Re: Why is the Y12 support 12-bit grey formats at the CCDC input (Y12) is truncated to Y10 at the CCDC output?

[Michael Jones <michael.jones@matrix-vision.de>]

Hi James,

On 12/15/2011 10:49 AM, James wrote:
> Hi Michael,
>
> On Thu, Dec 15, 2011 at 3:58 PM, Michael Jones
> <michael.jones@matrix-vision.de>  wrote:
>> Hi James,
>>
>>
>> On 12/15/2011 08:14 AM, James wrote:
>>>
>>> Hi all,
>>>
>>> I'm using an OMAP3530 board and a monochrome 12-bit grey sensor.
>>>
>>> Can anyone enlighten me why is the 12-bit grey formats at the CCDC
>>> input (Y12) is truncated to Y10 at the CCDC output?
>>
>>
>> There are 2 CCDC outputs: CCDC_PAD_SOURCE_OF and CCDC_PAD_SOURCE_VP. Only
>> the VP (video port) truncates data to 10 bits, and it does that because the
>> subdevs it feeds can only handle 10 bits max.
>
> Thank you for the clarification.
>
>>> I need to read the entire RAW 12-bit grey value from the CCDC to
>>> memory and the data does not pass through other OMAP3ISP sub-devices.
>>>
>>> I intend to use Laurent's yavta to capture the data to file to verify
>>> its operation for the moment.
>>>
>>> Can this 12-bit (Y12) raw capture be done?
>>
>>
>> Yes. If you are writing the 12-bit gray value directly into memory, you will
>> use SOURCE_OF and can write the full 12-bits into memory.  You need to set
>> up your media pipeline to do sensor->CCDC->OMAP3 ISP CCDC output.
>
> Is there further modification needed to apply to the OMAP3ISP to achieve this?
>
> Do you have an application to test the pipeline for this setting to
> simple display?

Let's establish where you're coming from.  Are you familiar with the 
media controller?  Laurent has a program 'media-ctl' to set up the 
pipeline (see http://git.ideasonboard.org/?p=media-ctl.git).  You will 
find many examples of its usage in the archives of this mailing list. 
It will look something like:
media-ctl -r
media-ctl -l '"OMAP3 ISP CCDC":1 -> "OMAP3 ISP CCDC output":0 [1]'
media-ctl -l '"your-sensor-name":0 -> "OMAP3 ISP CCDC":0 [1]'

you will also need to set the formats through the pipeline with 
'media-ctl --set-format'.

After you use media-ctl to set up the pipeline, you can use yavta to 
capture the data from the CCDC output (for me, this is /dev/video2).

-Michael


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