KR100469266B1 - apparatus for recording/playing of digital broadcast signal - Google Patents

Abstract

The present invention does not change the storage location on the hard disk as much as possible in order to simultaneously record multiple programs, thereby minimizing the movement time of the head of the hard disk to maintain data transfer efficiency at a level similar to that of recording a single program. PID filtering classifies the input packets to be stored through the PID filtering among the broadcast streams that are input in the form of packets into buffer indexes for each program, and divides the PID packets into read and write buffer areas by the number of programs classified by the PID filter. A storage unit for storing a plurality of programs transmitted through the storage unit, a storage / reproducing controller for generating respective addresses of the plurality of programs stored in the storage unit using a buffer index for each program classified by the PID filter, and the PID filter Multiple programs to be input or duplicates stored in the storage unit There is to be input to the program to be reproduced of the program receiving decoding system configured to include a decoding and outputting.

Description

Apparatus for recording / playing of digital broadcast signal

The present invention relates to an apparatus for recording / reproducing a digital broadcast signal capable of simultaneously storing or reproducing two or more programs coming through a plurality of virtual channels in a personal video recorder (PVR).

Recently, an application device of a type in which an auxiliary storage device such as a hard disk is combined with a DTV / STB has been developed. This is called a PVR, and is intended to store a digital broadcast input based on MPEG-2 or an analog (NTSC) broadcast encoded with MPEG-2 on a digital storage medium.

To do this, unlike a conventional system decoder which does not consider storage, a stream input at the time of recording is stored in a medium such as a hard disk, and at the time of reproduction, a stream stored in a medium such as a hard disk is read and transmitted to a decoder input. It must be structured.

Here, the system decoder refers to a stream that conforms to a standard such as ISO / IEC 13818-1 (information technology-generic coding of moving pictures and associated audio information (system)), which is a standard for time-dividing and transmitting a plurality of audio, video, and other data. Decoder for decoding to obtain a configuration stream.

PVR can be used to record the current analog TV broadcasts to MPEG after digital compression encoding by MPEG, but it was mainly developed for storing digital TV broadcasts.

In particular, in the case of a digital TV, a plurality of virtual channels exist in one channel to transmit several programs.

Therefore, the demand for recording of a large number of programs is inevitably increased compared to the conventional analog TV environment.

In the case of ATSC, which is a digital TV broadcasting standard, HD-quality high-definition programs use 19.4Mbps of data allocated to one channel to transmit a single program. Can be transmitted through.

This means that a general receiver having one tuner and a demodulator can simultaneously watch a plurality of programs.

In order for a PVR user to record a plurality of virtual channels, a system decoder needs to process a program coming through each virtual channel, and a device for storing them on a hard disk is required.

Hard disk performance is very limited due to its mechanical characteristics.

Hard disks currently used for home use generally have slower disk rotation and data transfer speeds than those used in ordinary PCs due to noise and heat problems, and provide the performance to reliably record and play a single HD program. have.

Considering the data volume alone, there should be no problem because the data volume of one HD program and multiple SD programs are similar.However, when recording one program, the storage space is frequently used when recording multiple programs. Because of the time it takes for the head of the disk to move, it is common for data transfer efficiency to decrease.

Therefore, when recording a plurality of programs, it is not possible to provide a stable service without maximizing data transmission efficiency.

Therefore, the present invention has been made to solve the above problems, by not changing the storage location on the hard disk as much as possible to record a plurality of programs at the same time, minimizing the time to move the head of the hard disk data transfer efficiency Aims to maintain the same level as when recording a single program.

Another object of the present invention is to define a storage method for selectively reproducing a plurality of recorded programs.

1 is a diagram showing the structure of an apparatus for recording / reproducing a digital broadcast signal according to the present invention.

2 is a diagram showing a register of a PID filter for storing a general single program.

3 is a diagram showing a register of a PID filter for storing multiple programs according to the present invention.

4 illustrates a general single program disk read / write buffer.

5 is a diagram illustrating a disk read / write buffer for storing multiple programs according to the present invention.

6 is a diagram illustrating a packet arrangement sequence on a hard disk when recording multiple programs according to the present invention.

* Explanation of symbols for main parts of the drawings

10: channel input 20: PID filter

30: system decoder 40: storage / playback controller

50: channel output unit 60: disk read / write buffer

70: HDD

Features of the recording / reproducing apparatus of the digital broadcast signal according to the present invention for achieving the above object is a PID filter for classifying the input packet to be stored through the PID filtering of the broadcast stream input in the form of a packet to the buffer index for each program; A storage unit storing a plurality of programs transmitted through PID filtering by dividing the read and write buffers by the number of programs classified by the PID filter, and using the program-specific buffer indexes classified by the PID filter. A storage / playback controller for generating respective addresses of a plurality of programs stored in the system; and a system decoder for receiving and decoding a plurality of programs input through the PID filter or a program to be played back among a plurality of programs stored in the storage unit. It is composed.

