JPH09219852A - Time difference signal sending device and its receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize time difference sending effectively utilizing the channel. SOLUTION: A recording time series signal obtained by mutually setting and assembling the same unit time series block signals obtained by n-dividing the time series signal of the same program and furthermore n-dividing it by n-dividing unit in a recording medium. Then at the time of broadcasting the program of 120min by using four channels a compressed time difference signal read by quadruple speed itself is sent to a communication line, and a reception side separate-processes a multiplexed time difference signal to obtain the time difference signal for four channels. At the time of four-channel multiplexing, the same program is broadcasted from its start at the interval of 120/4=30min. Consequently a desired program can be watched from its start after waiting 30min. As the portion of four channels are multiplex-transmitted, the communication line is effectively utilized to multi-channel-transmit plural programs.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a time difference signal transmission device and a reception device thereof suitable for application to a Video On Demand) system and the like. For more information,
By compressing and transmitting m programs for n channels, the time series signals of the same program are compressed to 1 / n and transmitted so that the same program can be viewed from the beginning at m / n minute intervals. This is a signal for transmitting the time difference signal with a channel selection identification signal, so that the playback channel can be specified on the receiving side, and the transmission channel can be effectively used by compression transmission. is there.
Then, by selecting one of the n channels, m
The transmitted program can be viewed from the beginning at an interval of / n minutes.

[0002]

2. Description of the Related Art NVOD broadcasting, which has recently attracted attention as a form of broadcasting service, is a simple system of VOD (Video On Demand), and is used when a same program having a length of m is reproduced on an n channel on a receiving side. Is a time difference program transmission system in which the transmission side transmits the same program at an interval of m / n minutes so that the same program can be viewed with a time difference of m / n. As a result of the same program being broadcast with a time difference of m / n, the viewer can enjoy the program from the beginning by waiting for m / n.

Of such simple DOV systems, the program sending side may have a configuration as shown in FIG. In the time difference signal transmitting apparatus 10 shown in the figure, the recording medium 12 records time series signals constituting a plurality of programs to be transmitted. When the broadcast channel is a program having n channels and a length of m minutes, the time-series signals are multiplexed and recorded so that the same program is broadcast every m / n minutes. The multiplexed time series signal reproduced from the recording medium 12 is supplied to the fixed-rate compression means 16 via the interface 14, and the multiplexed time series signal is compressed at the fixed rate.
This is because the compression process cuts off information such as fast moving parts.

The multiplexed time-series signal is separated into n channels by the demultiplexing means 18, the separated time-series signal is returned to the original by the decompression means 20, and then sent to the transmitter (not shown). It is supplied and sent as a time difference signal. As the communication line for the time difference signal, a communication line using terrestrial waves, satellite waves, cable waves, etc. is used.

[0005]

By the way, in the conventional time difference signal transmitting apparatus 10 as shown in FIG. 10, since the time series signal (compressed data) compressed on the signal transmitting side is expanded, The time difference signal for n channels requires transmission channels for n channels. As a result, the communication line cannot be effectively used, and as a result, the number of NDOV transmission channels cannot be increased. Further, since the sending side must perform compression / expansion processing, the sending device 10
However, there is a problem that the cost becomes very high.

Therefore, the present invention solves such a conventional problem, and it is possible to effectively utilize the number of channels of a communication line and to reduce the cost of the transmitting device and the time difference signal transmitting device. A receiver is proposed.

[0007]

In order to solve the above-mentioned problems, a transmitting apparatus according to the present invention converts a program for m minutes into n channels and compresses and transmits the same program at an interval of m / n minutes. In order to be viewed from, the time series signal of the same program is divided into n to generate a divided time series signal,
Each of the n-divided time-series signals is further divided into n'to form a unit time-series block signal, and the recording time-series signals assembled by collecting the same unit time-series block signals in n'division units are used as time difference signals. The recording time series signal recorded on a recording medium and reproduced at n-times speed from this recording medium is added with an identification signal for channel selection and is transmitted using a single channel.

