KR100243416B1 - Method and apparatus for re-multiplexing in mpeg-2 ts - Google Patents

Abstract

The present invention relates to an MPEG-2 transport stream (TS) remultiplexer and a remultiplexing method. The present invention relates to a FIFO for receiving and temporarily storing TS packet string data, and confirming PCR for PCR. A plurality of input handlers including a PCR correction unit for correcting the PCR after calculating the time delay, if included; A 27 MHz oscillator for providing a clock to the input handler; A scheduler which receives state information indicating the amount of TS packet sequence stored in the FIFO from an input handler, determines an input handler to be multiplexed next according to a scheduling algorithm, and informs the corresponding input handler of the input handler; When the input handler receiving the multiplexing selection signal outputs one TS packet sequence in accordance with the output clock and TS frame synchronization, and the PCR information is included in the output TS packet sequence, the original PCR value is positioned by using the PCR correction unit. It consists of a TDM multiplexer for output by replacing with the corrected PCR value. Therefore, when the PCR is corrected, the random value generated during the multiplexing process is corrected by considering the minimum delay time of all input stream stream sequences. Even with time delay, the MPEG decoder can perform the decoding process stably.

Description

MPEG-2 Transport Stream Remultiplexer and Remultiplexing Method

The present invention relates to an MPEG-2 transport stream (TS) remultiplexer and a remultiplexing method. Specifically, the present invention relates to a program clock reference (PCR) to compensate for a random time delay occurring during the multiplexing process. The present invention relates to an MPEG-2 TS remultiplexer and a method having a function of correcting a program clock reference.

The MPEG-2 system standard requires that PCR values be corrected by a random time delay occurring in the remultiplexer. Therefore, the present invention calculates the time delay that occurs during the multiplexing process, uses the value to correct the PCR value in the TS packet sequence, and receives a plurality of MPEG-2 TS streams. It is an object of the present invention to provide an MPEG-2 transport stream remultiplexer and a method of remultiplexing which are multiplexed with MPEG-2 rows.

1 is a block diagram of an MPEG-2 transport stream packet.

Figure 2 is a flow diagram of the MPEG-2 transport stream remultiplexer PCR correction according to the present invention.

3 is a block diagram of an MPEG-2 TS remultiplexer according to the present invention;

4 is a delay time waiting for input TS strings to be multiplexed.

* Description of the symbols for the main parts of the drawings *

10: input handler 11: FIFO

12: PCR correction unit 20: oscillator

30: scheduler 40: TDM multiplexer

The MPEG-2 TS remultiplexer for achieving the above object is the first time in first out (FIFO) for receiving and temporarily storing the TS packet sequence data, and the PCR (Program Clock Reference) to check the presence of the time An input handler arranged in plural with a PCR correction unit for correcting the PCR after calculating the delay; A 27 MHz oscillator for providing a clock to the plurality of input handlers; A scheduler which receives the state information indicating the amount of TS packet sequence stored in the FIFO from the input handler, determines an input handler to be multiplexed next according to a scheduling algorithm, and informs the corresponding input handler of the input handler; The input handler receiving the multiplex selection signal outputs one TS packet sequence in accordance with the output clock and TS frame synchronization. If the output TS packet sequence includes PCR information, the PCR modulator is used to access the original PCR value. Characterized in that it consists of a TDM multiplexer for outputting by replacing the corrected PCR value.

In the MPEG-2 transport stream re-multiplexing method according to the present invention, after receiving an input transport stream (TS) packet sequence, data is temporarily stored, and the presence or absence of PCR is determined. Correcting; Determining an input handler to be multiplexed next according to a scheduling algorithm based on state information indicating the amount of transport stream packet streams stored in the FIFO, and notifying the corresponding input handler; Outputting, by the input handler receiving the multiplexed selection signal, one transport stream packet sequence through the TDM multiplexer in accordance with the output clock and transport stream frame synchronization; When PCR information is included in the transport stream packet sequence, a plurality of MPEG-2 transport stream (MPEG-2 TS) packets are performed by performing a step of replacing the corrected PCR value at the original PCR value position using a PCR modulator. It receives a column and multiplexes it into one MPEG-2 column.

FIG. 1 shows an MPEG-2 Transport Stream (TS) packet. As shown, a transport stream packet is composed of 188 bytes and a header (1) consisting of 4 bytes including a sync signal of 1 byte, and conditionally indicated adaptation. It consists of a field 2 and a payload 3 of variable length.

