Vidio/README.md

Vidio

A simple Video I/O library written in Go. This library relies on FFmpeg, and FFProbe which must be downloaded before usage.

Video

The Video struct stores data about a video file you give it. The code below shows an example of sequentially reading the frames of the given video.

video := NewVideo("input.mp4")
for video.NextFrame() {
	// "frame" stores the video frame as a flattened RGB image.
    frame := video.framebuffer // stored as: RGBRGBRGBRGB...
}

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
}

Camera

The Camera can read from any cameras on the device running Vidio.

type Camera struct {
	name        string
	width       int
	height      int
	depth       int
	fps         float64
	codec       string
	framebuffer []byte
	pipe        *io.ReadCloser
	cmd         *exec.Cmd
}

camera := NewCamera(0) // Get Webcam
defer camera.Close()

// Stream the webcam.
for camera.NextFrame() {
	// "frame" stores the video frame as a flattened RGB image.
	frame := camera.framebuffer // stored as: RGBRGBRGBRGB...
}

VideoWriter

The VideoWriter is used to write frames to a video file. You first need to create a Video struct with all the desired properties of the new video you want to create such as width, height and framerate.

type Options struct {
	width       int			// Width of Output Frames
	height      int			// Height of Output Frames
	bitrate     int			// Bitrate
	loop        int			// For GIFs only. -1=no loop, 0=loop forever, >0=loop n times
	delay       int			// Delay for Final Frame of GIFs
	macro       int			// macro size for determining how to resize frames for codecs
	fps         float64		// Frames per second
	codec       string		// Codec for video
	in_pix_fmt  string		// Pixel Format of incoming bytes
	out_pix_fmt string		// Pixel Format for video being written
}

type VideoWriter struct {
	filename    string
	width       int
	height      int
	bitrate     int
	loop        int
	delay       int
	macro       int
	fps         float64
	codec       string
	in_pix_fmt  string
	out_pix_fmt string
	pipe        *io.WriteCloser
	cmd         *exec.Cmd
}

w, h, c := 1920, 1080, 3
options = Options{width: w, height: w, bitrate: 100000}

writer := NewVideoWriter("output.mp4", &options)
defer writer.Close() // Make sure to close writer.

frame = make([]byte, w*h*c) // Create Frame as RGB Image and modify.
writer.Write(frame) // Write Frame to video.

Examples

Copy input to output.

video := NewVideo(input)
options := Options{
	width: video.width,
	height: video.height,
	fps: video.fps,
	bitrate: video.bitrate
}

writer := NewVideoWriter(output, &options)
defer writer.Close()

for video.NextFrame() {
    writer.Write(video.framebuffer)
}

Acknowledgements

• Special thanks to Zulko and his blog post about using FFmpeg to process video.
• The ImageIO-FFMPEG project on GitHub.