KR101290072B1 - Section filter of linked-list type for transport stream parsing for low power set-top boxes - Google Patents

Abstract

PURPOSE: A linked list type section filter for transport stream parsing for a low power set-top box is provided to reduce power consumption by reducing access to an inefficient memory. CONSTITUTION: A transport stream (TS) provided from outside is stored as section data in a packet memory (110). A section filter memory stores a section filter consisting of multiple unit filters configured as a linked list. In case section filtering about the section data fails, a section filter engine (130) changes the size of the section filtering. The section filter engine reads additional section data from the packet memory and applies the section filter to the additional section data. [Reference numerals] (100) Connection list section filter; (110) Packet memory (SRAM I/F); (130) Section filter engine; (131) Match filter; (140) Register interface; (150) Section filter memory; (BB) 32bit; (CC) PKT_DONE interrupt

Description

SECTION FILTER OF LINKED-LIST TYPE FOR TRANSPORT STREAM PARSING FOR LOW POWER SET-TOP BOXES}

The present invention relates to a connected list section filter for parsing transport streams as a technique suitable for use in digital set-top boxes, particularly low-power set-top boxes. More specifically, the present invention relates to a structure of a module for receiving and parsing a transport stream (TS) of video data, which is a key technical element of a set-top box, and is generally a TS demux. The present invention relates to a connection list type section filter which reduces power consumption by reducing the overall memory size required by the section filter while further improving the performance of the section filters disposed therein and further reducing inefficient memory access.

Recently, with the rapid development of digital technologies such as digital image compression and digital modulation and demodulation, standardization and commercialization of digital television (DTV) broadcasting is rapidly developing. In this situation, the set-top box receiving the digital television broadcast restores the broadcast program selected by the user to the original A / V (Audio / Video) data using a decoder provided in the receiver, and then outputs the A / V like a general television. By transmitting to the device, the user can selectively watch the broadcast program.

On the other hand, the standardization of digital broadcasting is progressing variously, and various technical developments are being conducted in the fields of transmission of digital signals through a broadcasting network, multiplexing of data, processing video and audio signals, and display of digital television. Digital broadcasting can compress information data compared to analog broadcasting, and has high transmission speed and excellent sound quality and image quality. In addition, unlike analog broadcasting, digital broadcasting has an advantage of enabling efficient use of frequency by digital modulation. Thus, various information can be broadcast through hundreds of channels, and the viewer can access various information through the television.

The digital broadcast signal is delivered in the form of a transport stream after data compression using a technique such as MPEG. The user receives the transport stream through a digital television or digital set-top box, and then parses and decompresses the data. Implement / V on the screen. Devices such as digital televisions and digital set-top boxes are generally referred to as broadcast receivers, and are referred to herein as "set top boxes" for convenience. Digital televisions are applicable to the scope of the present invention because they can be modeled as an integrated set-top box and display device.

The transport stream (TS) is composed of a series of TS packets. Each TS packet is provided with a packet identifier (PID) in a header part. Such PID is usually 13 bits of data, which is used to distinguish each TS packet primarily when parsing a transport stream in a set-top box. Accordingly, the set-top box generates a section data by performing PID filtering to extract a TS packet having a desired PID from the transport stream, and then provides it as a description element (TS demux) for parsing the transport stream.

TS Demux performs section filtering on the provided section data for various purposes. Typically, filters of section data for valid PIDs are stored and used in memory or registers allocated thereto. However, as the number of PIDs used is increasing these days, the method of storing them in registers requires the allocation of one filter per PID, which leads to a sharp increase in chip size. Accordingly, a method of storing a filter in a memory for section filters for various PIDs is common, and the present invention mainly relates to a section filter of this type.

1 is a diagram conceptually showing an internal configuration of an 8-byte section filter 10 according to the prior art. That is, when 8-byte section filtering is performed for one PID, the scheme of FIG. 1 is generally used. One section filter 10 is composed of 8 bytes of data to be compared (comparative vector) and 8 bytes of bit mask (valid bit-wise interval).

When using the section filter 10 in this manner, when applying one section filtering to the input data for one PID, a total of four 32-bit (4 byte) read accesses are required. Since digital broadcasting utilizes multiple PIDs, a total of 4 × N memory read accesses are performed assuming that N section filters are generally applied. When data for a specific PID is set in the set-top box, a method of comparing section filters by reading the memory of the allocated area according to the PID is mainly used.

If only one 8-byte section filter 10 is applied to one PID, the prior art according to [FIG. 1] requires four read accesses of any value of the mask vector. Even if you set the mask vector to 0xff000000 to filter only the first 1 byte, four read accesses are required because the mask vector must be read. As such, the section filter 10 of the related art has a large number of memory accesses, which limits the performance of the section filtering.

