ghostream/stream/multicast/muticast.go

package multicast

import (
	"bufio"
	"io"
	"log"
	"os/exec"
)

type Options struct {
	Outputs map[string][]string
}

var (
	options            Options
	ffmpegInstances    = make(map[string][]*exec.Cmd)
	ffmpegInputStreams = make(map[string][]*io.WriteCloser)
)

// New Load configuration
func New(cfg *Options) error {
	options = *cfg
	return nil
}

// RegisterStream Declare a new open stream and create ffmpeg instances
func RegisterStream(streamKey string) {
	ffmpegInstances[streamKey] = []*exec.Cmd{}
	ffmpegInputStreams[streamKey] = []*io.WriteCloser{}

	// TODO Export the list of multicasts
	for _, stream := range options.Outputs[streamKey] {
		// Launch FFMPEG instance
		// TODO Set optimal parameters
		ffmpeg := exec.Command("ffmpeg", "-re", "-i", "pipe:0", "-f", "flv", "-c:v", "libx264", "-preset",
			"veryfast", "-maxrate", "3000k", "-bufsize", "6000k", "-pix_fmt", "yuv420p", "-g", "50", "-c:a", "aac",
			"-b:a", "160k", "-ac", "2", "-ar", "44100", stream)

		// Open pipes
		input, err := ffmpeg.StdinPipe()
		if err != nil {
			panic(err)
		}
		output, err := ffmpeg.StdoutPipe()
		if err != nil {
			panic(err)
		}
		errOutput, err := ffmpeg.StderrPipe()
		if err != nil {
			panic(err)
		}
		ffmpegInstances[streamKey] = append(ffmpegInstances[streamKey], ffmpeg)
		ffmpegInputStreams[streamKey] = append(ffmpegInputStreams[streamKey], &input)

		if err := ffmpeg.Start(); err != nil {
			panic(err)
		}

		// Log ffmpeg output
		go func() {
			scanner := bufio.NewScanner(output)
			for scanner.Scan() {
				log.Println("[FFMPEG " + streamKey + "] " + scanner.Text())
			}
		}()
		// Log also error output
		go func() {
			scanner := bufio.NewScanner(errOutput)
			for scanner.Scan() {
				log.Println("[FFMPEG ERROR " + streamKey + "] " + scanner.Text())
			}
		}()
	}
}

// SendPacket When a SRT packet is received, transmit it to all FFMPEG instances related to the stream key
func SendPacket(streamKey string, data []byte) {
	for _, stdin := range ffmpegInputStreams[streamKey] {
		_, err := (*stdin).Write(data)
		if err != nil {
			log.Println("Error while sending a packet to external streaming server for key "+streamKey, err)
		}
	}

}

// CloseConnection When the stream is ended, close FFMPEG instances
func CloseConnection(streamKey string) {
	for _, ffmpeg := range ffmpegInstances[streamKey] {
		if err := ffmpeg.Process.Kill(); err != nil {
			panic(err)
		}
	}
	delete(ffmpegInstances, streamKey)
	delete(ffmpegInputStreams, streamKey)
}