README
¶
Vidio
A simple Video I/O library written in Go. This library relies on FFmpeg, and FFProbe which must be downloaded before usage and added to the system path.
All frames are encoded and decoded in 8-bit RGB format.
Installation
go get github.com/AlexEidt/Vidio
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.
Calling the Read() function will fill in the Video struct framebuffer with the next frame data as 8-bit RGB data, stored in a flattened byte array in row-major order where each pixel is represented by three consecutive bytes representing the R, G and B component of that pixel.
vidio.NewVideo() (*Video, error)
FileName() string
Width() int
Height() int
Depth() int
Bitrate() int
Frames() int
Duration() float64
FPS() float64
Codec() string
AudioCodec() string
FrameBuffer() []byte
SetFrameBuffer(buffer []byte)
Read() bool
Close()
video, err := vidio.NewVideo("input.mp4")
for video.Read() {
// "frame" stores the video frame as a flattened RGB image in row-major order
frame := video.FrameBuffer() // stored as: RGBRGBRGBRGB...
// Video processing here...
}
If all frames have been read, video will be closed automatically. If not all frames are read, call video.Close() to close the video.
Camera
The Camera can read from any cameras on the device running Vidio. It takes in the stream index. On most machines the webcam device has index 0. Note that audio retrieval from the microphone is not yet supported.
vidio.NewCamera(stream int) (*Camera, error)
Name() string
Width() int
Height() int
Depth() int
FPS() float64
Codec() string
FrameBuffer() []byte
SetFrameBuffer(buffer []byte)
Read() bool
Close()
camera, err := vidio.NewCamera(0)
defer camera.Close()
// Stream the webcam
for camera.Read() {
frame := camera.FrameBuffer()
// Video processing here...
}
VideoWriter
The VideoWriter is used to write frames to a video file. The only required parameters are the output file name, the width and height of the frames being written, and an Options struct. This contains all the desired properties of the new video you want to create.
vidio.NewVideoWriter() (*VideoWriter, error)
FileName() string
Width() int
Height() int
Bitrate() int
Loop() int
Delay() int
Macro() int
FPS() float64
Quality() float64
Codec() string
AudioCodec() string
Write(frame []byte) error
Close()
type Options struct {
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. Default -1 (Use same delay as previous frame)
Macro int // macro size for determining how to resize frames for codecs. Default 16
FPS float64 // Frames per second. Default 25
Quality float64 // If bitrate not given, use quality instead. Must be between 0 and 1. 0:best, 1:worst
Codec string // Codec for video. Default libx264
Audio string // File path for audio for the video. If no audio, audio=""
AudioCodec string // Codec for audio. Default aac
}
w, h, c := 1920, 1080, 3
options := vidio.Options{} // Will fill in defaults if empty
writer, err := vidio.NewVideoWriter("output.mp4", w, h, &options)
defer writer.Close()
frame := make([]byte, w*h*c) // Create Frame as RGB Image and modify
writer.Write(frame) // Write Frame to video
The SetFrameBuffer(buffer []byte) method
For the SetFrameBuffer() method, the buffer parameter must have a length of at least video.Width() * video.Height() * video.Depth() bytes to store the incoming video frame. The length of the buffer is not checked. It may be useful to have multiple buffers to keep track of previous video frames without having to copy data around.
Images
Vidio provides some convenience functions for reading and writing to images using an array of bytes. Currently, only png and jpeg formats are supported.
w, h, img, err := vidio.Read("input.png")
err := vidio.Write("output.jpg", w, h, img)
Examples
Copy input.mp4 to output.mp4. Copy the audio from input.mp4 to output.mp4 as well.
video, err := vidio.NewVideo("input.mp4")
options := vidio.Options{
FPS: video.FPS(),
Bitrate: video.Bitrate(),
Audio: "input.mp4",
}
writer, err := vidio.NewVideoWriter("output.mp4", video.Width(), video.Height(), &options)
defer writer.Close()
for video.Read() {
writer.Write(video.FrameBuffer())
}
Grayscale 1000 frames of webcam stream and store in output.mp4.
webcam, err := vidio.NewCamera(0)
defer webcam.Close()
options := vidio.Options{FPS: webcam.FPS()}
writer, err := vidio.NewVideoWriter("output.mp4", webcam.Width(), webcam.Height(), &options)
defer writer.Close()
count := 0
for webcam.Read() {
frame := webcam.FrameBuffer()
for i := 0; i < len(frame); i += 3 {
r, g, b := frame[i+0], frame[i+1], frame[i+2]
gray := uint8((3*int(r) + 4*int(g) + int(b)) / 8)
frame[i] = gray
frame[i+1] = gray
frame[i+2] = gray
}
writer.Write(frame)
count++
if count > 1000 {
break
}
}
Create a gif from a series of png files enumerated from 1 to 10 that loops continuously with a final frame delay of 1000 centiseconds.
w, h, img, err := vidio.Read("1.png") // Get frame dimensions from first image
options := vidio.Options{FPS: 1, Loop: 0, Delay: 1000}
gif, err := vidio.NewVideoWriter("output.gif", w, h, &options)
defer gif.Close()
for i := 1; i <= 10; i++ {
w, h, img, err := vidio.Read(strconv.Itoa(i)+".png")
gif.Write(img)
}
Acknowledgements
- Special thanks to Zulko and his blog post about using FFmpeg to process video.
