Grandstream GXV3501 Series User Manual - Manual (Page 18)

GXV3501/GXV3504 Digital Video Server
Firmware 1.0.4.6 Page 18 of 36
Grandstream Networks, Inc. 09/2010
and Constant Bit Rate (CBR).
Variable Bit Rate
- If VBR is selected, the codec varies the amount of output data per time
segment. VBR produces a better quality-to-space ratio. The bits available are used to enable
more flexibly and encode sound or video data more accurately, with fewer bits used in less
demanding passages and more bits used in difficult-to-encode passages.
Constant Bit Rate
- If CBR is selected, the codec’s output data is constant regardless of the
input data. The output bit rate is defined in “Bit rate”. CBR is useful for streaming multimedia
content on limited capacity channels. It is easier to calculate required bandwidth as well as
the required storage space using CBR.
Image Quality
– If ‘Bit Rate Control’ is set to “VBR”, “Image quality” needs to be configured.
The better the video quality is, the higher the bit rate will be.
I-frame Interval
– While streaming video over a network, compression technologies are used
to show the incremental difference between each frame. I-frames are used to help keep the
video looking normal. When intervals are shorter, the video quality is higher but uses more
bandwidth.
NOTE: The users might need to configure the Primary Stream and Secondary Stream
properly. Sometimes, the user might like to watch the live video stream from the web GUI in
low resolution mode while recording a copy via GSurf/GS_NVR in high resolution due to the
limitation of internet bandwidth. In this case, for example, primary stream can be configured
to have better resolution, and then the users can use primary stream to record while watching
secondary video streams.
Audio Settings
Preferred Audio Codec – The GXV3501/GXV3504 supports up to 3 different Vocoder types,
a-law (PCMA), u-law (PCMU) and G.726.
The audio can also be turned off by
switching the setting to “Disabled”
Audio Compression
– Audio
compression is a form of data
compression designed to reduce the size
of audio files. Usually, the higher the audio compression is, the better the audio quality is.
NOTE: GXV3504 has 4 individual Video & Audio settings for each channel.
GXV3501/GXV3504 Networking Page – Assign an IP to GXV3501/GXV3504
GXV3501/GXV3504 supports IP version 4. The IP address can set automatically via DHCP,
or a static IP address can be set manually. To make GXV3501/GXV3504 work properly, the
user needs to set the DNS configuration properly. For security purposes, the user can also
assign the GXV3501/GXV3504 an HTTP Port other than 80.