distortion in video (ffmpeg, vlc and iSPY)

[tomasz320]

Hi

I'm using few IP cameras with below configuration:

- 3xFullHD cameras from China - capturing with ffmpeg on Linux computer
- 1x1.3MP camera Icybox CAM2002 - capturing with VLC on Linux

all cameras are also connected to the second computer with iSPY - which is detecting motion only.

I replaced all cables, bought Gig-LAN router, but I still have distortions

it looks like a "shadow" when for example someone is walking, like the frames before the person are freezing.
I thought this is a network problem - but replaced everything - no difference, no packet loss, no dropped packets etc, logs are clear.

Problem is for all different kind cameras
and I see this on 2 separate computers and for 3 different capture method.

any idea what can I check?

btw do you know where can I find latest firmware for camera:

looks like this:



Device Type: C6F0SgZ3N0P0L0
Software Version: V6.1.10.2.1-20151201

Thanks

 

[bp2008]

Try to set the iframe interval to be equal to the frame rate.

 

[nayr]

reduce Noise Reduction levels in Video Processing if possible

try forcing tcp streams instead of UDP, if you dropping UDP packets it gets ugly.. I believe both ffmpeg and vlc default to UDP and you'll need to tune the default receive buffers to get HD video to go smooth.

 

[tomasz320]

Ok, so now I have:

Maximum frame rate: 25
Key frame interval: 25 (it was 50)

I will check tomorrow if it is better or not, if it doesn't help I will try with TCP instead of UDP.

Thank you

 

[VorlonFrog]

Looks like Shenzhen HongJingTian Electronics HJT-IP60 camera, similar to many other Hi3516/Hi3518 based Chinese cameras. There appears to be a firmware version from February 2016 named V6.1.1.4.1-20160204

https://gist.github.com/gabonator/74cdd6ab4f733ff047356198c781f27d

http://s.click.aliexpress.com/e/bEC18exO

 

[tomasz320]

I tested Key frame interval: 25 (default was 50) but it didn't help.

I set 2 for now, tomorrow I will make next test.
This is value is seconds right?

and "Maximum frame rate" is 25, but in movie properties I see 12,5 fps.

Thanks

 

[bp2008]

Your key-frame interval is in frames, not seconds. It usually is frames, but when the default is 50, it definitely is in frames. Usually, security camera streams have an iframe interval between 1 and 4 seconds (between 1 and 4 times the frame rate).

So if you set it to 2, then every other frame will be an iframe and the compression will be pretty bad.

 

[tomasz320]

ok, understand. First I will see if with 2 is ok, if yes, then I will increase this value to get good picture and quite-good compression.
But of course, video without distortion is the priority.

Thanks.

 

[nayr]

have you tried: -rtsp_transport tcp ​on your ffmpeg command yet?

 

[tomasz320]

Hi

No, I didn't try TCP yet, this is because I have this problem also in iSPY so I prefer to fix it first from the camera side.
ok, today when the value is 2, I see that file is about 5-6 times bigger so I hope quality is much much better.
I will let you know.

 

[tomasz320]

I just checked and I have already -rtsp_transport tcp for ffmpeg.

Today I played with the Key frame interval, for sure is much much better now, not perfect yet but better.

What else can I check? below is the screen from my camera settings:

 

[bp2008]

I suggest you try a lower frame rate (less work for the camera to do) of around 15 FPS. And also CBR (constant bit rate) encoding may be more reliable as it is conceptually simpler than VBR (variable bit rate). Harder for them to screw up CBR. However if it is anything like my old chinese cameras, the only thing that really matters is that iframe interval.

Oh and also, some cameras have an interface option for using TCP or UDP as the transport layer for RTSP streaming. If you have not already you should hunt for that option. I've heard of chinese cameras having buggy TCP implementations before, such that someone actually patched a firmware image to fix the bug (that is way above my pay grade haha).

 

[tomek.tomek]

Hi

This is tomasz320, I forgot my password so I have to create new account.
Of course your suggestions about Key frame interval were very useful and with that I have now my video more "smooter".

but I resolved finaly the problem with -rtsp_transport tcp for ffmpeg but
it must be right after "ffmpeg" command, if it is later, after for example stream address, the rtsp_transport is ignored.

So, this is working:

ffmpeg -rtsp_transport tcp -i rtsp://192.168.1.201:554/11 -c:v copy -an out.mkv

this is not working:

ffmpeg -i rtsp://192.168.1.201:554/11 -c:v copy -rtsp_transport tcp -an out.mkv

Thanks