Further, the time difference signal receiving apparatus according to the present invention makes it possible to view the same program from the beginning at m / n minute intervals by converting the m time program into n channels and reproducing the compressed time difference signal. In the time difference signal receiving device, when the time difference signal sent with the identification signal for channel selection attached and compressed to 1 / n is received, the time difference multiplexed by designating the identification signal for channel selection is received. From the signal, only the compression time difference signal corresponding to the designated channel is sequentially separated, and the separated compression time difference signal is expanded / demodulated in the order of the time series to obtain m.
The feature is that the same program can be viewed from the beginning at an interval of / n minutes.

According to the present invention, the time series signals of the same program are
Division is performed to generate a division time series signal. Each time-series signal divided into n is further divided into n'to obtain a unit time-series block signal. A recording time-series signal assembled by collecting the same unit time-series block signals in n'division units is recorded as a time difference signal on a recording medium. An identification signal for channel selection is attached to a recording time-series signal reproduced at n times speed from a recording medium, and the signal is transmitted in a single channel.

For example, when reproducing a 120-minute broadcast program using four channels, the compressed time difference signal itself read out at quadruple speed is sent to the communication line, and the receiving side separates the multiplexed time difference signal. Processing is performed to obtain time difference signals for four channels. On the receiving side, the channel broadcast from the beginning of the program is selected. In the case of 4-channel multiplexing, the same program is broadcast from the beginning at 120/4 = 30 minute intervals. Therefore, if you wait 30 minutes, you can watch the desired program from the beginning. The user selects such a channel.

Since the four channels are multiplexed and transmitted as described above, the communication line can be effectively used, and a plurality of programs can be transmitted on multiple channels. Since the demultiplexing process is placed on the receiving side, the program sending system can be simplified.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an example of a time difference signal transmitting apparatus and its receiving apparatus according to the present invention will be described in detail with reference to the drawings.

In the present invention, an example in which a 120 minute broadcast program can be viewed using 4 channels as shown in FIG. 3 will be described as a case where an mDO broadcast program is NDOV broadcast using the n channel.

In the case of using 120 minutes / 4 channels, the time series signals of the same program are divided into four (n = 4) to generate the divided time series signals A, B, C and D. S1, the contents of them
Let S2, S3 and S4. 4 channels (p, q,
To reproduce in r, s), when the reproduction time-series signal in the p channel is the same as shown in FIG. 4 (1), as shown in FIG. (= M /
n) The same program is broadcast with a delay.

In the r channel, the same program is broadcast at time t2 which is delayed by 30 minutes as shown in FIG. 3C, and the program is broadcast from the s channel at time t3 which is delayed by 30 minutes. In this way, at the time points t1, t4, ..., By viewing the broadcast program from the beginning by selecting the channel p, similarly, by selecting the channel q at the time points t2, t5 ,. t6, ...
Now by selecting channel r and at time t
, T7, ... By selecting the channel s, the same broadcast program can be viewed from the beginning.
This realizes simple DOV broadcasting.

In order to realize such a time difference broadcasting NDOV system using a single channel, the four time-divided time series signals A, B, C and D are further divided into 4 (= n '). A unit time series block signal Ai, B shown in FIG.
i, Ci, Di (i = 0, 1, 2, 3). The time width is 30/4 minutes. The number of divisions n ′ is merely for convenience and differs from the actual number of divisions.

Next, the same unit time-series block signals are assembled by n'division unit and assembled to generate the recording time-series signal shown in FIG. 5B. This is recorded on the recording medium as a time difference signal.

A recording time-series signal is read out from the recording medium at n times speed. In this way, the program for m can be read in the time of 1 / n = 1/4, so that another channel q is used at the timing of reproducing the divided time series signal B whose time axis is expanded on the receiving side. It is possible to reproduce the divided time series signal A whose time axis is expanded. Similarly, at the timing of reproducing the divided time series signal C whose time axis is expanded using the channel p,
The divided time series signal A whose time axis is expanded by using another channel r is further divided time series signal D (for channel p)
The divided time series signal A can be reproduced from the channel s at the reproduction timing of.

Next, an example of encoding and decoding of such a time difference signal will be described with reference to FIG. The above-mentioned processing is performed by the packetized time difference signal.
FIG. 6A shows a packet configuration example, and FIG. 6B shows a simplified model of a recording format (recording time series signal).

