Impath Networks i-Volution iN7000 Pro, User Manual

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- Pre-compress Cache Size : the size of the buffer that stores uncompressed data. A large value con-
sumes more system memory, while a small size can render the “Pre-event time” ineffective. You should
calculate an appropriate size according to the frame rate and resolution of your capture source. For ex-
ample, a video capture source with resolution 640x480 at 30fps and I420 pixel format requires
640x480x30x1.5 = around 13 MB per second. So if you set the “Pre-event time” to 2000 milliseconds (2
seconds), you would need about 26 MB cache size just for video.
Storage and broadcast share the same cache buffer.
The Filter modules (such as timestamp OSD, de-interlace, and mask-region filter) modify
data of the uncompress stream, and require software compression to propagate the result
to local storage or Internet broadcast. If you checked “Use existing compressed stream”
and a compressed stream really exists, the result generated in data filters will not be
propagated to storage or broadcast but just reflected on preview.
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iN7000 User Guide