In this case, the upper bit of each address generated by the storage / playback controller is determined by the buffer index, and the lower bit is determined by the size of the unit buffer.

In this case, the storage unit classifies each program into a decoding flag field indicating whether to decode each input packet, a recording flag field determining whether to store the storage, a decoding buffer index field specifying a buffer for each PID, and a buffer designated for each PID. It is composed of a recording buffer index field and has another feature.

In addition, the storage unit collects the input broadcast stream in units of data blocks for each program and stores the collected data.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments taken in conjunction with the accompanying drawings.

A preferred embodiment of a device for recording / reproducing digital broadcast signals according to the present invention will be described below with reference to the accompanying drawings.

1 is a diagram showing an apparatus for recording / reproducing a digital broadcast signal according to the present invention.

Referring to FIG. 1, a PID filter 20 for classifying input packets to be stored through PID filtering among broadcast streams input in the form of packets into buffer indexes for each program, and reading as many as the number of programs classified by the PID filter 20 is provided. And a disk read / write buffer unit 60 for dividing into a write buffer area and storing a plurality of programs transmitted through PID filtering, and the disk read / write using a buffer index for each program classified by the PID filter 20. A storage / reproducing controller 40 which generates respective addresses of a plurality of programs stored in the buffer unit 60, and a plurality of programs or the disk read / write buffer unit 60 inputted through the PID filter 20. It is composed of a system decoder 30 that receives a program to be reproduced from a plurality of stored programs to decode and output.

And a channel input unit 10 for forming a channel for inputting the data stream, a channel output unit 50 for forming a channel for outputting the data stream, and a plurality of programs temporarily stored in the disk read / write buffer unit 60. It further comprises a hard disk (HDD) 70 for storing.

Here, the PID filter 20 selects only packets belonging to the stream selected by the user by using the packet ID (PID) in the header of each packet when the broadcast stream is transmitted in the form of a packet. In addition, the PVR storing the input stream is also subjected to the process of selecting only packets to be stored using the PID filter 20.

In the case of the PVR, the extracted packets are temporarily stored in the disk read / write buffer 60 before being transmitted to the hard disk (HDD) 70.

In the case of playing back a program recorded in the PVR, only packets belonging to the program selected by the read / write buffer 60 in the HDD 70 are read, and then sent to the system decoder 30 for processing.

In order to be able to handle multiple channels, the structure of these PID filters needs to be improved.

In the case of a single channel, as shown in FIG. 2, the PID filter has a decoding flag indicating whether to decode each input packet.

In addition, when supporting the PVR has a recording flag for determining whether to save.

In the system processing a single program as described above, only one of the input programs is activated as in the example shown in FIG. 2, but in the case of a system processing a plurality of programs, the number of programs activated as in the example of FIG. 3 is not limited.

In decoding, since a packet carrying video, audio, and program information must be classified and processed, the buffer must be separated for each PID regardless of the number of programs to be processed. As shown in FIG.

In addition, since only video and audio packets are stored in the storage, the recording buffer index is not defined when a single program is processed.

However, when recording multiple programs, it is necessary to classify the currently stored packet by program and store it in the disk read / write buffer 60. As shown in FIG. 3, a recording buffer index field is assigned to designate a buffer area for each PID of a program to be stored. do.

However, as in the case of storing a single program, only video and audio packets are stored without distinction, so even if the PIDs are different, all packets corresponding to the same program have the same buffer index.

When decoding in real time at the same time as recording, this field is used by the storage and reproducing controller 40 to allocate the decoding buffer independently of the decoding buffer index that designates the buffer of the decoder.

Disk read and write buffers 60 must also refine the buffer allocation accordingly.

As shown in FIG. 4, in a single program storage device, the memory may be divided into the same size and the same number (L) of read buffers and write buffers 60.

Here, the minimum number of buffers for double buffering is two read buffers and two write buffers.

However, in a device capable of storing a plurality of programs, as shown in FIG. 5, each area of the read and write buffer 60 is divided and rewritten as many as the number of programs to be stored.

In FIG. 5, L disk write buffers are allocated to each of the M recorded programs, and L disk read buffers are allocated to each of the N playback programs.

At this time, the size of one disk read and write buffer is determined by the size of data to be transferred to the HDD 70 at a time, but for convenience Decide on the form.

The storage and reproduction controller 40 generates the address of the write or read buffer by using the buffer index specified in the PID filter register.

In this case, the buffer index determines the upper bits of the buffer address and the number of lower bits is determined according to the size of the unit buffer.

For example, to record four programs, a 2-bit recording buffer index is required, and each buffer size is 64KB ( Bytes), the size of the register representing the address of the buffer is 18 bits.

Therefore, if the buffer index is 2, the address will be from 20000h to 2FFFFh.