A time-series signal (video / audio signal) of a program is packetized in units of several hundred bytes. One packet has an S for identifying the beginning of the packet at the beginning thereof.
Control data such as YNC bytes, a packet ID for indicating data connection, and a clock reference for defining a transfer rate when transferring from the transmitting side to the receiving side are inserted, and then a compressed data sequence of video and audio is inserted. Continue.

FIG. 6B shows a signal sequence (divided time-series signal) in which a 120-minute time-series signal is compressed and packetized. This one
The compressed data of 20 minutes is further divided into unit blocks for simplification to form unit time series block signals of A0 to D3.

The unit time-series block signal is a recording time-series signal by collecting the same blocks as shown in FIG. At this time, for the same unit time series block signal, the same packet ID is used as the same time series holding identification signal.
Is given.

For example, the unit time series block signal Ai (A
0, A1, A2, A3) has ID0, and unit time series block signals Bi (B0, B1, B2, B3) have ID1.
However, it seems that they are applied to each.

This is because the unit time-series block signals are aligned and recorded as a time difference signal. Therefore, if the time-series holding identification signal is not added, the original time-series signal cannot be restored. Because. Further, as will be described later, the packet ID at the time of signal transmission is changed to another identification signal (identification signal for channel selection, IDp, IDq, IDr,
This is to simplify the change process when changing to (IDs).

In the state of FIG. 6C, it is recorded on the recording medium as an NDOV transmission time difference signal.

When the time difference signal is transmitted, as shown in FIG. 7D,
This time difference signal is read from the recording medium at n times speed (4 times speed in this example), and the packet ID of the read time difference signal is changed to the reception channel selection identification signal as shown in FIG.

In this example, it is assumed that the broadcast program is reproduced by using four reception channels of p, q, r, and s for the sake of convenience. Therefore, the unit time series block signal Ai (A0,
A1, A2, A3) packet ID0 is IDp, unit time series block signal Bi (B0, B1, B2, B3) packet ID1 is IDq, ID2 is IDr, and I
D3 is changed to IDs.

The packet ID for specifying the channel
When the same broadcast program makes a round, its value is sequentially p → s →
Shifted like q → r. For example, as shown in FIG. 7E, in the second round, ID0 is IDs, ID1 is IDs, and ID1 is IDs.
2 is changed to IDq and ID3 is changed to IDp.

By doing this, the same packet ID
The compressed data of packets (unit time-series blocks) that have is continuous. For example, when the channel p is selected, the unit time series block signal with the packet ID p is
As shown in FIG. 7F, A0, A1, A2, A3, B0, B1, B2, B3, C
Since 0, C1, C2, C3, D0, D1, D2 and D3 are separated in this order, if they are decompressed and reproduced, the continuous original time-series signal ('is shown as shown in FIG. :
6B) is obtained.

When the q channel is reproduced instead of the p channel, the time difference signal of FIG. However, the same program cannot be viewed from the beginning on this q channel. This is because the same program is being broadcast from the beginning on the p-channel side at the same time. Therefore, based on 0 minutes, from 0 minutes for the p channel, 30 minutes after the q channel, 60 minutes after the r channel, and 9 minutes for the s channel.
The same program will start from 0 minutes later.

FIG. 1 shows a specific example of the sending device 10 for realizing such an NVOD system. As the recording medium 12 for recording the compressed time difference signal (FIG. 6C) in which n channels are multiplexed, a large-capacity and fast-access recording medium such as a hard disk or a magneto-optical disk is used.

For the access to the recording medium 12, a command is issued from the control unit 26 having a CPU configuration. Recording medium 12
The compressed time difference signal is read out at 4 × speed and is supplied to the packet ID changing means 22 via the interface 14. In this changing means 22, a process of changing the ID to the identification signal for channel selection is executed. It is assumed that the number of rounds of the compression time difference signal is included in the ID change information provided from the control unit 26. The compressed time difference signal after the ID change is processed by the transfer rate adjusting means 24 at an appropriate transfer rate (variable length) according to the amount of compressed information. After that, it is transmitted to the communication line using the transmitter.

