Spirent Tech-X Flex, Руководство пользователя

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Tech-X Flex™ Base Unit User Guide Issue 1
5: IP and Video Testing 5-11
Intro
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Jitter Mode Type of jitter buffer emulation used.
Options include:
•
F or FIXED - The jitter buffer uses a constant fixed delay. The jitter buffer is
bounded by a nominal and maximum delay, where the nominal delay dictates
the actual delay and the maximum delay dictates the maximum number of
packets that can be stored in the jitter buffer.
• A or ADAPTIVE - The jitter buffer is bounded by a minimum, nominal and
maximum delay, where the minimum delay dictates the minimal accepted jitter
buffer delay, nominal delay dictates the starting delay and the maximum delay
dictates the maximum delay of the jitter buffer. The maximum number of
packets that can be stored in the jitter buffer is a set fraction of the maximum
delay.
GOP Type Video coder group of pictures (GOP) structure, representing the frame sequence
in use on the stream with respect to I, P, and B frames. This value is used only as
a default if the actual frame types and GOP structure cannot be dynamically
detected from the stream.
Options include:
•
A - I-frames only, for example:
III…I
• B - One I-frame followed by P-frames, for example:
IPPP...PIPPP...
• C - One I-frame followed by P- and B-frames with two B-frames between each
pair of anchor frames, for example:
IBBPBBP...BBIBBP...
• D - All P-frames, for example:
PPPP...P
• E - One I-frame followed by P- and B-frames with one B-frame between each
pair of anchor pictures, for example:
IBPBP...BIBP...
For more information about MPEG pictures, see About IP multicast on
page 5-25.
Table 5-6 Video QoS test - Setup parameters
Parameter Description