- The ImageIO-FFMPEG project on GitHub.
Documentation
¶
Index ¶
- func Read(filename string) (int, int, []byte, error)
- func Write(filename string, width, height int, data []byte) error
- type Camera
- func (camera *Camera) Close()
- func (camera *Camera) Codec() string
- func (camera *Camera) Depth() int
- func (camera *Camera) FPS() float64
- func (camera *Camera) FrameBuffer() []byte
- func (camera *Camera) Height() int
- func (camera *Camera) Name() string
- func (camera *Camera) Read() bool
- func (camera *Camera) SetFrameBuffer(buffer []byte)
- func (camera *Camera) Width() int
- type Options
- type Video
- func (video *Video) AudioCodec() string
- func (video *Video) Bitrate() int
- func (video *Video) Close()
- func (video *Video) Codec() string
- func (video *Video) Depth() int
- func (video *Video) Duration() float64
- func (video *Video) FPS() float64
- func (video *Video) FileName() string
- func (video *Video) FrameBuffer() []byte
- func (video *Video) Frames() int
- func (video *Video) Height() int
- func (video *Video) Read() bool
- func (video *Video) SetFrameBuffer(buffer []byte)
- func (video *Video) Width() int
- type VideoWriter
- func (writer *VideoWriter) AudioCodec() string
- func (writer *VideoWriter) Bitrate() int
- func (writer *VideoWriter) Close()
- func (writer *VideoWriter) Codec() string
- func (writer *VideoWriter) Delay() int
- func (writer *VideoWriter) FPS() float64
- func (writer *VideoWriter) FileName() string
- func (writer *VideoWriter) Height() int
- func (writer *VideoWriter) Loop() int
- func (writer *VideoWriter) Macro() int
- func (writer *VideoWriter) Quality() float64
- func (writer *VideoWriter) Width() int
- func (writer *VideoWriter) Write(frame []byte) error
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
Types ¶
type Camera ¶
type Camera struct {
// contains filtered or unexported fields
}
func NewCamera ¶
Creates a new camera struct that can read from the device with the given stream index.
func (*Camera) FrameBuffer ¶
func (*Camera) SetFrameBuffer ¶ added in v1.1.0
Sets the framebuffer to the given byte array. Note that "buffer" must be large enough to store one frame of video data which is width*height*3.
type Options ¶
type Options struct {
Bitrate int // Bitrate.
Loop int // For GIFs only. -1=no loop, 0=infinite loop, >0=number of loops.
Delay int // Delay for final frame of GIFs.
Macro int // Macroblock size for determining how to resize frames for codecs.
FPS float64 // Frames per second for output video.
Quality float64 // If bitrate not given, use quality instead. Must be between 0 and 1. 0:best, 1:worst.
Codec string // Codec for video.
Audio string // File path for audio. If no audio, audio="".
AudioCodec string // Codec for audio.
}
Optional parameters for VideoWriter.
type Video ¶
type Video struct {
// contains filtered or unexported fields
}
func NewVideo ¶
Creates a new Video struct. Uses ffprobe to get video information and fills in the Video struct with this data.
func (*Video) AudioCodec ¶
func (*Video) FrameBuffer ¶
func (*Video) Read ¶
Reads the next frame from the video and stores in the framebuffer. If the last frame has been read, returns false, otherwise true.
func (*Video) SetFrameBuffer ¶ added in v1.1.0
Sets the framebuffer to the given byte array. Note that "buffer" must be large enough to store one frame of video data which is width*height*3.
type VideoWriter ¶
type VideoWriter struct {
// contains filtered or unexported fields
}
func NewVideoWriter ¶
func NewVideoWriter(filename string, width, height int, options *Options) (*VideoWriter, error)
Creates a new VideoWriter struct with default values from the Options struct.
func (*VideoWriter) AudioCodec ¶
func (writer *VideoWriter) AudioCodec() string
func (*VideoWriter) Bitrate ¶
func (writer *VideoWriter) Bitrate() int
func (*VideoWriter) Close ¶
func (writer *VideoWriter) Close()
Closes the pipe and stops the ffmpeg process.
func (*VideoWriter) Codec ¶
func (writer *VideoWriter) Codec() string
func (*VideoWriter) Delay ¶
func (writer *VideoWriter) Delay() int
func (*VideoWriter) FPS ¶
func (writer *VideoWriter) FPS() float64
func (*VideoWriter) FileName ¶
func (writer *VideoWriter) FileName() string
func (*VideoWriter) Height ¶
func (writer *VideoWriter) Height() int
func (*VideoWriter) Loop ¶
func (writer *VideoWriter) Loop() int
func (*VideoWriter) Macro ¶
func (writer *VideoWriter) Macro() int
func (*VideoWriter) Quality ¶
func (writer *VideoWriter) Quality() float64
func (*VideoWriter) Width ¶
func (writer *VideoWriter) Width() int
func (*VideoWriter) Write ¶
func (writer *VideoWriter) Write(frame []byte) error
Writes the given frame to the video file.
Source Files