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DS90UB954-Q1: FV_LV timing for RAW mode

Tomoaki Yoshida91
Genius 5255 points
Part Number: DS90UB954-Q1

Hi team,

I have a question about how to use Raw mode.

I understand that the a minimum FV to LV timing is required when processing RAW video frames at the serializer input.

When this timing does not meet the requirements,  the first video line miss some number of pixels at the start of the line.

Will this always be the first few pixels missing?

In our usage, if only the first few pixels of the first line are missing, the first few lines are front porches, and missing data has no effect.

We are considering PORT_CONFIG: DISCARD_1ST_ON_ERR enabled and discarding the first line with data on the SoC side.

We think it is easier and more reasonable than changing the imager timing.

If the imager's FV_LV timing does not meet the minimum, is it okay to take this approach instead of adjusting the imager's timing?

Best regards,

Tomoaki Yoshida

  • 0
    TI__Genius 11340 points

    Hi Yoshida-san,

    If the FV_LV timing doesn't meet the minimum requirement, then there's going to be actual pixel data missing in the first line, not the front porch.

    You can either discard the first line or adjust the timing, otherwise it's going to show up as errors when you do the video processing.

    Best,

    Jiashow

  • 0 in reply to Jiashow Ho
    Genius 5255 points

    Hi Jiashow-san,

    Thank you for your support.

    I'm sorry, there was a mistake in my description.

    The several lines of start and end from camera video are not used in our system.

    The few lines are not output to the display.

    Don't discard the first line that contains an error, SoC discard that line after received.

    First, in order to use this, the error must be on the first line only.

    Does this error happened only  on the first line?

    I think the imager's FV_LV timing should be adjusted, but can it be used in this way?

    Best regards,

    Tomoaki Yoshida

  • 0 in reply to Tomoaki Yoshida91
    TI__Genius 11340 points

    Hi Yoshida-san,

    Yes, the errors will only be in the first line.

    Best,

    Jiashow

  • 0 in reply to Jiashow Ho
    Genius 5255 points

    Hi Jiashow-san,

    Thank you for your reply.

    I understand.

    In the worst case, is there a case where the entire first line is not received?

    If we can recognize that it is the first line even if there is an error, there is no problem in our use case.

    If the first line is dropped without being received and the second line seems to be mistaken for the first line, it will not fit our use case.

    I want to know if that is possible.

    In the worst case for us, the camera's FV_LV cannot be adjusted and the camera needs to be changed.

    Best regards,

    Tomoaki Yoshida

  • 0 in reply to Tomoaki Yoshida91
    TI__Genius 11340 points

    Hi Yoshida-san,

    What is the resolution and other parameters of the camera you are using? Is there a specific reason why you aren't able to meet the FV_LV requirement?

    Best,

    Jiashow

  • 0 in reply to Jiashow Ho
    TI__Genius 11340 points

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