Digital watermarking

Claim 3

The method of claim 1 further comprising repeating (a)-(c) for a plurality of consecutive watermark bits and a plurality of consecutive blocks, wherein the second block is used as a new first block, and a third consecutive block is used as a new second block.

Claim 4

The method of claim 1 wherein setting the first difference to a predetermined value according to the watermark bit further comprises setting the first difference to a first level if the watermark bit is a one, and setting the first difference to a second level if the watermark bit is a zero.

Claim 5

The method of claim 3 wherein the first level is a binary even level and the second level is a binary odd level.

Claim 6

The method of claim 4 , wherein setting the first difference to a binary even level further comprises adding a quantization level to the corresponding first coefficient if the first difference is odd, and wherein setting the first difference to a binary odd level further comprises adding a quantization level to the corresponding first coefficient if the first difference is even.

Claim 7

The method of claim 1 further comprising: providing a second watermark bit; and setting a second difference to a predetermined value according to the second watermark bit, the second difference being a difference between a second coefficient of the first block and a corresponding second coefficient of the second block.

Claim 8

The method of claim 2 wherein the plurality of consecutive watermark bits comprises an encrypted watermark.

Claim 9

The method of claim 1 wherein the digital media stream comprises a Motion Picture Expert Group video stream, the first coefficient being a DC coefficient.

Claim 10

The method of claim 1 wherein the digital media stream comprises a Motion Picture Expert Group video stream, the first coefficient being an AC coefficient.

Claim 13

The method of claim 10 further comprising repeating (a)-(c) for a plurality of consecutive blocks, wherein the second block is used as a new first block, and a third consecutive block is used as a new second block, thereby determining a plurality of consecutive watermark bits.

Claim 14

The method of claim 10 , the predetermined value being a one if the first difference has a first level, and the predetermined value being a zero if the first difference has a second level.

Claim 15

The method of claim 12 wherein the first level is a binary even level and the second level is a binary odd level.

Claim 16

The method of claim 10 further comprising: determining a second difference between a second coefficient of the first block and a corresponding second coefficient of the second block; and determining a second watermark bit, the second watermark bit having a second predetermined value according to the second difference.

Claim 17

The method of claim 11 wherein the plurality of consecutive watermark bits comprises an encrypted watermark.

Claim 18

The method of claim 10 wherein the digital media stream comprises a Motion Picture Expert Group video stream and the first coefficient is a DC coefficient.

Claim 19

The method of claim 10 wherein the digital media stream comprises a Motion Picture Expert Group video stream and the first coefficient is an AC coefficient.

Claim 22

The system of claim 18 wherein the first level is a binary even level and the second level is a binary odd level.

Claim 23

The system of claim 18 further comprising: means for providing a second watermark bit; and means for either setting a second difference to be even if the watermark bit is a one, or setting the second difference to be odd if the watermark bit is a zero, the second difference being a difference between a second coefficient of the first block and a corresponding second coefficient of the second block.

Claim 24

The system of claim 18 further comprising means for encrypting the plurality of consecutive watermark bits into an encrypted watermark.

Claim 25

The system of claim 18 further comprising means for variable-length decoding the first plurality of coefficients and the second plurality of coefficients before applying the determining means and the setting means, and means for variable-length coding the first plurality of coefficients and the second plurality of coefficients after applying the determining means and the setting means.

Claim 26

A digital video encoder comprising: a watermark source, the watermark source providing a plurality of watermark bits; a transform unit, the transform unit receiving a plurality of blocks of video data and performing a two-dimensional transform on each block to provide a transformed block, each transformed block including a plurality of coefficients; a quantizer, the quantizer receiving each transformed block and scaling each coefficient of each transformed block using a quantization index, thereby providing a plurality of quantized blocks; and a watermark unit, the watermark unit receiving one of the plurality of watermark bits from the watermark source, a first one of the plurality of quantized blocks, and a second one of the plurality of quantized blocks, the watermark unit encoding the one of the plurality of watermark bits by setting a difference to be even if the one of the plurality of watermark bits has a first value and setting the difference to be odd if the one of the plurality of watermark bits has a second value, the difference being a difference between a first coefficient of the first one of the plurality of quantized blocks and a corresponding first coefficient of the second one of the plurality of quantized blocks.

Claim 27

A digital video encoder comprising: a watermark source, the watermark source providing a plurality of watermark bits; a transform unit, the transform unit receiving a plurality of blocks of video data and performing a two-dimensional transform on each block to provide a transformed block, each transformed block including a plurality of coefficients; a quantizer, the quantizer receiving each transformed block and scaling each coefficient of each transformed block using a quantization index, thereby providing a plurality of quantized blocks; and a watermark unit, the watermark unit receiving one of the plurality of watermark bits from the watermark source, a first one of the plurality of quantized blocks, and a second one of the plurality of quantized blocks, the watermark unit encoding the one of the plurality of watermark bits by setting a difference to be even if the one of the plurality of watermark bits has a first value and setting the difference to be odd if the one of the plurality of watermark bits has a second value, the difference being a difference between a first coefficient of the first one of the plurality of quantized blocks and a corresponding first coefficient of the second one of the plurality of quantized blocks.

