Section 3 introduces the background (e.g., the traditional motion estimation and mode decision) and methodology (e.g., the PBMA and mode decision at the decoder).
In order to alleviate the computational burden, the proposed architecture adopts the Partial Boundary Matching Algorithm (PBMA) and four flexible types of mode decision at the decoder; this circumvents the traditional use of motion estimation and mode decision at the encoder.
Although the R-D models, presented in Subsection 2.2 below, can be used for fast optimization, in a typical encoder such as the H.264/AVC[10, 11], the selection of QP, MV, and mode is performed separately in three consecutive stages of rate control (RC), motion estimation, and mode decision, respectively.
For this reason, the proposed PB-based LVC mitigates the encoder complexity with motion estimation and mode decision.
In short, the re-encoding time for our proposed ROI-based transcoder gets speeded up by ignoring the motion estimation and mode decision for non-ROI MBs.
In traditional video coding, the high computational complexity encoder algorithms, where motion estimation and mode decision, are the main transferred objects.
Moreover, the PBMA and four flexible block type mode decision scheme is able to effectively transfer the motion estimation and the mode decision algorithms to the decoder.
This section contains two subsections: motion estimation [17] and mode decision [18].
However, the encoder complexity is greatly increased mainly due to motion estimation (ME) and mode decision.
In this subsection, we study the complexity-quality performance of different combinations of motion estimation algorithm and mode decision methods.
