Vivotek IP7142 - Manual (Page 43)

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User's Manual - 43
If MPEG-4 is selected, it is streamed in RTSP protocol. There are four dependent parameters provided
in MPEG-4 mode for video performance adjustment.
■ Frame size
Select the video size. Note that a larger frame size takes up more bandwidth. The frame sizes are
selectable in the following resolutions: 176 x 144, 352 x 240 and 720 x 480.
■ Maximum frame rate
This limits the maximal refresh frame rate per second. Set the frame rate higher for a smoother video
quality.
If the power line frequency is set to 50Hz, the frame rates are selectable at the following rates: 1fps,
2fps, 3fps, 5fps, 8fps, 10fps, 15fps, 20fps and 25fps. If the power line frequency is set to 60Hz, the
frame rates are selectable at the following rates: 1fps, 2fps, 3fps, 5fps, 8fps, 10fps, 15fps, 20fps,
25fps and 30fps.
■ Intra frame period
Determine how often to plant an I frame. The shorter the duration, the more likely you will get a
better video quality, but at the cost of higher network bandwidth consumption. Select the intra frame
period from the following duration: 1/4 second, 1/2 second, 1 second, 2 seconds, 3 seconds and 4
seconds.
■ Video quality
A complex scene generally produces larger file size, meaning that higher bandwidth will be needed
for data transmission. Therefore, if Constant bit rate is selected, the bandwidth utilization is fixed at
a selected level, resulting in mutable video quality performances. The bit rates are selectable at the
following rates: 20Kbps, 30Kbps, 40Kbps, 50Kbps, 64Kbps, 128Kbps, 256Kbps, 512Kbps, 768Kbps,
1Mbps, 2Mbps, 3Mbps and 4Mbps.
On the other hand, if Fixed quality is selected, all frames are transmitted with the same quality;
bandwidth utilization is therefore unpredictable. The video qualities are selectable at the following
settings: Medium, Standard, Good, Detailed and Excellent.
If JPEG mode is selected, the Network Camera continuously sends JPEG images to the clients,
producing dynamic effects similar to movies. Every single JPEG image transmitted guarantees the same
image quality, which in turn comes at the expense of variable bandwidth usage. And because the media
contents are a combination of JPEG images, no audio data is transmitted to the clients.
■ Frame size
Select the video size. Note that a larger frame size takes up more bandwidth. The frame sizes are
selectable in the following resolutions: 176 x 144, 352 x 240 and 720 x 480.