Grandstream GXV3175 User Manual User Manual
Page 60
FIRMWARE VERSION 1.0.3.76 GXV3175 USER MANUAL Page 60 of 139
to use H.264.
Enable RFC5168 support
Select Yes to enable RFC5168 support. The default is set to No.
Video Bit Rate
Rate of information content in a video stream. (Ranges from 32
– 1024
kbps)
H.264 Image Size
Select the type of H.264 compression (4CIF, VGA, WQVGA, CIF, QVGA,
QCIF, QQVGA)
H.264Payload type
Selects the dynamic H.264 codec payload type (ranges from 96-127). The
default setting is 99.
H.263+ Payload type
Selects the H.263+ codec payload type (ranges from 96-127). The default
setting is 103.
L16-256 Payload type
Selects the L16-256 codec payload type (ranges from 96-127). The default
setting is 103.
H.263 Encoder Resolution Selects the resolution (CIF/QCIF) used for H.263 codec. The default
resolution is CIF.
SRTP Mode
This is option to secure the RTP audio
Silence Suppression
This controls the G723/G729 silence suppression/VAD. If set to Yes, when
no audio is detected, the phone will send a small number of VAD packets
(instead of audio packets). If Set to No, this feature is disabled. The default
setting is No.
Voice Frame per TX
This configures the number of voice frames transmitted per packet. (It is
recommended to set this based on the Ethernet IS packet limitation
– 1500
Byte or 120kb/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 and the actual frames transmitted during the in payload call.
For example: if the codec
is configured to be G.723 and “Voice Frames per
TX” is set to 2. Then in the INVITE request, the “ptime” value for SDP will be
60 ms. This is because the G723 voice frame is 30 ms. Similarly, if the
setting is 2 and the codec is G729 or G711 or G726, the “ptime” value for
SDP in the INVITE request will be 20 ms.
If the voice frames per TX configuration exceeds the maximum value
allowed, the phone will choose the preferred codec and use the maximum
value allowed.
The maximum value is 64 frames.
Adjusting these values will also change the jitter buffer. The phone has an
algorithm for setting the jitter buffer and the jitter buffer rate is around