AETA Scoopy+ S, Руководство пользователя

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S
COOPY
+ S - User Manual 19
2.2.10. OPUS coding
Application mono or stereo music, low capacity transmission channels. Moderate latency.
Opus is an open source coding algorithm (under BSD license), described by RFC6716 from the IETF. Like
MPEG coding algorithms, it is a wide band audio codec, but it features distinctive characteristics:

Low latency; the algorithmic delay of Opus is very low compared to MPEG coding (Layer 2, AAC,
HE-AAC...).

Adaptability: Opus features many parameters influencing its performance, but it is possible to
adapt them automatically depending on the external constraints and the signal characteristics.
In the S
COOPY
+ S, the configuration stays very simple: the user just imposes the audio channel
format (mono/stereo) and the desired bit rate, and the codec automatically adjusts the other
parameters (for instance the audio bandwidth).

Capacity to apply changes "on the fly": the coding allows changing its operation parameters on
the fly, with no interruption and no artefacts when switching. In this way the bit rate can be
changed during the link on the S
COOPY
+ S, without any audio noise or dropout.
In addition, when the remote device is another AETA codec, it will automatically apply the same
bit rate change to the stream it is transmitting.
Opus coding is only available for IP networks, wired or mobile.
You can adjust the bit rate during a link using the "C
ONNECTION PARAMETERS
" frame of the " C
ONNECTIONS
"
web page, or using the joystick on the front panel.
Note: the quality indicators on the front panel or the "Status" page of the web interface provide
information in real time about the transmission quality (for the transmit direction, this depends on the
capability of the remote codec).
2.2.11. Linear coding
Application mono or stereo music, transmission media with very high capacity and reliability.
The linear coding is in fact the absence of coding/compression, the audio data are transmitted without
information loss and with no bit rate reduction. Obviously this implies a very high bit rate; therefore
linear coding is only usable over an IP network, and with a very high bandwidth and a very good quality
of service, such as a local area network or a high reliability private WAN.
The coding features three variations L16, L20 and L24, corresponding respectively to a sample resolution
of 16 bits, 20 bits, or 24 bits for the transmitted audio. With each variation it is possible to select a
sampling frequency of 32 or 48 kHz, and a mono or stereo channel mode.
The linear coding is only available for IP networks.

It is not recommended on mobile IP networks due to the required bit rate and the poor quality of
service expected from a mobile network.