score::gfx::BayerDecoder Struct Reference

Demosaics a single-channel colour-filter-array frame into RGB. More...

Inheritance diagram for score::gfx::BayerDecoder:

Detailed Description

Demosaics a single-channel colour-filter-array frame into RGB.

The mosaic arrives as one sample per pixel in an R8 or R16 texture and is expanded by bilinear interpolation: at a site carrying its own colour the sample is kept, and the two missing channels are averaged from the four orthogonal and four diagonal neighbours (or, on a green site, from the two horizontal and two vertical ones).

The CFA order is a constructor parameter rather than a baked assumption: a capture that crops to an odd origin flips the phase, and a wrong phase does not look broken – it looks like a colour cast, which is easy to mistake for white balance.

sampleScale accounts for a mosaic that does not fill its container. Ten bits right-aligned in a 16-bit lane – what V4L2 specifies for SRGGB10 and friends – normalise to 1/64 of full scale and need 65535/1023, exactly as Mono10 does. A producer that instead replicates the high bits down into the low ones already spans the full range and needs 1.0.

Black level, white balance, exposure and the transfer curve are applied after the reconstruction, from the material block rather than baked in – see CaptureAdjustGLSL.hpp. They are per-sensor corrections, not part of turning a mosaic into RGB, and every one of them is the identity by default. Lens shading is still absent.

Public Types
enum class	Phase { RGGB , GRBG , GBRG , BGGR }

Public Member Functions
	BayerDecoder (QRhiTexture::Format fmt, int bytesPerSample, Video::ImageFormat &d, Phase phase, double sampleScale=1.0)
std::pair< QShader, QShader >	init (RenderList &r) override
	Initialize a GPUVideoDecoder.
void	exec (RenderList &, QRhiResourceUpdateBatch &res, AVFrame &frame) override
	Decode and upload a video frame to the GPU.
Public Member Functions inherited from score::gfx::GPUVideoDecoder
virtual void	release (RenderList &)
	This method will release all the created samplers and textures.

Public Attributes
QRhiTexture::Format	format
int	bytesPerSample {}
Video::ImageFormat &	decoder
Phase	phase {}
double	sampleScale {1.0}
Public Attributes inherited from score::gfx::GPUVideoDecoder
std::vector< Sampler >	samplers
bool	hasFrame {}
bool	failed {}
bool	formatChanged {}

Static Public Attributes
static const constexpr auto	frag

Additional Inherited Members
Static Public Member Functions inherited from score::gfx::GPUVideoDecoder
static QRhiTextureSubresourceUploadDescription	createTextureUpload (uint8_t *pixels, int w, int h, int bytesPerPixel, int stride)
	Utility method to create a QRhiTextureSubresourceUploadDescription.
static QString	vertexShader (bool invertY=false) noexcept

Member Enumeration Documentation

Phase

enum class score::gfx::BayerDecoder::Phase

strong

Offset of the red site within the 2x2 cell, which is what distinguishes the four CFA orders from one another.

Enumerator
RGGB	red at (0,0)
GRBG	red at (1,0)
GBRG	red at (0,1)
BGGR	red at (1,1)

Member Function Documentation

exec()

void score::gfx::BayerDecoder::exec ( RenderList &  , QRhiResourceUpdateBatch &  res, AVFrame &  frame  )

inlineoverridevirtual

Decode and upload a video frame to the GPU.

Implements score::gfx::GPUVideoDecoder.

init()

std::pair< QShader, QShader > score::gfx::BayerDecoder::init ( RenderList &  r )

inlineoverridevirtual

Initialize a GPUVideoDecoder.

This method must :

• Create samplers and textures for the video format.
• Create shaders that will render the data put into these textures.

It returns a {vertex, fragment} shader pair.

Implements score::gfx::GPUVideoDecoder.

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The documentation for this struct was generated from the following file:

• Bayer.hpp