In addition, the section filter 10 of the prior art has a problem that takes a lot of memory. If you want to apply N 8-byte section filters per PID, you need N × 16 bytes, and if you want to set M PIDs, you need M × N × 16 bytes of memory. If you use a 16 byte filter, you need M × N × 16 × 2 bytes. If a filter to be used for each PID is allocated, even though the same filter is used for two different PIDs, the structure of FIG. 1 requires two filter memories, which wastes memory for duplicate contents.

As described above, the section filter 10 according to the related art has a problem in that it is necessary to perform a plurality of memory accesses in the filtering process, and thus there is a limitation in improving the filtering performance and a large amount of memory consumption for filtering. There is this. Therefore, there is a need for the development of a new type of section filter technology to solve this problem.

It is an object of the present invention to provide a connected list section filter for parsing transport streams as a technique suitable for use in digital set top boxes, in particular low power set top boxes. More specifically, the present invention relates to a structure of a module for receiving and parsing a transport stream (TS) of video data, which is a key technical element of a set-top box, in order to improve the performance of a section filter disposed in a TS demux. To improve the power consumption by reducing the overall size of the memory required by the section filter, and further reduce the inefficient memory access to provide a connection list section filter.

According to an embodiment of the present invention, there is provided a connection list section filter including: a packet memory 110 in which a transport stream provided from the outside is stored as section data; A section filter memory 150 for storing a section filter including a plurality of unit filters in a linked list; A section filter engine 130 that reads section data from the packet memory and reads the section filter from the section filter memory, and sequentially determines whether the section data matches with respect to the unit filter belonging to the connection list of the section filter. do.

In the section filter of the linked list method according to the present invention, when the section filter engine achieves a matching success with respect to the section data within a specific unit filter belonging to the linked list, the section filter is treated as successful in the unit filter. If the engine fails to match the section data within a specific unit filter belonging to the linked list, the engine proceeds to the next filter of the linked list and determines whether to match.

In addition, in the section filter of the linked list method according to the present invention, the unit filter includes a plurality of line filters corresponding to the basic unit of the determination of a match in the linked list method, and the section filter engine provides section data for a series of line filters. Is determined in units of the line filter, but if the matching is successful until the end of the line filter connection list, the unit filter treats the section filtering on the section data as successful. In this case, the line filter includes a comparison vector, which is a data value to be compared with the section data, a mask vector indicating only a portion of the comparison vector data value to be compared in units of bits, and a mode vector indicating an operation type.

In addition, in the section filter of the linked list method according to the present invention, if the section filtering for the section data fails as a result of matching all the plurality of unit filters belonging to the linked list, the section if the preset condition is satisfied After changing the size of the filtering, additional section data is read from the packet memory and the section filter is applied again.

According to the present invention, there is an advantage of improving the operation performance of a section filter for receiving and parsing a transport stream for digital broadcasting in a digital television or a digital set-top box.

In addition, according to the present invention, it is possible to reduce the overall size of the memory required by the section filter, and further reduce the power consumption of the section filter by reducing inefficient memory access.

1 conceptually illustrates the internal configuration of an 8 byte section filter according to the prior art;
2 is a block diagram illustrating an internal configuration of a section filter of a linked list method according to the present invention.
3 is a diagram conceptually showing a structure of a section filter memory suitable for use in a linked list section filter according to the present invention;
FIG. 4 is a diagram showing an example of a link data field used in the section filter memory of FIG. 3; FIG.
5 is a view showing an example of the field configuration of the section data to be filtered by the section filter of the linked list method in the present invention.
6 is a flowchart illustrating an example of a process for performing filtering in a section filter of a linked list method according to the present invention;

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

2 is a block diagram showing the internal configuration of the section filter 100 of the linked list method according to the present invention. Referring to the drawings, the connection list section filter 100 according to the present invention is for performing various filtering required by the software from the section data, and includes a packet memory 110, a packet memory interface (PKTM I / F) 120, and a section. Filter engine 130, register interface 140, section filter memory 150, and CRC32 module 160. The section filter engine 130 also includes a match filter 131.

The internal structure of the connection list section filter 100 according to the present invention will be described with reference to the drawings. The transport stream is provided to the packet memory 110 in the form of section data after PID filtering and is temporarily stored. The section filter engine 130 receives the section data from the packet memory 110 by accessing the packet memory 110 through the packet memory interface 120.

The section filter memory 150 is a space for storing a variety of information for configuring a section filter in the present invention, and stores a filter structure and a configuration to be used for filtering section data.

The section filter engine 130 reads information for configuring individual filters from the section filter memory 150, configures a filter, and performs filtering by comparing with the section data provided from the packet memory 110. The match filter 131 determines whether the set value of the individual filter matches the section data.

