ViewCast 2120 manual Is no reason to use it

Appendix: Advanced Settings for H.264

Setting	Explanation
	Because teas (10) is not achievable in real time encoding there
	is no reason to use it.
	dia – (diamond) is the simplest search. It starts at the best
	predictor, checks the motion vectors at one pixel upwards,
	left, down, and to the right, chooses the best, and repeats the
	process until it no longer finds any better motion vectors. This
	setting is the fastest.
	hex – (hexagon) is the default setting. It uses a similar strategy
	to dia, except it uses a range-2 search of 6 surrounding points.
	It is considerably more efficient than dia and hardly any
	slower. This setting is a good choice for general use.
	umh – (uneven multi-hex) is considerably slower than hex. It
	searches a complex multi-hexagon pattern to avoid missing
	harder-to-find motion vectors. umh is about 40 % slower than
	hex.
	esa – (exhaustive) is a highly optimized intelligent search of
	the entire motion search space within range of the best
	predictor. It is the mathematically equivalent to the brute
	force method of searching every single motion vector in that
	area, though faster. It is still considerably slower than umh.
	teas – (transformed exhaustive) attempts to approximate the
	effect of running a Hadamard transform comparison at each
	motion vector. It’s a little bit better than esa but a little bit
	slower, too slow for practical use.
MotionEstimationRange	This value controls the maximum range of the motion search.
	For hex and dia, the encoder only uses between 4 and 16. umh
	and esa allow you to increase past 16 to allow a wider range of
	motion search, which is useful for high-definition footage and
	for high-motion footage. Increasing MotionEstimationRange
	significantly slows down encoding.
MotionEstimationSubPelQuality	This value controls the subpixel motion estimation quality.
	Higher numbers are better. Levels 1 through 5 simply control
	the subpixel refinement strength. Level 6 enables RDO for
	mode decision, and level 8 enables RDO for motion vectors
	and intra prediction modes. RDO levels are significantly slower
	than the previous levels.
	0 — fullpel only (not recommended)
	1 — QPel SAD 1 iteration
	2 — QPel SATD 2 iterations
	3 — HPel on MB then Qpel
	4 — Always Qpel
	5 — Multi QPel + bime

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