Abstract: A video encoder/decoder utilizes a bistream syntax that provides an independently decodable, partial picture unit, which may be in the form of a unit containing one or more contiguous rows of macroblocks (called a slice). This slice layer provides a flexible combination of error-resilience and compression efficiency. The slice layer encodes an efficient addressing mechanism (e.g., a syntax element specifying a beginning macroblock row of the slice layer), as well as an efficient mechanism to optionally retransmit picture header information. The slice layer provides decoding and reconstruction independence by disabling all forms of prediction, overlap and loop-filtering across slice-boundaries. This permits a slice coded in intra-mode to be reconstructed error-free, irrespective of errors in other regions of the picture.

Abstract: 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.

Abstract: A video decoder receives an entry point key frame comprising first and second interlaced video fields and decodes a first syntax element comprising information (e.g., frame coding mode) for the entry point key frame at a first syntax level (e.g., frame level) in a bitstream. The first interlaced video field is a predicted field, and the second interlaced video field is an intra-coded field. The information for the entry point key frame can be a frame coding mode (e.g., field interlace) for the entry point key frame. The decoder can decode a second syntax element at the first syntax level comprising second information (e.g., field type for each of the first and second interlaced video fields) for the entry point key frame.

Abstract: A video codec efficiently signals that a frame is identical to its reference frame, such that separate coding of its picture content is skipped. Information that a frame is skipped is represented jointly in a coding table of a frame coding type element for bit rate efficiency in signaling. Further, the video codec signals the picture type (e.g., progressive or interlaced) of skipped frames, which permits different repeat padding methods to be applied according to the picture type.

Abstract: A decoder receives an entry point header comprising plural control parameters for an entry point segment corresponding to the entry point header. The entry point header is in an entry point layer of a bitstream comprising plural layers. The decoder decodes the entry point header. The plural control parameters can include various combinations of control parameters such as a pan scan on/off parameter, a reference frame distance on/off parameter, a loop filtering on/off parameter, a fast chroma motion compensation on/off parameter, an extended range motion vector on/off parameter, a variable sized transform on/off parameter, an overlapped transform on/off parameter, a quantization decision parameter, and an extended differential motion vector coding on/off parameter, a broken link parameter, a closed entry parameter, one or more coded picture size parameters, one or more range mapping parameters, a hypothetical reference decoder buffer parameter, and/or other parameter(s).

Abstract: Techniques and tools for coding/decoding of digital video, and in particular, for determining, signaling and detecting entry points in video streams are described. Techniques and tools described herein are used to embed entry point indicator information in the bitstream that receivers, editing systems, insertion systems, and other systems can use to detect valid entry points in compressed video.

Abstract: A decoder receives a field start code for an entry point key frame. The field start code indicates a second coded interlaced video field in the entry point key frame following a first coded interlaced video field in the entry point key frame and indicates a point to begin decoding of the second coded interlaced video field. The first coded interlaced video field is a predicted field, and the second coded interlaced video field is an intra-coded field. The decoder decodes the second field without decoding the first field. The field start code can be followed by a field header. The decoder can receive a frame header for the entry point key frame. The frame header may comprise a syntax element indicating a frame coding mode for the entry point key frame and/or a syntax element indicating field types for the first and second coded interlaced video fields.

Abstract: A decoder processes a first bitstream element (e.g., a pull-down flag) in a first syntax layer (e.g., sequence layer or entry point layer) above frame layer in a bitstream for a video sequence, the bitstream comprising encoded source video having a source type (e.g., progressive or interlace). The decoder processes frame data in a second syntax layer (e.g., frame layer) of the bitstream for a frame (such as an interlaced frame or progressive frame, depending on source type, or a skipped frame) in the video sequence. The first bitstream element indicates whether a repeat-picture element (e.g., a repeat-frame element or a repeat field-element) is present or absent in the frame data in the second syntax layer.

Abstract: Techniques and tools are described for signaling hypothetical reference decoder parameters for video bitstreams, including signaling of buffer fullness. For example, a buffer size syntax element indicates a decoder buffer size, and a buffer fullness syntax element indicates a buffer fullness as a fraction of the decoder buffer size. As another example, buffer fullness is signaled in one or more entry point headers and other hypothetical reference decoder parameters are signaled in a sequence header.

