Abstract: In one example, an apparatus for encoding video data includes a video encoder configured to select an intra-prediction mode to use to encode a block of video data, determine whether the block includes a sub-block of a size for which multiple transforms are possible based on the size of the sub-block and the selected intra-prediction mode, when the block includes the sub-block of the size for which multiple transforms are possible based on the size of the sub-block and the selected intra-prediction mode, select one of the multiple possible transforms, transform the sub-block using the selected one of the multiple possible transforms, and provide an indication of the selected one of the multiple possible transforms for the size of the block.

Abstract: In one example, an apparatus for encoding video data includes a video encoder configured to scan a two-dimensional block of transform coefficients to produce a one-dimensional vector of the transform coefficients, determine values indicative of whether the transform coefficients in the one-dimensional vector are significant; and entropy encode at least one of the values using a context model selected based on at least a percentage of significant coefficients in a predetermined number of the values encoded before the at least one of the values.

Abstract: In one example, an apparatus for encoding video data includes a video encoder configured to calculate a residual block for a block of video data based on a predicted block formed using an intra-prediction mode, and transform the residual block using a transform mapped from the intra-prediction mode. In another example, an apparatus includes video encoder configured to receive an indication of a first intra-prediction mode in a first set of intra-prediction modes for a block of video data, determine a second intra-prediction mode from a second set of intra-prediction modes, smaller than the first set of intra-prediction modes, to which the first intra-prediction mode is mapped, determine a directional transform to which the second intra-prediction mode is mapped, and apply the directional transform to residual data of the block.

Abstract: In one example, an encoder may apply a plurality of pre-defined interpolation filters to units of video data, such as frames of reference video, in order to generate a plurality of different interpolated prediction data. The encoder may also at times determine that a new interpolation filter or set of interpolation filters might improve coding quality by either improving video compression or improving reconstructed image quality. The encoder may also signal to a video decoder whether one of the pre-defined interpolation filters was used or a new set of interpolation filters was used. The encoder may also signal to a video decoder whether to continue using the new set of interpolation filters, or whether to revert back to using the pre-defined set of interpolation filters. A video decoder can decode video data based on data received from the video encoder.

Abstract: During the prediction stage of a video encoding and/or decoding process, a video coder can use relatively longer filters for certain motion vectors pointing to certain sub-pixel positions and relatively shorter filters for motion vectors pointing to other sub-pixel positions, where a longer filter generally refers to an interpolation filter with a greater number of filter coefficients, also called taps, while a shorter filter generally refers to an interpolation filter with fewer taps.

Abstract: A video coding unit may be configured to encode or decode chrominance blocks of video data by reusing motion vectors for corresponding luminance blocks. A motion vector may have greater precision for chrominance blocks than luminance blocks, due to downsampling of chrominance blocks relative to corresponding luminance blocks. The video coding unit may interpolate values for a reference chrominance block by selecting interpolation filters based on the position of the pixel position pointed to by the motion vector. For example, a luminance motion vector may have one-quarter-pixel precision and a chrominance motion vector may have one-eighth-pixel precision. There may be interpolation filters associated with the quarter-pixel precisions. The video coding unit may use interpolation filters either corresponding to the pixel position or neighboring pixel positions to interpolate a value for the pixel position pointed to by the motion vector.

Abstract: In one example, an apparatus includes a video encoder configured to partition a block of video data into a first partition and a second partition using a geometric motion partition line, calculate a slope value and a y-intercept value of the geometric motion partition line, wherein the slope value and the y-intercept value comprise integer values, calculate a mask indicative of pixels of the block in the first partition and pixels of the block in the second partition, encode the first partition and the second partition based on the mask, and output the encoded first partition, the encoded second partition, the slope value, and the y-intercept value. This may allow for a fixed point implementation. A video decoder may receive the slope and y-intercept values to calculate the mask and decode the block based on the mask.

Abstract: In general, techniques are described for implementing a 16-point inverse discrete cosine transform (IDCT) that is capable of applying multiple IDCTs of different sizes. For example, an apparatus comprising a 16-point inverse discrete cosine transform of type II (IDCT-II) unit may implement the techniques of this disclosure. The 16-point IDCT-II unit performs these IDCTs-II of different sizes to transform data from a spatial to a frequency domain. The 16-point IDCT-II unit includes an 8-point IDCT-II unit that performs one of the IDCTs-II of size 8 and a first 4-point IDCT-II unit that performs one of the IDCTs-II of size 4. The 8-point IDCT-II unit includes the first 4-point DCT-II unit. The 16-point IDCT-II unit also comprises an inverse 8-point DCT-IV unit that includes a second 4-point IDCT-II unit and a third 4-point IDCT-II unit. Each of the second and third 4-point IDCT-II units performs one of the IDCTs-II of size 4.

Abstract: In general, techniques are described for implementing a 16-point discrete cosine transform (DCT) that is capable of applying multiple IDCT of different sizes. For example, an apparatus comprising a 16-point discrete cosine transform of type II (DCT-II) unit may implement the techniques of this disclosure. The 16-point DCT-II unit performs these DCTs-II of different sizes to transform data from a spatial to a frequency domain. The 16-point DCT-II unit includes an 8-point DCT-II unit that performs one of the DCTs-II of size 8 and a first 4-point DCT-II unit that performs one of the DCTs-II of size 4. The 8-point DCT-II unit includes the first 4-point DCT-II unit. The 16-point DCT-II unit also comprises an 8-point DCT-IV unit that includes a second 4-point DCT-II unit and a third 4-point DCT-II unit. Each of the second and third 4-point DCT-II units performs one of the DCTs-II of size 4.

