Sub stream resolution has different aspect ratio

R

reahducks

n3wb
May 19, 2023
10
5
Germany
Hi,

while the main stream of my 2431R is in 16:9 aspect ratio (except if I chose 1280*960), the sub stream is offered in 1,33 or 1,22 (e.g. (704 × 576). But it's not a cropped version of the sensor, it's a distored, sqashed version. Why would anybody do this?
Does Dahua do this with all their cameras? What can be done against it?

Regards,
Reah
 
No, it's not all of their cams. I have seen others complain about a few like yours that only have a single substream and no matching 16:9 substream. I was kind of surprised to see that too.
 
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All of my cameras are like that, even the 4k-x.
 
Perimeter said:
Have you changed the substream channel? I have different offers on different substream channels.
Click to expand...
No I haven't, but now that you pointed it out to me, substream2 can be enabled and set to 16:9 aspect ratio.
 
I had the same issue/observation when I started using substreams on my Dahua 5231-ze and 5442 cams, annoyed the hell out of me so I switched them all over to use the 720p stream from substream2 which has the same aspect ratio as the main stream. I'm probably not getting the full benefit of using a very low res substream but am happy as there's no stretchy weirdness when watching the overview screen.
 
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Thanks for all sharing your thoughts and experiences. Unfortunatelly my 2431 only has one substream only offering 704x576, 640x480 and 352x288.
Some design decissions are just unreproducible.
 
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For absolutely idiotic reasons that are unfathomable to me, IP cameras today continue to be affected by design choices made for analog video many decades in the past. Sub stream resolutions are one of those things which are affected.

If your camera is in PAL mode, you tend to get 704x576 and 352x288 as sub stream choices, and a frame rate limit of 25 or 50 FPS affecting all streams. If NTSC mode, you tend to get 704x480 and 352x240 as sub stream choices with a frame rate limit of 30 or 60 FPS affecting all streams. Neither of these resolutions is natively 16:9 aspect ratio. They are meant to be scaled by the video player to the desired aspect ratio. Of course, this is often overlooked by the software makers.

Back when Blue Iris was implementing sub stream support, I gave early and loud feedback to make sure the sub stream got properly scaled to the aspect ratio of the main stream, and thanks to this capability those of us using Blue Iris can more or less ignore the fact that the sub streams are the wrong aspect ratio because it doesn't affect us.
 
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IAmATeaf said:
I had the same issue/observation when I started using substreams on my Dahua 5231-ze and 5442 cams, annoyed the hell out of me so I switched them all over to use the 720p stream from substream2 which has the same aspect ratio as the main stream. I'm probably not getting the full benefit of using a very low res substream but am happy as there's no stretchy weirdness when watching the overview screen.
Click to expand...
I did that also with my 4MP Loryta IPC-T5442TM-AS, set its substream 2 to 1080p, 16:9.
I also changed my Amcrest IP5M-T1179EW-28MM's default main stream 2592 x 1944 (4:3) to 2688 x 1520 (16:9)

Looks better, IMO...especially since the 2 cams are set next to each other and their views slightly overlap for thorough coverage of a back fenced area.
 
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Ah, thanks bp2008 for mentioning NTSC mode! Just switched to it and while it's still no 16:9, it's somewhat nearer to it. I'm losing resolution, but let's see in the next days if that matters.
 
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