libcamerasrc and formats?

[Florian Echtler]

P.S. a follow-up question: at the moment, I can't use libcamerasrc to directly 
stream H.264 from the camera, correct?

On 17.03.23 20:21, Nicolas Dufresne wrote:
> Hi,
> 
> Le vendredi 17 mars 2023 à 10:21 +0100, Florian Echtler a écrit :
>> Thank you - turns out it's rather hard to build libcamera on the target device,
>> which is a Raspberry Pi Zero. I'll test with another Raspi ASAP.
>>
> 
> Meson based projects aren't too hard to cross compile, there is a concises
> instruction how to set this up a toolchain for RPi OS:
> 
> https://deardevices.com/2019/04/18/how-to-crosscompile-raspi/
> 
> I would have hoped for already made docker image. I never tried this. An
> alternative I've used (though I have a Pi4 now with 8G of RAM), is to use qemu
> to chroot into the SD card rootfs and just build using emulation.
> 
> regards,
> Nicolas
> 
>>
>> Best, Florian
>>
>> On 15.03.23 19:13, Nicolas Dufresne wrote:
>>> Hi,
>>>
>>> Le mercredi 15 mars 2023 à 17:24 +0100, Florian Echtler via gstreamer-devel a
>>> écrit :
>>>> Hello everyone,
>>>>
>>>> I'm experimenting with a Raspberry Pi camera and would like to process the
>>>> frames with OpenCV. Apparently, the "modern" way of doing so is through
>>>> libcamera, and for OpenCV, this means using a GStreamer pipeline with libcamerasrc.
>>>>
>>>> For efficiency reasons, I'd like to get a grayscale image directly from the
>>>> camera to avoid unneeded conversions; so I used the following pipeline:
>>>>
>>>> libcamerasrc !
>>>> video/x-raw,width=(int)640,height=(int)480,framerate=(fraction)30/1,format=GRAY
>>>> ! appsink
>>>>
>>>> "GRAY" is listed as a supported format for the camera in the Video4Linux device,
>>>> but I don't get a working pipeline when I try that. If I leave out the format
>>>> parameter, then I'm getting NV12 (or I can pick something generic like RGB). How
>>>> can I see which formats I can actually get out of libcamerasrc and the sensor?
>>>
>>> Any chance you can give this patch a try ? I'll post it to the libcamera project
>>> if you can confirm its working. Note that libcamerasrc is entirely developed as
>>> part of libcamera project.
>>>
>>> ---
>>> commit abf017f5c0f547ceaa863e658f22af9f547a863d (HEAD -> logger-crash)
>>> Author: Nicolas Dufresne <nicolas.dufresne at collabora.com>
>>> Date:   Wed Mar 15 14:10:08 2023 -0400
>>>
>>>       gstreamer: Map R8 pixel format
>>>       
>>>       This enables monochrome 8bit to be supported in libcamerasrc.
>>>       
>>>       Signed-off-by: Nicolas Dufresne <nicolas.dufresne at collabora.com>
>>>
>>> diff --git a/src/gstreamer/gstlibcamera-utils.cpp b/src/gstreamer/gstlibcamera-
>>> utils.cpp
>>> index 750ec351..f1e34b60 100644
>>> --- a/src/gstreamer/gstlibcamera-utils.cpp
>>> +++ b/src/gstreamer/gstlibcamera-utils.cpp
>>> @@ -26,6 +26,9 @@ static struct {
>>>           { GST_VIDEO_FORMAT_ENCODED, formats::SGRBG8 },
>>>           { GST_VIDEO_FORMAT_ENCODED, formats::SRGGB8 },
>>>    
>>> +       /* Monochrome */
>>> +       { GST_VIDEO_FORMAT_GRAY8, formats::R8 },
>>> +
>>>           /* RGB16 */
>>>           { GST_VIDEO_FORMAT_RGB16, formats::RGB565 },
>>>    
>>>
>>>
>>>
>>
>> -- 
>> SENT FROM MY DEC VT50 TERMINAL
>>
> 

-- 
SENT FROM MY DEC VT50 TERMINAL

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