A comparison of temporal scalability techniques

A temporally scalable video coding algorithm allows extraction of video of multiple frame rates from a single coded stream. In recent years, several v ideo coding techniques have been proposed that provide temporal scalability using subband coding, both without and with motion compensation. With a tw o-band subband decomposition applied hierarchically, frame rates halve afte r each filtering operation. Alternatively, motion-compensated prediction (a s used in MPEG) can provide temporal scalability and the same frame rates a s temporal subband coding through strategic placement of reference frames a nd selective decoding of frames, This paper compares three temporal coding techniques with respect to providing temporal scalability: temporal subband coding (TSB), motion-compensated temporal subband coding (MC-TSB), and mot ion compensated prediction (MCP), Predicted rate-distortion performances at full- and lower frame rates and experimental quantitative and visual perfo rmances from coding several video sequences are compared. The comparison is explicitly for temporal coding when the dimensionality of the subsequent s ource coding is held constant; any spatial or higher dimensional source cod ing can follow. In theory and in practice, MCP and MC-TSB always outperform TSB. For high-bit-rate full-frame-rate video, the performances of MCP and MC-TSB are approximately equivalent. However, to provide temporal scalabili ty, MCP clearly provides the best performance in terms of visual quality, q uantitative quality, and bit rate of the lower frame-rate video.