The n-channel multiplexed compressed time difference signal sent from the sending device 10 in FIG. 1 is received by the receiving device 30 in FIG. The compressed time difference signal is supplied to the terminal 32, which is supplied to the demultiplexing means 34, and the channels to be separated are designated based on the channel selection signal supplied from the operating section 36 side.

The demultiplexing means 34 demultiplexes and outputs only the packet data having the same channel selection packet ID as the designated channel number. For example, when the p channel is selected, the unit time series block signal with IDp as shown in FIG. 7F is separated and output.

The separated unit time-series block signal is decompressed by the decompression means 38 to decompress the compressed data into data having the original time axis (FIG. 7G), and the decompressed time difference signal causes the monitor 40 to display an image or The sound is reproduced.

FIG. 8 and FIG. 9 are flowcharts showing an example of the above-mentioned ID changing process. Packet IDs are fetched one by one from the recording medium, and the fetched packet I is fetched.
D is changed to the channel selection ID (step 51,
52, 53). When the compressed time difference signal makes one round, the packet IDs are fetched one by one again from the recording medium, and the fetched packet IDs are changed to the channel selection IDs for the second round (steps 54, 55, 56). At the third round, the channel selection ID for the third round is changed by the processing shown in steps 57 and 58 of FIG. 9, and the channel selection for the fourth round is performed at the corresponding steps 59, 60, and 61 for the fourth round. For I
D, and when this has elapsed, the process returns to step 51 in FIG. This continues until the end of program transmission.

In the above-mentioned example, the case of 120-minute 4-channel reproduction has been illustrated, but this is for convenience only and is not limited to the above example.

[0038]

As described above, according to the present invention, since the compressed time difference signal in which n channels are multiplexed is transmitted, the communication line can be effectively used and, as a result, a plurality of communication lines can be used. Programs can be transmitted on multiple channels.

Since the compressed time difference signal is packetized in units of several hundreds of bytes, a small buffer amount is required for the interface, and therefore the sending device itself has a feature that it can be greatly simplified as compared with the prior art. Since the data expansion means is not provided on the sending device side, the device can be simplified accordingly. Since the time difference transmission can be realized only by changing the identification signal for holding the time series on the transmission side, the time difference transmission system can be simplified. Therefore, this invention is NDO
It is very suitable when applied to a V system.

[Brief description of drawings]

FIG. 1 is a system diagram of essential parts showing an embodiment of a time difference signal transmitting apparatus according to the present invention.

FIG. 2 is a system diagram of essential parts showing an embodiment of the time difference signal receiving apparatus according to the present invention.

FIG. 3 is an explanatory diagram showing a time series signal of a program.

FIG. 4 is an explanatory diagram showing an example of time difference reproduction in the case of 4-channel reproduction.

FIG. 5 is an explanatory diagram showing time-series states of compressed time difference signals before and after recording on a recording medium.

FIG. 6 is an explanatory diagram showing a time difference transmission example (1/2).

FIG. 7 is an explanatory diagram showing a time difference transmission example (2/2).

FIG. 8 is a diagram showing a flowchart (1/2) for changing an ID.

FIG. 9 is a diagram showing a flowchart (2/2) for changing an ID.

FIG. 10 is a system diagram showing an example of a conventional time difference signal transmission device.

[Explanation of symbols]

10 ... Time difference signal sending device, 12 ... Recording medium, 2
2 ... Packet ID changing means, 24 ... Transfer rate adjusting means, 26 ... Control unit, 30 ... Receiving device, 3
4 ... Multiplexing / separating means, 38 ... Expanding means

[Procedure amendment]

[Submission date] July 26, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction contents]

In such a simple VOD system, the program sending side may have a configuration as shown in FIG. In the time difference signal transmitting apparatus 10 shown in the figure, the recording medium 12 records time series signals constituting a plurality of programs to be transmitted. When the broadcast channel is a program having n channels and a length of m minutes, the time-series signals are multiplexed and recorded so that the same program is broadcast every m / n minutes. The multiplexed time series signal reproduced from the recording medium 12 is supplied to the fixed-rate compression means 16 via the interface 14, and the multiplexed time series signal is compressed at the fixed rate.
This is because the compression process cuts off information such as fast moving parts.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction contents]