In the MPEG-2 system standard, PCR is information for setting the value of STC (System Timing Clock) as a reference in the MPEG system decoder including video and audio decoders as intended by the encoder. to be. Since the PCR value is not included in all transport stream packet sequences and is inserted into the transport stream packet sequence at intervals of 10 msec or less, it is impossible to operate the decoder simply by using the value. Therefore, the decoder operates the STC counter by restoring a clock synchronized with the 27 MHz system clock used by the encoder using irregular and discretely input PCR values, and performs a decoding function by referring to the clock and the STC counter.

2 is a flowchart illustrating a process of processing a transport stream packet sequence according to the presence or absence of PCR in the multiplexing of the transport stream sequence. As shown in FIG. 2, the PCR correction process in the MPEG-2 transport stream multiplexer is performed when a transport stream packet is input (110). The Adaptation Field Control Flag (120) and the PCR Flag (150) are found using the transport stream packet synchronization signal included in the header portion of the packet, and the presence or absence of PCR in the packet is determined using this value. If it does not include PCR, it is stored in the FIFO until it is multiplexed (130), and then only the time division multiplexing (TDM) process is performed in units of 188 byte transport stream packets (140). After storing (160) in consideration of the time delay from when the packet is input to the output (170) by correcting the PCR according to the following equation (1) (180) to the new PCR value (190) Multiplex and output (140).

FIG. 3 illustrates an MPEG-2 transport stream remultiplexer. As shown in FIG. 3, a FIFO 11 for receiving and temporarily storing transmission (TS) packet string data and a time when a PCR is included by checking the presence or absence of PCR An input handler (10) having a plurality of input correctors (12) arranged to calculate a delay and then correct the PCR; A 27 MHz oscillator (20) for providing a clock to the plurality of input handlers (10); Receives state information indicating the amount of transport stream packet stream stored in the FIFO 11 from the input handler 10 to determine an input handler to be multiplexed next according to a scheduling algorithm, and informs the corresponding input handler. A scheduler 30; The input handler receiving the multiplexed selection signal outputs one transport stream packet sequence in accordance with the output clock and the transport stream frame synchronization. If the outputted transport stream packet sequence includes PCR information, the PCR correction unit 12 is used. And a TDM multiplexer 40 for outputting by replacing the corrected PCR value at the original PCR value position.

The input transmission (TS) packet string data is temporarily stored in the FIFO 11, and the PCR correction unit 12 checks the presence or absence of PCR, calculates a time delay, and corrects the PCR. The input handler 10 is arranged in plurality. The 27 MHz oscillator 20 provides a clock to the plurality of input handlers 10 arranged therein, and the scheduler 30 is configured to transmit a stream of transport stream packets stored in the FIFO 11 from the input handler 10. Based on the state information indicating the quantity, the scheduling algorithm decides which input handler to multiplex next and informs the input handler. The input handler receiving the multiplexed selection signal outputs one transport stream packet sequence in accordance with the output clock and the transport stream frame synchronization. The TDM multiplexer 40 performs PCR when the output transport stream packet sequence includes PCR information. The correction unit 12 is used to substitute the corrected PCR value at the original PCR value position for output.

The input handler 10 may include a 27 MHz independent oscillator for correcting PCR.

The MPEG-2 transport stream remultiplexer performs a function of remultiplexing a plurality of transport stream packet streams multiplexed into a primary transport stream packet stream. In this process, each transport stream packet stream is randomly delayed in the remultiplexer. The output is remultiplexed. The MPEG-2 system standard allows constant time delays for all transport stream sequences, but does not allow variable delays with different delay times for different packets. This is because, as described above, the STC counter, which is the reference for the decoder operation, is restored by restoring a clock whose discrete PCR value is synchronized with the 27 MHz system clock used by the encoder. Therefore, for the stable operation of the decoder, the remultiplexer must find the transport stream packet containing the PCR, calculate the time delay of the transport stream packet sequence in the remultiplexer, and correct the PCR value by this delay time.

4 illustrates a delay time waiting for multiplexing an input transport stream packet sequence. As illustrated, a vertical axis represents a transport stream packet sequence multiplexed and a horizontal axis represents a delay time waiting for multiplexing. The algorithm of the present invention for correcting PCR values in a remultiplexer operates a counter using a precise 27 MHz clock when a transport stream sequence with PCR is input, and corrects only the value obtained by subtracting the time delay of all input transport stream packet sequences. do. The MPEG-2 decoder operates the STC based on the received PCR, and the data having a decoding time stamp (DTS) and presentation time stamp (PTS) smaller than this STC is discarded without decoding. Will cause unstable operation. This algorithm can minimize the above-described problem by correcting the PCR value in consideration of the minimum delay time that all input stream stream sequences have equally. The PCR correction equation of the present invention is shown in Equation 1 above.