When the filtering operation is completed, the connection list section filter 100 transmits the filtering result to the CPU through the PKT_DONE interrupt.

3 is a diagram conceptually showing a structure of a section filter memory 150 suitable for use in the linked list type section filter 100 according to the present invention, and FIG. 4 is a section filter memory 150. FIG. 1 is a diagram illustrating an example of a field configuration of link data used in a system. FIG. 5 is a diagram illustrating an example of field configuration of section data corresponding to a target to be filtered by the section filter 100 of the linked list method according to the present invention.

Referring to FIG. 3, the section filter memory 150 according to the present invention includes a total of 128 unit filters (unit filters # 0 to # 127), and each unit filter includes eight line filters. The line filter serves as a basic unit of the matching decision in the section filter according to the present invention. In the present embodiment, the line filter is configured based on 1 byte but may be implemented differently according to the design purpose. The line filter has a comparison vector (1 byte), a mask vector (1 byte), a mode vector (1 byte), and a next link (1 bit), and the last line filter of the unit filter has link data (1 byte) instead of the next link. It is provided.

In the present embodiment, since the section data (Section Data, SD) is composed of 8 bytes (see [Fig. 5]), the unit filter is composed of eight line filters (see [Fig. 3]). The data field configuration of FIGS. 3 to 5 is presented as an example.

A comparison vector (CV) refers to a data value to be compared with section data provided through the packet memory 110.

The mask vector (MV) designates only the portion of the input data to be actually compared in bits.

The mode vector (Mode Vecotr, DV) represents a positive / negative operation. As an example, the positive operation is a mode for treating as a match when the bit values are the same, and the negative operation is a mode for treating as a match when the bit values are different.

Nextlink (1 bit) indicates whether or not to compare the next byte in the unit filter. That is, for example, after comparing the comparison vector 0, the next link 0 associated with it is examined. If the next link 0 is '1', the next comparison vector 1 is also compared, and if the next link 0 is '0', the comparison ends.

Link data (1 byte) indicates whether to use the following unit filter. Referring to FIG. 4, the link data includes a next filter valid field and a next filter number. The Next Filter Valid field indicates whether there is a next unit filter following the current filter in the linked list. If the next filter valid is '1', there is a next unit filter, and the next unit filter is identified by the next filter number. On the contrary, if the next filter validity is '0', it means that the current filter is the last and there is no next filter, so the next filter number is meaningless. Optionally, it can be used in a special way, and when the next filter validity is '0', the next filter number can be configured to terminate 8-byte filtering and switch to 16-byte filtering if a predetermined value, for example, 127.

By utilizing the next link (1 bit) and link data (1 byte) as described above, in the present invention, filtering by byte unit and various kinds of filters can be applied in a linked list method.

6 is a flowchart illustrating an example of a process of performing filtering in the section filter 100 of the linked list method according to the present invention.

First, when section data having a valid PID is received from the outside, once stored in the packet memory 110, the section filter engine 130 reads the section data to start filtering (S110).

The line matching process is performed on the first unit filter of the linked list by byte unit. That is, the filter match is checked for the first byte of the section data through the operation of Equation 1 (S120).

[Equation 1]

{[(Section Data (SD) 0 & Mask Vector (MV) 0) xor [(Compare Vector (CV) 0 & Mask Vector (MV) 0] xor Mode Vector (DV) 0}

If the first byte unit match fails, the current unit filter does not need to be examined anymore, and thus the process fails to match (S170). On the contrary, if the first byte match succeeds, it moves to the next byte and continues matching. To this end, the next link related to the corresponding comparison vector is reviewed (S130). If the next link is '0', the unit filter being processed is processed as a success (S150). If the next link is '1', there are still bytes to be compared. Proceed to the next byte. This procedure is repeated for a total of eight bytes.

In this manner, as shown in [Equation 2], the filter is checked to the last eighth byte (S140). If the match is successful, the current unit filter is regarded as a successful match.

&Quot; (2) "

{[(Section Data (SD) 7 & Mask Vector (MV) 7) xor [(Compare Vector (CV) 7 & Mask Vector (MV) 7] xor Mode Vector (DV) 7}

Next, the next filter valid field of the link data attached to the current unit filter is checked (S160). When the value of the next filter valid value is '1', it means that the next unit filter exists in the linked list. Therefore, the next process is performed by referring to the next filter number field of the link data (S180) and the same process is performed. . On the contrary, if the value of the next filter validity is '0', it means that there are no more unit filters in the linked list and proceeds to the next step (S190). In the present invention, it is determined whether to use the next byte or the next filter by referring to the next link, the next filter validity, and the next filter number in order to use the linked list to repeat the process of comparing the section data and the comparison vector. In addition, it is configured in a linked list manner, and various types of filters can be used.

