Sencore DMG 3000, User Manual

Page: 211 / 306

DMG 3200/3100/3000 – User Manual
Page 211 (306)
Figure 8.26– H.264 configuration for Encoders
Reference B-Frames Enables B frames to be referenced to I, P or B frames. When
disabled, B and P frames can only reference I or P frames.
8x8 transform Available in high profile mode only. This enables 8x8 transform
for residual coding. This can provide significant advantages for
HD encoding.
CABAC
CABAC (Context Adaptive Binary Arithmetic Coding) is an
entropy coding scheme introduced in H264. When enabled,
CABAC is used instead of CAVLC. CABAC is the most efficient
of the two, and should be the default choice. Some legacy
decoders might not support CABAC.
Loop Filter Mode This controls the encoder output de-blocking loop filter. The
loop filter is designed to remove blocking artefacts resulting
from the compression process. Settings should reflect customer
preferences and content. The trade-off is between visible
artefacts and a softening of the video, especially sports and
other difficult, high-motion content. Detail, especially grass, can
look better with this feature disabled.
Loop Filter
Alpha CO offset.
When the loop filter is enabled, the Alpha offset allows the user
to adjust the strength of the loop filter i.e. how much the video is
softened. Negative values will soften the video less, but at the
risk of showing more blocking artefacts. Positive values will
soften video more, but at the risk of removing more detail. The
value ‘0’ is often considered to be a good compromise.
Loop Filter
Beta Offset.
When loop filter is enabled, the Beta offset allows the user to
adjust the threshold for what the filter considers a blocking
artefact. A negative value will lower the threshold and preserve
more detail but at the risk of showing more blocking artefacts. A
positive value will remove more blocking artefacts but may also