Abstract: Innovations in the area of prediction of block vector (“BV”) values improve encoding or decoding of blocks using intra block copy (“BC”) prediction. For example, some of the innovations relate to use of a default BV predictor with a non-zero value. Other innovations relate to use of a selected one of multiple BV predictor candidates for a current block. Still other innovations relate to use of a skip mode in which a current intra-BC-predicted block uses a predicted BV value.

Abstract: Innovations in the area of prediction of block vector (“BV”) values improve encoding or decoding of blocks using intra block copy (“BC”) prediction. For example, some of the innovations relate to use of a default BV predictor with a non-zero value. Other innovations relate to use of a selected one of multiple BV predictor candidates for a current block. Still other innovations relate to use of a skip mode in which a current intra-BC-predicted block uses a predicted BV value.

Abstract: Innovations in the area of prediction of block vector (“BV”) values improve encoding or decoding of blocks using intra block copy (“BC”) prediction. For example, some of the innovations relate to use of a default BV predictor with a non-zero value. Other innovations relate to use of a selected one of multiple BV predictor candidates for a current block. Still other innovations relate to use of a skip mode in which a current intra-BC-predicted block uses a predicted BV value.

Abstract: Innovations in the area of prediction of block vector (“BV”) values improve encoding or decoding of blocks using intra block copy (“BC”) prediction. For example, some of the innovations relate to use of a default BV predictor with a non-zero value. Other innovations relate to use of a selected one of multiple BV predictor candidates for a current block. Still other innovations relate to use of a skip mode in which a current intra-BC-predicted block uses a predicted BV value.

Abstract: Video frames of a higher-resolution chroma sampling format such as YUV 4:4:4 are packed into video frames of a lower-resolution chroma sampling format such as YUV 4:2:0 for purposes of video encoding. For example, sample values for a frame in YUV 4:4:4 format are packed into two frames in YUV 4:2:0 format. After decoding, the video frames of the lower-resolution chroma sampling format can be unpacked to reconstruct the video frames of the higher-resolution chroma sampling format. In this way, available encoders and decoders operating at the lower-resolution chroma sampling format can be used, while still retaining higher resolution chroma information. In example implementations, frames in YUV 4:4:4 format are packed into frames in YUV 4:2:0 format such that geometric correspondence is maintained between Y, U and V components for the frames in YUV 4:2:0 format.

Abstract: Innovations in the area of prediction of block vector (“BV”) values improve encoding or decoding of blocks using intra block copy (“BC”) prediction. For example, some of the innovations relate to use of a default BV predictor with a non-zero value. Other innovations relate to use of a selected one of multiple BV predictor candidates for a current block. Still other innovations relate to use of a skip mode in which a current intra-BC-predicted block uses a predicted BV value.

Abstract: Variations of rho-domain rate control for video encoding or other media encoding are presented. For example, in some of the variations, an encoder sets a rho value for a unit of media based at least in part on a bit allocation for the unit. The encoder also computes transform coefficients for the unit using a frequency transform having multiple location-dependent scale factors, sets a value of quantization parameter (“QP”) for the unit using a mapping of QP values to rho values, and uses the value of QP for the unit during quantization of the transform coefficients of the unit. When the QP-rho mapping is determined, a location-independent scale factor that approximates the multiple location-dependent scale factors is used and/or certain scaling operations are integrated, which reduces computational complexity while still supporting accurate rate control decisions. Implementations of such variations of rate control can exploit opportunities for caching and parallel computation.

Abstract: Video frames of a higher-resolution chroma sampling format such as YUV 4:4:4 are packed into video frames of a lower-resolution chroma sampling format such as YUV 4:2:0 for purposes of video encoding. For example, sample values for a frame in YUV 4:4:4 format are packed into two frames in YUV 4:2:0 format. After decoding, the video frames of the lower-resolution chroma sampling format can be unpacked to reconstruct the video frames of the higher-resolution chroma sampling format. In this way, available encoders and decoders operating at the lower-resolution chroma sampling format can be used, while still retaining higher resolution chroma information. In example implementations, frames in YUV 4:4:4 format are packed into frames in YUV 4:2:0 format such that geometric correspondence is maintained between Y, U and V components for the frames in YUV 4:2:0 format.

Abstract: Video frames of a higher-resolution chroma sampling format such as YUV 4:4:4 are packed into video frames of a lower-resolution chroma sampling format such as YUV 4:2:0 for purposes of video encoding. For example, sample values for a frame in YUV 4:4:4 format are packed into two frames in YUV 4:2:0 format. After decoding, the video frames of the lower-resolution chroma sampling format can be unpacked to reconstruct the video frames of the higher-resolution chroma sampling format. In this way, available encoders and decoders operating at the lower-resolution chroma sampling format can be used, while still retaining higher resolution chroma information. In example implementations, frames in YUV 4:4:4 format are packed into frames in YUV 4:2:0 format such that geometric correspondence is maintained between Y, U and V components for the frames in YUV 4:2:0 format.

