Selection of I-frames for client-side watermarking

• US 8,457,349 B2
• Filed: 07/01/2011
• Issued: 06/04/2013
• Est. Priority Date: 11/02/2006
• Status: Expired due to Fees

• Current Assignee: Qurio Holdings Incorporated
• Original Assignee: Qurio Holdings Incorporated
• Inventors: Roberts, Thomas A., Evans, Gregory Morgan, Adams, Cheryl
• Primary Examiner(s): Vu, Le
• Assistant Examiner(s): Abdi, Amara
• Application Number:
  US13/174,810
• Publication Number:
  US 20110261998A1
• Time in Patent Office: 704 Days
• Field of Search: 382/100, 382/232, 713/176, 358/3.28, 380/51, 380/45, 380/210, 380/287
• US Class Current: 382/100
• CPC Class Codes: H04N 1/32272 Encryption or ciphering
• CPC Class Codes: H04N 1/32277 Compression
• CPC Class Codes: H04N 1/32336 Informed embedding, i.e. the original image being known for the encoding or decoding method
• CPC Class Codes: H04N 21/23892 involving embedding information at multiplex stream level, e.g. embedding a watermark at packet level
• CPC Class Codes: H04N 21/44 Processing of video elementary streams, e.g. splicing a video clip retrieved from local storage with an incoming video stream or rendering scenes according to encoded video stream scene graphs
• CPC Class Codes: 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

Abstract

A system and method are provided for selecting frames of a compressed video stream that may be used for client-side watermarking. In general, a content source evaluates a number of Intra-Frames (I-Frames) in the compressed video stream using a sample watermark that is similar to actual watermarks that may be used for client-side watermarking. More specifically, each of a number of I-Frames in the compressed video stream is evaluated by first watermarking the I-Frame with the sample watermark. Associated frames in the compressed video stream are then decoded using the watermarked I-Frame. An error value for the decoded video frames is then computed. If the error value is outside of a predetermined error threshold range, the I-Frame is selected as an I-Frame that may be used for client-side watermarking.

Claims

1. A method comprising:

monitoring a compressed video stream;

detecting an Intra-Frame (I-Frame) in the compressed video stream;

generating a watermarked I-Frame corresponding to the I-Frame in the compressed video stream that is watermarked with a sample watermark similar to an actual watermark to be used for client-side watermarking;

encoding the plurality of associated frames referencing the I-Frame based on the watermarked I-Frame to provide a plurality of encoded video frames;

decoding the plurality of associated frames referencing the I-Frame based on the watermarked I-Frame to provide a plurality of decoded video frames;

comparing the decoded plurality of associated frames referencing the I-Frame based on the watermarked I-Frame with raw digital video input to determine an error; and

determining whether to select the I-Frame as an I-Frame to be used for client-side watermarking based on the comparison.

2. The method of claim 1 wherein:

generating the compressed video stream comprises encoding the raw digital video input according to an encoding algorithm wherein each frame of the raw digital video input is transformed to a frequency domain and entropy encoded to provide the compressed video stream; and

generating the watermarked I-Frame comprises;

entropy decoding the I-Frame in the compressed video stream;

watermarking the entropy decoded I-Frame with the sample watermark according to a frequency domain watermarking algorithm; and

entropy encoding the watermarked, entropy decoded I-Frame to provide the watermarked I-Frame.

3. The method of claim 2 wherein encoding the raw digital video input comprises encoding the raw digital video input with an industry standard video encoder.

4. The method of claim 3 wherein encoding the raw digital video input with the industry standard video encoder comprises encoding the raw digital video input with an encoder selected from a group consisting of:

an MPEG2 video encoder and an MPEG4 video encoder.

5. The method of claim 3 wherein decoding the plurality of associated frames referencing the I-Frame comprises decoding the plurality of associated frames with an industry standard video decoder.

6. The method of claim 5 wherein decoding the plurality of associated frames with the industry standard video decoder comprises decoding the plurality of associated frames with a decoder selected from a group consisting of:

an MPEG2 video decoder and an MPEG4 video decoder.

7. The method of claim 1 wherein:

generating the compressed video stream comprises encoding the raw digital video input according to an encoding algorithm wherein each frame of the raw digital video input is transformed to a frequency domain and entropy encoded to provide the compressed video stream; and

generating the watermarked I-Frame comprises;

entropy decoding the I-Frame in the compressed video stream; and

watermarking the decoded I-Frame with the sample watermark according to a frequency domain watermarking algorithm to provide the watermarked I-Frame.

8. The method of claim 1 wherein determining whether to select the I-Frame comprises:

determining an error value for each one of the plurality of decoded video frames based on a comparison of the one of the plurality of decoded frames and a corresponding segment of the raw digital video input used to generate the compressed video stream;

combining the error values for each one of the plurality of decoded video frames to provide a combined error value for the plurality of decoded video frames; and

determining whether to select the I-Frame based on the combined error value.

9. The method of claim 8 wherein determining whether to select the I-Frame based on the combined error value comprises:

comparing the combined error value to an error threshold range; and

selecting the I-Frame as an I-Frame to be used for client-side watermarking based on whether the combined error value is outside of the error threshold range.

10. The method of claim 1 further comprising, if the I-Frame is selected as an I-Frame to be used for client-side watermarking:

obtaining a segment of the raw digital video input used to generate the compressed video stream corresponding to the I-Frame;

generating a hybrid I-Frame from the segment of the raw digital video input, wherein the hybrid I-Frame is a low-loss version of the I-Frame in the compressed video stream;

providing the compressed video stream and the hybrid I-Frame to a client; and

at the client;

watermarking the hybrid I-Frame; and

replacing the I-Frame in the compressed video stream with the watermarked hybrid I-Frame.

11. A system comprising:

an Intra-Frame (I-Frame) detector configured to;

monitor a compressed video stream; and

detect an I-Frame in the compressed video stream;

a watermarking system configured to generate a watermarked I-Frame corresponding to the I-Frame in the compressed video stream that is watermarked with a sample watermark similar to an actual watermark to be used for client-side watermarking;

a second encoder configured to encode the plurality of associated frames referencing the I-Frame based on the watermarked I-Frame to provide a plurality of encoded video frames;

a decoder configured to decode the plurality of associated frames referencing the I-Frame based on the watermarked I-Frame to provide a plurality of decoded video frames;

an error calculation function configured to;

compare the decoded plurality of associated frames referencing the I-Frame based on the watermarked I-Frame with raw digital video input to determine an error; and

determine a combined error value for the plurality of decoded video frames based on the comparison; and

a decision function configured to determine whether to select the I-Frame as an I-Frame to be used for client-side watermarking based on the combined error value.