Operation Manual

 Aspect Ratio: The H.264 bitstream includes aspect ratio information in the VUI

Parameters part of the Sequence Parameter Set. Normally, the encoder will automatically

set the correct aspect ratio code. However, in some situations, it may be necessary to

override this (for example, when scaling HD to SD). Use this control to override the

default aspect ratio set by the encoder. In particular, if the video input is 1920x1080i,

and the content is being scaled to SD, use either 16:11 (PAL Widescreen) or 40:33

(NTSC Widescreen) to get the correct aspect ratio.

 GOP Structure: Select between IBBP, IBP and IP. Selecting IBBP gives the best

video quality, but some low-end decoders require IP. If Profile is set to Baseline Profile,

this control will not be selectable and will be forced to IP.

 Coding Delay: This parameter controls the size of the H.264 Coded Picture Buffer

(CPB), expressed in milliseconds. This is one component of the end-to-end

encoder/decoder delay. The B264 latency is 150 milliseconds plus the value of this

control. For example, if the Coding Delay is set at its default of 500 milliseconds, the

B264 latency will be 650 milliseconds. Note that the overall encoder/decoder latency is

also a function of the latencies in the decoder. Please note that reducing the coding

delay will reduce latency at the expense of video quality! Use VBR if at all possible

when reducing the latency, and set the peak rate as high as you can afford. For example,

if the encoder output is 1920×1080i , a bit rate on the order of 10 to 12 Mb/s (either CBR

average or VBR peak) is required to produce a stream without artifacts with a Coding

Delay of 100 milliseconds.

Note that if the Output Resolution setting in the Basic Tab – Video Configuration is set to one

of the low resolutions (480×270, 320×240, or 320×180), the Profile and GOP Structure

controls will not be selectable; this section will appear as follows:

Also note that if the Input Resolution setting in the Basic Tab – Video Configuration is set to

1920×1080p, the Profile and GOP Structure controls will not be selectable; this section will

appear as follows: