Looking for H.264 DVR, any suggestion

[cctvsentry 0]

I need 240 fps CIF recording at least for 4, 8 and 16 channel. SATA is necessary. Somebody said YOKO has new H.264 DVR and it is in mass production. Where is this company? is it a good unit? if you have nice piece, let me know.

[todd2 0]

Are you sure you only need CIF? I tried CIF on my avtech and it was

really crappy quality. Even frame at best resolution is disappointing.

Make sure you actually see the CIF format in person if you're going to

drop a lot of coin.

[cctvsentry 0]

Are you sure you only need CIF? I tried CIF on my avtech and it was

really crappy quality. Even frame at best resolution is disappointing.

Make sure you actually see the CIF format in person if you're going to

drop a lot of coin.

 

I said at least CIF 240 fps, becuase i thought they may give me 120fps as HD1 for 4 channel and 30 fps at D1 for 8 and 16 channel.

[todd2 0]

I wasn't talking about the fps, I meant the quality of CIF independent of

the fps--the fidelity of the pixel capture. On the AVC761, even frame best

is not very good. I can accept the 7.5 fps per channel, but don't like the

fact that I'm not getting DVD resolution capture.

[BennyBoy 0]

I need 240 fps CIF recording at least for 4, 8 and 16 channel. SATA is necessary. Somebody said YOKO has new H.264 DVR and it is in mass production. Where is this company? is it a good unit? if you have nice piece, let me know.

 

Are you sure you need h.264? I ask because I've been looking for a good 264 DVR myself and I'm finding the Mpeg4 units seem to have much better image quality. Dont get me wrong, I know H.264 is far better than the standard mpeg4 if implemented correctly. I'm finding the current DVR's under a $1000. do not have the processing power to give a high quality image.

 

I use a Mac PC, its a two cpu G5 @ 2 ghz and for me to compress a 90 min DVD movie in the highest quality H.264 takes about 6 hours. The same movie in the same quality with Mpeg4 takes about 30 mins. both files look as good as the DVD but the 264 file is about 1/4 the size of the Mpeg4.

 

 

My point is this, wait a couple of years for a H.264 dvr and settle for a good Mpeg4 dvr.

 

If you must have one now, I feel the G4-RTA D1 is the best for the money.

Edited June 17, 2008 by Guest

[jasmilelv 0]

I need 240 fps CIF recording at least for 4, 8 and 16 channel. SATA is necessary. Somebody said YOKO has new H.264 DVR and it is in mass production. Where is this company? is it a good unit? if you have nice piece, let me know.

 

Leave me your contact information.

I will send you our new DVR items for your reference.

[scorpion 0]

This may, or may not suit your needs, but I would have you look at ICRealtime.

 

http://icrealtime.com/solutions/index.asp

 

I would recommend the Flex Series with the R30 upgrade.

 

What do you think?

[cctvintegration 0]

Are you sure you only need CIF? I tried CIF on my avtech and it was

really crappy quality. Even frame at best resolution is disappointing.

Make sure you actually see the CIF format in person if you're going to

drop a lot of coin.

 

AVTech uses their own DISASTROUS MPEG4 algorithm. My guess is a T.I or ADI (BLackfin) dsp h.264 at 1CIF looks better than most 2CIF or even a few D1 standard MPEG4 units. I've seen the Texas Instruments Davinci DSP recording at 1CIF and it was near DVD quality. Not D1 of course, but I was blown away. And, there are now a ton of Davinci installed DVR units to choose from. H.264 is the standard now. Even Apple uses H.264, I think that says it all.

 

Not to be too hard on AVTech, for 99.00 FOB Taiwan, the 760 is a decent disposable 4ch DVR.

[Jovacom 0]

I need 240 fps CIF recording at least for 4, 8 and 16 channel. SATA is necessary. Somebody said YOKO has new H.264 DVR and it is in mass production. Where is this company? is it a good unit? if you have nice piece, let me know.

 

Hi,

We have used from factory direct models from Dahua technolgy in China. i can say, never seen better. you can forget the old things about china manufacturer, this company make totally new way to use DVR.

look from dahuasecurity dot com

 

i can give you login to our DVR if you like to test online features.

 

Chris

[cctvintegration 0]

yes, certainly a step up from the old China stuff. I give kudo's to Dahua, Dali, and the bigggest of them all, Hikvision.

 

So my question is:

Why do so many distributors stick a 2 dollar name plate on these DVR and pretend they are the manufacturers of something so incredibly special, that a 16CH D1 DVR should cost 4k?

 

I understand oem branding, but be real, charge a reasonable price.

[ClosedCircuitCom 0]

aventura has unparalleled picture quality compared to all other h.264 dvr's i have seen even at cif.

[cctvintegration 0]

aventura has unparalleled picture quality compared to all other h.264 dvr's i have seen even at cif.

 

Again, please tell me why Aventuras Hikvison DVR is better than all the other OEM suppliers. If I buy a Hikvision from China and stick my name on it, will mine be better?

 

If I buy the spot on exact DVR on Ebay as opposed to ADI, and I save 2000.00 dollars, is my DVR of lesser quality?

[oldtimer 0]

We have been using some low priced H264 recorders for some time now.

We install them on cheapy installations but we want a fairly decent recording. The fast food people wont pay big money for installations of

CCTV. A good supplier is in Florida. 888 233 3478. Ask for Henry.

Tell them John from Indiana referred you. Not looking for a comission,

I send him a lot of dealers because he has good service and prices are right.

[dudu_georgescu 0]

Are you sure you only need CIF? I tried CIF on my avtech and it was

really crappy quality. Even frame at best resolution is disappointing.

Make sure you actually see the CIF format in person if you're going to

drop a lot of coin.

 

AVTech uses their own DISASTROUS MPEG4 algorithm. My guess is a T.I or ADI (BLackfin) dsp h.264 at 1CIF looks better than most 2CIF or even a few D1 standard MPEG4 units. I've seen the Texas Instruments Davinci DSP recording at 1CIF and it was near DVD quality. Not D1 of course, but I was blown away. And, there are now a ton of Davinci installed DVR units to choose from. H.264 is the standard now. Even Apple uses H.264, I think that says it all.

 

Not to be too hard on AVTech, for 99.00 FOB Taiwan, the 760 is a decent disposable 4ch DVR.

 

Can you pls give some examples of DVRs that come with Davinci DSPs?

[amirm 0]

My guess is a T.I or ADI (BLackfin) dsp h.264 at 1CIF looks better than most 2CIF or even a few D1 standard MPEG4 units.

CIF images are going to be soft no matter how little compression artifacts there are. Sure, if you are bandwidth starved, then an H.264 at lower resolution may be superior but if motion is small, even that won't be the case.

I've seen the Texas Instruments Davinci DSP recording at 1CIF and it was near DVD quality.

How do you get near DVD when you have one quarter the resolution?

 

Even Apple uses H.264, I think that says it all.

I am not sure that says anything . Apple's profile of H.264 is the lower complexity one anyway. The highest fidelity is HP which is used in production of Blu-ray.

 

The issue here is that standards do not specify encoder performance. Two H.264 could be wildly different from each other. With H.264 specially, there are a ton of shortcuts that can be made to achieve high frame rate. Software solutions running in DSP/PCs are liable to take the most shortcuts. Best solutions are used in broadcast products and even there, they take shortcuts relative to PC software professional encoders.

 

Broadcom has nice H.264 encoder silicon but I am not sure any DVR vendor uses it yet.

[wattwire 0]

My guess is a T.I or ADI (BLackfin) dsp h.264 at 1CIF looks better than most 2CIF or even a few D1 standard MPEG4 units.

CIF images are going to be soft no matter how little compression artifacts there are. Sure, if you are bandwidth starved, then an H.264 at lower resolution may be superior but if motion is small, even that won't be the case.

I've seen the Texas Instruments Davinci DSP recording at 1CIF and it was near DVD quality.

How do you get near DVD when you have one quarter the resolution?

 

I'm working with a Blackfin DSP based H.264 DVR now and I can vouch for the concept that the 1CIF looks very good and exceeds the quality of "D1" recordings from other DVRs. Unfortunately, for my DVR, the D1 quality only increases marginally--even when testing with a very high quality 540tvl camera. There's definitely a difference between the two, but not nearly what you'd expect for having 4X the frame size.

 

My theory on why 1CIF can look nearly as good as D1 is based on the belief that the image constructed in the DVR's frame buffer doesn't come anywhere near representing the resolution we think it does. As a matter of fact, I bet the real resolution is closer to 1 CIF than it is to 4 CIF. The frame buffer is 4 CIF, but the image has been expanded to fit. An analogy can be made from working with an image editing program like Photoshop. You can take a not so sharp looking picture and make it look good by shrinking it some (1CIF)...and if you expand the shrunk image back up, it doesn't look that much different from the original. However, there's very little you can do to improve the original picture because the image information just isn't there, even if you try to expand/increase the resolution (4CIF).

[amirm 0]

I'm working with a Blackfin DSP based H.264 DVR now and I can vouch for the concept that the 1CIF looks very good and exceeds the quality of "D1" recordings from other DVRs.

I can certainly buy that to some extent. But that is a different argument than it being "near DVD." Composite video has nothing close to DVD resolution given the limitations of NTSC modulation. So it is not surprising that a CIF encoding doesn’t lose much in resolution in that scenario. And in the case of a DVR doing a poor job of compressing the content, then the extra resolution NTSC has over CIF is probably lost.

Unfortunately, for my DVR, the D1 quality only increases marginally--even when testing with a very high quality 540tvl camera. There's definitely a difference between the two, but not nearly what you'd expect for having 4X the frame size.

Per my post here: http://www.cctvforum.com/viewtopic.php?t=10415&postdays=0&postorder=asc&start=45, (see middle of the page), 540 TVL refers to sensor resolution, not what comes out of the camera. The output of the camera is limited to NTSC spec which is 330 lines. So good to hear that your experience matches theory .

My theory on why 1CIF can look nearly as good as D1 is based on the belief that the image constructed in the DVR's frame buffer doesn't come anywhere near representing the resolution we think it does. As a matter of fact, I bet the real resolution is closer to 1 CIF than it is to 4 CIF. The frame buffer is 4 CIF, but the image has been expanded to fit.

That is a correct description of the end results. Technical explanation is that the DVR NTSC decoder, demodulates the source and separates the signal into YUV components (i.e. black and white and color). It then digitizes these samples at D1 resolution if told to, but that source being NTSC, was filtered at the camera end to 330 lines. So even though the DVR input logic attempts to sample the source at higher resolution (fill the buffer as you state), the samples do not change at higher frequency than 330 lines.

An analogy can be made from working with an image editing program like Photoshop. You can take a not so sharp looking picture and make it look good by shrinking it some (1CIF)...and if you expand the shrunk image back up, it doesn't look that much different from the original. However, there's very little you can do to improve the original picture because the image information just isn't there, even if you try to expand/increase the resolution (4CIF).

Well said.

[amirm 0]

Adding on to my previous post, what of the things H.264 does well over MPEG-4 (part 2), is that it degrades much more gracefully when pushed. A lot of detail gets lost in a sea of compression artifacts when things move, or there is picture noise. H.264 deals with this much more effectively (assuming all the features are implemented).

 

So in some sense, the dynamic resolution of H.264 is higher than that of MPEG-4.

[tesc_cctvpro 0]

Hope this is not out of line..but we are distributors of the Dahua dvr which was mentioned by another poster. We chose this as a mid to high end offering and suggest you have a look at their website.

 

Mpeg4 vs H.264 , if you're in this debate it's not about image quality. it's a ROI issue regarding quality to storage ratio, and network transmission performance and load. In both these cases h.264 wins.

 

CIF as mentioned will only suffice for "Observation" level surveillance which may be ok for residential or low level purposes. If you at any point will need "Recognition" or "Identification" level then you may want to consider Higher than CIF which is basically a "Pixel Resolution" or just a measure of the image size that can be displayed .

 

Reagrding frame rate which is considered "temporal" resolution you need to strike a balance between the size of image (CIF/4CIF) you need at "real time" with regard to your storage requirement. (4CIF) will result in shorter recording time than CIF, and Network transmission of 4CIF images will place a heavier burden on your network capacity.

 

In the end it comes down to striking the maximum ratio of image size:temporal resolution:Compression Standard:recording time:network capacity for your requirements. Mostly each case will have unique requirements.

[wattwire 0]

That is a correct description of the end results. Technical explanation is that the DVR NTSC decoder, demodulates the source and separates the signal into YUV components (i.e. black and white and color). It then digitizes these samples at D1 resolution if told to, but that source being NTSC, was filtered at the camera end to 330 lines. So even though the DVR input logic attempts to sample the source at higher resolution (fill the buffer as you state), the samples do not change at higher frequency than 330 lines.

 

Amir, that was a nicely written tutorial in the drama filled thread about camera resolution. I feel very lucky to have the attention of an experienced video engineer. More people need to point out that we're working with a signal standard here (NTSC) that doesn't dynamically change to accommodate higher resolution cameras and recording equipment. Having said this, I'm still struggling a bit trying to understand the maximum resolution that video transmitted over coaxial cable can be recorded at.

 

In particular, I have to ask, "How is it that recordings at 4CIF look better than 1CIF given the fact that 1CIF exceeds the 330tvl frequency limitation of NTSC?"

 

Is it possible that the baseband signal from cameras is exceeding the NTSC standard of 4.2 Mhz and approaching the 6.75Mhz "studio frequency" you mention in the other thread?

[amirm 0]

Amir, that was a nicely written tutorial in the drama filled thread about camera resolution. I feel very lucky to have the attention of an experienced video engineer.

Appreciate the kind words . I know very little about video used in CCTV applications so am learning a lot here. And thought I pass on the bits I know.

 

In particular, I have to ask, "How is it that recordings at 4CIF look better than 1CIF given the fact that 1CIF exceeds the 330tvl frequency limitation of NTSC?"

Actually, that assumption is not correct. NTSC does exceed the resolution of CIF. As I said: "And in the case of a DVR doing a poor job of compressing the content, then the extra resolution NTSC has over CIF is probably lost," it is the combination of poor video compression and NTSC that might eliminate the extra resolution benefits of 4CIF.

 

Put another way, if you have a static shot with a lot of bandwidth, then 4CIF will look better. But once the image moves, and you introduce compression artifacts, then much of that resolution might be lost. As a way of example, I was at some IP camera company web site showing how they could easily capture license plate of a car and showed the difference between their megapixel solution and that of analog camera. Then I go look at their live feed of the parking lot, and the license plate is a complete blur with blocking artifacts of MPEG-4!

 

So one needs to look at these platforms as complete systems end to end and evaluate that. Unfortunately, despite research for a while I have not found anyone benchmarking these cameras side by side with all of these considerations thrown in. It is not an easy test but a necessary one to gather good data.

 

Is it possible that the baseband signal from cameras is exceeding the NTSC standard of 4.2 Mhz and approaching the 6.75Mhz "studio frequency" you mention in the other thread?

The camera portion certainly goes beyond what NTSC can handle. Per above though, that is not the real explanation.

 

However, there is one topic I did not cover there that I will here. Namely, if you take a higher resolution sensor, and then filter it down to what NTSC can handle, you get some natural noise reduction out of it. In layman terms, assume that we average pixels to arrive at fewer ones to transmit. If average a noise pixel with a black one, then the noise level goes down by a factor of two. So in some sense, an ultra high resolution sensor helps produce a cleaner picture.

[wattwire 0]

 

In particular, I have to ask, "How is it that recordings at 4CIF look better than 1CIF given the fact that 1CIF exceeds the 330tvl frequency limitation of NTSC?"

Actually, that assumption is not correct. NTSC does exceed the resolution of CIF. As I said: "And in the case of a DVR doing a poor job of compressing the content, then the extra resolution NTSC has over CIF is probably lost," it is the combination of poor video compression and NTSC that might eliminate the extra resolution benefits of 4CIF.

 

Bear with me a bit as I suffer from mild retardation at times. I'm probably missing something here about the basics. For a moment, let's put aside discussion about compression. My understanding is that TVL represents resolution going horizontally across the video scan line. I understand that the scan lines are interlaced and alternately refreshed. The resolution of CIF for NTSC is 352x240. So my original question was focusing on the fact that 352 > 330. What am I missing here?

[amirm 0]

Bear with me a bit as I suffer from mild retardation at times. I'm probably missing something here about the basics. For a moment, let's put aside discussion about compression. My understanding is that TVL represents resolution going horizontally across the video scan line. I understand that the scan lines are interlaced and alternately refreshed. The resolution of CIF for NTSC is 352x240. So my original question was focusing on the fact that 352 > 330. What am I missing here?

Simple: there are two different measures here: one is the number of pixels and the other is "TV lines." The two are related but through a complex chain which I described in the lengthy post. Quick summary is this:

 

To get horizontal TV lines from X number of pixels, first you multiple X by 3 and then divide by 4 to compensate for the fact that NTSC uses rectangular pixels which have a 4:3 aspect ratio. So your CIF horizontal pixel resolution of 352 just shrank to 264 TV Lines. This is lower than 330 TV lines which NTSC can carry at the limit.

 

In other words, the TV line metric derates the horizontal resolution as to normalize it to the vertical resolution.

 

Hope this makes it more clear.

[wattwire 0]

Simple: there are two different measures here: one is the number of pixels and the other is "TV lines."

 

Yes, different metrics. This is the key to my confusion.

 

To get horizontal TV lines from X number of pixels, first you multiple X by 3 and then divide by 4 to compensate for the fact that NTSC uses rectangular pixels which have a 4:3 aspect ratio. So your CIF horizontal pixel resolution of 352 just shrank to 264 TV Lines. This is lower than 330 TV lines which NTSC can carry at the limit.

 

In other words, the TV line metric derates the horizontal resolution as to normalize it to the vertical resolution.

 

The arithmetic of reducing the horizontal resolution to accommodate a 4:3 aspect ratio is pretty straight forward. But isn't the CIF standard for NTSC already set at a 4:3 ratio? (352/264). So the theoretical maximum number of horizontal pixels that would benefit the quality of a digitized image is 440? (330 * 4 / 3). The only reason I referred to CIF in the first place was because it was a known number of pixels. Hmmm, maybe we need to investigate what pixel is and what TVL is.

 

Hope this makes it more clear.

 

Actually, I'm more confused than ever now. This is a good thing though, because I'm probably on the verge of learning something.

 

Amir, thanks for having the patience in explaining this. Understanding how TVLs relate to pixel dimensions of digital images recorded by a DVR has got to be one of the most important concepts there is in CCTV. It plays a hand in how we select cameras, transmission methods, DVRs, and display devices, and more. So at the risk sounding ignorant, I'm going to take another shot at trying to get at the bottom of what a DVR can record (with no compression) from a baseband signal coming from a camera over coaxial cable.

 

I think my biggest stumbling block is understanding what a TVL is. Here's what I've gathered from what I've read and been told: The maximum number of vertical lines going across the screen whereby each can be individual resolved. Said another way, if you could make a uniform bar code and place it in front of a camera, how many vertical lines there would be before the black ones merged together. I guess this also relates to the modulated electrical pulses in the signal (but we don't need to get this deep).

 

I feel much more confident about what a pixel is as it relates to a digital image. It is the smallest unique picture element that can be modified.

 

What I really want to know is: What is the maximum number of unique (not merged) pixels of information than can be recorded/digitized on a DVR coming from the baseband signal of an analog camera? If we took the uniform barcode example, how many white spaces and black bars could we individually distinguish before they started to merge together in the digitized image?

 

Thanks!

[amirm 0]

Ah, I see what the issue is. You are actually trying to understand this stuff .

 

So let me expand a bit. There are actually two definitions here, both with the same name but each mean a different thing! The first should more correctly be called, "TV Lines per picture height" but unfortunatley, people omit everything after "TV Lines." This is the one I described above in my post.

 

The motivation for this definition was to make sure that if a circle is drawn at 1 inch radius, that it has the same number of pixels in horizontal and vertical dimensions. Since NTSC pixels are rectangular by the 4:3 ratio, we use that math to arrive at the normalized horizontal resolution to go with our vertical resolution (which never changes in NTSC). In this kind of conversation, no one really cares about how many lines this actually captures from real life. We arrive at a number and use that to compare equipment.

 

What you seek is the true definition of "TV line." That, the exact resolution one can capture out of the system. Alas, this is a tricky problem to solve because it is a subjective discussion, not objective.

 

Now if you read my long post, I talked about something called a Kell factor. That is an attempt to answer your question. That is, if I have 10 pixels of resolution, how many pixels of real life can I capture? The answer may seem simple but it is not.

 

Imagine you have a series of alternating white and block dots you are trying to capture. I will represent White with X and Black with O. So assume the following simple example of the source:

 

X O X O X

 

Now let's assume we have a camera with 3 pixels worth of resolution. For the sake of simplicity, let's position these pixels precisely where the white dots are (each camera sensor pixel is shown as "C"):

X O X O X      <--- image you are trying to capture
C   C   C      <--- camera pixels

In this scenario, the camera sees only the Xs and outputs all white:

 

X X X <---- output

 

It is obvious that we lost the original image and that we need more than 3 pixels to detect three white dots seperated with blacks.

 

Now, if we had an extra sensor pixel in between, that is, 6 pixels total, we could capture the true transitions from black to white. This leads us to think that the true resolution of such a system is half as much. But this would be too pessimistic view of the world. Why? Because the pixels don't have to match the way I showed. And that if the subject moves, and/or pixels don't align, then we are likely to pick up the black and white pixels.

 

An RCA engineer in 1930s by the name of Kell studied this effect and came up with percentage to use here that is more optimistic than the 50% shown in my example. Based on his work, the number 0.7 is used as the effective resolution for CRT systems. That is what I used in my math in the long thread to arrive at the true vertical resolution. That is, you multiple your pixesl by the Kell factor to arrive at the subjective resolution of the system.

 

Of course, there is no telling what this number should be since subjects vary as do sensor sizes. Kell himself went from 0.64 I think to 0.85 and others have come up with different numbers.

 

Net, net, if you are shopping for stuff and want to equalize specs then use the first definition because that is what the industry uses. The number won't translate into real life resolution but maybe we don't care to actually measure the resolution .