Video timings for different video standards

[sudhanayaks]

Hi,

I am working on a HDMI video project by using z-turn board (with zynq-7010) with 2560x2160 resolution at 15fps. I am using Vivado 2017.4 tool to implement the design. Since Video timing controller IP requires video timing information, I searched online for video timing calculators which are generating timings for VESA video standard.

By using different video timings generators, I understood that video timings are different for VESA ans SMPTE standards. 

I wanted to understand whether can we use VESA standards in Xilinx IPs?

Will HDMI Transmitter(SIL 9022A) supports Vesa standards?

Thanks and Regards,

Sudha Nayak

[kvasantr]

Hello @sudhanayaks 

If you are referring to Xilinx HDMI SS IPs, they are as per HDMI specification, means they follow VESA specs for video applications and SMPTE specification for HDMI audio applications. I will recommend you to refer the specification docs before developing solutions around custom resolutions.

Regards

Kunal

[kvasantr]

Hello @sudhanayaks 

Please use following set of ARs for more help around custom resolution support with HDMI

https://www.xilinx.com/support/answers/68227.html

https://www.xilinx.com/support/answers/68138.html

Regards

Kunal

[sudhanayaks]

Hi @kvasantr ,

Thank you for the information.

Currently for testing purpose am using ZC702 Evaluvation board. I need to test custom resolution (1280x1080@30Hz). Video path is TPG ->VTC ->Axi to video out -> ADV7511 -> HDMI.

I have tested the design for 1080P@30Hz and its working as expected, however if i set custom resolution (1280x1080@30Hz) in VTC and test, am observing video input is not supported in the HDMI display.

To calculate video parameters in VTC for custom resolution, I used video timing calculator ie https://tomverbeure.github.io/video_timings_calculator

If I test 1080P@30Hz using video paramters calculated using above calculator am observing video input is not supported in the HDMI display.

I wanted to know from where we can get video timings if we set custom resolution in VTC.

Thank you!!

[watari]

Hi @sudhanayaks 

Which video timing do you choose in your mentioned URL ?

I'm sure that you follow CEA video timing...

Best regards,

[sudhanayaks]

Hi @watari ,

I have used CVT timings from the mentioned URL.

Thank you!!

[watari]

Hi @sudhanayaks 

Did you refer @kvasantr 's suggestion (AR #68227) ?

If no, I suggest you to refer it, too.

Also, if you can change video timing, I suggest you to follow CEA video timing.

Because there are two kind of pixel clock in CEA video timing.

This concept is key point.

So, would you consider it ?

Best regards,

[sudhanayaks]

Hi @watari 

AR #68227 is useful when we use HDMI RX/TX Subsystem in the design. Am using VTC IP, where I am setting timing information.

Could you please tell me from where I can get CEA video timing for custom resolutions?

Thank you!!

[watari]

Hi @sudhanayaks 

In CEA video timing, it basically uses two kind of pixel clock even if vertical frequency is different.

They are 148.5[MHz] and 74.25[MHz].

But in VESA video timing, it uses so many kind of pixel clocks.

The concept is different between CEA and VESA.

In this case, I suggest you to adjust data enable period in CEA video timing.

This concept is proper way in CEA video timing.

Would you consider and try it ?

Best regards,

[florentw]

HI @sudhanayaks 

The first thing you need to check is if your monitor can support the resolution you are trying to achieve. It might no be the case.

Then you need to make sure the pixel clock is the correct one. Only changing the resolution in the VTC is not enough. Refer to:

Video Series 22: Supporting multiple video resolutions on ZC702 HDMI

[sudhanayaks]

Hi @florentw ,

Monitor supports the resolutions which I am trying to achieve.

As I mentioned above, if I use custom resolution in VTC and update timing parameters using https://tomverbeure.github.io/video_timings_calculator link, am observing video input is not supported in the HDMI display.

I am updating pixel clock as required for the particular resolution.

Thank you!!!

[florentw]

Hi @sudhanayaks

Were you able to solve your issue by updating the pixel clock?

Regards

[sudhanayaks]

Hi @florentw ,

Even after updating the pixel clock, am observing video input is not supported in the HDMI display.=

Thank you!!

[florentw]

Hi @sudhanayaks 

Could you give the parameters + pixel clocks you used for 1280x1080@30Hz?

Are you configuring the VTC through its GUI or using the AXI4-Lite interface?