Grandstream Networks WP820 Administration Manual page 23

DTMF Payload Type
Enable Audio RED with
FEC
Audio FEC Payload Type
Audio RED Payload Type
Silence Suppression
Minimum Jitter Buffer
Length
Maximum Jitter Buffer
Length
Voice Frames Per TX
Preferred Video Codec
Enable Video FEC
Enable RFC5168 Support
FEC Payload Type
H.264 Image Size
respectively.
The default setting is "RFC2833".
Configures the RTP payload type using RFC2833 that indicates the transmitted packet contains DTMF
digits. Valid range is from 96 to 127.
Default value is 101.
If set to "Yes", FEC will be enabled for audio call.
The default setting is "No".
Configures audio FEC payload type. The valid range is from 96 to 127.
The default value is 121.
Configures audio RED payload type. The valid range is from 96 to 127.
The default value is 124
Enables the silence suppression/VAD feature. If it is set to "Yes", when silence is detected, a small quantity
of VAD packets (instead of audio packets) will be sent during the period of no talking. If set to "No", this
feature is disabled.
The default setting is "No".
Set minimum jitter buffer length based on network conditions.
The default value is 0ms.
Set maximum jitter buffer length based on network conditions.
The default value is 1000ms.
Configures the number of voice frames transmitted per packet (It is recommended that the IS limit value of
Ethernet packet is 1500 bytes or 120Kbit/s). When configuring this, it should be noted that the "ptime"
value for the SDP will change with different configurations here. This value is related to the codec used in
the codec table or negotiate the payload type during the actual call. For example, if the setting is set to 2 and
the first code is G. 729 or G. 711, the "ptime" value in the SDP datagram of the INVITE request is 20
milliseconds. If the "Voice Frame/TX" setting exceeds the maximum allowable value, the phone will use
and save the maximum allowable value for the selection of the first encoding. It is recommended to use the
default setting provided, and incorrect setting may affect the voice quality.
Preferred Video Codec
This parameter is to configure the preferred Video Codec used to receive and display video for SIP calls on
WP820. The default setting is H.264.
When enabled, the video sender will temporarily allocate part of the bandwidth to one data channel to send
FEC data to system, thus, to improve the video quality the WP820 gets. Enabling this function will take up
part of bandwidth and reduce call rate. The default setting is "Yes".
Enables/disables RFC5168 mechanism for video calls to WP820. RFC5168 allows SIP party to request the
sender to refresh its video frame in H.264.The default setting is "No".
Configures FEC payload type. The range is 96-126.
Default setting is 120.
Sets the H.264 image size. It can be selected from the dropdown list.
● 720P
● 4CIF
● VGA
● CIF
● QVGA
● QCIF