Abstract: 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.

Abstract: Techniques and tools for intensity compensation for interlaced forward-predicted fields are described. For example, a video decoder receives and decodes a variable length code that indicates which of two reference fields for an interlaced forward-predicted field use intensity compensation (e.g., both, only the first, or only the second). The decoder performs intensity compensation on each of the two reference fields that uses intensity compensation. A video encoder performs corresponding intensity estimation/compensation and signaling.

Abstract: Entropy coding and decoding techniques are described, which may be implemented separately or in combination. For example, a video encoder uses two-layer run level coding to reduce bitrate for frequency transform coefficients in a quick and efficient manner, and a video decoder uses corresponding two-layer run level decoding. This two-layer coding/decoding can be generalized to more than two layers of run level coding/decoding. The video encoder and decoder exploit common patterns in run level information to reduce code table size and create opportunities for early termination of decoding. Using zoned Huffman code tables helps limit overall table size while still providing a level of adaptivity in encoding and decoding. Using embedded Huffman code tables allows the encoder and decoder to reuse codes for 8×8, 8×4, 4×8, and 4×4 blocks.

Abstract: A video encoder/decoder utilizes a bistream syntax that provides an independently decodable, partial picture unit, which may be in the form of a unit containing one or more contiguous rows of macroblocks (called a slice). This slice layer provides a flexible combination of error-resilience and compression efficiency. The slice layer encodes an efficient addressing mechanism (e.g., a syntax element specifying a beginning macroblock row of the slice layer), as well as an efficient mechanism to optionally retransmit picture header information. The slice layer provides decoding and reconstruction independence by disabling all forms of prediction, overlap and loop-filtering across slice-boundaries. This permits a slice coded in intra-mode to be reconstructed error-free, irrespective of errors in other regions of the picture.

Abstract: 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.

Abstract: A video encoder performs multi-resolution video coding. For example, the encoder adaptively changes frame sizes to reduce blocking artifacts at low bitrates. A video decoder performs corresponding multi-resolution decoding.

Abstract: Techniques and tools for performing fading estimation and compensation in video processing applications are described. For example, a video encoder performs fading compensation on one or more reference images to encode images in which fading is detected. A video decoder performs corresponding fading compensation on the one or more reference images.

Abstract: Techniques and tools for signaling for fading compensation in video processing applications are described. For example, a video encoder performs fading compensation on a reference image, signals that fading compensation is used, and signals fading parameters for the fading compensation. A video decoder receives the signaled information and performs fading compensation on the reference image according to the fading parameters.

Abstract: A set of one and two-dimensional transforms is constructed subject to certain range limited constraints to provide a computationally efficient transform implementation, such as for use in image and video coding. The constraints can include that the transform has a scaled integer implementation, provides perfect or near perfect reconstruction, has a DCT-like basis, is limited to coefficient within a range for representation in n-bits (e.g., n is 16 bits), has basis functions that are close in norm, and provides sufficient headroom for overflow of the range. A set of transforms is constructed with this procedure having an implementation within a 16-bit integer range for efficient computation using integer matrix multiplication operations.

Abstract: Techniques and tools for performing fading compensation in video processing applications are described. For example, during encoding, a video encoder performs fading compensation using fading parameters comprising a scaling parameter and a shifting parameter on one or more reference images. During decoding, a video decoder performs corresponding fading compensation on the one or more reference images.

Abstract: A method is described for efficiently determining total end-to-end distortion of a pre-compressed data stream, such as video streams or other media streams, at the time of delivery over a lossy-network, and for providing adaptive error-resilient delivery schemes based on distortion estimates. The methods can be utilized with single or multilayer packet streams and are particularly well suited for video streams. By way of example, distortion estimates are performed by generating side-information at the time of data stream compression, wherein the side-information is used in conjunction with information about the network status to determine an estimated distortion for the group of packets when the data stream is transported over the network to a destination end. This estimation may be utilized within described resiliency techniques in which the error correction mechanism is selected in response to the estimated distortion, which may be additionally refined in reference to cost factors.