Image quality issue with still captures
Hi, I am running SS successfully monitoring vehicle movements in the road - I have iGeek IP Cameras 1080 HD streaming via WiFi. I have a fairly fast frame rate within the camera to freeze movement of vehicles that are unavoidably close to the camera. This has an impact on low light performance of the camera - that's a compromise I am happy with. My SS motion capture is set for stills only Frequency 1 and post capture 1. The stills are OK recorded to my iMac locally. However when compared with still captures directly from the same camera's software (very basic Chinese IP Camera software) sent directly to FTP on my own domain (avoiding SS completely) the SS captures are noticeably softer, a lot of the detail is lost in trees. The file sizes are slightly greater in the SS jpegs. (I can post a link to comparison images if useful)
So my question is where can I tweak the still capture settings in SS to improve IQ? Are they dictated by the SS video settings? (currently H.264RTSP video and audio) Would I have to up the bit rate leaving the camera to give me equivalent IQ of the stills taken in SS?
Note: I am not using audio - does the codec still compress audio as well even though there is no signal?
So my question is where can I tweak the still capture settings in SS to improve IQ? Are they dictated by the SS video settings? (currently H.264RTSP video and audio) Would I have to up the bit rate leaving the camera to give me equivalent IQ of the stills taken in SS?
Note: I am not using audio - does the codec still compress audio as well even though there is no signal?
Comments
Brightness, Gamma, Sharpness all at default
WDR: = OFF
Aemode: = AUTO
Imgmode: = Illuminance (can't see difference between Frame Rate and Illuminance)
IR LED Control: = ON
Shutter: (1-10000) = 50 (default is 10000, but I deduce this is a max shutter level, 50 gives sharper, frozen stills)
IRCut: (1-1024,the late value,the greater the switching time) = 150 stops switching too early at dusk, and prevents switching from IR to colour when headlights overexpose
Noise: (0-100,Lower according to the work) = 0
Video Settings:
Video format: 50Hz
Video Coding: highprofile (I record to a iMac)
First stream Resolution: 1920x1080
Bit rate: kbps (32-8192) = 2000
Maximum frame rate: = 8 fps (balance between sharp images and reactiveness)
Key frame interval: (2-150) =16
Bit rate control: VBR
Image quality: = 1 (best)
Audio Off
In Security Spy I have used:
H.264 RTSP
Motion Capture (masked):
One movie per event, 8fps, PreCap 1, Post Cap 1
Still Cap: Freq:1 Post Cap:1
When SecuritySpy captures a still JPEG image, it has to re-encode this from the H.264 stream, which does involve a slight loss in quality. Perhaps the other software you mention is instead receiving a JPEG stream? I'm not sure. If you can email us examples of the different images we'll take a look.
I use VBR but I wonder if the instant presence of a big vehicle (from a static image previously) is just too much change in compression required for the VBR to respond.. so the VBR is still on a low compression rate when the capture occurs. I will experiment with CBR at 3000kbs and see if that improves.
Here is the direct from camera to FTP image:
https://duaw26jehqd4r.cloudfront.net/items/3p1Y0w3c3w2T1m2O2A01/iGeek to FTP A18123009010011.jpg?v=4f7ec621
Here is the SS image: (note the lack of detail in foliage)
https://duaw26jehqd4r.cloudfront.net/items/1l2108272r0N161Y0i3P/Sec Spy 30-12-2018 09-00-59 East.jpg?v=9603a846
Note: there is a slight over exposure issue too... a large dark mass of foliage is then dominated by a white truck and the autoexposure is unable to clamp down exposure in time. It is almost impossible to trigger motion detect accurately so trying to tweak the exposure response is unlikely to help. For oncoming traffic at night, even with IR illumination the exposure is dominated by the headlights so the captures are useless. Views of the rear of cars still require to under expose to get reg. plates readable. For the future it would be good to be able to have two exposure modes - one for IR and one for day.
Note: the Motion capture in camera is basic Lo/med/high, without masks, so I'd prefer to use SS for captures (especially if it can pre-capture stills)
The difference in quality does appear to be down to the encoding - whether this is the H.264 encoding provided by the camera, or the JPEG encoding performed by SS. First, try CBR with the maximum bit rate to test the camera's encoding, and then try increasing SecuritySpy's JPEG encoding quality to see if this makes a difference.
https://duaw26jehqd4r.cloudfront.net/items/3F2b0G1D102X0H1b423e/31-12-2018 11-38-00 East to Dunsfold.jpg?v=022b8f7f
I have been tweaking the shutter speed - as fast moving objects will be blurred unless the shutter is fast.. and that reduces the camera's capability in lower light.
Out of interest, what shutter speed are you finding that works well for you?