Patent application number | Description | Published |
20080240235 | Adaptive deadzone size adjustment in quantization - Techniques and tools are described for adaptive deadzone (“DZ”) resizing during quantization. For example, in some embodiments, for quantization of an AC frequency coefficient of a block, a video encoder adjusts DZ size of a selected quantizer depending on the texture of the block. In other embodiments, a video encoder adjusts DZ size depending on the frequency of a coefficient being quantized. In still other embodiments, for quantization of an AC frequency coefficient of a block, a video encoder adjusts DZ size depending on the texture of the block and the frequency of the coefficient being quantized. | 10-02-2008 |
20080240250 | Regions of interest for quality adjustments - Quality settings established by an encoder are adjusted based on information associated with regions of interest (“ROIs”). For example, quantization step sizes can be reduced (to improve quality) or increased (to reduce bit rate). ROIs can be identified and quality settings can be adjusted based on input received from a user interface. An overlap setting can be determined for a portion of a picture that corresponds to an ROI overlap area. For example, an overlap setting is chosen from step sizes corresponding to a first overlapping ROI and a second overlapping ROI, or from relative reductions in step size corresponding to the first ROI and the second ROI. ROIs can be parameterized by information (e.g., using data structures) that indicates spatial dimensions of the ROIs and quality adjustment information (e.g., dead zone information, step size information, and quantization mode information). | 10-02-2008 |
20080240257 | Using quantization bias that accounts for relations between transform bins and quantization bins - Techniques and tools are described for using quantization bias that accounts for relations between transform bins and quantization bins. The techniques and tools can be used to compensate for mismatch between transform bin boundaries and quantization bin boundaries during quantization. For example, in some embodiments, when a video encoder quantizes the DC coefficients of DC-only blocks, the encoder compensates for mismatches between transform bin boundaries and quantization bin boundaries. In some implementations, the mismatch compensation uses an offset table that accounts for the mismatches. In other embodiments, the encoder uses adjustable thresholds to control quantization bias. | 10-02-2008 |
20080260278 | Encoding adjustments for animation content - Techniques and tools are described for encoding animation video. In some embodiments, a video encoder designates animation video for encoding as animation content, which typically involves changing one or more encoder settings or rules to improve encoding performance for the animation content. When the encoder encodes the animation video, the encoder detects edges in the animation video using texture and changes settings for areas that include detected edges so as to improve encoding quality for the areas. In some embodiments, a video encoder adjusts differential quantization rules and quantizes animation video according to the adjusted differential quantization rules. | 10-23-2008 |
20080304562 | Adaptive selection of picture-level quantization parameters for predicted video pictures - Techniques and tools for adaptive selection of picture quantization parameters (“QPs”) for predicted pictures are described. For example, a video encoder adaptively selects a delta QP for a B-picture based on spatial complexity, temporal complexity, whether differential quantization is active, whether the B-picture is available as a reference picture, or some combination or subset of these or other factors. The delta QP can then be used to adjust the picture QP for the B-picture (e.g., to reduce bit rate for the B-picture without appreciably reducing the perceived quality of a video sequence. | 12-11-2008 |
20090238279 | Motion-compensated prediction of inter-layer residuals - Techniques and tools are described for scalable video encoding and decoding. In some embodiments, an encoding tool encodes base layer video and outputs encoded base layer video in a base layer bit stream. The encoding tool encodes inter-layer residual video (representing differences between input video and reconstructed base layer video) using motion compensation relative to previously reconstructed inter-layer residual video. For the inter-layer residual video, the encoding tool outputs motion information and motion-compensated prediction residuals in an enhancement layer bit stream. A decoding tool receives the base layer bit stream and enhancement layer bit stream, reconstructs base layer video, reconstructs inter-layer residual video, and combines the reconstructed base layer video and reconstructed inter-layer residual video. Using motion compensation for the inter-layer residual video facilitates the use of separate motion vectors and separate codecs for the base layer video and inter-layer residual video. | 09-24-2009 |
