The adv7481 is used to convert HDMI IN data to CSI data. there is a issue about the HDMI in with size 720x576 from DV device, the output image after ADV7481 is stretched, for example, the cricle in the scene is outputed to be a oval.
I cannot find such function that adv7481 could do the streched things, but actually it really does, and we also checked the DV device, it's okay if we connect the DV to PC displayer or some other HDMI IN supported devices.
so, how to make the shape okay as original?
Are you getting stretch image only at this format 720x576?
The output is strictly based on your 27MHz incoming clock. Of course you could change the pixel clock but then it would be a non-standard format and the monitor may have issues with it. If you had a variable pixel clock that was fast on the line edges and slow in the middle of the line and kept the same number of clocks per line then in theory you could stretch the image.
Thanks Poornima for your suggestion. we have double checked the issue. it looks like it's related with the signal detection.
with the same DV and same HDMI in put size setting(576P), but the adv7481 first detected it as output 720x480 for several times, then there is some crash in kernel about null potiner address. so then detect the signal, then it's detected as 720x576 for several times, then the image is stretched.
I dumped the original UYVY stretched image, size is 720x576, then I convert to jpeg and do some change, make the size to be 720x480, then it looks like no stretching. so that should be the issue with the wrong size or wrong data. but that is only a test ans suspicious point.
do you have some suggestion on this issue? maybe some register should be updated if detected size is changed.
Thanks so much.
Have you observe the same behavior in our evaluation board ?
It seems like scaling and also have you changed the aspect ratio to see any improvement ?
Note: The csc_scale[1:0] bits allow the user to implement conversion formulae in which the coefficients exceed the standard range of [-4095/4096 .. 4095/4096]. The overall range of the CSC is [0..1] for unipolar signals (for example, Y, R, G, and B) and [-0.5..+0.5] for bipolar signals (for example, Pr and Pb). To support larger coefficients, the csc_scale[1:0] function should be used. Determine the setting for csc_scale[1:0] and adjust coefficients, if necessary For further details Refer Page187 in ADV748x_Hardware Manual_Rev
Thanks for your reply. I cannot find adv7481 evaluation board currently. we also didn't change the aspect ratio.
I double checked the DV setting, it outputs 720x576, and can display on the TV screen as shape or other paltform with some other convert chipset. but only with adv7481 gets such issue. I still have no idea how the aspet ratio register wroks.
You will need to contact local FAE/sales team and they will be able to assist you for purchase an evaluation board.In our evaluation board, We don't face this kind of issues.
Please check this with our evaluation board.