公开(公告)号：US20230208614A1

公开(公告)日：2023-06-29

申请号：US18084905

申请日：2022-12-20

Applicant: Axis AB

Inventor： Björn VÖLCKER ,  Stefan LUNDBERG

IPC: H04L9/06 ,  H04L9/32

CPC classification number: H04L9/0643 ,  H04L9/3247

Abstract: A signed media bitstream comprises data units and signature units. Each signature unit is associated with one or more nearby data units and include at least one fingerprint derived from the associated data units and a digital signature of the at least one fingerprint. A storing method comprises: receiving a segment of the media bitstream; identifying N≥2 instances of a repeating data unit in the received segment; pruning up to N−1 of the identified instances of the repeating data unit; and storing the received segment after pruning. A validation method comprises: receiving a segment of the media bitstream stored in accordance with the storing method; and validating a signature unit using a digital signature contained therein. Despite the pruning of the repeating data unit, the received associated data units can be successfully validated, either directly or indirectly, by means of different embodiments herein.

公开(公告)号：US20240205426A1

公开(公告)日：2024-06-20

申请号：US18510996

申请日：2023-11-16

Applicant: Axis AB

Inventor： Björn VÖLCKER ,  Stefan Lundberg

IPC: H04N19/176 ,  H04L9/32

CPC classification number: H04N19/176 ,  H04L9/3247

Abstract: A signed video bitstream obtained by prediction coding of a video sequence includes data units and associated signature units, wherein each data unit represents one macroblock in a video frame. Each signature unit includes a digital signature of a bitstring derived from fingerprints, and each fingerprint has been computed from a macroblock reconstructed from one data unit associated with the signature unit. The bitstream is edited by: receiving a request to substitute a region; reconstructing a first set of macroblocks, in which said region is contained, and a second set of macroblocks referring to macroblocks in the first set; adding an archive object that includes fingerprints of the first set of macroblocks; editing the first set of data units and encoding them; re-encoding the second set of macroblocks; and adding the new data units to the signed video bitstream.

公开(公告)号：US20230114200A1

公开(公告)日：2023-04-13

申请号：US17957775

申请日：2022-09-30

Applicant: Axis AB

Inventor： Björn VÖLCKER ,  Stefan LUNDBERG

IPC: H04L9/40 ,  G08B13/196

Abstract: The present application relates to detecting if video images captured by a camera are depicting a live scene or a recorded video played on a monitor, display or computer screen, which is setup to hide the scene from the camera. Metadata regarding the mapping operation used to transform image data between different intensity ranges, or bit depths, is included with the video and evaluated in order to determine if a video replay attack has taken place.

公开(公告)号：US20240155146A1

公开(公告)日：2024-05-09

申请号：US18490269

申请日：2023-10-19

Applicant: Axis AB

Inventor： Stefan LUNDBERG ,  Björn VÖLCKER

IPC: H04N19/46 ,  H04N19/136 ,  H04N19/184 ,  H04N19/40

CPC classification number: H04N19/46 ,  H04N19/136 ,  H04N19/184 ,  H04N19/40

Abstract: A method for providing a signed video bitstream suitable for transcoding from a first video format into a second video format, the method comprising: obtaining first video data in a lossy first video format; reconstructing a video sequence from the first video data; encoding the reconstructed video sequence as second video data in a second video format; computing first fingerprints of the first video data and second fingerprints of the second video data; deriving a first bitstring from the first fingerprints and a second bitstring from the second fingerprints; and providing a signed video bitstream, which includes the first video data and signature units, each signature unit including a first digital signature of the derived first bitstring and second digital signature of the derived second bitstring.

公开(公告)号：US20230179787A1

公开(公告)日：2023-06-08

申请号：US17980138

申请日：2022-11-03

Applicant: Axis AB

Inventor： Björn VÖLCKER ,  Stefan LUNDBERG

IPC: H04N19/46 ,  H04N19/159 ,  H04N19/169 ,  H04N19/177 ,  H04N19/172

CPC classification number: H04N19/46 ,  H04N19/159 ,  H04N19/188 ,  H04N19/177 ,  H04N19/172

Abstract: A device and a method of signing an encoded video sequence comprising: obtaining an encoded video sequence composed of encoded image frames; generating a set of one of more frame fingerprints for each encoded image frame; generating a document comprising a header of a supplemental information unit, and a representation of the generated sets of one or more frame fingerprints; generating a document signature by digitally signing the document; generating the supplemental information unit to only consist of the document, the document signature and an indication of an end of the supplemental information unit; and signing the encoded video sequence by associating the generated supplemental information unit with the encoded video sequence.

