Relying on a Rate Constraint to Reduce Motion Estimation Complexity

Abstract

This paper proposes a rate-based candidate elimination strategy for Motion Estimation, which is considered one of the main sources of encoder complexity. We build from findings of previous works that show that selected motion vectors are generally near the predictor to propose a solution that uses the motion vector bitrate to constrain the candidate search to a subset of the original search window, resulting in less distortion computations. The proposed method is not tied to a particular search pattern, which makes it applicable to several ME strategies. The technique was tested in the VVC reference software implementation and showed complexity reductions of over 80% at the cost of an average 0.74% increase in BD-Rate with respect to the original TZ Search algorithm in the LDP configuration.

Learning adaptive motion search for fast versatile video coding in visual surveillance systems

“…TZ search has also been adopted in the VVC standard due to its efficiency in reducing the number of search points and hence achieving low complexity motion search [30, 31]. TZ search originally includes four main steps: Step 1—Initialize the search centre: First, to quickly find the matching block, TZ search will initialize a search centre at a matched position in reference picture associated with the MV derived from neighbouring blocks.…”

“…Learning adaptive TZ search TZ search has also been adopted in the VVC standard due to its efficiency in reducing the number of search points and hence achieving low complexity motion search [30,31]. TZ search originally includes four main steps:…”

“…Since TZ search has originally shown the high performance in reducing the motion search complexity [25,30,31], to further generalize this work, we have presented in Section 3.4 an adaptive TZ algorithm where based on the content analysis, we can adaptively stop some steps in the TZ flow. This is expected to reduce the total amount of search points in TZ computation.…”