Mini PTZ bug? Recorded bitrate is lower then what is set in the UI

[klasipca]

One member reported bad IQ and low bitrate for recorded files, after some quick check it appears that Mini PTZ doesn't record at full bitrate that you have set. I didn't notice this issue because it set at high bit rate.

In my testing:

if I set 4000 kbps bit rate, video gets recorded at ~800 kbps
if you set 8000 kbps you will get ~4000 kbps
At max allowed bitrate 10240 kbps, I get ~8000 kbps for recorded files

Constant or VBR doesn't seem to make noticeable difference in my tests.

Please confirm if you are getting the same results? Once we have enough info we'll forward this to Monica


1. Set your bit rate 4000
2. Set frames per second to some lower value 10*
3. Go to Live Page
4. Click record button to start recording
5. Click record button to stop it (you can record a few seconds of this)
6. If you didn't change it file is saved in default location C:\Users\** Your WIndows Account ** \AppData\Roaming\WebNP\records
7. Right click on the recorded file and click Properties
8. Click Details tab
9. Scroll down to see what's the Data Rate and verify it's the same as what you have set in the camera UI.


* If you set to 30 fps, it appears to work as expected.

 

[Larebear]

In Blue Iris with manual recording to .avi, I get almost 7000Kbps with bitrate set at 8192 and Frame Rate 30. Recorded for about 1 minute.

 

[klasipca]

In Blue Iris with manual recording to .avi, I get almost 7000Kbps with bitrate set at 8192 and Frame Rate 30. Recorded for about 1 minute.

Set to 6 FPS

 

[Larebear]

Set to 6 FPS

Ok, testing at 6 FPS now.

 

[klasipca]

I tried with 15 fps, recorded for about a minute and got 1600Kbps when I had 4000 set.

 

[Larebear]

bitrate dropped to 1600 with 6 FPS.

 

[klasipca]

Comparing to Hikvision and obviously there is something isn't right, but I am not an expert in this bitrate business. Perhaps someone else can weight in their opinion.

 

[Larebear]

I tried the same test with one of my Hik 2432's and the bitrate stayed closed to 4096 which is what it's set for. Test was done at 10 FPS.

 

[klasipca]

Yup and if you compare the results with Hikvision and Huisun in VLC you will see what's actually happening:


Steps:
Start file playback in VLC
In VLC right click and go to Tools > Media Information > Statistics
Expand Input Bitrate to see graph and specifics

 

[Chust]

2388kbps with 4096 bit rate set 30 fps. variable

 

[Larebear]

Strange. I'm no expert when it comes to bitrate either but my Huisun IQ still looks better than my Hik's.

 

[klasipca]

Strange. I'm no expert when it comes to bitrate either but my Huisun IQ still looks better than my Hik's.

IQ is good in the live view, but recorded files quality is clearly compromised.

 

[Chust]

2388kbps with 4096 bit rate set 30 fps. variable

No motion.

 

[Chust]

IQ is good in the live view, but recorded files quality is clearly compromised.

I agree

 

[Chust]

Thanks for testing klasipca!!!

 

[alphawave7]

Set for max (10240, 30fps, 50 iframe) and constant, enabled 'display code rate' under Configuration-Local Configuration, and see about 1MB/s code rate.

 

[klasipca]

Set for max (10240, 30fps, 50 iframe) and constant, enabled 'display code rate' under Configuration-Local Configuration, and see about 1MB/s code rate.

Maxed out setting doesn't seem to be an issue, it's when you try lower fps/bit rate

 

[alphawave7]

Maxed out setting doesn't seem to be an issue, it's when you try lower fps/bit rate

But isn't that the expected behaviour? Is this Live View as well as recording issue?

 

[klasipca]

Try for instance 4000 bit rate with 15 fps and compare the results with live view and recorded file. Recorded file will show lower bit rate as well as will have worse quality then live view. With Hikvision I doesn't seem to be an issue.

 

[jptheking]

The reason why most of you say the IQ is correct is that you are looking at a still image.

Try the following:

Go from a preset to another one and watch closely.
When it gets to the target preset, the camera stops moving.

At this precise moment, the image is full of macroblocks. It should'nt.
But it improves over time because the following frames help to fill the areas. This is what I call 3D optimization (third dimension beeing the time).
The whole process takes a couple of seconds. When it is done, the image is perfect (or so).
Of course, this process cannot be done if there is movement.

My goal when I bought this camera was to take closeups of intruders and report evidence.

When I read the specifications of this camera I thought they were OK for this project, as far as they are complied with.

Because of the closeup requirement, any small movement is magnified.
But with a shutter speed of say 1/100 or 1/200, there shouldn't have been any problem in getting a perfect image.
But this 3D optimization totally ruins the IQ as it doesn't have time to refine the moving macroblocks.

Thats the reason why I wanted to go deeper in the analysis and undertand why I was not able to get proper images.
The bitrate is only one of the many reasons.