mediadevices/pkg/frame/yuv_cgo.go

// +build cgo

package frame

import (
	"fmt"
	"image"
)

// #include <stdint.h>
// void decodeYUY2CGO(uint8_t* y, uint8_t* cb, uint8_t* cr, uint8_t* yuy2, int width, int height);
// void decodeUYVYCGO(uint8_t* y, uint8_t* cb, uint8_t* cr, uint8_t* uyvy, int width, int height);
import "C"

func decodeYUY2() decoderFunc {
	return func(frame []byte, width, height int) (image.Image, func(), error) {
		yi := width * height
		ci := yi / 2
		fi := yi + 2*ci

		if len(frame) != fi {
			return nil, func() {}, fmt.Errorf("frame length (%d) less than expected (%d)", len(frame), fi)
		}

		y := make([]byte, yi)
		cb := make([]byte, ci)
		cr := make([]byte, ci)

		C.decodeYUY2CGO(
			(*C.uchar)(&y[0]),
			(*C.uchar)(&cb[0]),
			(*C.uchar)(&cr[0]),
			(*C.uchar)(&frame[0]),
			C.int(width), C.int(height),
		)

		return &image.YCbCr{
			Y:              y,
			YStride:        width,
			Cb:             cb,
			Cr:             cr,
			CStride:        width / 2,
			SubsampleRatio: image.YCbCrSubsampleRatio422,
			Rect:           image.Rect(0, 0, width, height),
		}, func() {}, nil
	}
}

func decodeUYVY() decoderFunc {
	return func(frame []byte, width, height int) (image.Image, func(), error) {
		yi := width * height
		ci := yi / 2
		fi := yi + 2*ci

		if len(frame) != fi {
			return nil, func() {}, fmt.Errorf("frame length (%d) less than expected (%d)", len(frame), fi)
		}

		y := make([]byte, yi)
		cb := make([]byte, ci)
		cr := make([]byte, ci)

		C.decodeUYVYCGO(
			(*C.uchar)(&y[0]),
			(*C.uchar)(&cb[0]),
			(*C.uchar)(&cr[0]),
			(*C.uchar)(&frame[0]),
			C.int(width), C.int(height),
		)

		return &image.YCbCr{
			Y:              y,
			YStride:        width,
			Cb:             cb,
			Cr:             cr,
			CStride:        width / 2,
			SubsampleRatio: image.YCbCrSubsampleRatio422,
			Rect:           image.Rect(0, 0, width, height),
		}, func() {}, nil
	}
}