KR100235616B1 - Track assigning method of digital data using time stamp - Google Patents

Abstract

Digital data by time stamp to accurately maintain the arrival time of data entering a D-VHS recorder in which a track number and a sequence number designate a place to be recorded on the recording tape according to the value of the time stamp. A track designation method is disclosed. The track designation method of digital data by the time stamp designates a place to be recorded on the recording tape according to the value of the time stamp attached to the input digital data in order to accurately maintain the arrival time of the data coming into the D-VHS type recorder. Allow track numbers and sequence numbers to meet certain constraints.

Description

How to specify the track of digital data by time stamp

The present invention relates to a digital-home home system (D-VHS). More specifically, the present invention provides the arrival of input data by ensuring that a track number and a sequence number designating a place to be recorded on the recording tape according to a value of a time stamp attached to the input data in a D-VHS recorder satisfy certain constraints. The present invention relates to a track designation method of digital data by a time stamp for accurately maintaining time.

D-VHS is a bit stream storage device having a function of storing and outputting compressed or processed data such as digital broadcasting on a tape without processing. Therefore, the bit stream recording apparatus does not need the analog-to-digital converter / digital-analog converter and the compression / reduction function. Of course, these signals are converted into video and audio signals through a conversion device and output as signals that can be recognized by humans. D-VHS functions first as a home data server (VCR and V & DR) for the multimedia era, secondly, to bridge the innovation from analog to digital signals, and thirdly, as a high-density storage medium for electronic files. Finally, the use of a generalized ferric oxide tape (SVHS), which has a function and finally has a proven production system, provides a high level of stability and price competitiveness. The recording performance of the D-VHS is capable of storing 7 hours of data for an input data rate of 14.1 MBPS and 14 hours of data for 7 MBPS in LP mode. This represents a storage capacity of 44 gigabytes. Application fields may be used in video servers, safety monitoring devices, data recording storage media, and the like.

Each transport packet should be recorded on the recording tape in the order of the value of the time stamp. The transport packet recorded on this recording tape must satisfy the relationship between the time stamp and track / sink block number shown in the following equation (1). That is, the transport packet stamped with time stamp T.S [m, n] should be recorded at the position indicated by [t, s], and the range of [t, s] is as follows.

[Equation 1]

[X-1, Y] <[t, s] <[X + 1, Y]

Where t is the track number, s is the sync block number

X = integer (m / 2), Y = integer [(n / N + mod2) * 153]

m is the upper 4 bits of the time stamp and n is the lower 18 bits of the time stamp.

For example, X-1 = -1 means track number 5 with sequence number sn-1 and X + 1 = 6 means track number 0 with sequence number sn + 1.

It is conceivable to implement [Equation 1] in hardware as a method of constructing the relationship as a circuit. A bit calculator, an 18 bit adder, and an 18 bit multiplier are basically needed, and time is needed to calculate it. In other words, there is a time constraint to process these on the system.

According to Equation 1, first, the value of the time stamp is read, and [t, s] within the range is assigned. If there are less than 153 transports in a track, fill the track with dummy (stuffing) data, and if there are more than 153 transport packets (that is, have the same m value) assigned to a track, Moves these packets forward and backward within the range allowed by Equation 1.

The present invention has been made in view of the above-described problems, and includes a track number and a sink designating a place to be recorded on a recording tape according to a value of a time stamp in order to accurately maintain the arrival time of data entering a D-VHS type recorder. Its purpose is to provide a way for the block number to satisfy certain constraints.

1 is a diagram schematically showing the format of MPEG 2 transport stream recording data that can be used in the present invention.

FIG. 2 is a diagram for describing a format of a packet header shown in FIG. 1.

FIG. 3 is a diagram for describing a format of a time stamp shown in FIG. 2.

4 is a flowchart illustrating a track designation method of digital data by time stamps according to an embodiment of the present invention.

In order to achieve the above object, the present invention provides a method comprising: i) reading a track number of a first time stamp and storing the first block with the first time stamp attached thereto; ii) increasing the time stamp value by 1 and reading the track number of the second time stamp by the increased time stamp; iii) determining whether the track number of the second time stamp is the same as the track number of the first time stamp; iv) if the track number of the second time stamp is the same as the track number of the first time stamp, it is determined whether the number of sync blocks stored in the first track is greater than or equal to the limit value, and the track number of the second time stamp. If is different from the track number of the first time stamp, determining whether the number of sync blocks stored in the second track is greater than or equal to the limit value; And iv) a dummy sink block or a sink block to which the leaded second stamp is attached according to whether the number of sink blocks stored in the first track or the second track is greater than or equal to the limit. And storing the second track and returning to step ii).

According to the present invention, a track number and a sync block number for designating a place to be recorded on a recording tape according to a value of a time stamp attached to input digital data in order to accurately maintain the arrival time of data coming into a D-VHS type recorder are restricted. Ensure that the conditions are met.

