Abstract: A communication device and method for controlling a bit rate when encoding video data that includes a plurality of frames. The method includes partitioning a received current frame into groups of blocks; estimating an energy for a current group of blocks, where the energy of the current group of blocks depends from a same group of blocks in a previous frame; determining a target number of bits for the current group of blocks; calculating a quantization parameter for the current group of blocks of the current frame based on the estimated energy of the current group of blocks and the determined target number of bits for the current group of blocks; and encoding the current group of blocks based on the calculated quantization parameter.

Abstract: Method of encoding an input video frame into an encoded video frame. The method comprises the steps of disassembling the input video frame into a plurality of blocks of pixels; and for each block being a current block, generating a corresponding predicted block from already reconstructed pixels, generating a residual block by subtracting the predicted block from the current block, and generating a reconstructed block from the residual block and the predicted block, generating the encoded video frame from the residual block, creating a local structure of reconstructed pixels in a region of the predicted block and aligning the predicted block with the local structure to produce an aligned predicted block, wherein the aligned predicted block is used in the steps of generating the residual block and generating the corresponding reconstructed block.

Abstract: In video encoding and decoding predictions may be generated by intra-frame prediction. Intra-frame prediction uses reconstructed pixels in a reconstructed frame. Intra-frame prediction is performed by extending the reconstructed pixels into a predicted block using intra-frame prediction modes, each intra-frame prediction mode indicating a direction of the extension. In order to reduce the number of possible intra-frame prediction modes, a subset is selected from a predetermined set of possible intra-frame prediction modes. A subset of intra-frame prediction modes can be created by forming preselection sets of intra-frame prediction modes on the basis of similarity of their associated predicted blocks and selecting a representative intra-frame prediction mode from each preselection set.

Abstract: A method of encoding a plurality of adaptive filter coefficients (104, 107, 112) into a bitstream (110). The method comprises the steps of entropy encoding (109) the adaptive filter coefficients (104, 107, 112) into the bitstream (110), whereby a prediction (202) for an instance (204) of the adaptive filter coefficients is determined (201) based on at least one of the remaining adaptive filter coefficients (206), a prediction error (205) is determined (203) based on the difference between the instance (204) of the adaptive filter coefficients and the prediction (202), and wherein the step of entropy encoding (109) the plurality of adaptive filter coefficients (104, 107, 112) comprises entropy encoding (109) the prediction error (205) for the instance (204) of the adaptive filter coefficients and entropy encoding (109) the remaining adaptive filter coefficients (206).

Abstract: A method and device for determining an adaptive filter having multiple filter parameters, wherein a first filter parameter has a first level of adaptivity and a second filter parameter has a second, different level of adaptivity. Parameter values for the first filter parameter are determined among a first set of allowable filter parameter values. Parameter values for the second filter parameter are correspondingly determined among a second, different set of allowable filter parameter values. The different levels of adaptivity in the filter parameters are achieved because the second set includes more allowable filter parameter values than the first set. The adaptive filter is advantageously used in filtering in intra- or inter-predication during video encoding and decoding.

Abstract: The present application discloses systems and methods for using DC change parameters in video coding. In one embodiment, the method includes the steps of: (a) obtaining a DC change parameter; (b) decoding encoded video data to obtain reconstructed pixel values; and (c) using the reconstructed pixel values, a filter, and the DC change parameter to obtain filtered reconstructed pixel values with a DC change.

Abstract: A secondary stream of rich media packets defining scene states of a sub-portion of a scene representable by a primary stream or rich media packets. Local random access data defining instructions for enabling creation, when being processed, of a starting state of the scene sub-portion without affecting the scene state of scene portions is provided. The local random access data is packed into at least one rich media packet, which is inserted into the secondary stream and transmitted to at least one user terminal. The local random access data can be used by terminals for tuning-in to the secondary stream and/or for error recovery relating to the secondary stream.

Abstract: A method of seeking in a rich media stream provided from a multimedia server to at least one multimedia client, wherein the method may be executed in an encoder of a multimedia server or a decoder or a multimedia client. A seeking instruction is inserted into the media stream at time instance X, comprising an offset time instance Y, in order to be used for seeking at a global time rate. A method for enabling synchronisation in a rich media stream wherein the synchronisation is based on a global timeline is also provided.

Abstract: The invention teaches a media container file comprising media data organized into media source blocks. Forward error correction (FEC) redundancy data is pre-calculated for the different source blocks and organized into the container file as different FEC reservoirs. The container file also comprises meta data providing an association between the media source blocks and the respective FEC reservoirs. The container file can be employed by a media server in a media session for compiling media data packets to be transmitted to requesting clients without the need of extensive data processing and FEC calculation.

Abstract: A media stream comprising rich media scene packets and scene update packets is complemented with a data packet defining an exit point for interrupting rendering rich media of the stream and a scene update packet associated with the data packet and defining an entry point back to rendering rich media of the stream. The exit-entry point pair defines an alternative media rendering route that can be used by user terminals to recover from errors in the media stream.

Abstract: The present invention relates to a new type of random access point adapted to be included in a media representation comprising a plurality of data objects. The random access point is characterized by a reference to a data element in another data object of said plurality of data objects, wherein said referenced data element at least partly describes how to reconstruct media from said media representation. The invention further relates to a method and apparatus of reconstructing media from a media representation. The method comprises receiving a data object comprising at least one reference to a data element in another data object of the media representation; and re-constructing the media by use of information associated with said referenced data element(s).

