Dmitry Sergeev
85 lines
2.1 KiB
Go
85 lines
2.1 KiB
Go
package generator
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import (
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"encoding/binary"
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"fmt"
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)
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type YCbCr10 struct {
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Y uint32
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Cb uint32
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Cr uint32
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}
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// FrameRenderer writes a complete frame or patches part of an existing frame.
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type FrameRenderer func(dst []byte, width, height, frameIndex int) error
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type CPUGenerator struct {
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width int
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height int
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base []byte
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patch FrameRenderer
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}
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func NewCPUGenerator(
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width, height uint,
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baseRenderer FrameRenderer,
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patch FrameRenderer,
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) (*CPUGenerator, error) {
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if width == 0 || height == 0 {
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return nil, fmt.Errorf("cpu: width and height must be greater than zero, got %dx%d", width, height)
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}
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if width%2 != 0 {
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return nil, fmt.Errorf("cpu: width must be even for 4:2:2 video, got %d", width)
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}
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if baseRenderer == nil {
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return nil, fmt.Errorf("cpu: base renderer is nil")
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}
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g := &CPUGenerator{
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width: int(width),
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height: int(height),
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base: make([]byte, V210FrameSize(int(width), int(height))),
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patch: patch,
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}
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if err := baseRenderer(g.base, g.width, g.height, 0); err != nil {
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return nil, fmt.Errorf("cpu: render base frame: %w", err)
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}
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return g, nil
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}
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func (g *CPUGenerator) GenerateFrame(dst []byte, frameIndex int) error {
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if len(dst) < len(g.base) {
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return fmt.Errorf(
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"cpu: destination is too small: got %d bytes, need %d",
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len(dst),
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len(g.base),
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)
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}
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copy(dst, g.base)
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if g.patch != nil {
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if err := g.patch(dst[:len(g.base)], g.width, g.height, frameIndex); err != nil {
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return fmt.Errorf("cpu: patch frame %d: %w", frameIndex, err)
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}
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}
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return nil
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}
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func (g *CPUGenerator) Close() error { return nil }
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func packV210Block(dst []byte, pixels [6]YCbCr10) {
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const mask uint32 = 0x3ff
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word0 := pixels[0].Cb&mask | (pixels[0].Y&mask)<<10 | (pixels[0].Cr&mask)<<20
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word1 := pixels[1].Y&mask | (pixels[2].Cb&mask)<<10 | (pixels[2].Y&mask)<<20
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word2 := pixels[2].Cr&mask | (pixels[3].Y&mask)<<10 | (pixels[4].Cb&mask)<<20
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word3 := pixels[4].Y&mask | (pixels[4].Cr&mask)<<10 | (pixels[5].Y&mask)<<20
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binary.LittleEndian.PutUint32(dst, word0)
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binary.LittleEndian.PutUint32(dst[4:], word1)
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binary.LittleEndian.PutUint32(dst[8:], word2)
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binary.LittleEndian.PutUint32(dst[12:], word3)
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}
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