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

1 shows a format of MPEG 2 transport stream record data that can be used in the present invention. One sync block consists of 112 bytes. MPEG-2 transport packets of 188 bytes and packet header information of 4 bytes are recorded in two sync blocks.

FIG. 2 shows the packet header shown in FIG. The lower 22 bits of the packet header are used for time stamps indicating the input time of the transport packet.

Fig. 3 shows the format of the time stamp shown in Fig. 2. The time stamp is recorded as the sampled value of the local time stamp generator so that it is the input time of the transport packet and the reproduction time interval is exactly equal to the input time. The clock frequency of the local time stamp generator is 27 MHz (± ppm) and is phase-locked to the input reference program clock (PCR) at writing. The default value of the time stamp generated by the local time stamp generator is '0'. The drum rotation phase is synchronized with the value of the local time stamp generator upon recording and playback. The upper 4 bits of the time stamp represent the counted up value every quarter of the drum, which is the number of the track and repeated from 0 to 11 times (mode 12). The lower 18 bits of the time stamp represent the value counted up by the local time stamp generator and repeat from 0 to 224999 (mode 225000; 180 rpm).

Hereinafter, the method of the present invention will be described in detail with reference to FIG. 4. 4 illustrates a method according to an embodiment of the invention.

First, the control unit initializes the counter (step S1).

As shown in Figs. 2 and 3, the control unit reads the upper four bits m of the first time trap of the first transport packet in which the time stamp generator is generated (step S2), and the first transport packet with the time stamp is attached. (transport packet: TP) determines which track to go to and stores the first sync block composed of the first transport packet in the track according to the determination, for example, track '0' (step S3).

In step S4, the controller controls the counter to increase the time stamp value by one (TS → TS + 1), and reads m of the second time stamp attached to the second transport packet (step S5).

It is determined whether m of the second time stamp read in step S5 and m of the first time stamp read in step 2 are the same (step S6).

In step S6, when it is determined that m of the second time stamp and m of the first time stamp are the same, the controller determines whether the number of sync blocks stored in the track '0' is 306 or more (step S7). ).

If it is determined in step S7 that the number of sync blocks stored in the track '0' is 306 or more, the second sync block with the second time stamp is stored in the next track, that is, the track # 1 ', and the flow goes to step S4. To return. However, if it is determined in step S7 that the number of sync blocks stored in the track '0' is less than 306, the second sync block is stored in the track '0' (step S9).

On the other hand, if it is determined in step S6 that m of the second time stamp and m of the first time stamp are different, it is determined whether or not the number of sync blocks stored in the track # 1 is more than 306 (step S10). ).

If it is determined in step S10 that the number of sync blocks stored in the track # 1 'is 306 or more, the second sync block with the second time stamp is stored in the next track, that is, the track # 1' (step S8). ). However, if it is determined in step S10 that the number of sync blocks stored in the track '0' is less than 306, the dummy data is stored in the track '0' until the track '0' is filled with 306 sync blocks and dummy data. (Step S11).

As described above, the present invention provides a track number and sequence for designating a place to be recorded on a recording tape according to a value of a time stamp attached to input digital data in order to accurately maintain the arrival time of data entering a D-VHS type recorder. Allow the number to satisfy certain constraints.

Although this invention was demonstrated concretely by the said Example, this invention is not restrict | limited by this, A deformation | transformation and improvement are possible within the range of common knowledge of a person skilled in the art.

None.

Claims (3)

i) reading the track number of the first time stamp and storing the read first block with the first time stamp attached to the first track; ii) increasing the time stamp value by 1 and reading the track number of the second time stamp by the increased time stamp; iii) determining whether the track number of the second time stamp is the same as the track number of the first time stamp; iv) if the track number of the second time stamp is the same as the track number of the first time stamp, it is determined whether the number of sync blocks stored in the first track is greater than or equal to the limit value, and the track number of the second time stamp. If is different from the track number of the first time stamp, determining whether the number of sync blocks stored in the second track is greater than or equal to the limit value; And iv) the first track, or the first track or the first track or the first block or the sink block to which the lead second stamp is attached according to whether the number of sink blocks stored in the first track or the second track is greater than or equal to a limit value. Storing in two tracks and returning to step ii). The method according to claim 1, wherein in step iv), if the number of sink blocks stored in the first track is greater than or equal to the limit, the sink block with the second lead stamped on the first track is stored in the second track and stored in the first track. And storing the sink block to which the read second stamp is attached to the first track, when the number of sink blocks is less than the limit value. The method according to claim 1, wherein in step iv), if the number of sink blocks stored in the second track is greater than or equal to a limit, the sink block to which the lead second stamp is attached is stored in the second track and stored in the second track. And storing the dummy sync block in the first track if the number of stored sync blocks is less than the limit value.