Recording: Encode - Swann Digital Video Recorder Manual

English
Camera No.: The camera feed you want to alter the settings
for. These will be numbered sequentially, and correspond to
the BNC video inputs labelled on the rear of the DVR. Note
that the channel name here is independent of the Camera Name
selected on the Display: Camera menu screen.
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. This DVR will record at Full HD 1080p (1920 x 1080
pixels) on all channels, will do so at any frame rate up to the
maximum the DVR can handle.
If you want to alter the visual quality of your images then you
should change the Max. Bitrate (Kbps) setting. This controls
how much data the DVR will use to represent your images.
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 bit-rate - see the next
point).
Remember that your FPS count is the same as saying "take
X photograph per second" (where X is your FPS setting).
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
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Recording: Encode

lower the frame rate.
As with all settings on this screen, some experimentation is
encouraged to find the settings which will work best for you!
Max. BitRate(Kbps): The actual amount of data that the DVR
will use to record video.
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 bit-rate. 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.
Note: Although using the highest bitrate will result in the
smoothest recorded video it will also consume Hard Disk
space at the highest rate. When choosing a bitrate for record-
ed video consider the amount of time before the HDD is full or
the existing recordings are over-written automatically. If this
time is too short you may have to consider adding additional
HDDs to provide more storage space. After setting the bitrate
initally, check back on the HDD using the information "Device:
HDD" on page 49 to see how fast the HDD is being filled. "
The Recording: Encode menu allows 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), and
• 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.