Abstract: An input of an encoder receives moving image data comprising a sequence of frames to be encoded, each frame comprising a plurality of blocks in two dimensions with each block comprising a plurality of pixels in those two dimensions. A motion prediction module performs encoding by, for at least part of each of a plurality of said frames, coding each block relative to a respective reference portion of another frame of the sequence, with the respective reference portion being offset from the block by a respective motion vector. According to the present disclosure, the moving image data of this plurality of frames comprises a screen capture stream, and the motion prediction module is configured to restrict each of the motion vectors of the screen capture stream to an integer number of pixels in at least one of said dimensions.

Abstract: A format for use in encoding moving image data, comprising: a sequence of frames including plurality of the frames in which at least a region is encoded using motion estimation; a respective set of motion vector values representing motion vectors of the motion estimation for each respective one of these frames or each respective one of one or more regions within each of such frames; and at least one respective indicator associated with each of the respective frames or regions, indicating whether the respective motion vector values of the respective frame or region are encoded at a first resolution or a second resolution.

Abstract: A LED drive circuit according to the present invention comprises a controller and a programmable signal. The controller generates a switching signal coupled to switch a magnetic device for generating an output current to drive a plurality of LEDs. The programmable signal is coupled to regulate a current-control signal of the controller. The switching signal is modulated in response to the current-control signal for regulating the output current, and the level of the output current is correlated to the current-control signal.

Abstract: Techniques and tools for video coding/decoding with motion resolution switching and sub-block transform coding/decoding are described. For example, a video encoder adaptively switches the resolution of motion estimation and compensation between quarter-pixel and half-pixel resolutions; a corresponding video decoder adaptively switches the resolution of motion compensation between quarter-pixel and half-pixel resolutions. For sub-block transform sizes, for example, a video encoder adaptively switches between 8×8, 8×4, and 4×8 DCTs when encoding 8×8 prediction residual blocks; a corresponding video decoder switches between 8×8, 8×4, and 4×8 inverse DCTs during decoding.

Abstract: Video streams are generated using a combination of Multiple Bit Rate (MBR) encoding and Scalable Video Coding (SVC). Capabilities and requests of the clients are used in determining the video streams to generate as well as what video streams to deliver to the clients. The clients are placed into groups based on a resolution capability of the client. For each resolution grouping, MBR is used for generating spatial streams and SVC is used for generating temporal and quality streams.

Abstract: Multi-layered rate control for scalable video coding is provided. A parameter value may be calculated based on a current layer target bit rate and a current layer buffer state for a frame in a video stream. The frame may include a lower layer and one or more higher layers. A determination may then be made as to whether the current layer is the lower layer. If the current layer is the lower layer, a determination may then be made as to whether a coupling request has been received from a higher layer in the frame. If the coupling request has been received from the higher layer in the frame, the parameter value for the current layer may be increased based on a buffer state threshold value of the higher layer in the frame.

Abstract: Techniques and tools for video coding/decoding with motion resolution switching and sub-block transform coding/decoding are described. For example, a video encoder adaptively switches the resolution of motion estimation and compensation between quarter-pixel and half-pixel resolutions; a corresponding video decoder adaptively switches the resolution of motion compensation between quarter-pixel and half-pixel resolutions. For sub-block transform sizes, for example, a video encoder adaptively switches between 8×8, 8×4, and 4×8 DCTs when encoding 8×8 prediction residual blocks; a corresponding video decoder switches between 8×8, 8×4, and 4×8 inverse DCTs during decoding.

Abstract: An audio encoder implements multi-channel coding decision, band truncation, multi-channel rematrixing, and header reduction techniques to improve quality and coding efficiency. In the multi-channel coding decision technique, the audio encoder dynamically selects between joint and independent coding of a multi-channel audio signal via an open-loop decision based upon (a) energy separation between the coding channels, and (b) the disparity between excitation patterns of the separate input channels. In the band truncation technique, the audio encoder performs open-loop band truncation at a cut-off frequency based on a target perceptual quality measure. In multi-channel rematrixing technique, the audio encoder suppresses certain coefficients of a difference channel by scaling according to a scale factor, which is based on current average levels of perceptual quality, current rate control buffer fullness, coding mode, and the amount of channel separation in the source.

Abstract: Techniques and tools for video coding/decoding with sub-block transform coding/decoding and re-oriented transforms are described. For example, a video encoder adaptively switches between 8×8, 8×4, and 4×8 DCTs when encoding 8×8 prediction residual blocks; a corresponding video decoder switches between 8×8, 8×4, and 4×8 inverse DCTs during decoding. The video encoder may determine the transform sizes as well as switching levels (e.g., frame, macroblock, or block) in a closed loop evaluation of the different transform sizes and switching levels. When a video encoder or decoder uses spatial extrapolation from pixel values in a causal neighborhood to predict pixel values of a block of pixels, the encoder/decoder can use a re-oriented transform to address non-stationarity of prediction residual values.

Abstract: Optimization of conference call encoding processes is provided. A first client of a multi-party conference call may receive client capability data, including video scalability support, from each of the other clients to the conference call. Based on the client capability data and the transmission capabilities of the first client, including video scalability support, the first client may determine a total number of data streams and properties for each data stream, such that the total number of data streams and the plurality of properties for each data stream are optimized and supported by the respective client capability data and the transmission capabilities. Subsequently, the first client generates one or more data streams according to the total number of data streams and the properties that were determined for each data stream and transmits the one or more data streams to the other clients of the conference call.

