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13th Meeting: Marrakech, January 2019 2019-01-09 13:03
CE4: STMVP simplification (test 4.2.3a)
Authors: Yung-Hsuan Chao Qualcomm Y. Han Qualcomm Dmytro Rusanovskyy Qualcomm W.-J. Chien Qualcomm Marta Karczewicz Qualcomm
Abstract
This contribution proposes a simplification of the non-sub-PU based spatial-temporal merge mode (STMVP), described in JVET-L0399 in the JVET meeting in Macao (3-12 October, 2018). The simplification shows negligible losses in coding gain over VTM3.0. It is reported that the BD-rate gain is 0.00 % and 0.11 % in RA and LB condition respectively.
Meeting Notes
JVET-M0221 CE4: STMVP simplification (test 4.2.3a) [Y.-H. Chao, Y. Han, W.-J. Chien, M. Karczewicz (Qualcomm)]

In this proposal, four modifications are proposed to simplify the complexity in the non-sub-PU STMVP in JVET_L0399, as described as follows:

  1. No MV scaling for the two spatial neighbours.
  2. STMVP candidates with non-local spatial neighbours are removed. As a result, only one STMVP is added into merge candidate list.
  3. For STMVP with local spatial neighbours, instead of searching up to two positions for above (left) spatial neighbours, only one position is checked. The positions are the same as the 1st and 2nd checked candidates in the non-sub-block merge candidate list.
  4. If three candidates are available, i.e., the temporal candidate ( on co-located block is available and the two spatial candidates are available with reference index equals to zero, the STMVP candidate is calculated as

Note that the denominators in the divisions are always a power of two, and therefore can be implemented using shift operations.

References:
JVET-L0399 JVET-L1010
Cited:
JVET-M0024 JVET-M0518 JVET-M0820 X JVET-M0894
ARCHIVE v2 :
JVET-M0221-v1.docx JVET-M0221-v2.docx JVET-M0221.xlsm
Decisions
Note that the denominators in the divisions are always a power of two, and therefore can be implemented using shift operations.
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