Abstract: Techniques are described for performing multi-stage image classification. For example, multi-stage image classification can comprise a first classification stage and a second classification stage. The first classification stage can determine an overall classification for an input image (e.g., based on a relative entropy result calculated for the input image). The second classification stage can be performed by dividing the image into a plurality of blocks and classifying individual blocks, or groups of blocks, based on a classification model that is specific to the overall classification of the image determined in the first classification stage.

Abstract: Techniques are described for performing multi-stage image classification. For example, multi-stage image classification can comprise a first classification stage and a second classification stage. The first classification stage can determine an overall classification for an input image (e.g., based on a relative entropy result calculated for the input image). The second classification stage can be performed by dividing the image into a plurality of blocks and classifying individual blocks, or groups of blocks, based on a classification model that is specific to the overall classification of the image determined in the first classification stage.

Abstract: An invention is disclosed for encoding and decoding data in a 4:4:4 subsampling scheme, using an encoder/decoder that is not configured to encode or decode data in 4:4:4. In embodiments, an encoder planararizes an input frame into three component frames in a 4:0:0 scheme. The encoder then encodes each component frame in the 4:0:0 scheme, and aggregates the encoded component frames into a bit stream. A decoder receives such a bit stream, and decodes it with a component not configured to decode data in 4:4:4. The decoder decodes the bit stream to produce a representation of the three component frames in 4:0:0, then aggregates the three component frames into a representation of the original frame in 4:4:4.

Abstract: Techniques are described for performing multi-stage image classification. For example, multi-stage image classification can comprise a first classification stage and a second classification stage. The first classification stage can determine an overall classification for an input image (e.g., based on a relative entropy result calculated for the input image). The second classification stage can be performed by dividing the image into a plurality of blocks and classifying individual blocks, or groups of blocks, based on a classification model that is specific to the overall classification of the image determined in the first classification stage.

Abstract: An invention is disclosed for conducting a remote presentation session with a client that uses a web browser to conduct the session. The client previously received browser-native program code that executes within a runtime environment of the web browser. The browser-native program code instantiates a remote presentation client executing within a runtime environment of the web browser. The server generates graphics encoded according to a remote presentation protocol and sends them to the remote presentation client for display in the web browser. The client captures user input at the web browser and sends it to the remote presentation client, which encodes it with the remote presentation protocol and sends it to the server to be processed.

Abstract: Innovations in the area of prediction of block vector (“BV”) values improve encoding or decoding of blocks using intra block copy (“BC”) prediction. For example, some of the innovations relate to use of a default BV predictor with a non-zero value. Other innovations relate to use of a selected one of multiple BV predictor candidates for a current block. Still other innovations relate to use of a skip mode in which a current intra-BC-predicted block uses a predicted BV value.

Abstract: Techniques are described for performing multi-stage image classification. For example, multi-stage image classification can comprise a first classification stage and a second classification stage. The first classification stage can determine an overall classification for an input image (e.g., based on a relative entropy result calculated for the input image). The second classification stage can be performed by dividing the image into a plurality of blocks and classifying individual blocks, or groups of blocks, based on a classification model that is specific to the overall classification of the image determined in the first classification stage.

Abstract: Variations of rho-domain rate control for video encoding or other media encoding are presented. For example, in some of the variations, an encoder sets a rho value for a unit of media based at least in part on a bit allocation for the unit. The encoder also computes transform coefficients for the unit using a frequency transform having multiple location-dependent scale factors, sets a value of quantization parameter (“QP”) for the unit using a mapping of QP values to rho values, and uses the value of QP for the unit during quantization of the transform coefficients of the unit. When the QP-rho mapping is determined, a location-independent scale factor that approximates the multiple location-dependent scale factors is used and/or certain scaling operations are integrated, which reduces computational complexity while still supporting accurate rate control decisions. Implementations of such variations of rate control can exploit opportunities for caching and parallel computation.

Abstract: Methods and systems for processing graphical data received at a computing system from a remote source are described. One method includes decoding received graphical content, the received graphical content including an image being compressed using a plurality of codecs, wherein decoding the received graphical content includes creating a decoded image. The method also includes, based on quality of the received graphical content, selecting from among a plurality of filters to apply to the decoded image. The method further includes applying a plurality of filters to at least a portion of the decoded image.

Abstract: An invention is disclosed for performing differencing of graphical data in post-transform space for a remote presentation session. Graphical data is transformed from a first representation to a second representation (e.g. with a DWT), and then a difference is taken of the post-transform data and the post-transform data of the frame that preceded the current frame. This difference is then encoded and transmitted to a client, which decodes it, and creates a representation of the graphical data using the delta, and a previously determined representation of the previous frame. By performing differencing in post-transform space, fidelity of the remote presentation session is retained while it may decrease bandwidth. This may occur because the entropy of the delta representation is usually lower than a non-delta representation while the scheme retains the identical data of the final decoded image of the non-delta version of the same compression scheme.

Abstract: Methods and systems for delivering screen content to a client device are disclosed. One method includes, for each of a plurality of coding units corresponding to screen regions included in a screen at a particular time, classifying screen content included in the coding unit as having a content type selected from among a plurality of content types, at least one of the content types comprising a screen image type, and, based on a determination that the screen content has a screen image type, applying a progressive standards-based encoding to the screen content of that coding unit. The method also includes transmitting encoded screen content for each of the screen regions to the client device.