Medias Mediatrix 1204, Справочное руководство

Страница: 111 / 390

Voice & Fax Codecs Reference Manual (SIP Version)
Mediatrix 1204 85
G.711 Codec Parameters
The following are the G.711 codec parameters you can set.
X
To set the G.711 codec parameters:
1. Select to which port you want to apply the changes in the drop down menu at the top of the window.
2. In the Voice - G.711 section, enable the G.711 u-Law codec by selecting Enable in the G.711 u-Law
choice.
Figure 39: Telephony – G.711 Section
3. Set the minimum and maximum packetization time values for the G.711 u-Law codec in the
corresponding drop-down menu.
The packetization time (also called packetization period or ptime) is the duration, in ms, of the voice
packet.
• Minimum : Shortest packetization period allowed for the G.711 u-Law codec.
Authorized values start at 10 ms and come in discrete steps of 10 ms up to the one
specified by the corresponding
Maximum drop-down menu.
• Maximum : Longest packetization period allowed for the G.711 u-Law codec.
Authorized values go up to 100 ms, in discrete steps of 10 ms, and start at the one
specified by the corresponding
Minimum drop-down menu.
4. Enable the G.711 a-Law codec by selecting Enable in the G.711 a-Law field.
5. Set the minimum and maximum packetization time values for the G.711 a-Law codec in the
corresponding drop-down menu.
The packetization time (also called packetization period or ptime) is the duration, in ms, of the voice
packet.
• Minimum : Shortest packetization period allowed for the G.711 a-Law codec.
Authorized values start at 10 ms and come in discrete steps of 10 ms up to the one
specified by the corresponding
Maximum drop-down menu.
• Maximum : Longest packetization period allowed for the G.711 a-Law codec.
Authorized values go up to 100 ms, in discrete steps of 10 ms, and start at the one
specified by the corresponding
Minimum drop-down menu.
6. Enable the G.711 Voice Activity Detection (VAD) by selecting Enable in the G.711 VAD choice.
VAD defines how the Mediatrix 1204 sends information pertaining to silence. This allows the unit to
detect when the user talks, thus avoiding to send silent RTP packets. This saves on network
resources. However, VAD may affect packets that are not really silent (for instance, cut sounds that
are too low). VAD can thus slightly affect the voice quality.
7. Enable the G.711 Comfort Noise Generation (CNG) by selecting Enable in the G.711 Comfort
Noise Generation choice.
Comfort Noise (CN) defines how the Mediatrix 1204 processes silence periods information it
receives. During silence periods, the Mediatrix 1204 may receive CN packets containing information
about background noise. Those packets are used to generate local comfort noise.
8. Click Submit if you do not need to set other parameters.
2
3
4
5
6
7