VGADVI Recorder Pro User Guide
Configure encoding
sporting event, requires a high bitrate.
7. If all your changes are complete, scroll to the bottom of the page and click
Apply
.
Table 23
Stream settings guidance
Setting
Description
Key frame interval
The key frame interval feature specifies how often a key frame (a frame
that contains all the pixels) is sent when streaming the video. This setting
also impacts how quickly a video moves through the frames when a
viewer uses the search function of their media player.
Increasing the number of seconds between key frames can significantly
reduce your bandwidth and system resource usage with minor impact to
your video quality. A good rule of thumb is to keep the interval between 2
to 3 seconds and decrease the key frame interval as the motion increases.
Try different settings and note changes in the video quality. If your video
quality is poor and jittery you may need to decrease the interval between
key frames. If you have unlimited bandwidth and system resources you
can choose an option to stream key frames only.
Frame rate
Frame rate reflects the number of images captured by the device per
second. Reducing the frame rate reduces bandwidth usage, and vice versa.
The system's ability to maintain a set frame rate is based on several
factors, for example:
l
overall system load affects the ability for the device to process
pixels;
l
available network bandwidth;
l
the source and stream frame size (resolution);
l
the type of motion that is captured; and
l
number of users accessing the stream.
When adjusting the frame rate, you may need to try different values to
achieve the best outcome.
Bitrate
In general, higher bitrate mean higher image quality in the stream, at the
cost of higher bandwidth needed to transmit it.
For comparison against something you are likely familiar with, an HD Blu-
ray video is typically in the range of 20 mbps, standard-definition DVD is
usually 6 mbps.
140