I discovered this thread through Google and have been reading it with interest. Thanks for all the useful information!
I have a question: I can see that upgrading to the Dahua firmware adds some interesting features, but does it fix bugs?
The reason I ask: I have an IP8M-T2499EW, which I mostly use to take 1/second snapshots (that I later combine into a time-lapse video). I use the HTTP interface on the cameras to retrieve JPG snapshots. I've tested both the URL returned by ONVIF GetSnapshotURL and the /cgi-bin/snapshot.cgi documented in the
Amcrest API document.
I discovered that the IP8M is incapable of retrieving full 8MP snapshots: if you try to read the URL while the camera is set to full resolution it will fail 99.9% of the time with a HTTP 400 error code.
The only way to reliably retrieve snapshots is to set the resolution to 4MP or less.
I asked about the problem on the Amcrest forum and many other people have the same issue.
I have had a support request in with Amcrest since March. I gave them access to the camera and they admitted the problem exists, but I haven't heard anything since. They did release a firmware upgrade in October but that didn't fix the problem.
So, I'm wondering whether the Dahua firmware has the same problem. I'm getting the impression from the posts here, and from Amcrest's general lack of responsiveness and lack of firmware upgrades, that they don't really do significant software development or support (maybe just minimal rebranding?) so my guess is that the bug is in the original firmware and that Amcrest is incapable of fixing it (I've seen the same problem, but at a much reduced frequency) with some 4MP Amcrest cameras). Alternatively it's an issue that Amcrest introduced trying to add a feature to code they don't understand(?)
Is there anyone out there who is using the snapshot interface and can tell whether the Dahua firmware has the same problem? Obviously I'd rather not go through risk of switching firmware if it has the same low level bugs.
Thanks for any help/information on this.
PS: I did try using the NAS interface to get the snapshots. It does not seem to save them with anywhere near the desired 1/sec frequency. Actually, even through the HTTP interface, at reduced resolution, I only am able to get about 1 every 2 seconds, but I can live with that.