# US 6,295,407 B1 · Digital video copy protection system

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- Number: US 6,295,407 B1
- Document ID: US6295407B1
- Status: Granted
- Kind: B1
- Application number: 09/630,265
- Filed: 2000-08-01
- Granted: 2001-09-25
- Earliest claimed: 1995-09-01
- Assignees: Sony Corporation
- Inventors: Katsumi Tahara; Hideki Koyanagi; Yoichi Yagasaki; Yasushi Fujinami
- Web page: https://patentgrep.com/patent/US6295407B1

## CPC

- H04N 1/32149: {Methods relating to embedding, encoding, decoding, detection or retrieval operations}
- H04N 5/913: for scrambling {; for copy protection}
- H04N 21/2541: {Rights Management (protecting software against unauthorised usage in a vending or licensing environment G06F21/10; security in data switching network management H04L41/28; security management or policies for network security H04L63/20; access security in wireless networks H04W12/08)}
- H04N 21/4334: {Recording operations (recording of a television signal H04N5/76; arrangements for recording or accumulating broadcast information or broadcast-related information H04H60/27)}
- H04N 21/4627: Rights management {associated to the content (security in data switching network management H04L41/28; security management or policies for network security H04L63/20; access security in wireless networks H04W12/08)}
- H04N 21/835: Generation of protective data, e.g. certificates {(protecting software against unauthorised usage in a vending or licensing environment G06F21/10)}
- H04N 21/8355: involving usage data, e.g. number of copies or viewings allowed
- H04N 21/8358: involving watermark {(protecting executable software by watermarking G06F21/16; image watermarking in general G06T1/0021; watermarks inserted in still images for transmission purposes H04N1/32144; inserting watermarks during video coding H04N19/467)}
- H04N 5/9264: {using transform coding}
- H04N 2005/91321: {the copy protection signal being a copy protection control signal, e.g. a record inhibit signal}
- H04N 2005/91328: {the copy protection signal being a copy management signal, e.g. a copy generation management signal [CGMS]}
- H04N 2005/91335: {the copy protection signal being a watermark}
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

A formatting apparatus authenticates an information signal prior to mass duplication of the signal by analyzing the signal to detect the presence or absence of a security signal therein, inserting a security signal into the information signal, and recording the modified signal only if no security signal was detected.

## Claims

### Claim 1

Apparatus for recording data onto a storage medium, comprising:
detection means for detecting a region of user data within a bit stream of data to be recorded, said bit stream being in the MPEG standard format, and said region being a region of fixed length codes; and
insertion means for inserting copy protection key data into at least part of said region for the purpose of inhibiting unauthorized copying of data recorded onto said storage medium.

### Claim 2

A storage medium readable by a player, said storage medium having recorded thereon a player readable signal that includes a bit stream, a portion of said bit stream being allocated for user data in the form of fixed length codes, and said portion having inserted therein key data for the purpose of inhibiting unauthorized copying of said signal.

### Claim 3

Apparatus for encoding a moving picture signal, comprising:
quantizing means for quantizing said moving picture signal and thereby generating quantized data;
designating means for designating a portion of said quantized data;
insertion means for inserting key data into said designated portion of said quantized data to thereby produce modified quantized data; and
variable length coding means for performing variable length coding on said modified quantized data and generating a bit stream, said variable length coding means coding said designated portion of said quantized data as an escape code, and said escape code being a fixed length code.

### Claim 4 (depends on 3)

Apparatus according to claim 3, wherein:
said bit stream is an MPEG standard bit stream; and
said designated portion of said quantized data corresponds to a DCT coefficient of a predetermined block, said predetermined block corresponding to a predetermined picture which belongs to a predetermined group of pictures (GOP).

### Claim 5 (depends on 4)

Apparatus according to claim 4, wherein said predetermined picture is an MPEG standard B picture.

### Claim 6

A method for recording data onto a storage medium, comprising the steps of:
detecting a region of user data within a bit stream of data to be recorded, said bit stream being in the MPEG standard format, and said region being a region of fixed length codes; and
inserting copy protection key data into at least part of said region for the purpose of inhibiting unauthorized copying of data recorded onto said storage medium.

### Claim 7

A method for generating a player readable signal to be stored or a player readable storage medium, comprising the steps of:
generating a bit stream;
allocating a portion of said bit stream for user data in the form of fixed length codes; and
inserting key data into said allocated portion for the purpose of inhibiting unauthorized copying of said player readable signal.

### Claim 8

A method for encoding a moving picture signal, comprising the steps of:
quantizing said moving picture signal and thereby generating quantized data;
designating a portion of said quantized data;
inserting key data into said designated portion of said quantized data to thereby produce modified quantized data; and
variable length coding said modified quantized data and thereby generating a bit stream, said designated portion of said quantized data being coded as an escape code, and said escape code being a fixed length code.

### Claim 9 (depends on 8)

The method according to claim 8, wherein:
said bit stream is an MPEG standard bit stream; and
said designated portion of said quantized data corresponds to a DCT coefficient of a predetermined block, said predetermined block corresponding to a predetermined picture which belongs to a predetermined group of pictures (GOP).

### Claim 10 (depends on 9)

The method according to claim 9, wherein said predetermined picture is an MPEG standard B picture.

### Claim 11

Apparatus for recording data onto a storage medium, comprising:
quantizing means for quantizing data;
coding means for coding a portion of the quantized data into variable length coding data and a residual portion of the quantized data into a fixed length code; and
designating means for selecting a portion of the fixed length code and designing the selection portion as an area for recording copy protection key data;
wherein the coding means codes the designated portion of the fixed length code into an escape code.

### Claim 12 (depends on 11)

Apparatus according to claim 11, wherein the escape code includes an identification code that indicates escape code.

### Claim 13

Method for recording data onto a storage medium, comprising the steps of:
quantizing data;
coding a portion of the quantized data into variable length coding data and a residual portion of the quantized data into a fixed length code;
selecting a part of the fixed length code;
designating the selected part of the fixed length code as an area for recording copy protection key data; and
coding the designated part of the fixed length code into an escape code.

### Claim 14

Method for coding data comprising the steps of:
quantizing moving picture data;
coding at least a portion of the quantized moving picture data into an MPEG standard bit stream; and
inserting copy protection data into a B picture of said MPEG standard bit stream.

### Claim 15 (depends on 14)

Method according to claim 14, wherein the step of inserting comprises inserting the copy protection data into a discrete cosine transform coefficient corresponding to the highest frequency component in the MPEG standard B picture.

### Claim 16 (depends on 15)

Method according to claim 15, wherein the step of inserting comprises inserting the copy protection data into fixed length data in the discrete cosine transform coefficient.