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Recording: Encode
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 frame rate (how many images per second the DVR records)
• the
Advanced Configuration
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
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
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 three options available:
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.
HD1: Literally, half of D1 (352 x 480 NTSC / 352 x 576 PAL) and about the quality of a typical YouTube video. This won’t save HDD space - the bitrate is the important setting for determining how much space your recordings require on the HDD.
CIF: 1/4 of D1 (352 x 240 NTSC / 352 x 288 PAL), and about the same resolution as a low quality webcam. We can’t think of a good reason to use CIF as your resolution setting, unless you’ve some really cunning plan we didn’t think of. It won’t save any HDD space - for that, you’ll need to change the bitrate.
Frame Rate: The number of frames per second (fps) that the DVR will record. The default (and maximum) is referred to as
Reducing the number of frames per second will not save hard drive space but potentially will improve the
Remember that your FPS count is the same as saying “take X photographs 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 lower the frame rate.
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 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.
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