Abstract: In general, techniques are described for implementing an 8-point discrete cosine transform (DCT). An apparatus comprising an 8-point discrete cosine transform (DCT) hardware unit may implement these techniques to transform media data from a spatial domain to a frequency domain. The 8-point DCT hardware unit includes an even portion comprising factors A, B that are related to a first scaled factor (?) in accordance with a first relationship. The 8-point DCT hardware unit also includes an odd portion comprising third, fourth, fifth and sixth internal factors (G, D, E, Z) that are related to a second scaled factor (?) in accordance with a second relationship. The first relationship relates the first scaled factor to the first and second internal factors. The second relationship relates the second scaled factor to the third internal factor and a fourth internal factor, as well as, the fifth internal factor and a sixth internal factor.

Abstract: In general, techniques are described for implementing an 8-point inverse discrete cosine transform (IDCT). An apparatus comprising an 8-point inverse discrete cosine transform (IDCT) hardware unit may implement these techniques to transform media data from a frequency domain to a spatial domain. The 8-point IDCT hardware unit includes an even portion comprising factors A, B that are related to a first scaled factor (?) in accordance with a first relationship. The 8-point IDCT hardware unit also includes an odd portion comprising third, fourth, fifth and sixth internal factors (G, D, E, Z) that are related to a second scaled factor (?) in accordance with a second relationship. The first relationship relates the first scaled factor to the first and second internal factors. The second relationship relates the second scaled factor to the third, fourth, fifth and sixth internal factors.

Abstract: This disclosure describes video encoding and decoding techniques in which a first order prediction process and a second order prediction process are used in combination to generate predictive video blocks for video coding. First order prediction may be similar to conventional motion estimation and motion compensation that generates residual video blocks. The second order prediction may involve a process similar to conventional intra-prediction, but is performed on the residual video blocks. The techniques of this disclosure may pre-define the second order prediction to a specific mode, such as a mode similar to the intra-DC mode used in intra coding. In addition, the techniques of this disclosure may combine aspects of the first order and second order prediction into a single process so that the effects of second order prediction on the residuals are taken into account during the first order prediction process, which may improve compression.

Abstract: A system renders oblique slices through volumetric data accessed via a network using a client-server architecture. The system includes a server for processing and storing volumetric data comprising axial slices obtained from a diagnostic scanning system, a client for processing user requests related to specific views of the volumetric data, and a network protocol for connecting the client with the server over the network and obtaining data from the server for use by the client. A processing stage at the client specifies an oblique slice and communicates particulars of the oblique slice to the server, thereupon obtaining axial slice data from the server specifically for portions of the axial slices that are needed to render the oblique slice. Memory at the client stores the axial slice data, and a rendering stage at the client renders the oblique slice from the axial slice data in the memory.

Abstract: A JPEG2000 compressed image is transcoded to a lower bit-rate or lower resolution, or both, without having to decompress the initial JPEG2000 image and then recompress it to a lower bit-rate and/or resolution. Instead, arithmetic decoding is performed only to the nearest higher bit-rate layer, up to the desired resolution, before performing rate-distortion optimization to produce the transcoded image.

Abstract: A JPEG2000 compressed image is transcoded to a lower bit-rate or lower resolution, or both, without having to decompress the initial JPEG2000 image and then recompress it to a lower bit-rate and/or resolution. Instead, arithmetic decoding is performed only to the nearest higher bit-rate layer, up to the desired resolution, before performing rate-distortion optimization to produce the transcoded image.

Abstract: A method for simultaneously recording motion and still images, includes the steps of: capturing a motion image sequence and accompanying audio of a scene with a digital video camera adapted to record both motion and higher resolution still images; simultaneously capturing a still image sequence having a higher resolution and lower frame rate than the motion capture sequence; compressing the motion image sequence using interframe compression and the accompanying audio and storing the compressed motion image and audio data; and compressing the still images using intraframe coding and storing the compressed still image data.

Abstract: A method for generating an enhanced compressed digital image, including the steps of: capturing a digital image; generating additional information relating to the importance of photographed subject and corresponding background regions of the digital image; compressing the digital image to form a compressed digital image; associating the additional information with the compressed digital image to generate the enhanced compressed digital image; and storing the enhanced compressed digital image in a data storage device.

Abstract: A method for securely transacting a transaction based on a transaction document having an image contained within the document, the method includes the steps of compressing an image on the document; scrambling the structure of the compressed image according to a permutation; obtaining the inverse permutation; applying the inverse permutation to the scrambled image for obtaining an unscrambled image; and decompressing the unscrambled image.

Abstract: A method for encoding rate-distortion information associated with the compression of an input digital image includes the steps of: computing rate and distortion-reduction values associated with each coding pass of each compressed codeblock bit-stream, and encoding rate and distortion-reduction values associated with coding passes contained in the final compressed bit-stream. A method for using encoded rate-distortion information associated with a compressed digital image bit-stream during transcoding of said compressed digital image bitstream includes the steps of: parsing the compressed digital image bit-stream to obtain compressed codeblock bit-streams, decoding the encoded RD information to obtain rate and distortion-reduction values associated with codeblock coding passes, and using such rate-distortion information to optimally transcode such compressed digital image bit-stream to form a new compressed digital image bit-stream at a given bit-rate, resolution, and for given visual weights.

Abstract: A method for producing a compressed bit-stream from a digital image includes the steps of a) processing the digital image to produce a main subject belief map containing a continuum of belief values relating to the importance of subject and background regions in the image, b) performing a spatio-frequency transformation on the digital image to produce an array of transform coefficients, c) deriving a distortion-weighting factor for each transform coefficient from the belief map, and d) producing a compressed bit stream using an image compression system that is responsive to the distortion-weighting factors. The specific image compression system may be selected from a variety of image compression systems, including JPEG compression, JPEG2000 compression or vector quantization.