Display camera frame

vendor/gocv.io/x/gocv/videoio.go

@@ -0,0 +1,332 @@
+package gocv
+
+/*
+#include <stdlib.h>
+#include "videoio.h"
+*/
+import "C"
+import (
+	"errors"
+	"fmt"
+	"strconv"
+	"sync"
+	"unsafe"
+)
+
+// VideoCaptureProperties are the properties used for VideoCapture operations.
+type VideoCaptureProperties int
+
+const (
+	// VideoCapturePosMsec contains current position of the
+	// video file in milliseconds.
+	VideoCapturePosMsec VideoCaptureProperties = 0
+
+	// VideoCapturePosFrames 0-based index of the frame to be
+	// decoded/captured next.
+	VideoCapturePosFrames = 1
+
+	// VideoCapturePosAVIRatio relative position of the video file:
+	// 0=start of the film, 1=end of the film.
+	VideoCapturePosAVIRatio = 2
+
+	// VideoCaptureFrameWidth is width of the frames in the video stream.
+	VideoCaptureFrameWidth = 3
+
+	// VideoCaptureFrameHeight controls height of frames in the video stream.
+	VideoCaptureFrameHeight = 4
+
+	// VideoCaptureFPS controls capture frame rate.
+	VideoCaptureFPS = 5
+
+	// VideoCaptureFOURCC contains the 4-character code of codec.
+	// see VideoWriter::fourcc for details.
+	VideoCaptureFOURCC = 6
+
+	// VideoCaptureFrameCount contains number of frames in the video file.
+	VideoCaptureFrameCount = 7
+
+	// VideoCaptureFormat format of the Mat objects returned by
+	// VideoCapture::retrieve().
+	VideoCaptureFormat = 8
+
+	// VideoCaptureMode contains backend-specific value indicating
+	// the current capture mode.
+	VideoCaptureMode = 9
+
+	// VideoCaptureBrightness is brightness of the image
+	// (only for those cameras that support).
+	VideoCaptureBrightness = 10
+
+	// VideoCaptureContrast is contrast of the image
+	// (only for cameras that support it).
+	VideoCaptureContrast = 11
+
+	// VideoCaptureSaturation saturation of the image
+	// (only for cameras that support).
+	VideoCaptureSaturation = 12
+
+	// VideoCaptureHue hue of the image (only for cameras that support).
+	VideoCaptureHue = 13
+
+	// VideoCaptureGain is the gain of the capture image.
+	// (only for those cameras that support).
+	VideoCaptureGain = 14
+
+	// VideoCaptureExposure is the exposure of the capture image.
+	// (only for those cameras that support).
+	VideoCaptureExposure = 15
+
+	// VideoCaptureConvertRGB is a boolean flags indicating whether
+	// images should be converted to RGB.
+	VideoCaptureConvertRGB = 16
+
+	// VideoCaptureWhiteBalanceBlueU is currently unsupported.
+	VideoCaptureWhiteBalanceBlueU = 17
+
+	// VideoCaptureRectification is the rectification flag for stereo cameras.
+	// Note: only supported by DC1394 v 2.x backend currently.
+	VideoCaptureRectification = 18
+
+	// VideoCaptureMonochrome indicates whether images should be
+	// converted to monochrome.
+	VideoCaptureMonochrome = 19
+
+	// VideoCaptureSharpness controls image capture sharpness.
+	VideoCaptureSharpness = 20
+
+	// VideoCaptureAutoExposure controls the DC1394 exposure control
+	// done by camera, user can adjust reference level using this feature.
+	VideoCaptureAutoExposure = 21
+
+	// VideoCaptureGamma controls video capture gamma.
+	VideoCaptureGamma = 22
+
+	// VideoCaptureTemperature controls video capture temperature.
+	VideoCaptureTemperature = 23
+
+	// VideoCaptureTrigger controls video capture trigger.
+	VideoCaptureTrigger = 24
+
+	// VideoCaptureTriggerDelay controls video capture trigger delay.
+	VideoCaptureTriggerDelay = 25
+
+	// VideoCaptureWhiteBalanceRedV controls video capture setting for
+	// white balance.
+	VideoCaptureWhiteBalanceRedV = 26
+
+	// VideoCaptureZoom controls video capture zoom.
+	VideoCaptureZoom = 27
+
+	// VideoCaptureFocus controls video capture focus.
+	VideoCaptureFocus = 28
+
+	// VideoCaptureGUID controls video capture GUID.
+	VideoCaptureGUID = 29
+
+	// VideoCaptureISOSpeed controls video capture ISO speed.
+	VideoCaptureISOSpeed = 30
+
+	// VideoCaptureBacklight controls video capture backlight.
+	VideoCaptureBacklight = 32
+
+	// VideoCapturePan controls video capture pan.
+	VideoCapturePan = 33
+
+	// VideoCaptureTilt controls video capture tilt.
+	VideoCaptureTilt = 34
+
+	// VideoCaptureRoll controls video capture roll.
+	VideoCaptureRoll = 35
+
+	// VideoCaptureIris controls video capture iris.
+	VideoCaptureIris = 36
+
+	// VideoCaptureSettings is the pop up video/camera filter dialog. Note:
+	// only supported by DSHOW backend currently. The property value is ignored.
+	VideoCaptureSettings = 37
+
+	// VideoCaptureBufferSize controls video capture buffer size.
+	VideoCaptureBufferSize = 38
+
+	// VideoCaptureAutoFocus controls video capture auto focus..
+	VideoCaptureAutoFocus = 39
+)
+
+// VideoCapture is a wrapper around the OpenCV VideoCapture class.
+//
+// For further details, please see:
+// http://docs.opencv.org/master/d8/dfe/classcv_1_1VideoCapture.html
+//
+type VideoCapture struct {
+	p C.VideoCapture
+}
+
+// VideoCaptureFile opens a VideoCapture from a file and prepares
+// to start capturing. It returns error if it fails to open the file stored in uri path.
+func VideoCaptureFile(uri string) (vc *VideoCapture, err error) {
+	vc = &VideoCapture{p: C.VideoCapture_New()}
+
+	cURI := C.CString(uri)
+	defer C.free(unsafe.Pointer(cURI))
+
+	if !C.VideoCapture_Open(vc.p, cURI) {
+		err = fmt.Errorf("Error opening file: %s", uri)
+	}
+
+	return
+}
+
+// VideoCaptureDevice opens a VideoCapture from a device and prepares
+// to start capturing. It returns error if it fails to open the video device.
+func VideoCaptureDevice(device int) (vc *VideoCapture, err error) {
+	vc = &VideoCapture{p: C.VideoCapture_New()}
+
+	if !C.VideoCapture_OpenDevice(vc.p, C.int(device)) {
+		err = fmt.Errorf("Error opening device: %d", device)
+	}
+
+	return
+}
+
+// Close VideoCapture object.
+func (v *VideoCapture) Close() error {
+	C.VideoCapture_Close(v.p)
+	v.p = nil
+	return nil
+}
+
+// Set parameter with property (=key).
+func (v *VideoCapture) Set(prop VideoCaptureProperties, param float64) {
+	C.VideoCapture_Set(v.p, C.int(prop), C.double(param))
+}
+
+// Get parameter with property (=key).
+func (v VideoCapture) Get(prop VideoCaptureProperties) float64 {
+	return float64(C.VideoCapture_Get(v.p, C.int(prop)))
+}
+
+// IsOpened returns if the VideoCapture has been opened to read from
+// a file or capture device.
+func (v *VideoCapture) IsOpened() bool {
+	isOpened := C.VideoCapture_IsOpened(v.p)
+	return isOpened != 0
+}
+
+// Read reads the next frame from the VideoCapture to the Mat passed in
+// as the param. It returns false if the VideoCapture cannot read frame.
+func (v *VideoCapture) Read(m *Mat) bool {
+	return C.VideoCapture_Read(v.p, m.p) != 0
+}
+
+// Grab skips a specific number of frames.
