Converting frameBuffer to image fails due to image format issue

[dhaval-khatri1996]

[dhaval-khatri1996]

Hi, I have been working with waveshare-ov9281 camera module. I tried to use your code and everything worked fine expect I would get none when I tried to convert it from Frame buffer to numpy array using helpers.mfb_to_rgb . The issue was that the code is picking up format as NV12 instead of YUYV. The code seems to work fine when I manually set the format to YUYV. Please let me know if I am doing something wrong and hence this was happening or is there an issue with my camera driver or is it a code bug.

[kbingham]

Why is it the wrong format? Nv12 is usually a reasonable default format, unless the library is asked for something explicitly

[dhaval-khatri1996]

Maybe I am wrong, I am new to all this. I am not sure what is the format supposed to be. The camera is ov9218-110 monochrome global shutter camera. and here are the device details.

~ $ v4l2-ctl --device /dev/video0 --all

Driver Info:
	Driver name      : unicam
	Card type        : unicam
	Bus info         : platform:fe801000.csi
	Driver version   : 5.15.56
	Capabilities     : 0xa5a00001
		Video Capture
		Metadata Capture
		Read/Write
		Streaming
		Extended Pix Format
		Device Capabilities
	Device Caps      : 0x25200001
		Video Capture
		Read/Write
		Streaming
		Extended Pix Format
Media Driver Info:
	Driver name      : unicam
	Model            : unicam
	Serial           : 
	Bus info         : platform:fe801000.csi
	Media version    : 5.15.56
	Hardware revision: 0x00000000 (0)
	Driver version   : 5.15.56
Interface Info:
	ID               : 0x03000005
	Type             : V4L Video
Entity Info:
	ID               : 0x00000003 (3)
	Name             : unicam-image
	Function         : V4L2 I/O
	Flags         : default
	Pad 0x01000004   : 0: Sink
	  Link 0x02000007: from remote pad 0x1000002 of entity 'ov9281 10-0060': Data, Enabled, Immutable
Priority: 2
Video input : 0 (unicam-image: ok)
Format Video Capture:
	Width/Height      : 640/480
	Pixel Format      : 'BGR3' (24-bit BGR 8-8-8)
	Field             : None
	Bytes per Line    : 1920
	Size Image        : 921600
	Colorspace        : sRGB
	Transfer Function : sRGB
	YCbCr/HSV Encoding: ITU-R 601
	Quantization      : Full Range
	Flags  : 

[kbingham]

Can you share the code that you are trying to run ?
Are you accessing /dev/video0 directly? or using libcamera?

[dhaval-khatri1996]

Using libcamera, I took your sample code for simple-capture and helper functions to make a small code piece of my own as I am unable to use any other library(like opencv, pygame, Picamera2 and more all keep throwing different errors). Here is the code I am using right now (its your code just with few lines changed).

[tomba]

@tomba - Is this a case of mfb_to_rgb needing support for more pixelformats?

mfb_to_rgb is only sample code that does a very naive conversion for a few pixel formats. And yes, it doesn't support NV12.