JP3405344B2 - Information transmission method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to an information transmission method, which prevents illegal copying of digital information transmitted by broadcasting or communication, and is suitable for a copyright owner. The present invention relates to an information transmission method capable of achieving both copyright protection and provision of reproduction information such as various high-quality images. 2. Description of the Related Art As a copy guard technique for preventing infringement of copyright by illegally copying from a recorded recording medium on which information is recorded to another recording medium, digital audio has been developed. As a device capable of digital copying, such as a tape recorder (DAT), a serial copy management system (SCMS) that allows only one copy is known. In the SCMS, copy control is performed using a copy prohibition / permission flag included in the digital voice interface signal. Further, as a copy control method from a recording medium on which a video signal is recorded to another recording medium, copy / copy is performed.
Generation Management System (CGM
S) is known. This CGMS transfers a 2-bit copy generation control signal.
If the 2-bit value is "00", copy recording is permitted. If the value is "10", only one copy is permitted.
If the value is "1", the recording apparatus is configured to prohibit copying. If the value is "10", the value is set to "1".
1 "before recording. In addition, VTRs and DVDs (Digital Versatil
e Disc), each device has a unique ID,
In addition to modifying the video signal using an ID and random number during recording, inserting the random number into the vertical blanking period and recording it, and restoring using the random number and ID read from the vertical blanking period during playback, etc. There is also known a recording / reproducing apparatus in which means such as authentication of a device and exchange of a scramble key are taken (Japanese Patent Application Laid-Open Nos. 61-201586 and 9-83936). [0005] Thus, SCMS
With the use of CGMS, CGMS, and macrovision signals, a device development environment for a recording / reproducing apparatus in consideration of a copyright holder has been prepared. However, some copyright owners are concerned about the possibility of plagiarism by a computer in digital transmission, and are concerned about casual copying by a conventional device in analog transmission. Some copyright owners say that the environment for releasing high-quality prerecorded software is not yet in place. [0006] The present invention has been made in view of the above points,
An object of the present invention is to provide an information transmission method capable of preventing illegal copying more effectively by allowing a copyright holder to specify an output mode of reproduction information. [0007] In order to achieve the above object, the present invention provides: (1) information transmission in which at least video information is multiplexed with transport packets to transmit information constituting a transport stream; In the method, as an analog output signal form of the video information on the receiving device side, only a signal form limited to a predetermined resolution or less lower than the resolution of the video information is allowed to be output, or a signal not subjected to resolution restriction. An information transmission method, characterized in that a 1-bit flag for directly selecting and specifying an output signal form as to whether the form can be output is included in the information and transmitted. Is provided. Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a block diagram of an embodiment of a reproducing apparatus for reproducing information transmitted from a recording medium on which information transmitted is recorded by an embodiment of the information transmission method according to the present invention. This embodiment employs a D-VHS for recording and reproducing video information and audio information in the form of digital signals.
(Registered trademark) will be described as an example. In FIG. 1, a magnetic tape 1 is an embodiment of a recording medium on which information transmitted by one embodiment of an information transmission method according to the present invention is recorded. The digital signal is recorded on a digital signal recording track having a longitudinal direction inclined with respect to the tape longitudinal direction, and output control information OPC described later is also recorded on the digital signal recording track. As shown in FIG. 2, a digital signal recording track formed on the magnetic tape 1 includes a fixed amount of data area called a sync block (SB).
It is configured by arranging a plurality of units according to the scanning of the rotary head. That is, as shown in FIG. 2, the track format of the digital signal recording track is a margin area 21 of 2 sync blocks, a preamble area 22 of 3 sync blocks, and a subcode area 2 of 4 sync blocks.
3, 3 sync block postamble area 24, 3 sync block IBG area 25, 1 sync block preamble area 26, 336 sync block main code area (data area) 27, 2 sync block postamble area 28, and margin And a main code area 27 as an information recording area.
And a subcode area 23. [0010] The margin area 29 is formed by a rotary body to which the rotary head is attached, which is driven by a drum servo for 30 r.
Since it is controlled so as to rotate at ps or 29.97 rps, two sync blocks or 2.356 sync blocks are provided, so that one entire track is composed of 356 sync blocks or 356.356 sync blocks. In any case, the subcode area 23 is set to 4 sync blocks, and the main code area 27 is set to a fixed length of 336 sync blocks. In the main code area 27, for example, each 188-byte packet of a transport stream of MPEG (Moving Picture Experts Group) 2 is recorded in units of two adjacent sync blocks. As shown in FIG. 3, the format of the sync block in the main code area 27 of each of the sync blocks is a two-byte synchronous signal (Sync) area 31 for reproducing the sync block. A byte address information (ID) area 32; a 2-byte main header storage area 33 for storing various information;
A byte data spare area (DATA-AUX) 34;
The data storage area 35 of 96 bytes and the internal parity storage area 36 of 8 bytes for error correction of the information of the sync block are combined in a time series to form a total of 112 bytes. The last 9 out of 99 bytes in the data area
6 bytes are a data storage area 35 for information, and a main header storage area 33 and a data spare area 34 of the previous 3 bytes.
Is an information recording area for the system that cannot be rewritten by the user. In the main header storage area 33, as shown in FIG. 4, format information is allocated to the upper 4 bits of the first byte, and sync block information is allocated to the remaining lower 4 bits and the second byte, which is a total of 12 bits. I have. In FIG. 4, the “format ID” is
The “application detail” indicates whether the track format is a normal mode recording or another mode recording. The “application detail” indicates whether the recording digital signal is an MPEG2 transport packet having a packet size of 188 bytes or a packet size of 140 bytes. Information identifying whether the packet is of another transmission method,
“Time compression ratio” is information indicating a compression rate. Furthermore,
“D.T.” is 2-bit data type information for identifying MPEG packets, dummy data, or trick play data, and “SBC” indicates two sync blocks adjacent to the packet. When recorded as a unit, this is sync block counter information for identifying whether the sync block having the main header is the first or second of two adjacent sync blocks. The recording tracks of the magnetic tape 1 reproduced by this embodiment are output to the 2-byte main header storage area 33 shown in FIG. 3 together with the CGMS in each sync block of the main code area 27 shown in FIG. Control information OPC is recorded. Specifically, FIG.
As shown in the figure, of the main headers repeatedly recorded in the main header storage area 33 in units of 12 sync blocks and two bytes each, the main header recorded in the main header storage area 33 of the eleventh sync block in one cycle is The upper two bits are assigned to a copy generation control signal defined by the CGMS, and two bits from the upper third bit to the fourth bit of the main header recorded in the main header storage area 33 of the twelfth sync block in one cycle. Is assigned to the output control information OPC. In the 2-bit output control information OPC, the first bit indicates digital output permission information. The value "0" indicates permission, and the value "1" indicates disabling. The second bit of the output control information OPC indicates an analog output form. A value of “0” indicates only NTSC composite video signal output, and a value of “1” indicates that component output is possible.
As described above, the copy generation control signal defined by the CGMS permits copying (dubbing recording) when the 2-bit value is "00", and performs only one copy (dubbing recording) when the value is "10". And "11" indicates that copying (dubbing recording) is prohibited. Next, returning to FIG. 1, two rotating heads 2 (typically shown in FIG. 1) which are attached to the rotating surface of a rotating body (not shown) so as to face each other by 180 degrees and have different azimuth angles. (Only one is shown), the digital signal reproduced from the recording track of the magnetic tape 1 running at a constant speed while being wound obliquely over the outer surface of the rotator over an angle range of about 180 degrees After the signal is amplified by the equalizer 4 and given a predetermined equalizing characteristic by the equalizer 4, it is demodulated by the demodulator 5 and reproduced by the ECC circuit 6 from the internal parity area 36 and the main code area 27. ) Is used to correct the data reproduced from the data area 35. Thus, the MPEG-2 transport stream extracted from the ECC circuit 6 is supplied to a digital interface (DI / F) 7 while the MP2
It is supplied to the EG decoder 8 and decoded. Also, ECC
The control information from the main header area 33 extracted from the circuit 6 is supplied to an output control circuit 9 by a microcomputer, where various controls are performed, and the first bit of the output control information OPC is set to "0". When the first bit is "1", the input MPEG2 transport stream is output, and when the first bit is "1", the DI / F7 is disabled and the input MPEG2 transport stream is output. Prohibit port stream output. When the second bit of the output control information OPC is "0", the output control circuit 9 turns off the switch circuit 11 and the MPEG decoder 8
Prohibits the output of analog component signals from.
