Abstract: A user terminal for participating in video calls comprises: an encoder having a frame size, being the size in pixels at which it encodes frames of video; and a pre-processing stage which supplies a sequence of frames to the encoder at that frame size, each frame comprising at least an image region representing a source video image at a respective moment in time. The pre-processing stage is configured to supply at least some of the frames to the encoder in a modified form, by resizing the source video image to produce the image region of each modified frame with a size smaller than the frame size of the encoder, and combining with a border region such that the modified frame matches the frame size of the encoder. The encoder encodes the frames at the frame size and transmits them to a receiving terminal as part of a live video call.

Abstract: Method, device and computer program product for estimating quality of a video signal, wherein frames of the video signal are received at receiving means of the device, each frame comprising a plurality of blocks of pixels. A section of a first frame of the video signal, which is correctly received, is used to provide a concealed block for use in place of a block of a second frame of the video signal. A difference measure is determined indicative of a difference between at least some of the pixels surrounding the block in the second frame and the corresponding pixels surrounding the section in the first frame. The difference measure is used to estimate the quality of the second frame of the video signal.

Abstract: An encoder comprising an encoding module and an adaptation module. The encoding module is configured to encode video in at least one region-of-interest and outside the region-of-interest. The encoding comprises quantization, and the encoding module is operable to apply a difference in quantization granularity between the encoding inside and outside the region-of-interest. The adaptation module is configured to determine at least one metric representative of a difference in benefit of the quantization inside and outside the region-of-interest, and to adapt the difference in quantization granularity in dependence on this metric.

Abstract: Method, device and computer program product for estimating quality of a video signal, wherein frames of the video signal are received at receiving means of the device, each frame comprising a plurality of blocks of pixels. A section of a first frame of the video signal, which is correctly received, is used to provide a concealed block for use in place of a block of a second frame of the video signal. A difference measure is determined indicative of a difference between at least some of the pixels surrounding the block in the second frame and the corresponding pixels surrounding the section in the first frame. The difference measure is used to estimate the quality of the second frame of the video signal.

Abstract: The invention provides methods and devices for stereo encoding and decoding using complex prediction in the frequency domain. In one embodiment, a decoding method, for obtaining an output stereo signal from an input stereo signal encoded by complex prediction coding and comprising first frequency-domain representations of two input channels, comprises the upmixing steps of: (i) computing a second frequency-domain representation of a first input channel; and (ii) computing an output channel on the basis of the first and second frequency-domain representations of the first input channel, the first frequency-domain representation of the second input channel and a complex prediction coefficient. The upmixing can be suspended responsive to control data.

Abstract: An encoder comprising an encoding module and an adaptation module. The encoding module is configured to encode video in at least one region-of-interest and outside the region-of-interest. The encoding comprises quantization, and the encoding module is operable to apply a difference in quantization granularity between the encoding inside and outside the region-of-interest. The adaptation module is configured to determine at least one metric representative of a difference in benefit of the quantization inside and outside the region-of-interest, and to adapt the difference in quantization granularity in dependence on this metric.

Abstract: The invention provides methods and devices for stereo encoding and decoding using complex prediction in the frequency domain. In one embodiment, a decoding method, for obtaining an output stereo signal from an input stereo signal encoded by complex prediction coding and comprising first frequency-domain representations of two input channels, comprises the upmixing steps of: (i) computing a second frequency-domain representation of a first input channel; and (ii) computing an output channel on the basis of the first and second frequency-domain representations of the first input channel, the first frequency domain representation of the second input channel and a complex prediction coefficient. The method comprises performing frequency-domain modifications selectively before or after upmixing.

Abstract: The application relates to audio encoder and decoder systems. An embodiment of the encoder system comprises a downmix stage for generating a downmix signal and a residual signal based on a stereo signal. In addition, the encoder system comprises a parameter determining stage for determining parametric stereo parameters such as an inter-channel intensity difference and an inter-channel cross-correlation. Preferably, the parametric stereo parameters are time- and frequency-variant. Moreover, the encoder system comprises a transform stage. The transform to stage generates a pseudo left/right stereo signal by performing a transform based on the downmix signal and the residual signal. The pseudo stereo signal is processed by a perceptual stereo encoder. For stereo encoding, left/right encoding or mid/side encoding is selectable. Preferably, the selection between left/right stereo encoding and mid/side stereo encoding is time- and frequency-variant.

Abstract: The invention provides methods and devices for stereo encoding and decoding using complex prediction in the frequency domain. In one embodiment, a decoding method, for obtaining an output stereo signal from an input stereo signal encoded by complex prediction coding and comprising first frequency-domain representations of two input channels, comprises the upmixing steps of: (i) computing a second frequency-domain representation of a first input channel; and (ii) computing an output channel on the basis of the first and second frequency-domain representations of the first input channel, the first frequency-domain representation of the second input channel and a complex prediction coefficient. The upmixing can be suspended responsive to control data.

