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.

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.

Abstract: A method for verifying a digital signature in a video data segment generated by a video delivery chain comprises: obtaining the video data segment comprising encoded image frames and a plurality of node device datasets associated with respective labels; wherein one or more node device datasets include respective digital signatures; wherein the one or more node device datasets comprises a first node device dataset which includes a first digital signature generated by a first node device based on a first number of node device datasets that have been last added to the video data segment before the first node device dataset; locating the labels; identifying , using the labels, the first number of node device datasets; and verifying the first digital signature. The application also discloses a method of adding a digital signature to a video data segment.

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.

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.

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.

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.

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.

Abstract: A technique for estimating and enhancing audio quality in a real-time communication session between parties over a computer network produces real-time measurements of factors that are known to impact audio quality, assigns a separate MOS value to each of the measured factors, and combines the MOS values for the various factors to produce an overall measure of audio quality. At least one party to the real-time communication session operates a computing device that runs a software program, and the technique further includes directing the software program to render an indication of the overall audio quality, thereby enabling the party operating the computing device to take remedial action to improve the audio quality.

Abstract: A technique for estimating and enhancing audio quality in a real-time communication session between parties over a computer network produces real-time measurements of factors that are known to impact audio quality, assigns a separate MOS value to each of the measured factors, and combines the MOS values for the various factors to produce an overall measure of audio quality. At least one party to the real-time communication session operates a computing device that runs a software program, and the technique further includes directing the software program to render an indication of the overall audio quality, thereby enabling the party operating the computing device to take remedial action to improve the audio quality.

Abstract: One or more delay estimators are used to detect failure in a signal processing component, such as an acoustic echo canceller. A first delay estimator is used to generate i) an estimated post-processing delay between when a known audio signal was conveyed to a loudspeaker, and when a portion of the processed audio signal that includes the known audio signal was output from the signal processing component, and ii) a confidence level for the estimated post-processing delay. A failure of the signal processing component may be detected in response to the estimated post-processing delay exceeding a threshold. A second delay estimator may also be used to generate an estimated pre-processing delay and a confidence level for the estimated pre-processing delay for comparison to the estimated post-processing delay and confidence level for the estimated post-processing delay in order to provide further failure detection accuracy and specificity.

Abstract: One or more delay estimators are used to detect failure in a signal processing component, such as an acoustic echo canceller. A first delay estimator is used to generate i) an estimated post-processing delay between when a known audio signal was conveyed to a loudspeaker, and when a portion of the processed audio signal that includes the known audio signal was output from the signal processing component, and ii) a confidence level for the estimated post-processing delay. A failure of the signal processing component may be detected in response to the estimated post-processing delay exceeding a threshold. A second delay estimator may also be used to generate an estimated pre-processing delay and a confidence level for the estimated pre-processing delay for comparison to the estimated post-processing delay and confidence level for the estimated post-processing delay in order to provide further failure detection accuracy and specificity.

Abstract: Methods and systems are provided for speaker separated spatial acoustic echo cancellation (AEC). A new approach is provided to combat the non-identifiability issue in multiple loudspeaker arrangements with shared echo cancellation processing. By associating echo channels with actual speakers (e.g., participants, talkers, users, individuals, etc.) rather than loudspeakers, the methods and techniques provided allow for continued use of mono AEC. Also provided is a straightforward speaker detection scheme for identifying different speakers in a stereo loudspeaker environment.

Abstract: Methods, systems, and apparatus are provided for multiple-input multiple-output acoustic echo cancellation. A multiple-input multiple-output acoustic echo canceller (MIMO AEC) is provided as a high quality echo canceller for voice and/or audio communication over a network (e.g., packet switched network). The MIMO AEC is an extension of, as well as an application/usage of a single-input single-output acoustic echo canceller (“mono AEC”). The MIMO AEC is an extension of the mono AEC in that the code/theory underlying the mono AEC is adjusted for use with multiple channels. The manner in which AEC is applied (e.g., on each microphone signal using separate mono-AECs) is an application of mono-AECs.

Abstract: Methods, systems, and apparatus are provided for multiple-input multiple-output acoustic echo cancellation. A multiple-input multiple-output acoustic echo canceller (MIMO AEC) is provided as a high quality echo canceller for voice and/or audio communication over a network (e.g., packet switched network). The MIMO AEC is an extension of, as well as an application/usage of a single-input single-output acoustic echo canceller (“mono AEC”). The MIMO AEC is an extension of the mono AEC in that the code/theory underlying the mono AEC is adjusted for use with multiple channels. The manner in which AEC is applied (e.g., on each microphone signal using separate mono-AECs) is an application of mono-AECs.

Abstract: Methods and systems are provided for speaker separated spatial acoustic echo cancellation (AEC). A new approach is provided to combat the non-identifiability issue in multiple loudspeaker arrangements with shared echo cancellation processing. By associating echo channels with actual speakers (e.g., participants, talkers, users, individuals, etc.) rather than loudspeakers, the methods and techniques provided allow for continued use of mono AEC. Also provided is a straightforward speaker detection scheme for identifying different speakers in a stereo loudspeaker environment.

Abstract: An input signal is processed through noise suppression (NS) and echo control (EC) via a multipath model that reduces noise pumping effects while maintaining EC performance. A copy of a “noisy” input signal is sent to an EC component before the noisy signal is sent to a NS component, which processes the signal first, when there is a consistent noise level for estimation. The copy of the pre-processing noisy signal is sent to the EC component along with a “clean” or “noise-suppressed” signal output from the NS component. The EC component analyzes the noisy signal as if the EC was the first component in the signal chain to determine what actions to take. The EC component then applies these actions to the clean signal received from the NS component.

Abstract: The invention relates to a method, device and computer-program product for detection of undesired temporal variations (flicker) in a sequence of video frames. In one embodiment, frame-wise luminance means are compared with a reference level and the crossing frequency is compared with expected variation frequencies, such as frequencies associated with an illumination frequency through aliasing. The crossings count can be refined by introducing a latency zone around the reference level. In case of a positive detection of an undesired temporal variation, there is further provided a correction method, device and computer-program product using cumulated distribution functions. The visual detriment of flicker-induced saturation of pixels is alleviated either by brightening non-saturated pixels or by replacing the saturated pixels by randomly sampled values in accordance with a reference cumulated distribution function. The invention provides embodiments suitable for real-time processing of streamed video sequences.

Abstract: An input signal is processed through noise suppression (NS) and echo control (EC) via a multipath model that reduces noise pumping effects while maintaining EC performance. A copy of a “noisy” input signal is sent to an EC component before the noisy signal is sent to a NS component, which processes the signal first, when there is a consistent noise level for estimation. The copy of the pre-processing noisy signal is sent to the EC component along with a “clean” or “noise-suppressed” signal output from the NS component. The EC component analyzes the noisy signal as if the EC was the first component in the signal chain to determine what actions to take. The EC component then applies these actions to the clean signal received from the NS component.

Abstract: A method and apparatus for finding an estimate of the delay of a signal travelling between two points. A quantity is evaluated from the signal at a final number of time instants, at both a reference point and a reception point. The values are quantized by comparison with a threshold adapted to a typical magnitude of the quantity. If the quantized values from the reception point are shifted back by the true delay with respect to the quantized values from the reference point, then certain co-occurrences of quantized values have very low probability. Hence, the best delay estimate is that shift which yields the least number of low-probability co-occurrences.