20090245587 | Classifying and controlling encoding quality for textured, dark smooth and smooth video content - Techniques and tools for content classification and adaptive quantization are described. In an example implementation, a video encoding tool classifies blocks as textured, dark smooth or other smooth. The tool classifies a block as textured or non-textured by comparing the energy of AC coefficients for the block to a texture threshold, which can be set using a non-linear mapping of possible texture classification levels to possible texture thresholds. If a block is not textured, the tool further classifies the block as dark smooth or smooth depending on average intensity value for the block. Using the classification information and one or more control parameters to control bit allocation for dark smooth content relative to other smooth content, the tool encodes the video and outputs encoded video information. Example multi-pass approaches to setting the control parameters are also described. | 10-01-2009 |
20090273706 | Multi-level representation of reordered transform coefficients - Techniques and tools for encoding and decoding a block of frequency coefficients are presented. An encoder selects a scan order from multiple available scan orders and then applies the selected scan order to a two-dimensional matrix of transform coefficients, grouping non-zero values of the frequency coefficients together in a one-dimensional string. The encoder entropy encodes the one-dimensional string of coefficient values according to a multi-level nested set representation. In decoding, a decoder entropy decodes the one-dimensional string of coefficient values from the multi-level nested set representation. The decoder selects the scan order from among multiple available scan orders and then reorders the coefficients back into a two-dimensional matrix using the selected scan order. | 11-05-2009 |
20090296808 | Adaptive quantization for enhancement layer video coding - Techniques and tools for encoding enhancement layer video with quantization that varies spatially and/or between color channels are presented, along with corresponding decoding techniques and tools. For example, an encoding tool determines whether quantization varies spatially over a picture, and the tool also determines whether quantization varies between color channels in the picture. The tool signals quantization parameters for macroblocks in the picture in an encoded bit stream. In some implementations, to signal the quantization parameters, the tool predicts the quantization parameters, and the quantization parameters are signaled with reference to the predicted quantization parameters. A decoding tool receives the encoded bit stream, predicts the quantization parameters, and uses the signaled information to determine the quantization parameters for the macroblocks of the enhancement layer video. The decoding tool performs inverse quantization that can vary spatially and/or between color channels. | 12-03-2009 |
20100046612 | CONVERSION OPERATIONS IN SCALABLE VIDEO ENCODING AND DECODING - Techniques and tools for conversion operations between modules in a scalable video encoding tool or scalable video decoding tool are described. For example, given reconstructed base layer video in a low resolution format (e.g., 4:2:0 video with 8 bits per sample) an encoding tool and decoding tool adaptively filter the reconstructed base layer video and upsample its sample values to a higher sample depth (e.g., 10 bits per sample). The tools also adaptively scale chroma samples to a higher chroma sampling rate (e.g., 4:2:2). The adaptive filtering and chroma scaling help reduce energy in inter-layer residual video by making the reconstructed base layer video closer to input video, which typically makes compression of the inter-layer residual video more efficient. The encoding tool also remaps sample values of the inter-layer residual video to adjust dynamic range before encoding, and the decoding tool performs inverse remapping after decoding. | 02-25-2010 |
20100046626 | ENTROPY CODING/DECODING OF HIERARCHICALLY ORGANIZED DATA - Techniques and tools for encoding and decoding data values that are hierarchically organized are presented. For example, an encoder encodes data as a set that has a hierarchy of subsets with set symbols. In the encoding, the encoder evaluates the data values of the set and selectively encodes a symbol combination code that indicates the set symbols of multiple subsets of the set. Then, for each of the multiple subsets considered as a new set, the encoder selectively repeats the evaluating, selective encoding and selective repetition for the new set. In corresponding decoding, a decoder decodes data encoded as a set that has a hierarchy of subsets with set symbols. In some implementations, the encoding and decoding are adaptive and use a symbol alphabet with nested elements. | 02-25-2010 |
20100061447 | SKIP MODES FOR INTER-LAYER RESIDUAL VIDEO CODING AND DECODING - Techniques and tools for skip modes in encoding and decoding of inter-layer residual video are described. For example, an encoder encodes multiple macroblocks of a picture of inter-layer residual video. For a current macroblock that is skipped, the encoder selects a skip mode from among multiple available skip modes and uses the selected skip mode when encoding the current macroblock. The skip modes can include intra skip mode and predicted-motion skip mode. A corresponding decoder, for the current macroblock, selects and uses the skip mode for the current macroblock during decoding. As another example, an encoder encodes multiple channels of a picture of inter-layer residual video. For each channel, the encoder determines whether to skip the channel. The encoder signals channel skip information to indicate which channels are skipped. A corresponding decoder parses the channel skip information and determines on a channel-by-channel basis whether to skip the respective channels. | 03-11-2010 |