In FIG. 3, the input transport stream packet sequence includes an input consisting of a PCR correction unit for checking a FIFO having a function of temporarily storing input data and a presence of PCR, and correcting PCR after calculating a time delay when the PCR is included. It is entered into an input handler. Each input handler also passes to the scheduler status information indicating the amount of transport stream packet streams stored in the FIFO, and the scheduler uses this status information to determine which input handler to multiplex next according to a scheduling algorithm. Notify the handler. The input handler receiving the multiplex selection signal outputs one transport stream packet sequence through the TDM multiplexer in accordance with the output clock and transport stream frame synchronization. If the transport stream packet sequence includes PCR information, the input handler uses the PCR correction unit. The PCR value is replaced with the corrected PCR value and output.

According to the present invention, when a transport stream sequence with PCR is input, the MPEG-2 decoder receives the signal by operating the counter using a precise 27 MHz clock and correcting only the value obtained by subtracting the time delay of all the input transport stream packet sequences. The STC is operated based on PCR, and data having a Decoding Time Stamp (DTS) and Presentation Time Stamp (PTS) smaller than this STC is discarded without decoding. When there is a lot of discarded data, the decoder becomes unstable. . In the present invention, the PCR value is corrected in consideration of the minimum delay time of all input transport stream packet streams when the PCR is corrected, thereby providing an effect that the decoder operates stably against a random time delay occurring in the multiplexing process. do.

Even when there is a lot of data, it provides an effect of improving the stability of the decoder operation.

Claims (7)

A plurality of input handling arrangements are provided with a FIFO for receiving and temporarily transmitting transmission (TS) packet string data and a PCR correction unit for checking the presence of PCR and for calculating PCR after calculating a time delay. tile; A 27 MHz oscillator for providing a clock to the plurality of input handlers; A scheduler that receives state information indicating the amount of transport stream packet streams stored in the FIFO from the input handler, determines an input handler to be multiplexed next according to a scheduling algorithm, and informs the corresponding input handler of the input handler; The input handler receiving the multiplex selection signal outputs one transport stream packet sequence in accordance with the output clock and transport stream frame synchronization. If the output transport stream packet sequence includes PCR information, the original PCR is performed using a PCR modulator. Comprised of a TDM multiplexer for outputting by replacing the corrected PCR value in the value position, the MPEG characterized in that the multiplex of MPEG-2 TS (packet stream) (MPEG-2 TS) packet sequence is received and multiplexed into one MPEG-2 column -2 transport stream remultiplexer. The method of claim 1, The input handler, When correcting PCR, consider the minimum delay time that all input transport streams have equal,

Computed by the MPEG-2 transport stream remultiplexer. The method of claim 1, The input handler, An MPEG-2 transport stream remultiplexer comprising a 27 MHz independent oscillator for correcting PCR. Receiving an input transport stream (TS) packet sequence and temporarily storing data, checking for the presence of a PCR, correcting the PCR after calculating a time delay if the PCR is included; Determining an input handler to be multiplexed next according to a scheduling algorithm based on state information indicating the amount of transport stream packet streams stored in the FIFO, and notifying the corresponding input handler; Outputting, by the input handler receiving the multiplexed selection signal, one transport stream packet sequence through the TDM multiplexer in accordance with the output clock and transport stream frame synchronization; If PCR information is included in the transport stream packet sequence, performing a step of outputting by replacing the corrected PCR value at the original PCR value position using a PCR modulator. A MPEG-2 transport stream remultiplexing method comprising receiving multiple MPEG-2 TS streams and multiplexing them into one MPEG-2 stream. The method of claim 4, wherein The PCR correction step, When correcting PCR, consider the minimum delay time that all input transport streams have equal,

The MPEG-2 transport stream remultiplexing method, characterized by the above-mentioned. The method of claim 4, wherein The PCR correction step, When the transport stream packet is input, using the transport stream packet synchronization signal included in the header part of the packet, finding an adaptation field control flag and a program clock reference (PCR) flag and determining whether PCR is included in the packet based on the value; ; If it does not include PCR, storing in a FIFO until multiplexing, and then simply time-division multiplexing in units of 188Byte TS packets; When the PCR is included, the MPEG-2 transport stream re-multiplexing method, characterized in that the PCR is corrected in consideration of the time delay from the time of the packet input to the output and then multiplexed. The method of claim 4, wherein The PCR correction step, 27. A method for remultiplexing an MPEG-2 transport stream comprising a 27 MHz independent oscillator for synchronizing with a system clock.

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