Abstract: A LED drive circuit according to the present invention comprises a controller and a programmable signal. The controller generates a switching signal coupled to switch a magnetic device for generating an output current to drive a plurality of LEDs. The programmable signal is coupled to regulate a current-control signal of the controller. The switching signal is modulated in response to the current-control signal for regulating the output current, and the level of the output current is correlated to the current-control signal.

Abstract: An audio encoder implements multi-channel coding decision, band truncation, multi-channel rematrixing, and header reduction techniques to improve quality and coding efficiency. In the multi-channel coding decision technique, the audio encoder dynamically selects between joint and independent coding of a multi-channel audio signal via an open-loop decision based upon (a) energy separation between the coding channels, and (b) the disparity between excitation patterns of the separate input channels. In the band truncation technique, the audio encoder performs open-loop band truncation at a cut-off frequency based on a target perceptual quality measure. In multi-channel rematrixing technique, the audio encoder suppresses certain coefficients of a difference channel by scaling according to a scale factor, which is based on current average levels of perceptual quality, current rate control buffer fullness, coding mode, and the amount of channel separation in the source.

Abstract: Techniques and tools for video coding/decoding with sub-block transform coding/decoding and re-oriented transforms are described. For example, a video encoder adaptively switches between 8×8, 8×4, and 4×8 DCTs when encoding 8×8 prediction residual blocks; a corresponding video decoder switches between 8×8, 8×4, and 4×8 inverse DCTs during decoding. The video encoder may determine the transform sizes as well as switching levels (e.g., frame, macroblock, or block) in a closed loop evaluation of the different transform sizes and switching levels. When a video encoder or decoder uses spatial extrapolation from pixel values in a causal neighborhood to predict pixel values of a block of pixels, the encoder/decoder can use a re-oriented transform to address non-stationarity of prediction residual values.

Abstract: A LED drive circuit according to the present invention comprises a controller and a programmable signal. The controller generates a switching signal coupled to switch a magnetic device for generating an output current to drive a plurality of LEDs. The programmable signal is coupled to regulate a current-control signal of the controller. The switching signal is modulated in response to the current-control signal for regulating the output current, and the level of the output current is correlated to the current-control signal.

Abstract: The generation and delivery of key frames to clients of a video conference are performed in response to a need for a synchronization point. Instead of automatically sending a key frame periodically to each of the clients in the video conference, a key frame is sent to one or more clients upon the occurrence of an event in the video conference. For example, a key frame may be sent to a client when the client joins the video conference. A key frame may also be sent to a client that has packet loss, upon the request of a client, a speaker change within the video conference, when a new stream is added by the client, and the like. The clients in the video conference that are not affected by the event continue to receive predicted frames.

Abstract: An audio encoder implements multi-channel coding decision, band truncation, multi-channel rematrixing, and header reduction techniques to improve quality and coding efficiency. In the multi-channel coding decision technique, the audio encoder dynamically selects between joint and independent coding of a multi-channel audio signal via an open-loop decision based upon (a) energy separation between the coding channels, and (b) the disparity between excitation patterns of the separate input channels. In the band truncation technique, the audio encoder performs open-loop band truncation at a cut-off frequency based on a target perceptual quality measure. In multi-channel rematrixing technique, the audio encoder suppresses certain coefficients of a difference channel by scaling according to a scale factor, which is based on current average levels of perceptual quality, current rate control buffer fullness, coding mode, and the amount of channel separation in the source.

Abstract: Techniques and tools for bitstream-controlled filtering are described. For example, a video encoder puts control information into a bitstream for encoded video. A video decoder decodes the encoded video and, according to the control information, performs post-processing filtering on the decoded video with a de-ringing and/or de-blocking filter. Typically, a content author specifies the control information to the encoder. The control information itself is post-processing filter levels, filter selections, and/or some other type of information. In the bitstream, the control information is specified for a sequence, scene, frame, region within a frame, or at some other syntax level.

Abstract: Video encoding computations are optimized by dynamically adjusting slice patterns of video frames based on complexity of each frame and allocating multi-core threading based on the slices. The complexity may be based on predefined parameters such as color, motion, and comparable ones for each slice. Allocation is determined based on capacity and queue of each processing core such that overall computation performance for video encoding is improved.

Abstract: An improved loss recovery method for coding streaming media classifies each data unit in the media stream as an independent data unit (I unit), a remotely predicted unit (R unit) or a predicted data unit (P unit). Each of these units is organized into independent segments having an I unit, multiple P units and R units interspersed among the P units. The beginning of each segment is the start of a random access point, while each R unit provides a loss recovery point that can be placed independently of the I unit. This approach separates the random access point from the loss recovery points provided by the R units, and makes the stream more impervious to data losses without substantially impacting coding efficiency. The most important data units are transmitted with the most reliability to ensure that the majority of the data received by the client is usable. The I units are the least sensitive to transmission losses because they are coded using only their own data.

Abstract: Techniques and tools for video coding/decoding with motion resolution switching and sub-block transform coding/decoding are described. For example, a video encoder adaptively switches the resolution of motion estimation and compensation between quarter-pixel and half-pixel resolutions; a corresponding video decoder adaptively switches the resolution of motion compensation between quarter-pixel and half-pixel resolutions. For sub-block transform sizes, for example, a video encoder adaptively switches between 8×8, 8×4, and 4×8 DCTs when encoding 8×8 prediction residual blocks; a corresponding video decoder switches between 8×8, 8×4, and 4×8 inverse DCTs during decoding.