Aspects of the disclosure provide a method and an apparatus including processing circuitry for video decoding. The processing circuitry is configured to decode coding information for a current block. The coding information can indicate that the current block is coded in a string copy mode. The processing circuitry is configured to determine a string vector (SV) and a string length of a current string in the current block based on the coding information. The string length can be N3 times L where N3 and L are positive integers, and L is larger than 1. The processing circuitry is configured to reconstruct the current string based on the SV and the string length of the current string. In an example, the current block is a luma block and L is 4.

A better compromise between encoding complexity and achievable rate distortion ratio, and/or to achieve a better rate distortion ratio is achieved by using multitree sub-divisioning not only in order to subdivide a continuous area, namely the sample array, into leaf regions, but using the intermediate regions also to share coding parameters among the corresponding collocated leaf blocks. By this measure, coding procedures performed in tiles—leaf regions—locally, may be associated with coding parameters individually without having to, however, explicitly transmit the whole coding parameters for each leaf region separately. Rather, similarities may effectively exploited by using the multitree subdivision.

A better compromise between encoding complexity and achievable rate distortion ratio, and/or to achieve a better rate distortion ratio is achieved by using multitree sub-divisioning not only in order to subdivide a continuous area, namely the sample array, into leaf regions, but using the intermediate regions also to share coding parameters among the corresponding collocated leaf blocks. By this measure, coding procedures performed in tiles—leaf regions—locally, may be associated with coding parameters individually without having to, however, explicitly transmit the whole coding parameters for each leaf region separately. Rather, similarities may effectively exploited by using the multitree subdivision.

An image processing apparatus, including processing circuitry configured to decode a bit stream to generate quantized data. The bit stream includes a flag, for each block, that specifies whether or not a difference quantization parameter is present in the bit stream. The flag is included in a first layer that is higher than a second layer in which the difference quantization parameter is set. The processing circuitry is configured to set, according to the flag, a current quantization parameter for a current sub block formed by block partitioning, which splits a block into smaller sub blocks. The processing circuitry is configured to inversely quantize the generated quantized data using the set current quantization parameter.

An image processing apparatus, including processing circuitry configured to decode a bit stream to generate quantized data. The bit stream includes a flag, for each block, that specifies whether or not a difference quantization parameter is present in the bit stream. The flag is included in a first layer that is higher than a second layer in which the difference quantization parameter is set. The processing circuitry is configured to set, according to the flag, a current quantization parameter for a current sub block formed by block partitioning, which splits a block into smaller sub blocks. The processing circuitry is configured to inversely quantize the generated quantized data using the set current quantization parameter.

Methods of encoding and decoding for video data are described in which multi-level significance maps are used in the encoding and decoding processes. The significant-coefficient flags that form the significance map are grouped into contiguous groups, and a significant-coefficient-group flag signifies for each group whether that group contains no non-zero significant-coefficient flags. A multi-level scan order may be used in which significant-coefficient flags are scanned group-by-group. The group scan order specifies the order in which the groups are processed, and the scan order specifies the order in which individual significant-coefficient flags within the group are processed. The bitstream may interleave the significant-coefficient-group flags and their corresponding significant-coefficient flags, if any.

Methods of encoding and decoding for video data are described in which multi-level significance maps are used in the encoding and decoding processes. The significant-coefficient flags that form the significance map are grouped into contiguous groups, and a significant-coefficient-group flag signifies for each group whether that group contains no non-zero significant-coefficient flags. A multi-level scan order may be used in which significant-coefficient flags are scanned group-by-group. The group scan order specifies the order in which the groups are processed, and the scan order specifies the order in which individual significant-coefficient flags within the group are processed. The bitstream may interleave the significant-coefficient-group flags and their corresponding significant-coefficient flags, if any.

A method of encapsulating an encoded bitstream representing one or more images, the encapsulated bitstream comprising a data part and a metadata part. The method including providing image item information identifying a portion of the data part representing a sub-image or an image of a single image; providing image description information comprising parameters including display parameters and/or transformation operators relating to one or more images and outputting said bitstream together with said provided information as an encapsulated data file, wherein the image description information is stored in the metadata part.

A method of encapsulating an encoded bitstream representing one or more images, the encapsulated bitstream comprising a data part and a metadata part. The method including providing image item information identifying a portion of the data part representing a sub-image or an image of a single image; providing image description information comprising parameters including display parameters and/or transformation operators relating to one or more images and outputting said bitstream together with said provided information as an encapsulated data file, wherein the image description information is stored in the metadata part.

The present invention relates to a device and method for transmitting and receiving a broadcasting signal including a subtitle service. An embodiment of the present invention provides a broadcasting signal transmission method comprising the steps of: generating a broadcasting signal including video data and subtitle data; and transmitting the generated broadcasting signal. According to an embodiment of the present invention, a transmission stream providing a digital broadcasting subtitle service using XML subtitles can be transmitted.