AEQ
PHOENIX MERCURY
20
•
LOWEST: generates a 40% higher binary rate and produces a 575ms
additional delay.
•
LOW: generates a 50% higher binary rate and produces a 375ms additional
delay.
•
MIDDLE: generates a 66% higher binary rate and produces 225ms additional
delay.
•
HIGH: doubles the binary rate producing 125 ms additional delay.
-
Adaptive
/
Fixed:
you can set up the
reception buffer
as adaptive or fixed. In the first
case, its size will vary according to the network transmission quality. In fixed mode, its
size will be steady according to manual configuration.
-
Adaptive Buffer Max:
this is the maximum size of the reception buffer. When it is
defined as adaptive, Phoenix MERCURY will start to shorten it from this value as the
network´s transmission quality allows. If it is defined as FIXED, this max value will
remain, as the buffer’s size won’t be varied during the connection. This value must be
set in milliseconds. The longer the buffer is, packet misses will be less likely, but base
delay will also be longer, specially if the buffer is set to FIXED mode.
In order to help you select the best option for each application, we recommend to use a Fixed
buffer, with a low value (around 100ms) in applications where optimal audio quality is the main
concern (mainly when using PCM modes in suitably sized networks). If the received audio
quality is as expected, and the network allows for it, you can continue adjusting the buffer to
lower values in order to minimize delay, until you find that audio is compromised (as the buffer
size reaches the network maximum jitter value). At this point, just increase the buffer a little bit
to have some margin.
In high-quality PCM connections, you can start using highest quality modes (48KHz, 24 bits,
mono or stereo only if required), and if you can't obtain the desired quality and/or estability (no
noises present) and good delay, you can lower quality progressively until, for example, 16 bit
(CD quality audio).
On the other hand, for applications where lowest possible delay is the main goal, but
transparent audio is not necessary (for example, in voice connections with commentators), it is
better to select the Adaptive Buffer mode, starting from a 1000ms maximum size, approx. If the
network is not too bad, the unit won't increase the buffer to highest values from the network's
jitter value, and it will try to minimize delay continuously. Please not that if the network has very
variable delay, the adjusments required to increase or decrease the buffer size can produce
noticeable artifacts in the received audio, so this method is not recommended for PCM modes
where maximum quality is required, in this case a fixed buffer setting is preferred, as stated
above.
3.5. Coding profiles.
See section 6.1.3.1 (”Coding selection”) at “
AEQ ControlPHOENIX
” user’s manual
.
By clicking on the ”Select
codec” button located inside
the “ENCODER” area of the
general configuration window,
you can access the coding
selection screen. In this
window, with IP interface set
as ”RTP raw”, only the modes
that are compatible with the
communications interface
selected appear.
Note that the “DECODER” will
be automatically configured for
the same coding algorithm and
mode.