In actual recording of multiple programs, programs coming through the virtual channel are time-divided into each component packet and stored in the corresponding buffer.

When the buffer composed of multiple packets is full, the data of the buffer is transmitted to the HDD 70 at one time.

These data blocks are stored in the HDD 70 sequentially.

When buffers corresponding to different programs are stored in succession, they are also sequentially stored in the HDD 70.

As a result, a data array as shown in FIG. 6 is obtained.

Referring to FIG. 6, video and audio packets belonging to one program are arranged in a broadcast order, and several packets constitute one data block.

The data block corresponding to program 0 waits in recording buffer 0 and is transmitted to HDD 70, and the data block corresponding to program 1 waits in recording buffer 1 and is transmitted to HDD 70. And this process is carried out alternately.

If the user stops recording the program 1 during the recording, only the data block corresponding to the program 0 is transmitted through the buffer 0 thereafter, and as a result, only the program 0 is continuously recorded in the HDD 70.

When the storage area is separated and executed for each program, the data structure may be simplified and the efficiency may be improved when a single program is reproduced. However, when storing, the head position of the HDD 70 should be moved in units of packets. Since there is a way of alternately approaching other areas of the HDD 70 anyway, the load is increased and as a result, there is no great advantage.

Rather, it is difficult to ensure that the selected programs are normally recorded because the head of the HDD 70 must be moved in packet units during storage.

On the contrary, if the data is stored in the order of input packets without any program classification, the read performance of the HDD 70 is reduced because data must be read while skipping in packet units during reproduction.

In general, while the packet size is less than 200 bytes, it is known that an efficient unit for transferring data of the HDD 70 is 64 KB to 256 KB.

In particular, when playing a plurality of programs at the same time, the performance is worsened because packets scattered in the HDD 70 must be searched and read one by one.

If there is a limit on the number of programs that can be simultaneously recorded / reproduced due to the performance of the HDD 70, it is preferable to implement in a direction to alleviate the restriction at the time of recording.

In general, the purpose of the PVR is to freely adjust the viewing time of the program being broadcast. Therefore, it is appropriate to freely select and record the program being broadcast simultaneously as much as possible rather than the function of simultaneously viewing a plurality of recorded programs.

Therefore, by collecting and storing the input broadcast stream in units of data blocks for each program, it is possible to efficiently determine a unit for transmission at one time to the Hdd 70 while limiting the change in the storage location for each program to the size of the data block to suppress the decrease in transmission efficiency. Will have an effect.

At the time of reproduction, the data block corresponding to the selected program is retrieved from the HDD 70 and sequentially read.

At this time, data blocks of other programs that occur between them are skipped.

This does not significantly affect the read performance of the HDD 70.

The problem is that reads and writes occur at the same time.

Even in the case of a single program, when recording and playback occur at the same time, the performance degradation of the HDD 70 appears.

In particular, the farther the position of the read point and the write point is, the greater the influence.

In the case of recording a plurality of programs according to the above method, the same performance degradation may occur in the process of reading and writing the data blocks by programs.

However, the influence is not significantly different from the aspect in which the movement of the HDD 70 head occurs in units of data blocks when reading and writing in the unit program.

Therefore, the overall load applied to the HDD 70 is maintained at a similar level, and it can be seen that there is no big problem in implementing a multi-program recording / playback function in a system in which simultaneous recording / playback function of a single program is provided.

As described above, the apparatus for recording / reproducing a digital broadcast signal according to the present invention has the following effects.

First, in a system capable of recording a single program, there is an effect that can store multiple programs without significantly improving the performance of components such as HDD.

Second, the disk write buffer can be efficiently operated for recording of multiple programs.

Third, compared to the case of a single program, it is possible to play back a plurality of recorded programs without significantly increasing the load on the HDD.

Fourth, the number of recording channels can be freely extended within the limits allowed by the performance of the HDD.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

Claims (4)

PID filter for classifying input packets to be stored through PID filtering among broadcasting streams input in packet form as buffer index for each program; A storage unit which stores a plurality of programs transmitted through PID filtering by dividing the read and write buffers by the number of programs classified by the PID filter; A storage / playback controller for generating respective addresses of a plurality of programs stored in the storage unit by using the buffer index for each program classified by the PID filter; And a system decoder configured to receive, decode, and output a program to be reproduced from among a plurality of programs input through the PID filter or a plurality of programs stored in the storage unit. The method of claim 1, The upper bit of each address generated by the storage / playback controller is determined by the buffer index, and the lower bit is determined by the size of the unit buffer. The method of claim 1, wherein the storage unit A decoding flag field indicating whether or not to decode each input packet, a recording flag field determining whether to store each input packet, a decoding buffer index field for designating a buffer for each PID, and a recording buffer index field for classifying the program in a buffer designated for each PID. And a digital broadcast signal recording / reproducing apparatus. The method of claim 3, wherein the storage unit And recording and storing the input broadcast stream in data block units for each program.