Datavideo iCast 10NDI, Инструкция по эксплуатации

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However, depending on the decoder used when viewing the stream, such as with mobiles devices, a
Main or Baseline profile may be required.

High

Main

Baseline
Level
Levels specify the size of the video a decoder must be able to handle. They specify a maximum bit-
rate for the video and a maximum number of macroblocks per second. Level is a hardcoded
inaccessible parameter fixed at 4.2.
Level ID Max. Video
Bitrate in
kbits/s Max Frame
Size in
macroblocks Max decoding speed
in macroblocks per
second Resolution, Frame Rate
(Max Stored Frames)
4.2 (High) 50000 8704 522240 1,280×720@145.1 (9)
1,920×1,080@64.0 (4)
2,048×1,080@60.0 (4)
Entropy
There are two coding options available for generating H.264 content:

CAVLC (Context-Adaptive Variable Length Coding)

CABAC (Context-based Adaptive Binary Arithmetic Coding)
CABAC encoding provides a 7-10% quality improvement over CAVLC but requires an extra 10-15%
CPU. CABAC encoding is only available in H.264 Profiles Main & High. When targeting at low-
powered devices, such as older cell phones and tablets, we recommend the Baseline Profile that
uses CAVLC which requires less computing power.
GOP
GOP pattern with longer GOP length encodes video very efficiently. Shorter GOP lengths usually
work better with video that has quick movements, but they do not compress the data rate as much.
Depending on your applications, you can select 16 GOP sizes ranging from 1 to 255.

255

240

200

120

100

60

50

30

25

20

15

10

5