+func (v *VideoCapture) Grab(skip int) {
+	C.VideoCapture_Grab(v.p, C.int(skip))
+}
+
+// CodecString returns a string representation of FourCC bytes, i.e. the name of a codec
+func (v *VideoCapture) CodecString() string {
+	res := ""
+	hexes := []int64{0xff, 0xff00, 0xff0000, 0xff000000}
+	for i, h := range hexes {
+		res += string(int64(v.Get(VideoCaptureFOURCC)) & h >> (uint(i * 8)))
+	}
+	return res
+}
+
+// ToCodec returns an float64 representation of FourCC bytes
+func (v *VideoCapture) ToCodec(codec string) float64 {
+	if len(codec) != 4 {
+		return -1.0
+	}
+	c1 := []rune(string(codec[0]))[0]
+	c2 := []rune(string(codec[1]))[0]
+	c3 := []rune(string(codec[2]))[0]
+	c4 := []rune(string(codec[3]))[0]
+	return float64((c1 & 255) + ((c2 & 255) << 8) + ((c3 & 255) << 16) + ((c4 & 255) << 24))
+}
+
+// VideoWriter is a wrapper around the OpenCV VideoWriter`class.
+//
+// For further details, please see:
+// http://docs.opencv.org/master/dd/d9e/classcv_1_1VideoWriter.html
+//
+type VideoWriter struct {
+	mu *sync.RWMutex
+	p  C.VideoWriter
+}
+
+// VideoWriterFile opens a VideoWriter with a specific output file.
+// The "codec" param should be the four-letter code for the desired output
+// codec, for example "MJPG".
+//
+// For further details, please see:
+// http://docs.opencv.org/master/dd/d9e/classcv_1_1VideoWriter.html#a0901c353cd5ea05bba455317dab81130
+//
+func VideoWriterFile(name string, codec string, fps float64, width int, height int, isColor bool) (vw *VideoWriter, err error) {
+
+	if fps == 0 || width == 0 || height == 0 {
+		return nil, fmt.Errorf("one of the numerical parameters "+
+			"is equal to zero: FPS: %f, width: %d, height: %d", fps, width, height)
+	}
+
+	vw = &VideoWriter{
+		p:  C.VideoWriter_New(),
+		mu: &sync.RWMutex{},
+	}
+
+	cName := C.CString(name)
+	defer C.free(unsafe.Pointer(cName))
+
+	cCodec := C.CString(codec)
+	defer C.free(unsafe.Pointer(cCodec))
+
+	C.VideoWriter_Open(vw.p, cName, cCodec, C.double(fps), C.int(width), C.int(height), C.bool(isColor))
+	return
+}
+
+// Close VideoWriter object.
+func (vw *VideoWriter) Close() error {
+	C.VideoWriter_Close(vw.p)
+	vw.p = nil
+	return nil
+}
+
+// IsOpened checks if the VideoWriter is open and ready to be written to.
+//
+// For further details, please see:
+// http://docs.opencv.org/master/dd/d9e/classcv_1_1VideoWriter.html#a9a40803e5f671968ac9efa877c984d75
+//
+func (vw *VideoWriter) IsOpened() bool {
+	isOpend := C.VideoWriter_IsOpened(vw.p)
+	return isOpend != 0
+}
+
+// Write the next video frame from the Mat image to the open VideoWriter.
+//
+// For further details, please see:
+// http://docs.opencv.org/master/dd/d9e/classcv_1_1VideoWriter.html#a3115b679d612a6a0b5864a0c88ed4b39
+//
+func (vw *VideoWriter) Write(img Mat) error {
+	vw.mu.Lock()
+	defer vw.mu.Unlock()
+	C.VideoWriter_Write(vw.p, img.p)
+	return nil
+}
+
+// OpenVideoCapture return VideoCapture specified by device ID if v is a
+// number. Return VideoCapture created from video file, URL, or GStreamer
+// pipeline if v is a string.
+func OpenVideoCapture(v interface{}) (*VideoCapture, error) {
+	switch vv := v.(type) {
+	case int:
+		return VideoCaptureDevice(vv)
+	case string:
+		id, err := strconv.Atoi(vv)
+		if err == nil {
+			return VideoCaptureDevice(id)
+		}
+		return VideoCaptureFile(vv)
+	default:
+		return nil, errors.New("argument must be int or string")
+	}
+}