Claim 28

The digital video encoder of claim 23 wherein the first coefficient and the corresponding first coefficient are DC coefficients.

Claim 29

The digital video encoder of claim 23 wherein the first coefficient and the corresponding first coefficient are AC coefficients.

Claim 30

The digital video encoder of claim 23 wherein setting the difference to be even comprises adding a quantization level to the corresponding first coefficient if the difference is odd, and wherein setting the difference to be odd comprises adding a quantization level to the corresponding first coefficient if the difference is even.

Claim 31

The digital video encoder of claim 24 wherein the plurality of quantized blocks comprises a Motion Picture Expert Group video stream.

Claim 32

A digital watermark embodied in a digital video stream carrier signal, the digital watermark comprising a plurality of watermark bits, each watermark bit having a value encoded between consecutive blocks of the digital video stream, the value being a first value when a difference between a pair of consecutive corresponding coefficients is even, and the value being a second value when the difference between the pair of consecutive corresponding coefficients is odd.

Claim 33

A digital watermark embodied in a digital video stream carrier signal, the digital watermark comprising a plurality of watermark bits, each watermark bit having a value encoded between consecutive blocks of the digital video stream, the value being a first value when a difference between a pair of consecutive corresponding coefficients is even, and the value being a second value when the difference between the pair of consecutive corresponding coefficients is odd.

Claim 34

The digital watermark of claim 28 , wherein the first value is one and the second value is zero.

Claim 35

The digital watermark of claim 28 , wherein the first value is zero and the second value is one.

Claim 36

The digital watermark of claim 28 wherein the pair of consecutive corresponding coefficients are each DC coefficients.

Claim 37

The digital watermark of claim 28 wherein the pair of consecutive corresponding coefficients are each AC coefficients.

Claim 38

A computer program product for etching a digital watermark, embodied in machine executable code for performing the following steps: (a) providing a watermark bit; (b) providing a digital media stream comprising a first block and a second block, the first block comprising a first plurality of coefficients, and the second block comprising a second plurality of coefficients, each one of the second plurality of coefficients corresponding to one of the first plurality of coefficients; and (c) setting a first difference to a predetermined value according to the watermark bit, the first difference being a difference between a first coefficient of the first block and a corresponding first coefficient of the second block.

Claim 39

A computer program product for etching a digital watermark, embodied in machine executable code for performing the following steps: (a) providing a watermark bit; (b) providing a digital media stream comprising a first block and a second block, the first block comprising a first plurality of coefficients, and the second block comprising a second plurality of coefficients, each one of the second plurality of coefficients corresponding to one of the first plurality of coefficients; and (c) setting a first difference to a predetermined value according to the watermark bit, the first difference being a difference between a first coefficient of the first block and a corresponding first coefficient of the second block.

Claim 40

The computer program product of claim 33 , further comprising machine executable code for repeating (a)-(c) for a plurality of consecutive watermark bits and a plurality of consecutive blocks, wherein the second block is used as a new first block, and a third consecutive block is used as a new second block.

Claim 41

The computer program product of claim 33 wherein setting the first difference to a predetermined value according to the watermark bit further comprises setting the first difference to a first level if the watermark bit is a one, and setting the first difference to a second level if the watermark bit is a zero.

Claim 42

The computer program product of claim 35 wherein the first level is a binary even level and the second level is a binary odd level.

Claim 43

The computer program product of claim 36 wherein setting the first difference to a binary even level further comprises adding a quantization level to the corresponding first coefficient if the first difference is odd, and wherein setting the first difference to a binary odd level further comprises adding a quantization level to the corresponding first coefficient if the first difference is even.

Claim 44

The computer program product of claim 33 further comprising machine executable code for performing the following steps: providing a second watermark bit; and setting a second difference to a predetermined value according to the second watermark bit, the second difference being a difference between a second coefficient of the first block and a corresponding second coefficient of the second block.

Claim 45

The computer program product of claim 34 wherein the plurality of consecutive watermark bits comprises an encrypted watermark.

Claim 46

The computer program product of claim 33 wherein the digital media stream comprises a Motion Picture Expert Group video stream, the first coefficient being a DC coefficient.

Claim 47

The computer program product of claim 33 wherein the digital media stream comprises a Motion Picture Expert Group video stream, the first coefficient being an AC coefficient.