, an initial signal for outputting a reset signal or a preset reference value. A PCR detector 551; It is initialized according to the ON operation of the system encoder and satisfies the conditions of 27 MHz-810 Hz ≤ system_clock_frequency ≤ 27 MHz + 810 Hz, and the time-varying rate of system_clock_frequency ≤ 75 × 10 ^-3 Hz / sec. A system clock unit 552 for outputting a system clock; A first counter 553 that is initialized based on a reset signal or a reference value of the initial PCR detection unit 551, and outputs a counted value by increasing a 9-bit count by 1 for each clock of the system clock unit 552; A comparator 554 for generating a carry at a matching time point as a result of the comparison between the value counted by the first counter 553 and a predetermined reference value; A second counter 555 which is initialized based on a reset signal or a reference value of the initial PCR detection unit 551 and counts and outputs a carry of the comparator 554; And a combination processing unit 556 which uses the DTS memory 562 as a DTS in 33-bit units generated by logically combining the counted value output from the second counter 555 with an additional bit (6 bits). A DTS encoding apparatus of an MPEG system.