I have some HikVision cams and just configured the substream. The native resolution is 2560x1440. I set the substream to 640x480. However, all it does is zooming into the picture. It doesn't show me the same field of view with a higher resolution. How do I fixe that?
Substream Zooms
- Thread starter rfj
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Mike A.
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- May 6, 2017
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640x480 is a 4:3 ratio vs 2560x1440 which is 16:9. So seems it's cropping the image based on that. Can you change the substream to some other 16:9 lower resolution, e.g. 854x480? 640x360?
There is a 352x288 and 320x240 options that don't zoom in. However, I wanted to use a bit a higher resolution as the stream is rather fuzzy at those two lower resolutions. I don't quite understand why at the higher resolution it would zoom in/crop that much. I tried to zoom out in BI but it won't let me do that.
Mike A.
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- May 6, 2017
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I looked at a couple of my Hikvision cams to see what's there. Is there nothing higher than 352 or 320 in yours for substream? A couple of mine do offer 640x360 for the substream.
It's not actually zooming. As I said above, it's just adjusting the image to fit in a 4:3 format in the same way that a TV might do with options to letter box with black bars or fill the screen and scaling things to fit.
It's not actually zooming. As I said above, it's just adjusting the image to fit in a 4:3 format in the same way that a TV might do with options to letter box with black bars or fill the screen and scaling things to fit.
The options I have are 320x240, 352x288, 640x480, 704x576. The first two show pretty much the full FoV (Field of View). The other two zoom in. They are not just chopping of a bit of the frame to accommodate the different aspect ratio. If you look at the images in my first post you can see that the FoV on the substream image is MUCH smaller.
Mike A.
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Yes, looks like BI is using 16:9 for the format of the display frame (as it should). The difference in ratio and the scaling (or lack thereof to fit in this case) then causes more of the image to be lost. i.e., it's only displaying whatever fits starting from the top-left corner and everything else gets cut off. Not sure what you can do in that case where you have a mismatched main and substream ratio like that. Can't really have BI force the size since one still will be mismatched.
Some offer different options for second and third substreams but guessing you'd have seen that if it were there.
Some offer different options for second and third substreams but guessing you'd have seen that if it were there.
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Got it. I see that the top left corner is actually the same for both the FullRes.png and Substream.png. But then it cuts off like 1/2 in the horizontal and vertical for Substream.png . That leaves me with just the top left corner. I don't care if it need to chop off a bit on the right or bottom but as it is it decimates like 75% of the FoV.