On the other hand, when the second bit of the output control information OPC is “1”, the switch circuit 11 is turned on, and
The analog component signal from the EG decoder 8 is
Output through the switch circuit 11. The analog component signal from the MPEG decoder 8 is supplied to an NTSC encoder 10, where it is converted into an NTSC color video signal, that is, an analog composite signal, and then output. Therefore, when the second bit of the output control information OPC is “1”, both the output of the analog component signal from the MPEG decoder 8 and the output of the analog composite signal from the NTSC encoder 10 are permitted. If the information recorded on the magnetic tape 1 is a high-definition HD signal, when the second bit of the output control information OPC is "0", the down-converted NTSC composite signal is output. Only N
It is output from the TSC encoder 10, and when “1”, MP
HD component signal from EG decoder 8 and NT
An NTSC composite signal from the SC encoder 10 is output. Regarding the control operation of the copy generation control signal defined by the CGMS in the reproducing apparatus, the applicant of the present invention has previously described Japanese Patent Application Nos. 11-101178 and 11-31.
No. 9955, etc., and has no direct relation to the gist of the present invention, and therefore, detailed description thereof will be omitted. As described above, in this embodiment, the output control information OPC allows the output mode to be selected according to the intention of the copyright holder, so that the copyright can be protected more effectively. Also, copyright holders with different intentions can use the same software in the same format and the same playback device, so that various high-quality images can be enjoyed. Next, another embodiment will be described. In the above embodiment, the main header area 33 of the track is used.
In the embodiment, the output control information OPC and the copy generation control signal defined by the CGMS are arranged and recorded. However, in this embodiment, the known MPEG2 transport stream shown in FIG. This is to record and reproduce at least the output control information OPC in the payload 40 in the transport packet shown in (B). That is, after converting the transport packet into a signal of a sync block unit of a predetermined format, a digital signal modulated by a predetermined method (for example, NRZI) is generated, and the digital signal is converted on a magnetic tape using a rotary head. Is recorded in the main code area 27 of the track No. 2, and the magnetic tape is reproduced. In this case, it is a matter of course to record some information for identifying the output control information OPC, not the data, on the playback device side. Although the above embodiment has been described by taking a digital VTR as an example, the present invention is not limited to this, and it is needless to say that the present invention can be applied to an apparatus for reproducing a recording medium other than an optical disk and other magnetic tapes. May be a transmission path. Regardless of whether the transmission path is wireless or wired, the present invention is also applicable to a method of transmitting a signal (that is, transmission data) itself transmitted to a computer or other device in a signal form as shown in FIGS. . So, next,
An embodiment of a receiving apparatus for receiving and reproducing an information signal (transmission data) transmitted on a digital broadcast transmission path or the like, which is an information signal transmitted by one embodiment of the information transmission method according to the present invention, is shown in FIG. 6 and FIG. In most cases, video signals and audio signals transmitted by digital broadcasting or the like are transmitted using the above-described transport stream structure together with various information descriptors. The output control information OPC in the present invention can be transmitted using a transmission path such as a broadcast by transmitting the output control information OPC included in a payload in a transport packet constituting an MPEG2 transport stream. In this embodiment, transmission data in which the output control information OPC is multiplexed is received in various information descriptor areas in a payload as a signal form that is easy to handle in digital broadcasting or the like. MP
In the definition of the EG2 transport stream, a private descriptor that can be used by a business entity and the like is defined along with some essential descriptors such as identification information. This private descriptor is, for example, a PMT (Pr) of the MPEG2 transport stream shown in FIG.
(descriptor) is transmitted in the area shown in FIG. In FIG. 7 and FIG. 7 described later, bslbf is
Unimsbf means transmitting in order from the left bit, and unimsbf means transmitting in order from MSB. Also, rpchof
(remainder # polynomial # coefficients # highest # order # f
ast) means that the coefficients generated by the generator polynomial of the error correction code CRC are transmitted in descending order. Note that P
The description of the syntax of MT is not directly related to the gist of the present invention, and is described in the literature (ISO / IEC 13818-1 / ITU-T Rec.
H.222.0: 1996 (Information technology-Genericcoding
of moving pictures and associated audio informatio
n Part 1: Systems.))