Abstract: The application relates to audio encoder and decoder systems. An embodiment of the encoder system comprises a downmix stage for generating a downmix signal and a residual signal based on a stereo signal. In addition, the encoder system comprises a parameter determining stage for determining parametric stereo parameters such as an inter-channel intensity difference and an inter-channel cross-correlation. Preferably, the parametric stereo parameters are time- and frequency-variant. Moreover, the encoder system comprises a transform stage. The transform stage generates a pseudo left/right stereo signal by performing a transform based on the downmix signal and the residual signal. The pseudo stereo signal is processed by a perceptual stereo encoder. For stereo encoding, left/right encoding or mid/side encoding is selectable. Preferably, the selection between left/right stereo encoding and mid/side stereo encoding is time- and frequency-variant.

Abstract: A user terminal for participating in video calls comprises: an encoder having a frame size, being the size in pixels at which it encodes frames of video; and a pre-processing stage which supplies a sequence of frames to the encoder at that frame size, each frame comprising at least an image region representing a source video image at a respective moment in time. The pre-processing stage is configured to supply at least some of the frames to the encoder in a modified form, by resizing the source video image to produce the image region of each modified frame with a size smaller than the frame size of the encoder, and combining with a border region such that the modified frame matches the frame size of the encoder. The encoder encodes the frames at the frame size and transmits them to a receiving terminal as part of a live video call.

Abstract: The present invention teaches a new audio coding system that can code both general audio and speech signals well at low bit rates. A proposed audio coding system comprises linear prediction unit for filtering an input signal based on an adaptive filter; a transformation unit for transforming a frame of the filtered input signal into a transform domain; and a quantization unit for quantizing the transform domain signal. The quantization unit decides, based on input signal characteristics, to encode the transform domain signal with a model-based quantizer or a non-model-based quantizer. Preferably, the decision is based on the frame size applied by the transformation unit.

Abstract: An encoder comprising an encoding module and an adaptation module. The encoding module is configured to encode video in at least one region-of-interest and outside the region-of-interest. The encoding comprises quantization, and the encoding module is operable to apply a difference in quantization granularity between the encoding inside and outside the region-of-interest. The adaptation module is configured to determine at least one metric representative of a difference in benefit of the quantization inside and outside the region-of-interest, and to adapt the difference in quantization granularity in dependence on this metric.

Abstract: The present invention teaches a new audio coding system that can code both general audio and speech signals well at low bit rates. A proposed audio coding system comprises linear prediction unit for filtering an input signal based on an adaptive filter; a transformation unit for transforming a frame of the filtered input signal into a transform domain; and a quantization unit for quantizing the transform domain signal. The quantization unit decides, based on input signal characteristics, to encode the transform domain signal with a model-based quantizer or a non-model-based quantizer. Preferably, the decision is based on the frame size applied by the transformation unit.

Abstract: An apparatus for encoding video data, the apparatus comprising a compliance module configured to compare a resource requirement associated with encoding video data to form at least part of an encoded frame using a standard encoding mode with an acceptable resource level and an encoder configured to, responsive to a determination that the resource requirement will exceed the acceptable resource level, form the at least part of an encoded frame by encoding some of the video data using the standard encoding mode and filling a remainder of the at least part of the encoded frame with data that is associated with a lower resource usage than data generated using the standard encoding mode.

Abstract: An input receives a video signal comprising a plurality of frames, each comprising a plurality of image portions. Each of the image portions is encoded by an encoder, to generate an encoded signal. An adaptation module selects a respective encoding mode used to encode each of the image portions. The selection is based on a process that balances an estimate of distortion for the image portion if encoded using the respective encoding mode and a bitrate that would be incurred by encoding the image portion using the respective encoding mode. The adaptation module is also configured to determine, within each of one or more frames of the video signal, at least two different regions having different perceptual significance, and to adapt the above-mentioned process in dependence on which of the regions the image portion being encoded is in.

Abstract: Method, device and computer program product for transmitting a video signal from a user device includes capturing a plurality of frames of the video signal using a camera at the user device, determining a functional state of the device and selectively stabilizing the video signal prior to transmission based on the functional state.

Abstract: Method, device and computer program product for stabilizing a video signal. A plurality of frames of the video signal are captured using a camera. A motion sensor associated with the camera is used to generate a plurality of samples representing motion of the camera. The samples are used to determine a displacement of the camera between a first time and a second time, wherein the first time corresponds to an exposure time midpoint of a first frame of the video signal and the second time corresponds to an exposure time midpoint of a second frame of the video signal. The determined displacement is used to compensate for motion in the video signal between the first and second frames caused by the motion of the camera, to thereby stabilize the video signal.

Abstract: Method, device and computer program product for transmitting a video signal from a user device includes capturing a plurality of frames of the video signal using a camera at the user device, determining a functional state of the device and selectively stabilizing the video signal prior to transmission based on the functional state.

Abstract: Method, device and computer program product for stabilizing a video signal. A plurality of frames of the video signal are captured using a camera. A motion sensor associated with the camera is used to generate a plurality of samples representing motion of the camera. The samples are used to determine a displacement of the camera between a first time and a second time, wherein the first time corresponds to an exposure time midpoint of a first frame of the video signal and the second time corresponds to an exposure time midpoint of a second frame of the video signal. The determined displacement is used to compensate for motion in the video signal between the first and second frames caused by the motion of the camera, to thereby stabilize the video signal.