MTV-Player: Interactive Spatio-Temporal Exploration of Compressed Large-Scale Time-Varying Rectilinar Scalar Volumes

Abstract

We present an approach for supporting fully interactive exploration of massive time-varying rectilinear scalar volumes on commodity platforms. We decompose each frame into a forest of bricked octrees. Each brick is further subdivided into smaller blocks, which are compactly approximated by quantized variable-length sparse linear combinations of prototype blocks stored in a data-dependent dictionary learned from the input sequence. This variable bit-rate compact representation, obtained through a tolerance-driven learning and approximation process, is stored in a GPU-friendly format that supports direct adaptive streaming to the GPU with spatial and temporal random access. An adaptive compression-domain renderer closely coordinates off-line data selection, streaming, decompression, and rendering. The resulting system provides total control over the spatial and temporal dimensions of the data, supporting the same exploration metaphor as traditional video players. Since we employ a highly compressed representation, the bandwidth provided by current commodity platforms proves sufficient to fully stream and render dynamic representations without relying on partial updates, thus avoiding any unwanted dynamic effects introduced by current incremental loading approaches. Moreover, our variable-rate encoding based on sparse representations provides high-quality approximations, while offering real-time decoding and rendering performance. The quality and performance of our approach is demonstrated on massive time-varying datasets at the terascale, which are nonlinearly explored at interactive rates on a commodity graphics PC.