nightrider

2) It seems they've changed the password in the newer devices. 3) The algorithm is changed too. Perhaps they've changed only the static four numbers group and I guess it won't take too much time for someone to guess the new one.

Clearly the general idea behind the fairly new P2P service is convenience. But I am afraid that the design of it may contain the same security flaws.

Hello! I was kinda surprised when I discovered some serious security issues regarding allegedly all Dahua devices. 1) The administrative service which is public and required for access through web, *PSS, and the mobile client, requires no authentication nor authorization of any sort. Anybody could potentially retrieve or change various sensitive info. 2) The telnet root access with publicly known static password. 3) The publicly known date based password generation algorithm for the admin and probably other accounts too. 4) Most services credentials are stored and transferred as clear text. 5) UPnP requests from untrusted sources could be used to expose telnet or any other service of the device to the Internet. These have been well known issues for over a year now and from what I've read, it seems that they haven't been fixed yet. Do any of you know if the above issues are still present? Perhaps they are considered by Dahua as "features" and features never got fixed. Thank you.

How so? The maximum bandwidth (given as bitrate in the specs) per video stream is 8mbps. I am not referring to the maximum bandwidth of the device Ethernet port, which in the given IPC is 100mpbs, or the total bandwidth for all number of streams because there isn't such info. I meant and said stream bandwidth but also as I stated already, the vague specs does not make it easy. The root of the problem must be the correlation between the FPS and the bit-rate. Lower bit-rate means lower fps, which in turn means less smooth motion scenes. That would be a problem with all kind of video signal. But if there isn't too much motion then this shouldn't be an issue. If we put the motion scenes aside, is there noticeable difference in the details? I've already seen that video and many more. But I am not sure what were the stream details at the time the video was taken. I understand but that doesn't make it look good. Kudos! I'm pretty sure that is not the only reason. There are surely things like cheap labor and etc. But otherwise totally agree with you. Dahua referred me to the reseller I'm dealing with.

The specs about IPC-HFW4100S says main stream at 1.3M/720P(1 ~ 25/30fps), substream at D1/CIF(1 ~ 25/30fps) and max bandwidth (bit-rate) 8mbps. And I got that the given IPC support only 1 main and 1 substream within 8mbps limited bandwidth. As you can see it is pretty hard one to understand what is meant. But after you shed some light, now it looks like the given maximum bandwidth is per stream of some unknown number of streams /usually 4-5 as you wrote/. Is there noticeable difference between 2MP (1080p) at 4mpbs and at 8mpbs /for the naked eye/? Again, I've been told there isn't, yet the presentation was quick and I had no luck seeing it for myself. 3.6GB/h is at 8mpbs and to be honest I don't think it is even close to comparable with BR quality. After all, it is some "cheap" camera and I'm not fooling myself, not even looking for BR quality in budget cameras, but I expect something that hopefully will considerably outperform all mass analogue variants on the market. Good to hear but the info is from the Dahua official website and official IPC specs there - Link. All 1.3MP IPC specs there says that the effective pixels are 1.2MP = 1280Hx960V. It is hard to mistranslate numbers even in Chinglish. Can't recall, just popped out of my mind. Why, you like it, don't you? I've been told by the official reseller that the entire process of recording based on Motion Detection is done entirely by the NVR, even the MD itself. The reseller employees said that the IPC stream is continuous, regardless of whether actual motion is being detected or not, and that the NVR decides whether to record or not (i.e., if it detects motion). Sure thing! It's Bulgaria. I'm inclined to agree to some extend with you. But obviously "somehow" is not enough. Perhaps some of the manufacturers relies too heavily on resellers to do the job. Let me paraphrase the question. Can the main stream of 1.3MP camera be set to 4mpbs@30fps or is it maxed when the fps is maxed out? - 1.3MP@8mbps@30fps - 1.3MP@4mbps@15fps - so on

But if I bypass the NVR and connect directly to the camera then I would borrow bandwidth from its main stream or I would need extra stream that will reduce the available bandwidth for the main. Purely theoretical, that would be the case only if the camera main stream is maxed. I believe that in real scenario 4 mpbs stream is more than enough for decent 2MP and 2mps for 1.3MP. Btw, are the number of the IPC substreams limited by total bandwidth only? I've just noticed that Dahua IPCs are marketed as 1.3MP 1280x1024 when they're more like 1.2MP = 1280x960. At least that is that the specs says about the effective resolution. Guess it is another marketing stunt. Chinglish seems very convenient when it comes to that. Maybe decoding is also needed for the Motion Detection function to work. I've been told that it is done by the NVR. It is the only seller in my country and it seems fairly big but its employees are slightly more arrogant than they should be! I've already given a thought about going down the Ebay road, even for cheap solutions with flashy claims, and after a while decided that it's not a wise choice, mainly because of the warrant, support, and that the sellers I've contacted so far have no clue what they're selling, which is a real stopper. It would be a real relief if manufacturers and sellers heed your words! I really hope they do for the sake of all customers! Btw, I have a quick side question. It is a bit outside the scope but I hope you don't mind. So, here it goes, the question is, is there any correlation between the IPC fps and resolution in the context of stream bandwidth (bit-rate)? Can 1.3MP IPC be set to stream at 1.3MP@30fps as well as @1fps? Well, I suppose it can and obviously more fps would mean more bandwidth but is there any catch that I should be aware of? I am asking because I read in the specs the following "1.3M/720P(1 ~ 25/30fps)" for the main stream. I really want to thank you for your efforts so far! I really appreciate it!

