Recording: Encode - Swann 960H Digital Video Recorder Instruction Manual

MENU FUNCTIONS
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Recording: Encode

Camera No.: The camera feed you want to alter the settings
for. These are numbered sequentially, and correspond to the
BNC video inputs labelled on the rear of the DVR.
Encoding Parameters (advanced user option): Whether
you're editing the parameters for the mainstream or the
substream.
• Main Stream: The main stream is the video feed that the
DVR will record and display. This is the higher-quality
stream.
• Sub stream: The sub stream is the video stream that
the DVR will send to remote devices via a network or the
Internet. It is the lower-quality stream as a reduction in
video size makes it easier to send over a network.
Record Audio: Choose whether the channel you've selected
will record audio or not. If you don't have any audio devices
connected, it's a good idea to disable audio, as it will save
some space on your HDD.
Resolution: How many "little dots" are going to make up your
image. There are two options available:
960H: Encode recordings at (PAL: 960 x 576, NTSC: 960 x 480)
resolution. As noted in
page 20, a standard CCTV camera's image will be slightly
stretched horizontally when recorded by the DVR.
D1: About the same resolution as a DVD (704 x 480 for NTSC,
or 704 x 576 for PAL). This is the default resolution for all
channels, and we suggest leaving this setting well alone.
Frame Rate: The number of frames per second (fps) that the
DVR will record. The default (and maximum) is referred to as
"real-time" and is 30fps (NTSC) or 25fps (PAL).
Reducing the number of frames per second will not save hard
drive space but potentially will improve the data-rate per
frame (depending how you set the bitrate - see the next point).
Remember that your FPS count is the same as saying "take
X photographs per second" (where X is your FPS setting).
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"About 960H Widescreen Videos" on
The Recording: Encode menu allows you to
alter and customize how the DVR records
footage and "encodes" the files.
"Encoding" is a term which refers to the
compression algorithm (a fancy computer
term for "make the file smaller while retaining
visual quality") used by the DVR.
You can choose and alter:
• the resolution (per channel),
• the frame rate (how many images per
second the DVR records)
• the data-rate of each video stream. The
higher the data rate, the "better" your
images will look, but the more space
they'll require on your HDD
5fps doesn't sound like much, but it's still five individual
photographs per second. If maintaining image clarity while
reducing HDD consumption is your priority, it makes sense to
lower the frame rate.
Max. BitRate(Kbps): The actual amount of data that the DVR
uses to record video. The higher the bitrate, the more space
each recording takes up on the hard disk. Generally speaking,
recordings encoded at higher bitrates will be ofbetter quality,
especially when recording movement.
The main stream uses a variable bitrate to record video - the
more movement occurs in the video, the higher the bitrate
will have to be. When there's little movement in view, the DVR
will automatically reduce the bitrate to conserve HDD space.
If the amount of movement in a recording would require a
higher bitrate to accurately record than what you've selected
as the maximum, the DVR will attempt to preserve as much of
the quality as possible by applying compression to the image.
This compression will take the form of irregular, fuzzy blocks
over segments or the entire image. If you encounter this, it
indicates that you might need to increase the overall bitrate.
If you've set a high bitrate but a low frame rate, the DVR will
still use all the data it can, resulting in potentially higher
quality per frame than at higher frame rates.
The sub stream uses a constant bitrate. This makes the video
easier to stream over a network or the Internet.
Note: Both the main stream and the sub stream are always
operating - in fact, the sub stream forms part of the main
stream. The options will affect the output quality of each
stream, but won't change which one is being used in different
circumstances.