20100189183 | MULTIPLE BIT RATE VIDEO ENCODING USING VARIABLE BIT RATE AND DYNAMIC RESOLUTION FOR ADAPTIVE VIDEO STREAMING - A video encoding system encodes video streams for multiple bit rate video streaming using an approach that permits the encoded bit rate to vary subject to a peak bit rate and average bit rate constraints for higher quality streams, while a bottom bit rate stream is encoded to achieve a constant chunk rate. The video encoding system also dynamically decides an encoding resolution for segments of the multiple bit rate video streams that varies with video complexity so as to achieve a better visual experience for multiple bit rate streaming. | 07-29-2010 |
20100246671 | DC COEFFICIENT SIGNALING AT SMALL QUANTIZATION STEP SIZES - Described tools and techniques relate to signaling for DC coefficients at small quantization step sizes. The techniques and tools can be used in combination or independently. For example, a tool such as a video encoder or decoder processes a VLC that indicates a DC differential for a DC coefficient, a FLC that indicates a value refinement for the DC differential, and a third code that indicates the sign for the DC differential. Even with the small quantization step sizes, the tool uses a VLC table with DC differentials for DC coefficients above the small quantization step sizes. The FLCs for DC differentials have lengths that vary depending on quantization step size. | 09-30-2010 |
20110255595 | QUANTIZATION ADJUSTMENT BASED ON TEXTURE LEVEL - A video encoder identifies a current smooth region of a current picture in a sequence and performs temporal analysis by determining whether a corresponding region in at least one previous and/or future picture is smooth. Based at least in part on the temporal analysis, the encoder adjusts quantization in the current smooth region. An encoder determines a differential quantization interval for a sequence, the interval comprising an interval number. The interval constrains the encoder to skip differential quantization for at least the interval number of predicted pictures after a predicted differentially quantized picture. An encoder analyzes texture in a current picture and sets a smoothness threshold. The encoder compares texture data with the smoothness threshold and adjusts differential quantization for at least part of the current picture based on a finding of at least one smooth region in the current picture according to the smoothness threshold. | 10-20-2011 |
20110280303 | FLEXIBLE RANGE REDUCTION - Techniques and tools are described for flexible range reduction of samples of video. For example, an encoder signals a first set of one or more syntax elements for range reduction of luma samples and signals a second set of one or more syntax elements for range reduction of chroma samples. The encoder selectively scales down the luma samples and chroma samples in a manner consistent with the first syntax element(s) and second syntax element(s), respectively. Or, an encoder signals range reduction syntax element(s) in an entry point header for an entry point segment, where the syntax element(s) apply to pictures in the entry point segment. If range reduction is used for the pictures, the encoder scales down samples of the pictures. Otherwise, the encoder skips the scaling down. A decoder performs corresponding parsing and scaling up operations. | 11-17-2011 |
20120243615 | MULTI-LEVEL REPRESENTATION OF REORDERED TRANSFORM COEFFICIENTS - Techniques and tools for encoding and decoding a block of frequency coefficients are presented. An encoder selects a scan order from multiple available scan orders and then applies the selected scan order to a two-dimensional matrix of transform coefficients, grouping non-zero values of the frequency coefficients together in a one-dimensional string. The encoder entropy encodes the one-dimensional string of coefficient values according to a multi-level nested set representation. In decoding, a decoder entropy decodes the one-dimensional string of coefficient values from the multi-level nested set representation. The decoder selects the scan order from among multiple available scan orders and then reorders the coefficients back into a two-dimensional matrix using the selected scan order. | 09-27-2012 |
20120269266 | REGIONS OF INTEREST FOR QUALITY ADJUSTMENTS - Quality settings established by an encoder are adjusted based on information associated with regions of interest (“ROIs”). For example, quantization step sizes can be reduced (to improve quality) or increased (to reduce bit rate). ROIs can be identified and quality settings can be adjusted based on input received from a user interface. An overlap setting can be determined for a portion of a picture that corresponds to an ROI overlap area. For example, an overlap setting is chosen from step sizes corresponding to a first overlapping ROI and a second overlapping ROI, or from relative reductions in step size corresponding to the first ROI and the second ROI. ROIs can be parameterized by information (e.g., using data structures) that indicates spatial dimensions of the ROIs and quality adjustment information (e.g., dead zone information, step size information, and quantization mode information). | 10-25-2012 |
