driver done

drivers/video/ppm.go

@@ -0,0 +1,92 @@
+package video
+
+import (
+	"context"
+	"image"
+	"image/color"
+	"io"
+
+	"github.com/pion/mediadevices/pkg/frame"
+	"github.com/pion/mediadevices/pkg/io/video"
+	"github.com/pion/mediadevices/pkg/prop"
+	"github.com/sirupsen/logrus"
+
+	_ "github.com/jbuchbinder/gopnm"
+)
+
+const DefaultFPS float32 = 60.0
+
+type PPMStreamDriver struct {
+	Height, Width int
+	FPS           float32
+	PPMImage      <-chan io.ReadCloser
+	closed        <-chan struct{}
+	cancel        func()
+}
+
+func (v *PPMStreamDriver) Open() error {
+	defer logrus.Debug("device opened")
+	ctx, cancel := context.WithCancel(context.Background())
+	v.closed = ctx.Done()
+	v.cancel = cancel
+	return nil
+}
+
+func (v *PPMStreamDriver) Close() error {
+	v.cancel()
+	return nil
+}
+
+func (v *PPMStreamDriver) Properties() []prop.Media {
+	return []prop.Media{
+		{
+			Video: prop.Video{
+				Width:       v.Width,
+				Height:      v.Height,
+				FrameRate:   v.FPS,
+				FrameFormat: frame.FormatYUYV,
+			},
+		},
+	}
+}
+
+func (v *PPMStreamDriver) VideoRecord(p prop.Media) (video.Reader, error) {
+	r := video.ReaderFunc(func() (img image.Image, release func(), err error) {
+		canvas := image.NewYCbCr(
+			image.Rect(0, 0, p.Width, p.Height),
+			image.YCbCrSubsampleRatio420,
+		)
+
+		select {
+		case <-v.closed:
+			return nil, func() {}, io.EOF
+		case ppmF, ok := <-v.PPMImage:
+			if !ok {
+				return nil, func() {}, io.ErrClosedPipe
+			}
+			defer ppmF.Close()
+
+			img, _, err := image.Decode(ppmF)
+			if err != nil {
+				return nil, func() {}, err
+			}
+
+			// draw input image in middle of canvas
+			offsetX := (canvas.Bounds().Dx() - img.Bounds().Dx()) / 2
+			offsetY := (canvas.Bounds().Dy() - img.Bounds().Dy()) / 2
+			for x := 0; x < img.Bounds().Dx(); x++ {
+				for y := 0; y < img.Bounds().Dy(); y++ {
+					r, g, b, _ := img.At(x, y).RGBA()
+					Y, Cb, Cr := color.RGBToYCbCr(uint8(r), uint8(g), uint8(b))
+
+					canvas.Y[canvas.YOffset(offsetX+x, offsetY+y)] = Y
+					canvas.Cb[canvas.COffset(offsetX+x, offsetY+y)] = Cb
+					canvas.Cr[canvas.COffset(offsetX+x, offsetY+y)] = Cr
+				}
+			}
+		}
+
+		return canvas, func() {}, nil
+	})
+	return r, nil
+}