On Thu, Nov 26, 2020 at 7:00 PM Robert Foss <robert.foss@xxxxxxxxxx> wrote: > > On Wed, 25 Nov 2020 at 08:32, Tomasz Figa <tfiga@xxxxxxxxxxxx> wrote: > > > > Hi Bingbu, > > > > On Wed, Nov 25, 2020 at 1:15 PM Bingbu Cao <bingbu.cao@xxxxxxxxxxxxxxx> wrote: > > > > > > > > > > > > On 11/24/20 6:20 PM, Robert Foss wrote: > > > > On Tue, 24 Nov 2020 at 10:42, Bingbu Cao <bingbu.cao@xxxxxxxxxxxxxxx> wrote: > > > >> > > > >> Hi, Robert > > > >> > > > >> I remember that the full size of ov8856 image sensor is 3296x2480 and we can get the 3280x2464 > > > >> frames based on current settings. > > > >> > > > >> Do you have any issues with this mode? > > > > > > > > As far as I can tell using the 3280x2464 mode actually yields an > > > > output resolution that is 3264x2448. > > > > > > > > What does your hardware setup look like? And which revision of the > > > > sensor are you using? > > > > > > > > > > Robert, the sensor revision I am using is v1.1. I just checked the actual output pixels on our > > > hardware, the output resolution with 2464 mode is 3280x2464, no black pixels. > > > > > > As Tomasz said, some ISP has the requirement of extra pixel padding, From the ov8856 datasheet, > > > the central 3264x2448 pixels are *suggested* to be output from the pixel array and the boundary > > > pixels can be used for additional processing. In my understanding, the 32 dummy lines are not > > > black lines. > > > > The datasheet says that only 3264x2448 are active pixels. What pixel > > values are you seeing outside of that central area? In the datasheet, > > those look like "optically black" pixels, which are not 100% black, > > but rather as if the sensor cells didn't receive any light - noise can > > be still there. > > > > I've been developing support for some Qcom ISP functionality, and > during the course of this I ran into the issue I was describing, where > the 3280x2464 mode actually outputs 3264x2448. > > I can think of two reasons for this, either ISP driver bugs on my end > or the fact that the sensor is being run outside of the specification > and which could be resulting in differences between how the ov8856 > sensors behave. I just confirmed and we're indeed using this mode in a number of our projects based on the Intel ISP and it seems to be producing a proper image with all pixels of the 3280x2464 matrix having proper values. I'm now double checking whether this isn't some processing done by the ISP, but I suspect the quality would be bad if it stretched the central 3264x2448 part into the 3280x2464 frame. Best regards, Tomasz
