TANDBERG E5780, Справочное руководство

Страница: 114 / 298

Operating the Equipment Locally — Video Menu: Video Encoder Menu
Page 4-36 Reference Guide: evolution 5000 E5780 and E5782 Encoder
ST.RE.E10135.4
Selected Item Options Description
Min: 1
Maximum GOP lengths:
12 for 25 Hz
15 for 29.97/30 Hz
24 for 50 Hz
30 for 59.94/60 Hz.
I-Frame and IP encoding have 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15.
IBP and IB have 2, 4, 6, 8, 10, 12, 14.
IBBP and IBB have 3, 6, 9, 12, 15.
IBBBP and IBBB have 4, 8, 12. (SD Only) GOP Length:
Sets the video GOP
structure length.
GOP lengths available
depend on GOP structure
selected and the frame rate.
The structure length determines how regularly an I frame is transmitted. The I frame provides a regular
reference from which predicted frames can be generated, thereby ensuring that predictions do not become
wildly inaccurate.
Some of the settings may not be available if they are not valid for use with other current encoding parameters.
Also, changing the GOP structure automatically changes the GOP length if the current GOP length is not
compatible with the selected structure.
To set longer GOP values, use GOP length option with this option set to
On.
Long GOP structures can improve video encoding performance, particularly
at low bitrates. However, it can lead to compression artefacts being visible
on scene cuts, and a periodic build-up and removal of noise at the I-frame
rate. Long GOPs:
Enable or disable the use of
GOP structures that are
longer than 500 ms in
duration.
Only available if
M2/ESO2/PU has been
purchased.
CAUTION…
Long GOPs are not DVB compliant, and should be used with caution.
Adaptive GOP: This option is not valid in HD progressive modes.
The GOP structure is adapted in regard to the number of B and P frames
according to the motion detected in the video. It should be left ON unless
there is a compatibility issue with the receiver population.
Fields Field based pictures.
Frames Frame based pictures.
Auto Automatically chooses the correct option on a frame by frame basis.
Field/Frame (SD Only):
Choose either field or frame
based pictures.
MPEG-2 encodes video at the field/frame level in what are known as pictures. These are coding units within the
hierarchy of the spec. Pictures can be used in two ways, frame pictures and field pictures. With frame pictures
a frame of a field 1 and field 2 is encoded as a single unit. With field pictures each individual field of video is
encoded as a single unit, but must be followed or preceded by another field picture relating to its matching
field.
The option should be switched on if the video material originated on film
and has been converted from the 24 frames per second film rate to the
29.97 frames per second NTSC rate. This enables the Encoder to increase
the video compression by only including a flag in the transport stream to
represent a repeated field (when detected), rather than compressing the
repeated fields. 3:2 Pull-down:
Switch the 3:2 pull-down
(film) mode On and Off.
It is recommended to set this
option to On
This option is only available for 29.97 Hz, 30 Hz, 59.97 Hz and 60 Hz modes.
In SD, VBI in Picture is not supported when 3:2 Pull-down is active.
3:2 Pull-down is not valid for Very Low Delay and Mega Low Delay coding modes.
Concatenation (SD Only):
Only available when
software option
M2/ESO2/ACON is
purchased. Use this option if the signal has been coded, then decoded and is about to be
coded again. It reduces picture degradation associated with multiple
generation compression encoding. Setting this option may give better results
as it tries to line up the I-frames. Only available to video via the SDI input. See
Application Note, ST.AN.1110, Near Loss-less MPEG Concatenation Without
Helper Signals.
PID:
Enter or update the video
PIDs, as required. 32 to 8191 Enter a PID then press the Enter softkey to accept it. To be DVB compliant,
PIDs below 32 are reserved. In the event of a clash, one of the PIDs will be
changed by the Encoder’s internal checking algorithm.