20130010861 | USE OF FRAME CACHING TO IMPROVE PACKET LOSS RECOVERY - Various new and non-obvious apparatus and methods for using frame caching to improve packet loss recovery are disclosed. One of the disclosed embodiments is a method for using periodical and synchronized frame caching within an encoder and its corresponding decoder. When the decoder discovers packet loss, it informs the encoder which then generates a frame based on one of the shared frames stored at both the encoder and the decoder. When the decoder receives this generated frame it can decode it using its locally cached frame. | 01-10-2013 |
20130039414 | EFFICIENT MACROBLOCK HEADER CODING FOR VIDEO COMPRESSION - The coded block parameters used to code blocks of image samples into structures called macroblocks are compressed more efficiently by exploiting the correlation between chrominance and luminance blocks in each macroblock. In particular, the coded block pattern for chrominance and luminance are combined into a single parameter for the macroblock and jointly coded with a single variable length code. To further enhance coding efficiency, the spatial coherence of coded block patterns can be exploited by using spatial prediction to compute predicted values for coded block pattern parameters. | 02-14-2013 |
20130301704 | VIDEO CODING / DECODING WITH RE-ORIENTED TRANSFORMS AND SUB-BLOCK TRANSFORM SIZES - 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. | 11-14-2013 |
20130301732 | VIDEO CODING / DECODING WITH MOTION RESOLUTION SWITCHING AND SUB-BLOCK TRANSFORM SIZES - 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. | 11-14-2013 |
20140133583 | USE OF FRAME CACHING TO IMPROVE PACKET LOSS RECOVERY - Various new and non-obvious apparatus and methods for using frame caching to improve packet loss recovery are disclosed. One of the disclosed embodiments is a method for using periodical and synchronized frame caching within an encoder and its corresponding decoder. When the decoder discovers packet loss, it informs the encoder which then generates a frame based on one of the shared frames stored at both the encoder and the decoder. When the decoder receives this generated frame it can decode it using its locally cached frame. | 05-15-2014 |
20140294070 | ADAPTIVE QUANTIZATION FOR ENHANCEMENT LAYER VIDEO CODING - Techniques and tools for encoding enhancement layer video with quantization that varies spatially and/or between color channels are presented, along with corresponding decoding techniques and tools. For example, an encoding tool determines whether quantization varies spatially over a picture, and the tool also determines whether quantization varies between color channels in the picture. The tool signals quantization parameters for macroblocks in the picture in an encoded bit stream. In some implementations, to signal the quantization parameters, the tool predicts the quantization parameters, and the quantization parameters are signaled with reference to the predicted quantization parameters. A decoding tool receives the encoded bit stream, predicts the quantization parameters, and uses the signaled information to determine the quantization parameters for the macroblocks of the enhancement layer video. The decoding tool performs inverse quantization that can vary spatially and/or between color channels. | 10-02-2014 |
20140307776 | VIDEO CODING / DECODING WITH RE-ORIENTED TRANSFORMS AND SUB-BLOCK TRANSFORM SIZES - 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. | 10-16-2014 |
20140334534 | SUB-BLOCK TRANSFORM CODING OF PREDICTION RESIDUALS - Techniques and tools for sub-block transform coding 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. The encoder and decoder may use different scan patterns for different transform sizes when scanning values from two-dimensional blocks into one-dimensional arrays, or vice versa. The encoder and decoder may use sub-block pattern codes to indicate the presence or absence of information for the sub-blocks of particular blocks. | 11-13-2014 |
20140369405 | Multi-Layered Rate Control for Scalable Video Coding - 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. | 12-18-2014 |
20150043633 | ADAPTIVE QUANTIZATION FOR ENHANCEMENT LAYER VIDEO CODING - Techniques and tools for encoding enhancement layer video with quantization that varies spatially and/or between color channels are presented, along with corresponding decoding techniques and tools. For example, an encoding tool determines whether quantization varies spatially over a picture, and the tool also determines whether quantization varies between color channels in the picture. The tool signals quantization parameters for macroblocks in the picture in an encoded bit stream. In some implementations, to signal the quantization parameters, the tool predicts the quantization parameters, and the quantization parameters are signaled with reference to the predicted quantization parameters. A decoding tool receives the encoded bit stream, predicts the quantization parameters, and uses the signaled information to determine the quantization parameters for the macroblocks of the enhancement layer video. The decoding tool performs inverse quantization that can vary spatially and/or between color channels. | 02-12-2015 |
20150063459 | VIDEO CODING / DECODING WITH MOTION RESOLUTION SWITCHING AND SUB-BLOCK TRANSFORM SIZES - 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. | 03-05-2015 |