Got confirmation that it is analog technology and is developed to upgrade the current analog systems seamlessly and at low cost to the HD era.

That it can preview locally. Btw, if preview and real-time live view means the same thing, why the different terms? Perhaps it is a preview of the live stream. If the only job of the NVR is to act as a storage, then why it need to decode, can't it simply pass-through the streams? The seller pretty much said that everything is based on the record and outgoing bandwidth, in my case 80 and 8mbps. That I can do anything within these values.

So the NVR always need camera main stream+substream if one would want to watch real-time live view remotely multiple cameras because of the 8mpbs outgoing limit? Can't the NVR accept only main stream and then internally split it into multiple outgoing streams? I suppose the recording of the substream in that case isn't necessary, right, or is it mandatory? One can't simply record 4 x 4mbps streams because they will exceed the 8mbps NVR outgoing bandwidth and should record 4 + 4 mbps + 4 x 2mbps for example and then can view 4 cameras at once, is that right, or is there option for some stream/channel to skip recording /only real-time live view/? So remote playback is available only for single channel at a time, right? Also, if I'm on the right track, single channel is equal to single stream, correct? By remote preview I suppose you mean realtime-live view, right, and in my case it is limited to 8mpbs by the NVR outgoing bandwidth?

Btw, the specs doesn't say how many channels the NVR can preview, only that it can preview at up to 5Mp resolutions. Here is link to the discussed NVR specs. It would be kind of you if you can take a look! Thank you!

[quote="dexterash"] Not really. As I stated before, you have to sum up extra stream + main stream bitrate, not just main stream's bitrate. Should work if you setup 4Mbps for main stream and 1Mbps for extra stream. But 4Mbps for 5MP resolution is kind of low. [/quote] But the sub-stream is only needed if I want to watch it through smartphone for example, right? I suppose it is an option not requirement, correct? [quote="dexterash"] Preview refers to what the NVR decodes on local display. For example, a NVR could record 4 channels@1080p, but only display/decode 2 channels. [/quote] The specs says that the NVR has "sync playback: 1/4/9/16", which I assume means playback of 1 or 4, or 9, or 16 channels simultaneously and remotely at resolutions of up to 5MP, is it correct? It also says that the local display resolution is 1080p and the "Display-split: 1/4/8/9/16", which I assume has the exact same meaning as the above but with lower resolution, correct? I assume you mean decoding records, playback, not live view decoding, correct? But then it is in contradiction with the 1080p real-time live view specs. Or maybe Dahua specs has other meaning for "preview".

Hey, thanks for the reply! Lets take for example Dahua NVR 4116. It has 16 channels, 80mbps incoming bandwidth and up to 5Mp resolution preview & playback, the specs also says that the max recording resolution is 5Mp. So, in theory, it should be good to go with 16 5MP cameras, each streaming at 5mpbs CBR and at maximum resolution, right? Most of the Dahua IPC I've seen are limited to 8mpbs outgoing bandwidth /bit-rate/, which is why I think they can't output 10-12 mpbs. Is my assumption correct? Btw, what is the meaning of "preview" resolution in this context? Thank you!

@martin68, Personally I wound not buy cheap Ebay junk, unless it is second hand reputable brand or I've seen some reviews I can trust, or you're willing to throw some money away. Otherwise, there is almost certain possibility that you would end up with some low grade devices, backed up by some Chinglish manual. But hey, don't take my word for granted, everyone needs to bump their head in order to learn. @Stephens, It seems that only 2-3 models of the Dahua IP cameras are with built-in Mic/Speaker and few with available ports. Most of the HDCVI PTZ models seems to have input audio channel.

HDCVI composites video, audio, and control signals together and then transmits them over one coaxial cable.

Hello! Anyone got their hands on Dahua NVR 41XX series? According to the specs, the series are limited by incoming total bandwidth of 80 mbps (record rate) and outgoing total bandwidth of 8mpbs (bit-rate), and they can record in resolutions of up to 5MP. So, in theory, one should be able to throw in 10 cameras, streaming at 5MP, 8 mbps CBR, and 30 FPS, and the NVR should record without reducing the quality, right? Also, because of the maximum 8mbps outgoing bandwidth, one can playback remotely only single channel at full quality, correct? I found out that the "smart search" function is available only locally and not remotely via web or CMS. Do you know if they plan to fix that soon in some firmware/software update? I'm open and looking forward to suggestions about the Dahua or any other budget products! Please, share your insight and experience! Thank you in advance!