Abstract: The invention involves collective management of video and audio content in a content provider. The video and audio content is available in multiple potential versions, e.g. in the form of scalable media or media pre-encoded to fixed bandwidth levels. The video and audio data is associated with bandwidth share information enabling estimation of a respective apportionment of a total available bandwidth to the video and audio content. The provider uses this share information and information of the total assignable bandwidth level for providing a respective video version and audio version from the multiple potential versions. This allows for increased user-quality when rendering the video and audio data as optimal video and audio version can be dynamically provided during the media session.

Abstract: The invention teaches a media container file comprising media data organized into media source blocks. The media source blocks are partitioned into source symbols that can be processed by a forward error correction (FEC) algorithm for generation of FEC redundancy data. Information of this source block partitioning is included in the file in addition to the source blocks. The container file also comprises meta data providing an association between the media source blocks and the partitioning information. The container file can be employed by a media server in a media session for compiling media data packets to be transmitted to requesting clients without the need of extensive data processing before calculating FEC data.

Abstract: In a method of video data compression a video frame in a sequence of frames is divided into a number of macroblocks, a particular macroblock being adjacent to a number of previously coded macroblocks including both intra-coded and inter-coded macroblocks. The method includes selecting either a full prediction or limited prediction type in encoding the particular macroblock to provide a corresponding data bit stream, full prediction using both adjacent inter-coded and intra-coded macroblocks, and limited prediction using intra-coded macroblocks only. A signal is provided along with the bit stream to indicate the selected prediction type to a decoder disposed to recover data from the bit stream. The prediction type may be either signaled explicitly, such as by providing a code word in the bit stream, or may be inferred implicitly by selected values or levels of a coding variable.

Abstract: In a method for transmitting a multimedia presentation comprising a number of media objects: the media objects are organized in a multimedia container or container format; identifiers referring to the media objects are organized in the same container; and an identifiable file coordinating the media objects is also provided in the container.

Abstract: A method of video data compression is provided which is comparatively efficient in compressing data, and at the same time enables transmission of compressed data with sufficient robustness to withstand losses in the transmission channel. A frame of data is divided into coded macroblocks and skipped macroblocks which are grouped into respective slices in a sequence of slices. Respective slices are allowed to contain arbitrary numbers of consecutive macroblocks, and can begin and end at arbitrary positions within the frame. A run-length codeword, comprising a small number of bits, is inserted at the end of a slice to indicate the total number of skipped macroblocks between the final coded macroblock and the end of the slice. To further enhance error resilience an additional codeword, which also indicates the total number of skipped macroblocks, may be inserted at the beginning of the next-following slice.

Abstract: Disclosed is a method of compressing data contained in variable length or universal variable length code words to be carried in a digital bitstream. The method includes formatting a first set of code words for data and then constructing a second set of code words containing code words from the first set as well as concatenations of code words from the first set. Code words from the second set are to carry data in compressed form in the digital bitstream. One way in which the concatenation is accomplished includes selecting a code word from said first set of code words and applying it as a prefix to itself and to all of the other words in the first set, thereby constructing the second set. The code word selected from the first set for application as a prefix may be the shortest code word of the first set.

Abstract: A method and apparatus for maximizing the prediction utility of previously encoded macroblocks by adjusting the scanning order of the blocks within a macroblock to be encoded is disclosed. Where no previously encoded blocks are available above the macroblock being encoded, the alternative scanning orders allow for maximum utility of previously encoded blocks located to the left of the macroblock being encoded. Where no previously encoded blocks are available either above or to the left of the macroblock being encoded, the alternative scanning orders allow for maximum utility of information from blocks that are presently being encoded in the same macroblock. The particular scanning order used may be signaled implicitly based on the location of the macroblock being encoded, or it may be signaled explicitly by code words within the bitstream containing the encoded block information.

Abstract: A system and a method for coding and decoding video data are invented. In a system and method of video data compression a video frame is divided into a sequence of image blocks, wherein one of several possible block-coding modes is an implicit global motion compensation (IGMC) mode, which is used to copy pixels from a previous frame displaced by a predicted motion vector. In another embodiment of the invention, a system and method of a video data compression, a video frame is segmented into a sequence of slices, wherein each slice includes a number of macroblocks. Respective slices are encoded and a signal is included in the header of an encoded slice to indicate whether the slice is GMC enabled, that is, whether global motion compensation is to be used in reconstructing the encoded slice. If so, GMC information, such as information representing a set of motion vectors, is included with the slice.

Abstract: In a method of video data compression a video frame in a sequence of frames is divided into a number of macroblocks, a particular macroblock being adjacent to a number of previously coded macroblocks including both intra-coded and inter-coded macroblocks. The method includes selecting either a full prediction or limited prediction type in encoding the particular macroblock to provide a corresponding data bit stream, full prediction using both adjacent inter-coded and intra-coded macroblocks, and limited prediction using intra-coded macroblocks only. A signal is provided along with the bit stream to indicate the selected prediction type to a decoder disposed to recover data from the bit stream. The prediction type may be either signaled explicitly, such as by providing a code word in the bit stream, or may be inferred implicitly by selected values or levels of a coding variable.