Renamed videoio.go to video.go

video.go

@@ -0,0 +1,137 @@
+package vidio
+
+import (
+	"io"
+	"os"
+	"os/exec"
+	"os/signal"
+	"syscall"
+)
+
+type Video struct {
+	filename    string
+	width       int
+	height      int
+	depth       int
+	bitrate     int
+	frames      int
+	duration    float64
+	fps         float64
+	codec       string
+	pix_fmt     string
+	framebuffer []byte
+	pipe        *io.ReadCloser
+	cmd         *exec.Cmd
+}
+
+func NewVideo(filename string) *Video {
+	if !exists(filename) {
+		panic("File: " + filename + " does not exist")
+	}
+	// Check if ffmpeg and ffprobe are installed on the users machine.
+	checkExists("ffmpeg")
+	checkExists("ffprobe")
+	// Extract video information with ffprobe.
+	cmd := exec.Command(
+		"ffprobe",
+		"-show_streams",
+		"-select_streams", "v", // Only show video data
+		"-print_format", "compact",
+		"-loglevel", "quiet",
+		filename,
+	)
+
+	pipe, err := cmd.StdoutPipe()
+	if err != nil {
+		panic(err)
+	}
+
+	if err := cmd.Start(); err != nil {
+		panic(err)
+	}
+	// Read ffprobe output from Stdout.
+	buffer := make([]byte, 2<<10)
+	total := 0
+	for {
+		n, err := pipe.Read(buffer[total:])
+		total += n
+		if err == io.EOF {
+			break
+		}
+	}
+
+	if err := cmd.Wait(); err != nil {
+		panic(err)
+	}
+	video := &Video{filename: filename, depth: 3}
+	parseFFprobe(buffer[:total], video)
+	return video
+}
+
+func initVideoStream(video *Video) {
+	// If user exits with Ctrl+C, stop ffmpeg process.
+	video.cleanup()
+
+	cmd := exec.Command(
+		"ffmpeg",
+		"-i", video.filename,
+		"-f", "image2pipe",
+		"-loglevel", "quiet",
+		"-pix_fmt", "rgb24",
+		"-vcodec", "rawvideo", "-",
+	)
+
+	video.cmd = cmd
+	pipe, err := cmd.StdoutPipe()
+	if err != nil {
+		panic(err)
+	}
+	video.pipe = &pipe
+	if err := cmd.Start(); err != nil {
+		panic(err)
+	}
+	video.framebuffer = make([]byte, video.width*video.height*video.depth)
+}
+
+func (video *Video) Read() bool {
+	// If cmd is nil, video reading has not been initialized.
+	if video.cmd == nil {
+		initVideoStream(video)
+	}
+	total := 0
+	for total < video.width*video.height*video.depth {
+		n, err := (*video.pipe).Read(video.framebuffer[total:])
+		if err == io.EOF {
+			video.Close()
+			return false
+		}
+		total += n
+	}
+	return true
+}
+
+func (video *Video) Close() {
+	if video.pipe != nil {
+		(*video.pipe).Close()
+	}
+	if video.cmd != nil {
+		video.cmd.Wait()
+	}
+}
+
+// Stops the "cmd" process running when the user presses Ctrl+C.
+// https://stackoverflow.com/questions/11268943/is-it-possible-to-capture-a-ctrlc-signal-and-run-a-cleanup-function-in-a-defe
+func (video *Video) cleanup() {
+	c := make(chan os.Signal)
+	signal.Notify(c, os.Interrupt, syscall.SIGTERM)
+	go func() {
+		<-c
+		if video.pipe != nil {
+			(*video.pipe).Close()
+		}
+		if video.cmd != nil {
+			video.cmd.Process.Kill()
+		}
+		os.Exit(1)
+	}()
+}