公开(公告)号：US20230112135A1

公开(公告)日：2023-04-13

申请号：US17881983

申请日：2022-08-05

Applicant: Axis AB

Inventor： Björn VÖLCKER ,  Stefan LUNDBERG

IPC: G06T1/00 ,  H04N19/50

Abstract: A method of signing prediction-coded video data, comprising: obtaining a coded video sequence including at least one I-frame (I), which contains independently decodable image data, and at least one predicted frame (P1, P2, P3, P4), which contains image data decodable by reference to at least one other frame; generating a fingerprint (HI) of each I-frame; generating a fingerprint (HP) of each predicted frame by hashing a combination of data derived from the predicted frame and data derived from an I-frame to which the predicted frame refers directly or indirectly, wherein the fingerprint of the predicted frame is independent of any further predicted frame to which the predicted frame refers directly or indirectly; and providing a signature of the video sequence including the generated fingerprints.

公开(公告)号：US20240259580A1

公开(公告)日：2024-08-01

申请号：US18408946

申请日：2024-01-10

Applicant: Axis AB

Inventor： Björn VÖLCKER ,  Stefan Lundberg

IPC: H04N19/46 ,  H04N19/103 ,  H04N19/136 ,  H04N19/167 ,  H04N19/172

CPC classification number: H04N19/46 ,  H04N19/103 ,  H04N19/136 ,  H04N19/167 ,  H04N19/172

Abstract: A transmitter and a method therein for enabling validation of a video sequence comprising encoded image frames by providing the sequence with a data structure and a digital signature. The method comprises: performing lossless compression of each encoded image frame to obtain a respective losslessly compressed (LC) encoded image frame; identifying small frames each having a data size that is smaller than a predefined number of bytes as small LC encoded image frames; generating a data structure comprising: the small LC encoded image frames; and individual hashes of either all encoded image frames lacking a respective small frame or all other obtained LC encoded image frames being different from the small frames; generating a digital signature; and providing the data structure and the digital signature to the video sequence.

公开(公告)号：US20240048394A1

公开(公告)日：2024-02-08

申请号：US18358207

申请日：2023-07-25

Applicant: Axis AB

Inventor： Björn VÖLCKER ,  Stefan Lundberg

IPC: H04L9/32 ,  H04L9/30 ,  H04L9/06

CPC classification number: H04L9/3247 ,  H04L9/3073 ,  H04L9/065 ,  H04N19/187

Abstract: There is provided techniques for providing digital signatures to a video stream encoded in layers. Each layer comprises encoded image frames. A digital signature for layer k=0 is provided by providing by generating signing data for layer k=0 and generating the digital signature for layer k=0. A respective digital signature for each layer k=1, . . . , K−1 is provided by, for each layer k=1, . . . , K−1 generating signing data, and generating the digital signature for layer k by encrypting the signing data, or a hash thereof, for layer k with the private key of the private-public key pair. The digital signatures for all the layers are provide to the video stream.

公开(公告)号：US20230116909A1

公开(公告)日：2023-04-13

申请号：US17870454

申请日：2022-07-21

Applicant: Axis AB

Inventor： Björn VÖLCKER ,  Stefan LUNDBERG

IPC: G06F21/10 ,  H04L9/32

Abstract: A method of signing video data, comprising: obtaining video data representing a video sequence; obtaining a bitstring not extracted from the video data; generating a salt by hashing the bitstring, preferably using a secret hash function; generating a first/second fingerprint either by hashing a combination of the salt and a first/second portion of the video data, or by hashing a combination of the salt and a hash of a first/second portion of the video data; and providing a signature of the video data, which includes the first fingerprint. The first and second portions may encode consecutive time segments of the video sequence, such as consecutive frames.

公开(公告)号：US20230082211A1

公开(公告)日：2023-03-16

申请号：US17942592

申请日：2022-09-12

Applicant: Axis AB

Inventor： Mattias PETTERSSON ,  Björn VÖLCKER ,  Malte JOHANSSON

IPC: H04N19/15 ,  H04N19/184 ,  H04N19/177 ,  H04N19/107 ,  H04N19/423 ,  H04N19/136

Abstract: A computer implemented method for controlling a transmission of a video stream is provided. The method comprises estimating a number of bits for a group of pictures, GOP, of the video stream to be transmitted, setting a latency requirement for the transmission of the video stream, determining an average minimum video bitrate across the GOP based on the estimated number of bits and a time corresponding to a time period represented by a duration of the GOP, for video frames in the GOP setting an output bitrate for transmission of a video frame based on the latency requirement and the average minimum video bitrate, and transmitting the video frame using the output bitrate.