A method of encoding a three-dimensional point cloud. The method comprising: obtaining a set of points within the three-dimensional point cloud, a point within the set of points having a co-ordinate in three-dimensions; converting the points into a two-dimensional representation, wherein, for a point within the set of points, information describing the co-ordinate is represented as a location within the two-dimensional representation and a value at the location; and encoding the two-dimensional representation using a tier-based hierarchical coding format to output encoded data, wherein the tier-based hierarchical coding format encodes the two-dimensional representation as a plurality of layers, the plurality of layers representing echelons of data used to progressively reconstruct the signal at different levels of quality.

Innovations in stream configuration operations and playback operations for adaptive streaming of panoramic video are described. The innovations include features of adaptive streaming of panoramic video with composite pictures. For example, a stream configuration tool splits an input picture of panoramic video into multiple sections and creates multiple composite pictures. A composite picture includes one of the sections as well as a low-resolution version of the input picture. A playback tool reconstructs one or more composite pictures. Under normal operation, the playback tool can use the reconstructed section(s) of the composite picture(s) to render high-quality views of the panoramic video. If the view window dramatically changes, however, or if encoded data for a section is lost or corrupted, the playback tool can use the low-resolution version of the input picture to render lower-quality details for views of the panoramic video, without disruption of playback.

Innovations in stream configuration operations and playback operations for adaptive streaming of panoramic video are described. The innovations include features of adaptive streaming of panoramic video with composite pictures. For example, a stream configuration tool splits an input picture of panoramic video into multiple sections and creates multiple composite pictures. A composite picture includes one of the sections as well as a low-resolution version of the input picture. A playback tool reconstructs one or more composite pictures. Under normal operation, the playback tool can use the reconstructed section(s) of the composite picture(s) to render high-quality views of the panoramic video. If the view window dramatically changes, however, or if encoded data for a section is lost or corrupted, the playback tool can use the low-resolution version of the input picture to render lower-quality details for views of the panoramic video, without disruption of playback.

Different implementations are described, particularly implementations for video encoding and decoding based on wherein the partitioning tree structure is partially shared between luma and chroma blocks are presented. According to an implementation, a single partitioning tree structure is shared between luma and chroma blocks from a root node of the partitioning tree down to a switching node and a dual partitioning tree structure is determined for luma and chroma blocks from the switching node down to a leaf node of the partitioning tree. Thus, this implementation optimizes the coding efficiency by allowing separated trees for smaller blocks, while limiting the complexity of decoding pipeline.

Systems and methods for coding and decoding are provided. A method includes receiving a coded video stream including a picture partitioned into a plurality of sub-pictures, and further including adaptive resolution change (ARC) information that is signaled directly within a header of a sub-picture from among the plurality of sub-pictures, or that is signaled directly within a parameter set without any of the ARC information within the parameter set being referenced in any header or other parameter set, or that is provided within the parameter set and referenced in the header; and adaptively changing resolution of the sub-picture based on the ARC information.

Encoding an image stream may include receiving an image stream with an original image resolution; generating a plurality of copies of the image stream with the original image resolution; encoding, for each copy of the plurality of copies of the image stream, the copy of the image stream to generate an encoded copy of the image stream, wherein the encoded copy of the image stream comprises a first region having a first image resolution and a second region having a second image resolution, wherein each encoded copy of the plurality of encoded copies of the image stream has a different first region, and providing, to a playback device, at least one encoded copy of the plurality of encoded copies of the image stream.

Scalable video coding is rendered more efficient by deriving/selecting a subblock subdivision to be used for enhancement layer prediction, among a set of possible subblock subdivisions of an enhancement layer block by evaluating the spatial variation of the base layer coding parameters over the base layer signal. By this measure, less of the signalization overhead has to be spent on signaling this subblock subdivision within the enhancement layer data stream, if any. The subblock subdivision thus selected may be used in predictively coding/decoding the enhancement layer signal.

Scalable video coding is rendered more efficient by deriving/selecting a subblock subdivision to be used for enhancement layer prediction, among a set of possible subblock subdivisions of an enhancement layer block by evaluating the spatial variation of the base layer coding parameters over the base layer signal. By this measure, less of the signalization overhead has to be spent on signaling this subblock subdivision within the enhancement layer data stream, if any. The subblock subdivision thus selected may be used in predictively coding/decoding the enhancement layer signal.

A method for decoding an image, the method including receiving a bitstream including image information, decoding base block size information on a size of a base block, and a residual quantization parameter of a decoding object unit, from the bitstream, deriving a predicted quantization parameter of the decoding object unit based on the base block size information, deriving a quantization parameter of the decoding object unit based on the predicted quantization parameter and the residual quantization parameter, and decoding the decoding object unit based on the quantization parameter of the decoding object unit.

A method for decoding an image, the method including receiving a bitstream including image information, decoding base block size information on a size of a base block, and a residual quantization parameter of a decoding object unit, from the bitstream, deriving a predicted quantization parameter of the decoding object unit based on the base block size information, deriving a quantization parameter of the decoding object unit based on the predicted quantization parameter and the residual quantization parameter, and decoding the decoding object unit based on the quantization parameter of the decoding object unit.