score::gfx::PAL8Decoder Struct Reference

Decodes 8-bit palettized video (AV_PIX_FMT_PAL8): GIF, QuickTime and MS RLE, and the screen and game codecs of the 90s. More...

Inheritance diagram for score::gfx::PAL8Decoder:

Detailed Description

Decodes 8-bit palettized video (AV_PIX_FMT_PAL8): GIF, QuickTime and MS RLE, and the screen and game codecs of the 90s.

Each pixel is an index into a 256-entry palette that the frame carries in data[1] and that may change from one frame to the next, so it is uploaded with every frame into a 256x1 texture. The entries are native-endian 0xAARRGGBB words, i.e. B, G, R, A bytes on every platform score runs on: a BGRA8 texture reads them as they are, and the alpha is the palette's own (GIF transparency).

Public Member Functions
	PAL8Decoder (Video::ImageFormat &d, QString f="")
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
Video::ImageFormat &	decoder
QString	filter
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 bool	isTopField (const AVFrame &frame) noexcept
	Whether this frame carries the EVEN lines of its picture.
static PlaneRows	planeRows (const Video::ImageFormat &fmt, const AVFrame &frame, int textureRows) noexcept
static QString	vertexShader (bool invertY=false) noexcept

Member Function Documentation

exec()

void score::gfx::PAL8Decoder::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::PAL8Decoder::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.

Member Data Documentation

frag

const constexpr auto score::gfx::PAL8Decoder::frag

staticconstexpr

Initial value:

= R"_(#version 450
 
)_" SCORE_GFX_VIDEO_UNIFORMS R"_(
 
layout(binding=3) uniform sampler2D y_tex;
layout(binding=4) uniform sampler2D p_tex;
 
layout(location = 0) in vec2 v_texcoord;
layout(location = 0) out vec4 fragColor;
 
vec4 processTexture(vec4 tex) {
  vec4 processed = tex;
  { %1 }
  return processed;
}
 
void main ()
{
  float index = texture(y_tex, score_tc(v_texcoord)).r;
  fragColor = processTexture(texelFetch(p_tex, ivec2(int(index * 255.0 + 0.5), 0), 0));
})_"

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

• PAL8.hpp