摘要:
The present invention relates to a method of encoding blocks of values, e.g. DCT blocks, generated in accordance with an image compression scheme. The values are expressed as a set of bit planes, each bit plane comprising, for the values, all bits with a specific significance. In each bit plane at least one parameter is determined (7) in accordance with a predetermined definition, the parameter defining a partition of the bits in the bit plane which encloses all set bits. All bits in the partition are transferred (8) to a bit stream that may be truncated. This provides a method with low complexity. The invention further relates to a corresponding encoding device, a corresponding decoding device, and a corresponding bit-stream.
摘要:
A data compression apparatus receives a digital information signal, determines a probability signal from the digital information signal and at least one previously determined value of the probability signal, entropy encodes the digital information signal into a compressed digital information signal, in response to the probability signal, and transmits or records the compressed signal. Also, a data expansion apparatus receives the compressed signal and entropy decodes the compressed signal into a expanded replica of the digital information signal, in response to a second probability signal determined from the replica and at least one previously determined value of the second probability signal. Thus, complex division operations can be avoided.
摘要:
Storing of data items in a memory (31) is provided wherein the data items are divided into successive data pieces of decreasing significance, and the data pieces are stored in respective parts of the memory (31), and when applying a data piece to the memory (31) in case all candidate memory parts are assigned to other data pieces: if the significance of the applied data piece is lower than a lowest significance of the other data pieces, discarding the applied data piece; if the significance of the applied data piece is higher than the lowest significance, storing the applied data piece in one of the candidate memory parts at expense of a given other data piece which has a lower significance than the significance of the applied data piece. Advantageous use of the invention is made in applications using a device of fixed storage capacity for storing compressible data, such as video, images, audio, speech.
摘要:
The invention relates to measures to improve an arithmetic decoder. The method of arithmetically decoding an arithmetically encoded information signal into an information signal comprising a serial sequence of n-bit symbols is adapted to decode two subsequent symbols of the information signal in one decoding cycle if the first symbol to be decoded has the most probable symbol.
摘要:
The invention relates to a scalable video (de)coding method for wireless transmission of high definition television signals. Scalable means that the bitstream contains successively smaller quality refinements and that the bitstream can be truncated. The video images are divided in slices, and each slice is divided in blocks of 8×8 pixels. For each block, an optimal encoding method is chosen. Depending on whether the block is found to contain natural or synthetic image content, transform coding (DCT) or graphic coding is applied. Because the different encoding modes have different properties as regards picture quality, the bitstream format has to enable the encoder to very flexibly choose which bits to send first. The bitstream format in accordance with the invention consists of a multitude of scans (31-34) through the coded data of a series of individual blocks, e.g. a slice. In each scan, the encoder decides whether it will include data for natural blocks (BS1,BS2), for synthetic blocks (BS0,BS1), or both. For the DCT blocks, it can further choose between DC coefficient bits (22) and AC coefficient bits (23). For example, the encoder can choose to first send a few scans of DCT DC bits, then send a few scans of graphics bits and then send some DCT AC bits. The decisions that the encoder makes are signaled to the decoder in the form of flags that precede each block part (e.g. encoded bit plane) and/or plurality of blocks (e.g. a slice).
摘要:
Coding is provided in which a multi-media object is coded to obtain a bit-stream, and quality information is added to the bit-stream, which quality information indicates a quality of the object in relation to a given position in (or a given part of) the bit-stream. By adding quality information to the bit-stream, jointly storing or transmitting multiple coded objects can be optimized in that the quality of the object can be easily taken into account.
摘要:
In order to improve an arithmetic decoder, the method of arithmetically decoding an arithmetically-encoded information signal into an information signal including a serial sequence of n-bit symbols is adapted to decode two subsequent symbols of the information signal in one decoding cycle if the first symbol to be decoded has the most probable symbol value.
摘要:
The invention relates to a bit-plane coding method of signals, for example, an image or video signal in the DCT transform domain. The bit planes of the DCT blocks are transmitted bit-plane by bit-plane in order of significance. As each plane contains more signal energy than the lower significant layers together, the resulting bitstream is scalable in the sense that it may be truncated at any position. The later the bitstream is truncated, the smaller the residual error when the image is reconstructed. For each bit plane, a zone or partition of bit plane is created that encompasses all the non-zero bits of the DCT coefficients in that bit plane. The partition is created in accordance with a strategy that is selected from a number of options in dependence of the content of the overall signal and/or the actual bit plane. A different zoning strategy may be used for natural images than for graphic content, and the strategy may vary from bitplane to bitplane. The form as well as other properties such as size of each partition can thus be optimally adapted to the content. Two-dimensional rectangular zones and one-dimensional zigzag scan zones may be mixed within an image or even within a DCT block. The selected zone creating strategy is embedded in the bitstream, along with the DCT coefficient bits in the actual partition.
摘要:
Coding is provided in which a multi-media object is coded to obtain a bit-stream, and quality information is added to the bit-stream, which quality information indicates a quality of the object in relation to a given position in (or a given part of) the bit-stream. By adding quality information to the bit-stream, jointly storing or transmitting multiple coded objects can be optimized in that the quality of the object can be easily taken into account.
摘要:
The invention relates to a scalable video (de)coding method for wireless transmission of high definition television signals. Scalable means that the bitstream contains successively smaller quality refinements and that the bitstream can be truncated. The video images are divided in slices, and each slice is divided in blocks of 8×8 pixels. For each block, an optimal encoding method is chosen. Depending on whether the block is found to contain natural or synthetic image content, transform coding (DCT) or graphic coding is applied. Because the different encoding modes have different properties as regards picture quality, the bitstream format has to enable the encoder to very flexibly choose which bits to send first. The bitstream format in accordance with the invention consists of a multitude of scans (31-34) through the coded data of a series of individual blocks, e.g. a slice. In each scan, the encoder decides whether it will include data for natural blocks (BS1,BS2), for synthetic blocks (BS0,BS1), or both. For the DCT blocks, it can further choose between DC coefficient bits (22) and AC coefficient bits (23). For example, the encoder can choose to first send a few scans of DCT DC bits, then send a few scans of graphics bits and then send some DCT AC bits. The decisions that the encoder makes are signaled to the decoder in the form of flags that precede each block part (e.g. encoded bit plane) and/or plurality of blocks (e.g. a slice).