Polycom manual Option, Description, 10-28, 3:Basic Conference Parameters

Chapter 10 - Conference Templates – Full Parameters View

Table 10-3: Basic Conference Parameters

Option	Description
Annexes - P, N and	Annexes are additions to the Video Format when
F	using H.263 Video Protocol and increases the
	quality of the video display.
	Annexes N, P and F are enabled only when you are
	in Video Switching mode and the Video Protocol is
	set to H.263. The Video Format may be set to QCIF,
	CIF, 4CIF, 16CIF, VGA, SVGA, XGA, or NTSC.
	When Video Format is set to Auto, the system
	selects the appropriate annexes according to the
	endpoint's capabilities. The annexes are required in
	the Dual Stream mode, but may also be selected
	independently.
	• Annex F - Advanced Prediction Mode. This
	annex enables the transmitting encoder to use
	four motion vectors for every macro block (one
	motion vector per block). A macro block is a
	piece of the picture that contains four blocks.
	Without this annex, the transmitting encoder can
	only choose one motion vector for optimal
	prediction of the macro block.
	• Annex N - Reference Picture Selection Mode.
	This annex enables the conference to recover
	efficiently after transmission errors have
	occurred in the macro blocks, and reported via a
	relevant message to the speaker encoder.
	• Annex P - Reference Picture Re-sampling. This
	annex enables the transmitting encoder to apply
	a re-sampling process to the previous decoded
	reference picture in order to generate a warped
	picture, for use in predicting the current picture.
	The main purpose of this annex is to support the
	relationship of the current picture to a previous
	picture, which had a different source format,
	such as CIF, QCIF, 4CIF, etc.

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