suggestions on building or buying a NVR that can keep accurate time and also do a OSD of the time

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Gang, here is the problem that you might be able to help me with.


I need a single channel video camera system that will record continuous video data to a hard drive. here are some requirements:


1) recorder should write to removable HDD

2) shouldn't write more than 1 TB in ~20 days of 24 hour days

3) needs to write video continuous for those ~20 days

4) resolution can be poor to cut down on disk space- I am blurring the images for privacy- I just need to know people-shapes around the room. No audio needed either.

5) I have decided on a IP camera a this point because I can blur the images by tweaking the lens and it has a wide view (180)- also is cleanable and looks nice - Dlink DCS4622 . It can send frames via ethernet in H.264 or JPEG.

6) I have a local LAN and I cannot access the internet. I am just imaginging three things on it: IPcam, NVR, and the NTP server (see #7)

7) A node on the LAN is a NTP server that is high-precision- i want my recorder to get time from it. I need to use this as a source of truth for my project. It is very important that the timing on the OSD on the videos is accurate to the second.

8) I’d like the recorder to write video to file in something that VLC player will understand without any conversion. I want to feed all this data to some other 3rd party tools to annotate it. It plays the videos using VLC player and annotates on top of them.

9) I can’t use a windows laptop. This system needs to be rolled into a situation in a compact form and set up, then rolled out without much fuss. I don’t need to look at daily activity, (other than set it up and validate it is working). I want a small NVR and drive so it is hidden.

10) the good news is I am not really cost-constrained.



I am currently using a Dlink DNR 202L recorder which has two problems:

1) I’ve seen the OSD clock drift relative to my local NTP server for 15 seconds in 2 hours. I know it is getting NPT time from the local NTP server I have described in #7, but I have no control on how often it is getting it.

2) Basically #8 above. This Dlink DNR 202L writes videos to some funky file type that I can’t seem to efficiently convert. I’d rather not convert at all. The converter that Dlink provides is slow and also crashes. I am currently trying to see if ffmpeg will work with this format, but I am running out of time.



In my mind, there are three solutions. I think you guys might have some insights here.


(a) keep the NVR, try to get it to keep better time. Power-through the conversions.


(b) abandon the NVR- find a new one that is off the shelf that has a more precise clock and can also fetch ntp time more frequently, and also records in a more standard format.

(c) use a raspberry pi to keep system time and fetch new time (built into linux- no problem), and some how append the h.264 frames with OSD time (the tricky part) and then store the H.264 frames to a mounted HDD (the other tricky part). I don't mind doing the work, but I don't want to reinvent the wheel here. If there are existing software packages that will do this that will run on a rasp pi, I'd like to know...
 
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@looney2ns, thanks for the suggestions. I've been working on this for a few weeks, and I decided to roll my own with a Raspberry PI and some libraries like FFMPEG and python to write a statemachine to govern the control of the writing to disk. This gives me the options to record it the way I want to, to meet the requirements I've shared already on the thread above. If anyone wants me to share code I can. As it turns out, I am doing this really cheap. Raspberry pis are about $30 and the drives are, well, market price. I am using a 1TB drive, which is about $80. So, that's a $100 NVR with all the flexibility that I code in.
Cheers!
 

nats

Getting the hang of it
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I use mikeboers/PyAV quite a lot for in case you have not seen it.

If you are using raspbian, be carefull with the timezone settings and ntp config.

What kind of storage are you planning on using?
 
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