In step S190, it is determined whether the next filter number is a predetermined value, for example, 127. If the next filter number is not 127, it is treated as having completed section filtering (S200) and generates an interrupt (PKT_DONE_IRQ) (S210). Below is a case where the next filter number is 127.

Referring to the result of the determination in step S160, step S190 is interpreted as a situation in which there is no next valid filter since the next filter valid field is '0'. However, even in this case, if the next filter number is a specific value (for example, 127), the present invention ends the 8-byte filtering so far and starts the 16-byte filtering from now on (S220). That is, through the above process, the filtering was basically performed up to 8 bytes, and the process was enlarged while proceeding to step S220 to enable the maximum 16 bytes filtering. For 16-byte filtering, if the next filter validity is 0 and the next filter number is 127, the structure is configured to filter immediately after the current filter number. This approach uses 1 to 16 bytes of filtering on a per-byte basis, making it more efficient than a typical 8-byte filter.

Basically, each vector consists of 8 to 0 ~ 7 for 8-byte filtering, but the present invention supports the filter of the linked list structure, so all 1 to 16 bytes can be filtered. By checking the link in bytes, you can reduce unnecessary memory read access.

In addition, one filter ends and the link part can be checked to apply a new filter at a desired position. Since there is no inefficient management of modifying the contents of the filter memory each time or using only a fixed position filter, write access for re-entering the new filter value into the section filter memory 150 can be reduced. In addition, various filters can be applied by simply changing the start position, which reduces the memory size required to use multiple filters for each PID. This is because the memory location is not allocated for each PID, but the starting position of the filter is different for each PID, and various filters are applicable by changing only the link of the linked list.

The section filter 100 of the linked list method according to the present invention is configured to enable byte-by-byte comparison to reduce unnecessary memory read / write access, and to filter 128 filters for various PIDs through the linked list. The size of the section filter memory 150 can be reduced by freely using the configuration. In addition, the filter can be extended to 1 to 16 bytes as well as fixed 8 byte filtering, and can be appropriately set according to individual use. This reduction in memory read / write access reduces the time for section filtering, which naturally leads to improved section filter performance.

In addition, according to the present invention, since power access is reduced, power consumption is reduced, and memory size reduction due to efficient memory use can lower the cost of a chip, thereby increasing competitiveness.

The present invention can also be embodied in the form of computer readable code on a computer readable recording medium. At this time, the computer-readable recording medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of the computer-readable recording medium include a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage, and the like, and may be implemented in the form of a carrier wave . The computer-readable recording medium can also be stored and executed by a computer-readable code in a distributed manner on a networked computer system. And functional programs, codes, and code segments for implementing the present invention can be easily deduced by programmers skilled in the art to which the present invention belongs.

As described above, the embodiments of the present invention have been disclosed in the present specification and drawings, and although specific terms have been used, they have been used only in a general sense to easily describe the technical contents of the present invention and to facilitate understanding of the invention. And is not intended to limit the scope of the invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

100: connection list section filter
110: packet memory
120: packet memory interface
130: Section Filter Engine
131: match filter
140: register interface
150: section filter memory
160: CRC32

Claims (5)

A packet memory 110 in which a transport stream provided from the outside is stored as section data;
A section filter memory 150 for storing a section filter including a plurality of unit filters in a linked list;
The section data is read from the packet memory and the section filter is read from the section filter memory to determine whether the section data is matched sequentially with respect to a unit filter belonging to the connection list of the section filter, and belonging to the connection list. According to whether or not the section filtering succeeds in the unit filter according to whether or not the matching success is achieved with respect to the section data in a specific unit filter, and all of the plurality of unit filters belonging to the linked list are determined and matched with respect to the section data. If section filtering fails, a section filter engine 130 for changing section sizes and reading additional section data from the packet memory and applying section filters again;
Linked section filter section configuration, including.
The method according to claim 1,
If the section filter engine fails to achieve a matching success with respect to the section data within a specific unit filter belonging to the linked list, the section filter engine proceeds to a unit filter that is the next order of the linked list to determine whether to match. Linked section filter.
The method according to claim 1 or 2,
The unit filter may include a plurality of line filters corresponding to the basic unit of the determination of a match in a connected list method.
The section filter engine determines whether the section data is matched with the section data in the line filter unit, but if the matching is successful until the end of the line filter connection list, the section filtering for the section data in the unit filter succeeds. Linked section filter, characterized in that the processing.
delete The method according to claim 3,
The line filter may include a comparison vector corresponding to a data value to be compared with the section data, a mask vector indicating only a portion of the comparison vector data value to be compared in units of bits, and a mode vector indicating an operation type. Linked section filter.

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