Here, it is omitted. FIG. 7 shows the syntax of the OPC descriptor for transmitting the output control information OPC in this embodiment. In the drawing, a descriptor tag (descriptor_tag) is information specified by 8 bits in a syntax defined by MPEG, which specifies the type of the descriptor. Descriptor length (descript
or # length) indicates the length of the descriptor after this field in 8 bits. In addition, a digital output control flag (digital
#output_control_flag) is composed of 1 bit, and the value “0” indicates permission, and “1” indicates disabling. The system info loop length (s
ystem_info_loop_length) indicates that system IDs are transmitted by the number of loop lengths. In addition, the analog output control flag (analog # output # control
#flag) is composed of 1 bit and indicates an analog output form. A value of “0” indicates only NTSC composite video signal output, and a value of “1” indicates that component output is possible. The system identifier (system # i
dentifier) describes a system in which digital output is permitted in 8 bits. The 8-bit 256-state 0x01 indicates, for example, an IEEE1394 system, 0x02 indicates another system A, and 0x03 indicates another system. B is set as shown. IEEE 1394
When only a system-defined digital signal (hereinafter referred to as a 1394 digital signal) can be output, the system info loop length (system_info_loop_length) is set to “1”.
And an 8-bit system identifier (syste
Only one system identification signal of 0x01 is described in m_identifier and transmitted. The configuration of the receiving apparatus of this embodiment has a known receiving section for digital broadcasting signals instead of, for example, the magnetic tape 1, the rotary head 2 and the head amplifier 3 shown in FIG. This can be realized by a configuration in which a channel is selected and down-converted to a baseband signal of a desired broadcast station. The output control information OP
C is not limited to 2 bits, but may be a plurality of bits of 3 bits or more. In addition, if a unique definition is not made one bit at a time, but is 4 bits, for example, “0000” to “1”
In the 16 states of “111”, the output form, for example, “000”
"0" indicates that a 1394 digital signal can be output and an analog component signal can be output.
94 digital signal cannot be output and analog component signal can be output. "0010" can output 1394 digital signal and cannot output analog component signal. "0011" can output 1394 digital signal and cannot output HD analog signal. It may be as follows. Further, in the above-described embodiment, the selection of the output of the video information has been described. However, the selection of the output of the audio information, for example, the digital audio signal of 16 bits or more at a sampling frequency of 48 kHz or less. May be arranged in the main header area 33 or the like. As described above, according to the present invention,
In the receiving device that receives and reproduces the transmission information, when outputting the transmission information as one or more signal forms, the signal form output by the receiving apparatus can be specified based on the above flag input together with the transmission information, Output processing can be performed in a signal form intended by the copyright holder of the transmission information. Therefore, the copyright holder having a different intention in the output signal form can use the recording software by the same format and the same reproducing device, and receive and reproduce the broadcast signal on the same receiving device. It is possible to achieve both appropriate copyright protection according to the intention and provision of reproduction information such as various high-quality images, which is extremely useful in industry.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an embodiment of a reproducing apparatus for reproducing information transmitted from a recording medium in which information transmitted according to an embodiment of the information transmission method according to the present invention is recorded. is there. FIG. 2 is an explanatory diagram of an example of a format of a recording track of a magnetic tape in FIG. 1; FIG. 3 is an explanatory diagram of an example of a format of a sync block in a main code area in FIG. 2; 4 is a diagram showing that a flag for selecting and specifying an output signal form of video information is arranged in a main header in FIG. 3; FIG. 5 is a diagram showing a format of an example of a transmission signal in an embodiment of the information transmission method according to the present invention. FIG. 6 is a diagram illustrating a PMT syntax defined by the MPEG system. FIG. 7 is a diagram illustrating the syntax of an OPC descriptor transmitted in the present invention. [Description of Signs] 1 Magnetic tape 2 Rotating head 6 ECC circuit 7 Digital interface circuit (DI / F) 8 MPEG decoder 9 Output control circuit 10 NTSC encoder 11 Switch circuit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-9-214845 (JP, A) JP-A-9-163306 (JP, A) JP-A-7-235131 (JP, A) JP-A 8- 98205 (JP, A) JP-A-11-275513 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04N 5/91-5/956

Claims (1)

(57) In the information transmission method of Patent Claims 1, wherein at least video information transmitting information constituting a transport stream are multiplexed in the transport packet, the analog of the video information at the receiving apparatus side An output signal form as to whether only the signal form limited to a predetermined resolution lower than the resolution of the video information is allowed to be output or the signal form without limiting the resolution is allowed to be output. One for direct selection of
Information transmission method characterized by Tsu bets flags transmitted included in the information.