The difference between the main stream and the sub-stream in the view of Hai Kang Wei

The General HD Camera product encoder can simultaneously produce two different encoding formats, collectively known as Master Stream and sub-stream, and dual-stream technology combines high-quality image transmission and narrow

Bandwidth transfer.

The main stream is used for local storage, and the sub-stream is suitable for the transmission of images on low-bandwidth networks.

The dual stream uses a high bitrate code stream for local HD storage, such as QCIF/CIF/D1 encoding, where low bitrate streams are used for network transmission, such as Qcif/cif

Both local storage and remote network transmission. Dual-stream can realize local transmission and remote transmission of two different bandwidth stream needs, local transmission using high code

Stream can get higher high-definition video recording storage, remote transmission using low stream to adapt to various networks such as CDMA/ADSL for higher image fluency.

Hai Kang Wei first proposed the main stream and sub-code flow such concept, is to solve in the network situation is not good in order to meet the smoothness of the remote preview to reduce the code rate, and do not affect the local video proposed dual-stream technology, that is, one video into the DVR, DVR can encode to provide two kinds of code stream, main stream and sub- The main stream resolution is higher than the sub-code stream, the main stream is used for video recording, the sub-stream is used for network transmission, the default client access using the main code stream customers can select sub-stream access according to network conditions, the purpose is when I use the sub-stream preview if the network condition is not very good, can reduce the bit rate of sub-stream (as the bitrate decreases the quality) To improve the fluency of web browsing without changing the video effect of local video.

Knowing the above theory, you can understand why people on the Internet are always asking such questions:
Why video surveillance uses sub-stream image blur.

Why the Network Camera one with the main stream on the drag screen, sub-stream is no problem.

The main stream is the highest pixel resolution mode, and the sub-stream is a low-pixel low-resolution mode.

Select the main stream, high-quality, high bandwidth requirements, such as you say the situation screen drag screen or the appearance of the fault card screen is not over the network transmission.

The solution to this situation:

Select the sub-stream, low picture quality, improve the smoothness of the screen transmission

in the background, the corresponding frame rate of the code stream is lowered, the resolution is lowered, so that the bandwidth needs to

improve network bandwidth, to meet the needs of high-quality transmission.

The main stream and the sub-stream are two digitized data streams, usually the same encoding method (the individual vendors will use different encoding, mainly depends on the chipset used), the same digital algorithm, the image clarity is mainly determined by three aspects, resolution, bitrate, frame rate, So you can configure the parameters from the above three aspects to get the image quality you are satisfied with.
The main code flow is often used for video storage, sub-code flow is often used for network transmission, usually these two streams can be in the above three aspects of the parameters of the custom settings, for different network environment to configure the best parameters.
For your question, please first look at the video image of the main stream to see if you are satisfied, if the quality of the video is satisfactory, you can adjust the parameters of the sub-stream to get the image you think clear (at least the performance of the device itself can meet your requirements) Next, look at the rate parameters of the satisfied video you configured and whether the effective upstream bandwidth of the network environment matches, if the matching can get your satisfied image, you can also directly select the direct stream streams directly to the main stream to achieve your needs.
Most of the time is due to the current network bandwidth problems have to reduce resolution, code rate, frame rate to deal with, and most devices default sub-stream parameters are much lower than the main stream parameters, so remote from the network will see undesirable image effects.