Grandstream Networks WP820 Administration Manual page 25

FEC Payload Type
H.264 Image Size
Use H.264 Constrained
Profiles
Video Bit Rate
SDP Bandwidth Attribute
SRTP Mode
SRTP Key Length
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
Note: For some network environment, the default setting "720P" might be too high that causes
not receiving video or video quality issue during video call to WP820. In this case, please change
"H.264 Image Size" to "VGA" or "CIF" and change "Video Bit Rate" to "384kbps" or lower. The
default setting is 720P.
Configures that whether to set H.264 constrained profiles to use H.264 CBP to establish video
call with WebRTC. The function takes effect when H.264 profile setting includes BP type. It is
recommended to set to "Yes" when establishing video call with WebRTC
The default setting is "No".
Configures the bit rate for video stream received on the WP820. The default setting is 2048
kbps. The valid range is from 32 – 2048 kbps.
Note: The video bit rate can be adjusted based on the network environment. Increasing the video
bit rate may improve video quality if the bandwidth is permitted. If the bandwidth is not
permitted, the video quality will decrease due to packet loss. For some network environment, the
default setting "720P" might be too high that causes no video or video quality issue during video
call to WP820. In this case, please change "H.264 Image Size" to "VGA" or "CIF" and change
"Video Bit Rate" to "384kbps" or lower.
Sets the SDP bandwidth attribute. It can be selected from the drop-down list. The default setting
is "Media Level".
● Standard: use AS format in session level; use TIAS format in media level
● Media Level: use AS format in media level.
● Session Level: use AS format in session level.
● None: no modifications in the session format.
Note: Please do not modify this setting without knowing the session format supported by the
server. Otherwise, it might cause video decoding failure.
RTP Settings
Sets if the phone will enable the SRTP (Secured RTP) mode. It can be selected from dropdown
list:
● Disable
● Enabled but not forced
● Enabled and forced
● Follow SIP transport
The default setting is "Disable".
● SRTP uses encryption and authentication to minimize the risk of denial of service. (DoS). If
the server allows to use both RTP and SRTP, it should be configured as "Enabled but not
forced". It uses SDP security description to exchange key. Please refer to:
SDES: https://tools.ietf.org/html/rfc4568
SRTP: https://tools.ietf.org/html/rfc3711
● If set to "Follow SIP transport," the device will use RTP/SRTP according to the SIP transport
configured. The SIP transport may be automatically selected when using DNS NAPTR mode.
In this case, the RTP/SRTP will be automatically selected as well.
Configures all the AES (Advanced Encryption Standard) key size within SRTP. It can be selected
from dropdown list: