D1 @ 30fps, CBR... 2048k or 1536k bit rate? Big quality diff

[Toaster 0]

Curious from the pro's, is there a big quality difference between 2048k bit rate vs 1536k bit rate....?

[rory 0]

depends on the DVR, and in that case not that Ive noticed, in fact I just stick to 640/1024.

[SEANHAWG 1]

I cant really notice much of a difference from 800 and up from the DVR's I have tested.

[Toaster 0]

I'll post back in a week or so, at D1 30FPS 2048k bit rate recording 5 cameras 24/7 I get about 10 days recording on a 1TB HDD. I changed it back to what was the "default" 1536k bit rate on the 20th... so I'll see how many more days I get........

[Toaster 0]

Bumping bitrate down to 1536k from 2048k across all 5 cameras, D1 @ 30fps 24/7 gives me about 15 days recording on a 1TB HDD.

 

at 2048k (all else the same) yields about 10 days recording time on the same system.

 

Just FYI

[rory 0]

Cool .. i had the 32 channel at 1024 with 23 cameras connected and 6x 2TB drives and it was eating through those drives even at 7fps D1. After 2 weeks it had already eaten up one drive and was at 640GB of the second drive .....

 

So I dialed 7 of the inside cameras down to CIF and 256 and 1 main inside one left at D1 but switched it to 640 which is the default. Then changed 2 of the outdoor ones (front door cam and one that looks at the dogs eating LOL) to CIF and 256 and the rest to D1 but switched to 640 ...

 

Im hoping it will eat less.

 

Now that said .. another thing that eats the drive up ...

Consider "Pack Duration" ... basically how long each regular record file is saved for ..

default on dahua is 60 minutes.

 

Figure that each file has some header info .. as these files need to be identified by Dahua's player and conversion process.

 

It might seem better to set that Pack Duration lower like 3 minutes so you dont have to search through hour long videos, or download hour long videos ... but that would mean 19 more header info than if it was just a single 60 minute file .. add that up over 6x2TB Drives .. that COULD be considerable especially if each file also saves some footer info like to tell it end of file, etc.

 

Next consider Motion Record.

Motion Record is sweet as even with the odd false alarm it is easier to find events as long as masking is performed properly.

 

BUT, when you have Regular Record and Motion Record enabled in the schedule, when the DVR picks up a motion event it stops Regular Record (whap, 60 minute file gets closed and finished up at say for example the 20 minute mark), then Motion Record takes over and saves that file for however long. When the motion event has completed, Regular Record resumes and yet another file with headers etc is created.

 

SO even though they arent both recording at the same time, it seems possible that if using Regular AND Motion Record one actually takes up more space on the hard drive/s.

 

It would therefore lead me to believe that the longest record times will be achieved with EITHER the default settings of Regular Record at 60 Minute Pack Durations or Motion ONLY Record with proper Masking.

 

But tell that to the client that has to sit through playing 60 minute files to find an event or the tech that has to download 60 minute AVI files (eg 100MB) from slow household connection .. OR the possibility of loosing a motion ONLY event for lack of light or some other unforeseen reason.

 

Oh well .. just thinking out loud

[rory 0]

Just checked the DVR using PSS and its gone through 4.05TB since I installed the 6x2TB drives (12TB) approx 5 weeks ago. Each drive is actually 1.81TB.

 

2-3 weeks ago it was on Disk2 having used the full 1.81GB of Disk 1 and 640GB of Disk 2 totaling 2.5TB from day 1, and then I made the changes.

 

So from then, in approx 2-3 weeks, it ate up 1.17TB of the 2nd drive and 430GB of the 3rd drive totaling 1.6TB in 2-3 weeks across 23 cameras - note the application is either pitch dark or has a ton of infrared, 5 days a week there are 4 maids, 1 gardener, 1 handyman and 1 butler not to mention pool cleaning, outside landscapers and other service companies that come and go, its like a hotel - so that is alot of motion switching going on.

 

Also bear in mind one camera is looking at the front gate which picks up almost every car passing on the main road

 

So the changes HAVE helped somewhat, but I think it will mean either disabling Motion record all together or using ONLY motion record and not Regular Record. Since this DVR has 12TB its going to take a long time to find out. LOL. Time to do some tests on a DVR with a much smaller HDD!

[rory 0]

BTW I just played back Motion Events from the DVR from Friday from 8am-4.30pm, the time the staff are there from and until.

 

I got 133 total motion events.

I got a total of 10 false alarms out of that 133 events, which is not bad.

All but the following single motion events were People or Cars

 

rain drops

power surge

Sun comes out

Bird

Bird

Bird

Unknown

Shade & Wind

Bird

Bird

 

BTW there is alot of bush around the camera, and the poles the camera is mounted to is covered in bird crap, yes the bird love this pole

[SEANHAWG 1]

Why not just download video files specified by the time that you want instead of downloading the files via the pack time? For example, if there is only a 10 minute incident that you want to download, just search for it and write down the time that it happened and just download that specific time through the "BackUp" on the main menu.

[tesc_cctvpro 0]

Why not just download video files specified by the time that you want instead of downloading the files via the pack time? For example, if there is only a 10 minute incident that you want to download, just search for it and write down the time that it happened and just download that specific time through the "BackUp" on the main menu.

 

It's all related to what Rory said in the beginning ---- selected pack size!

[rory 0]

Why not just download video files specified by the time that you want instead of downloading the files via the pack time? For example, if there is only a 10 minute incident that you want to download, just search for it and write down the time that it happened and just download that specific time through the "BackUp" on the main menu.

Because you have to download the whole pack duration, eg. 60 minutes.

[SEANHAWG 1]

I assume now that you are talking about the network viewer and/or PSS and I understand what you mean. I forgot that you were a die hard PSS user. I'm a die hard direct DVR user. We were on different pages. I was talking about controlling it right at the DVR where no downloading would need to be done. What I meant was just search through records and find the time that the incident happened and then select the specific time through the backup method. But yes if your viewing it over the network, then you would have to download the whole pack time to view it.

 

But to be honest, if it were me searching for an incident that happened, I wouldn't be trying to find it via the download method unless I really had no choice. It seems much easier and quicker to search the recordings right at the DVR as opposed to waiting for 1 large file to download or several small files to download. Pack time really becomes irrelevant when you are right at the DVR when video files pull up in an instant.

Edited June 12, 2011 by Guest

[rory 0]

Far as I recall, the files are still based on the Pack Duration at the local playback also?

Unless its a Motion (M) event.

So you would still be saving a 60 minute file.

[SEANHAWG 1]

Yes your hard drive would be saving a 60 minute file but what is the different between (1) 60 minute file and (6) 10 minute files or (12) 5 minute files if you are a direct DVR user. In essence they are saving the same amount of space. It would actually be coutner productive to lower the pack time if you are a direct DVR user because you would constantly be having to "stop and go" to view the video files

 

If I notice something missing from my lot such as a car, I just play the process of time elimination to see when it went missing. I simply start out at 10 pm and I will notice the car is still there, then I view it at 2:00 AM and notice the car is gone, okay then I view it at 11 and see the car is there, and view the scene a 1 AM, and so on and so forth until I pinpoint the time that it happened. I finally find out that it happened between 12 and 1 AM. Actually the specific time is 12:10 to 12:22. Not I would simply go into the Backup and save that clip to a USB drive and choose the backup time from 12:10 to 12:22 it would be a 12 minute video clip specific to that time frame, regardless if my pack time was set at 60 minutes. You dont have to save the whole 60 minute pack time just to get the 12 minute clip.

[rory 0]

Because as I mentioned about if there are multiple files packed the total space used increases, so its important to note that especially if you have thousands of files, and many drives, it could mean a difference of a few days to a week - DVR hard drive space.

 

But why someone would WANT to decrease the pack duration is simple, when playing back multiple cameras you will have to sit there for 1 hour to go through the video and that is not acceptable to clients. You can use the drag but it is not the same as fast forward and most clients dont want to use it - in fact it would be fine if they could at least fast forward all cameras at once, which in the case of Dahua is not possible until the new firmware.

 

Going through just 1 file at a time is useless to most home users.

 

Ok so locally you can backup the specific time which is good, but you still have to find it first. Most clients get lost at playback because of the issues listed above, I havent found one that even wants to back it up yet (on the dahua), just playback the video to see who came and went. It makes more sense to back it up over the network though, as you can save it right to AVI.

[Toaster 0]

I can say that on these dvr's I have (qt428/qt528) both made by tvt I have the ability to search for and download (either over the internet/lan/or direct from dvr) the SECTION I want (ie: 12:01:00 to 12:06:00 and get only those 5 minutes of video - not get the entire 30 minute pack)

... or I can download the whole pack if I so choose.

 

These dvr's record is a pre-set 30 minute pack - not user changeable

 

The motion control is not what I'd like on these, but from what I gathered from another thread, its about the same with other brands too.

[SEANHAWG 1]

Because as I mentioned about if there are multiple files packed the total space used increases

 

I'm not a hard drive or computer expert but how? Logic would seem to say that it would be the other way around because it would mean the hard drive would save more files. To me, it would seem that the difference would be minimal. I'm not doubting you, I could be totally wrong, but just wondering so I could learn.

 

But why someone would WANT to decrease the pack duration is simple, when playing back multiple cameras you will have to sit there for 1 hour to go through the video and that is not acceptable to clients

 

I am not trying to be argumentative but to me, it would still seem dis-advantageous to do that. If you had to rewind and FF it would seem better to have a larger pack file. If you had say, several 5 minute files, you would have to Fast Forward until it reaches the end of the files and once it would get to the end, you would have to start another one, and once that one gets to the end you would have to start another one. And if you wanted to rewind it and you rewound it all the way to the beginning, you would have to go into the menu and start another one. It would seem easier to have longer pack times so that you would have several long continous video files to prevent the constant stopping and going of playback. The only advantage I could see of having lower pack times is if you are downloading it over the internet, but even then, you can still download the specific time that you want as opposed to downloading a certain pack time. If you needed to search for a specific time and you knew it happened around 12:45, you can simply search for the specific time starting at 12:45 and start the video then, you would not have to start at 12:00 at the beginning at the pack time. You can do this right at the DVR and over the network. This was the premise behind my original post regarding this subject. Why would you want to download the whole pack time when you dont have to? You can download time specific clips specified by you.

 

Ok so locally you can backup the specific time which is good, but you still have to find it first.

 

You dont have to download the entire pack time over the network either, you can download a specific time too. And when I mean backup, I just mean backup the specific time that something happened.

 

but you still have to find it first.

 

Thats not hard, you just play the process of time elimination like I stated in my previous post. But if you did have to search the whole day, to me it would seem better to have longer pack files to avoid the stopping and going as I stated above.

 

I can say that on these dvr's I have (qt428/qt528) both made by tvt I have the ability to search for and download (either over the internet/lan/or direct from dvr) the SECTION I want (ie: 12:01:00 to 12:06:00 and get only those 5 minutes of video - not get the entire 30 minute pack)

... or I can download the whole pack if I so choose.

 

You can with the Dahua DVR's as well, thats why I am curious as to why anyone would want to download the whole pack time.

[rory 0]

I'm not a hard drive or computer expert but how? Logic would seem to say that it would be the other way around because it would mean the hard drive would save more files. To me, it would seem that the difference would be minimal. I'm not doubting you, I could be totally wrong, but just wondering so I could learn.

Each file has some header information telling it what it is, so that it can be played and converted, or not. So if you have 20 files instead of 1, thats 19 more headers, more headers mean more bytes, and not sure how much information there is in there exactly but it can add up, they also have some info at the end of each file also.

 

I am not trying to be argumentative but to me, it would still seem dis-advantageous to do that. If you had to rewind and FF it would seem better to have a larger pack file. If you had say, several 5 minute files, you would have to Fast Forward until it reaches the end of the files and once it would get to the end, you would have to start another one, and once that one gets to the end you would have to start another one. And if you wanted to rewind it and you rewound it all the way to the beginning, you would have to go into the menu and start another one. It would seem easier to have longer pack times so that you would have several long continous video files to prevent the constant stopping and going of playback.

No they dont have to wait until the end, they can use the IR remote to select to start playing the next file or any other file. Ofcourse thats where motion recording comes in really handy, the files are even shorter so you dont always have to play the entire file to find an event, just click on it to start playing and see if anything is there, if not click on the next file. Plus you bypass all the times when there is no motion at all.

 

The only advantage I could see of having lower pack times is if you are downloading it over the internet, but even then, you can still download the specific time that you want as opposed to downloading a certain pack time. If you needed to search for a specific time and you knew it happened around 12:45, you can simply search for the specific time starting at 12:45 and start the video then, you would not have to start at 12:00 at the beginning at the pack time. You can do this right at the DVR and over the network. This was the premise behind my original post regarding this subject. Why would you want to download the whole pack time when you dont have to? You can download time specific clips specified by you.

Yes you are correct, if using Sort by file and you enter say 12:00AM-12:02AM then you can play or download that part only.

If you sort by Query then you will be playing and downloading the entire pack duration.

Problem with sort by time, you dont always know what time you are looking for so in most cases you still first have to play through each long file.

I didnt know you could download that sort by file though, I gave up on using that query before because I kept getting query errors from the DVRs when searching for motion events. So yes you schooled me on the download part ( ) but the issue still remains of finding that video .. for me and you its simple enough no matter what .. but for clients that dont even know what a left mouse click or desktop is ... oh boy ..

 

 

Thats not hard, you just play the process of time elimination like I stated in my previous post. But if you did have to search the whole day, to me it would seem better to have longer pack files to avoid the stopping and going as I stated above.

Tell it to the clients, they hate it as they cant fast forward, imagine that takes 1 day to play back 1 days worth of video. Remember they cant fast forward all cameras, just one at a time. However shorter motion event clips helps alot to quickly bypass the times where no motion occurred.

 

You can with the Dahua DVR's as well, thats why I am curious as to why anyone would want to download the whole pack time.

Yes see above.

[SEANHAWG 1]

So yes you schooled me on the download part ( ) but the issue still remains of finding that video

 

Ha ha, no schooling meant. I was just seeing if I was missing something.

 

for me and you its simple enough no matter what .. but for clients that dont even know what a left mouse click or desktop is ... oh boy ..

 

I hear ya on that one.

[Toaster 0]

I'll chime in on a couple of computer things here... As far as HDDs go, depending on SECTOR size - that directly affects size as related to "pack" size.

 

In as simple words as I can type. If a HDD has 1024k sectors (let's say), which 1024k is 1mb, and you write a file that is only 893 bytes (way less than 1mb), well it eats up a minimum of 1 sector, so 1024k (1mb) or if you write a file that is 1233k it would eat 2 sectors (2mb). That's how sector/block size works on HDD's... I have NO IDEA what the sector size is on CCTV stuff... I know on old school stand alone TiVo's (as an example) they used EXTRA LARGE sector/block sizes to minimize fragmentation on the disk since they knew all the files would be really large (30+ minutes of video) - My guess is CCTV writing logic works in the same sense... but I could be completely wrong. And going back to the 23 camera thing, if you're writing 5 minute packs across 23 cameras, that would seem to me there would be some wasted space -but maybe not enough to matter... I DON'T kNOW.

 

I just thought I'd chime in with my $0.02 worth of nerdy knowledge.

[rory 0]

thanks for the info

I put that back to 60 minute packs, but keeping motion record, even if it means more files created, its so much easier to search through for events at least in this application. I may need to go through some of the cameras and see which ones will pick up too much motion and just leave those on regular only, and maybe set some to motion only.

[norm51 0]

I'm late, of course, to the discussion but found this thread quite useful in understanding what "pack duration" is all about.

 

I've been a home user of a 4-channel Defender DVR for a bit more than a year (after several break-ins) and have gotten use to the ability to do time searches and 5 second downloads from my laptop - whether at home via WiFi, work or on the road. I've never had to deal with this pack size issue. I never touch that DVR for anything other than resetting the clock (slight drift of a few seconds over a month even with NTP enabled.)

 

I've just purchased a 16-camera unit as an upgrade from an online cctv dealer and am learning the new (Pro) lingo. I found it disheartning to learn that I could not do time searches from my browser now

 

Like most people that start with a small unit, it wasn't even a month before I wished I'd bought a unit capable of handling more cameras.

 

Cheers,

 

Norm

[Numb-nuts 1]

I'm late, of course, to the discussion but found this thread quite useful in understanding what "pack duration" is all about.

 

I've been a home user of a 4-channel Defender DVR for a bit more than a year (after several break-ins) and have gotten use to the ability to do time searches and 5 second downloads from my laptop - whether at home via WiFi, work or on the road. I've never had to deal with this pack size issue. I never touch that DVR for anything other than resetting the clock (slight drift of a few seconds over a month even with NTP enabled.)

 

I've just purchased a 16-camera unit as an upgrade from an online cctv dealer and am learning the new (Pro) lingo. I found it disheartning to learn that I could not do time searches from my browser now

 

Like most people that start with a small unit, it wasn't even a month before I wished I'd bought a unit capable of handling more cameras.

 

Cheers,

 

Norm

 

Norm you won't be the first nor will you be the last to wish you'd bought more capacity to add cameras.

You will find a willing market for your used DVR on ebay or Gumtree etc.

[norm51 0]

Thanks,

 

I've also upgraded my cameras from the crummy 420TVL ones they advertize as High Res.

 

My minimum is now 650TVL. I could only identify people I already knew with the old ones. Now to add more drives. After reading this thread I've been able to make a better assessment as to what I'll need in drive space in order to achieve my desired retention time. My unit will allow a maximun of 6TB across 2 drives and I've already installed my 1.5TB from the old unit and placed the original 500GB back into the old unit.

 

As for selling the old unit - not quite ready to hand it off. A few of us old guys are about to use it in a sting operation to catch some young punks that like to spray-paint fences in the neighborhood. I don't know about the UK, but here in the States - especially in the cities - that's one of our worst property crimes, after theft. We've not yet decided whether to print off some WANTED posters before or after handing the video over to the police.

 

 

Cheers,

 

Norm

San Antonio, Texas

[norm51 0]

I've got (at least) one more question about recording settings.

 

What am I not understanding when it comes to the difference between D1, HD1 and CIF?

 

My DVR playback looks fine when the recordiing was created on the CIF setting but looks like stop-motion video when the settings have been switched to the others.

 

I thought it could it be the limitations of the playback utilities that were supplied with the DVR until I played the same clip at the DVR and saw the same pulsing (once per second it seemed) video. There was a bird in the scene on the camera (600 TVL effio chipset) that I tested and its motion appeared normal. The blinking looks like a focus shift at the rate of once per second lasting about 1/5 of a second.

 

Any thoughts or suggestions?

 

Norm