Interesting. Where did you disable motion detect? I may do this also.
I have
Blue Iris doing the motion detect (on the substream), not from the camera input. I have constant record of the main stream to other NVR software. Another interesting thing I figured out recently, ever since moving the 1831's to the 2.8 series firmware, none of them show the bitrate that the camera is set to in the camera interface, at almost any resolution. If I have the iframe set to twice the frame rate, the bitrate runs at 50% higher than set in the camera. If I set the iframe equal to the frame rate, I get 50 to 100% higher bitrate than what the camera is set to. So if I set 8mp resolution, bitrate 8Mb/s, 30 fps, 60 iframe, bitrate runs at 10MB/s, but it is set to 8Mb/s. If I change the iframe to 30, bitrate runs up to 16Mb/s, but the camera is set to 8Mb/s. Most people would not mind this, but 1. these numbers are not consistent, even though I have CBR set, the higher it goes, the more the bitrate goes all over the place, almost acting like VBR is set, and 2. this isn't what the camera is set to, the camera should adhere to the settings. I've confirmed it's not the software I use to constant record the main stream, because I see the same issue of higher than camera setting bitrates in Blue Iris also.
I don't know what to do anymore, I just find a combination of resolution, frame rate, i frame, and bit rate settings that will keep the bitrate consistent. I'm just pissed, mostly at myself, partially at Dahua, because these are excellent cameras (for me).
My only speculation from all this is that the only firmware that has any type of quality testing would be the firware that the camera comes with. Otherwise the manufacturer risks an average user seeing these issues and just returning the camera or moving to another brand. Any other firmware update to the camera by the user, and it basically turns into the Wild West, and any expectation of things working correctly are now null and void.
I have contacted the vendor about this, but (in a very concise summary) it seems that this issue "is what it is". I guess because the issue isn't getting 100's of posts. I haven't even approached the topic of a warranty claim since I updated the firmware from what the camera originally came with, and because I have no guarantee that any replacement camera would come with 2.6 series firmware. I don't even care what changes 2.8 series firmware brings over 2.6 series, because all I know is that one main point of a security system is stability, and I didn't see any issues until moving to the 2.8 series firmware. And it does not matter which of the 2.8 series firmware I use, they all have the same issue. Any post I've made on the issue, usually results in a "if it ain't broke don't fix it" confirmation, so I must be the only person who sees this issue. So at least I've learned that from this issue.
Another interesting tidbit, using H.265, everything works perfectly flawless. I can run full 8MP resolution, 30fps, 30 i frame, 8Mb/s bitrate, and that's what the camera does, that's what is reported in any NVR software.
And before someone elses asks the next question of why don't I just run the cameras in H.265 all the time, it's because the software I currently use to record constantly on the main stream does not support H.265. I am currently investigating other NVR software to match the features I like in the current software, but also supports H.265.