[0005]

By the way, in the conventional time difference signal transmitting apparatus 10 as shown in FIG. 10, since the time series signal (compressed data) compressed on the signal transmitting side is expanded, The time difference signal for n channels requires transmission channels for n channels. As a result, the communication line cannot be effectively used, and as a result, the number of NVOD transmission channels cannot be increased. Further, since the sending side must perform compression / expansion processing, the sending device 10
However, there is a problem that the cost becomes very high.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction contents]

In the present invention, an example in which a program of 120 minutes broadcast can be viewed using 4 channels, as shown in FIG. 3, will be described as a case where a broadcast program of m minutes is NVOD broadcast using n channels.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction contents]

In the r channel, the same program is broadcast at time t2 which is delayed by 30 minutes as shown in FIG. 3C, and the program is broadcast from the s channel at time t3 which is delayed by 30 minutes. In this way, at the time points t1, t5, ..., It is possible to watch from the beginning of the broadcast program by selecting the channel p, and similarly, at the time points t2, t6 ,. t7, ...
Now by selecting channel r and at time t
At 4, t8, ..., By selecting the channel s, the same broadcast program can be viewed from the beginning.
This realizes simple VOD broadcasting.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction contents]

In order to realize such a time difference broadcasting NVOD system using a single channel, each of the four time-sequential signals A, B, C, and D is further divided into 4 (= n '). A unit time series block signal Ai, B shown in FIG.
i, Ci, Di (i = 0, 1, 2, 3). The time width is 30/4 minutes. The number of divisions n ′ is merely for convenience and differs from the actual number of divisions.

[Procedure correction 6]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction contents]

In the state of FIG. 3C, the time difference signal for NVOD transmission is recorded on the recording medium.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0039

[Correction method] Change

[Correction contents]

Since the compressed time difference signal is packetized in units of several hundreds of bytes, a small buffer amount is required for the interface, and therefore the sending device itself has a feature that it can be greatly simplified as compared with the prior art. Since the data expansion means is not provided on the sending device side, the device can be simplified accordingly. Since the time difference transmission can be realized only by changing the identification signal for holding the time series on the transmission side, the time difference transmission system can be simplified. Therefore, this invention is NVO
It is very suitable when applied to the D system.

Claims (6)

[Claims] 1. A time-series signal of the same program is divided into n so that the same program can be viewed from the beginning at m / n-minute intervals by compressing and transmitting m-number of programs into n channels and dividing time series. A signal is generated, and each time-series signal divided into n is further divided into n'to form a unit time-series block signal, and recording is performed by assembling the same unit time-series block signals into n'division units. A sequence signal is recorded on a recording medium as a time difference signal, and the recording time-series signal reproduced at n times speed from this recording medium is attached with an identification signal for channel selection and transmitted using a single channel. A time difference signal transmitting device characterized by: 2. The unit time-series block signals are provided with a time-series holding identification signal for ensuring time-series continuity of the same program, and at the time of time difference transmission, the time-series holding identification signal is applied to the channel. 2. The time difference signal sending device according to claim 1, wherein the time difference signal sending device is adapted to be sent after being converted into a selection identifying signal. 3. The time difference signal transmitting apparatus according to claim 1, wherein the channel selection identification signal is sequentially changed every time a time series signal of the same program makes a cycle. 4. The time difference signal transmitting device according to claim 1, wherein the identification signal for holding the time series is an identification signal for packet when the time series signal is packetized. 5. A time difference signal receiving apparatus in which the same program can be viewed from the beginning at m / n minute intervals by reproducing a compressed time difference signal by converting m time programs into n channels and selecting a channel. When receiving the time difference signal which is sent with the identification signal for use and compressed to 1 / n, it corresponds to the specified channel from the time difference signal multiplexed by specifying the identification signal for channel selection. It is characterized in that only the compressed time difference signal is sequentially separated, and the separated compressed time difference signal is expanded and demodulated in the order of the time series so that the same program can be viewed from the beginning at m / n minute intervals. Time difference signal receiving device. 6. The time difference signal receiving apparatus according to claim 5, wherein the transmission program can be viewed from the beginning by selecting the channel selection identification signal.