ace/drivers/video/ppm.go
2022-10-18 20:26:36 +08:00

103 lines
2.2 KiB
Go

package video
import (
"context"
"image"
"image/draw"
"io"
"time"
"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 Frame struct {
Time time.Time
Image io.ReadCloser
}
type PPMStreamDriver struct {
Height, Width int
FPS float32
PPMImage <-chan Frame
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) {
logrus.Debug(p)
canvas := image.NewRGBA(image.Rect(0, 0, p.Width, p.Height))
var (
prevHeight, prevWidth int
)
r := video.ReaderFunc(func() (img image.Image, release func(), err error) {
select {
case <-v.closed:
return nil, func() {}, io.EOF
case ppmF := <-v.PPMImage:
defer ppmF.Image.Close()
// skip timeouted frame
if time.Since(ppmF.Time) > time.Second/time.Duration(p.FrameRate) {
return canvas, func() {}, nil
}
img, _, err := image.Decode(ppmF.Image)
if err != nil {
return nil, func() {}, err
}
// screen geometroy change
if img.Bounds().Dx() != prevWidth || img.Bounds().Dy() != prevHeight {
draw.Draw(canvas, canvas.Rect, image.Black, image.Black.Bounds().Min, draw.Over)
prevWidth = img.Bounds().Dx()
prevHeight = img.Bounds().Dy()
}
offsetX := (canvas.Rect.Dx() - img.Bounds().Dx()) / 2
offsetY := (canvas.Rect.Dy() - img.Bounds().Dy()) / 2
draw.Draw(canvas, image.Rect(
offsetX, offsetY, offsetX+img.Bounds().Dx(), offsetY+img.Bounds().Dy(),
), img, img.Bounds().Min, draw.Over)
default:
}
return canvas, func() {}, nil
})
return r, nil
}