In December 2017, the security company that installed my original camera system replaced the original 3x 3 MP cameras and NVR with 3x new 4 MP cameras and a new NVR. There were problems with the NVR (noted in an earlier thread Ghosting; clock feezing then jumping forward).
The security company recently replaced the second replacement NVR with a new one. The third replacement NVR. They said this NVR is the latest model and that they have never installed this model nor worked with it.
DS-7608-NI-I2/8P
Firmware: V4.1.50. Build: 180423. 3 TB hard drive. H.264 (It also has H.264+ and H.265 but they are not enabled. The security company left the default setting, H.264.)
1. DUPLICATION OF FILES
In the File Management section of the system, each motion event has two recorded files.
The second file begins 1-3 seconds after the first file.
In each case, when playing the files, the first file is of poorer image quality than the second file.
<--Still image of thumbnails of duplicate files in File Management
In the Playback section of the system, there is only one file for each motion event.
I assumed one file per motion event was "normal" as all previous NVRs produced only one file per motion event.
<--Still image of thumbnails of single files in Playback
The security company said they did not know what was causing this anomaly.
What is causing the duplication of files in File Management? Is this normal? How to fix it...?
The problem may be linked to this next issue.
2. CAMERA SYSTEM OPERATING AT 15 fps--NOT FULL FRAME
The security company said:
a) the new NVR appeared "locked in" to a frame rate of 15 fps (15 frames per second)
b) that they could not find the setting for the I-Frame interval (and therefore they could not set the frame rate and I-Frame interval to full frame)
c) that it is critical that the frame rate and I-Frame interval be set to identical numbers of frames per second; and that
d) perhaps the I-Frame setting automatically corresponds to the frame rate
e) that as they could not find the setting for I-Frame interval, they would leave the mainstream frame rate at 15 fps.
After they left, I could see nothing to indicate the system was "locked in" to the frame rate.
As I understand it, the sub-stream is usually set to a lower frame rate than the mainstream.
(N.B. My camera system is not connected to the 'net.)
I looked online for the NVR's user manual. In the user manual, I could find no mention of I-Frame Interval.
I would like the mainstream frame rate to be full frame, to give the best possible image quality. This new, late-model NVR, one would expect, could handle the three 4 MP cameras at full frame.
Where might I find the I-Frame interval setting? (It is not in the "video parameters" part of the system with the other Record settings.)
Does the I-Frame interval automatically set itself to the same mainstream frame rate chosen by the user?
Can the system function properly with the mainstream set to a higher frame rate than the sub-stream?
Images of the screens showing some of the settings. All three cameras have the same Record settings; I have uploaded the settings for camera 1.
<--Mainstream settings
<--Substream settings
A few other settings

I understand these questions may be impossible to answer. I'd be grateful for any helpful replies/suggestions.
The security company recently replaced the second replacement NVR with a new one. The third replacement NVR. They said this NVR is the latest model and that they have never installed this model nor worked with it.
DS-7608-NI-I2/8P
Firmware: V4.1.50. Build: 180423. 3 TB hard drive. H.264 (It also has H.264+ and H.265 but they are not enabled. The security company left the default setting, H.264.)
1. DUPLICATION OF FILES
In the File Management section of the system, each motion event has two recorded files.
The second file begins 1-3 seconds after the first file.
In each case, when playing the files, the first file is of poorer image quality than the second file.

In the Playback section of the system, there is only one file for each motion event.
I assumed one file per motion event was "normal" as all previous NVRs produced only one file per motion event.

The security company said they did not know what was causing this anomaly.
What is causing the duplication of files in File Management? Is this normal? How to fix it...?
The problem may be linked to this next issue.
2. CAMERA SYSTEM OPERATING AT 15 fps--NOT FULL FRAME
The security company said:
a) the new NVR appeared "locked in" to a frame rate of 15 fps (15 frames per second)
b) that they could not find the setting for the I-Frame interval (and therefore they could not set the frame rate and I-Frame interval to full frame)
c) that it is critical that the frame rate and I-Frame interval be set to identical numbers of frames per second; and that
d) perhaps the I-Frame setting automatically corresponds to the frame rate
e) that as they could not find the setting for I-Frame interval, they would leave the mainstream frame rate at 15 fps.
After they left, I could see nothing to indicate the system was "locked in" to the frame rate.
As I understand it, the sub-stream is usually set to a lower frame rate than the mainstream.
(N.B. My camera system is not connected to the 'net.)
I looked online for the NVR's user manual. In the user manual, I could find no mention of I-Frame Interval.
I would like the mainstream frame rate to be full frame, to give the best possible image quality. This new, late-model NVR, one would expect, could handle the three 4 MP cameras at full frame.
Where might I find the I-Frame interval setting? (It is not in the "video parameters" part of the system with the other Record settings.)
Does the I-Frame interval automatically set itself to the same mainstream frame rate chosen by the user?
Can the system function properly with the mainstream set to a higher frame rate than the sub-stream?
Images of the screens showing some of the settings. All three cameras have the same Record settings; I have uploaded the settings for camera 1.


A few other settings


I understand these questions may be impossible to answer. I'd be grateful for any helpful replies/suggestions.
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