main.go

package main

import (
	"bufio"
	"context"
	"fmt"
	"io"
	"os"

	"github.com/asticode/go-astits"
)

func main() {
	if len(os.Args) < 2 {
		fmt.Println("supply input filename")
		os.Exit(1)
	}

	input := os.Args[1]

	tsFile, err := os.Open(input)
	if err != nil {
		panic(err)
	}
	defer tsFile.Close()

	dmx := astits.New(context.Background(), tsFile)

	pidFiles := make(map[uint16]io.Writer)
	var d *astits.Data
	for {
		if d, err = dmx.NextData(); err != nil {
			if err == astits.ErrNoMorePackets {
				break
			}

			panic(err)
		}

		if d.PES == nil {
			continue
		}

		pidWriter, ok := pidFiles[d.PID]
		if !ok {
			pidFile, err := os.Create(fmt.Sprintf("%d", d.PID))
			if err != nil {
				panic(err)
			}
			defer pidFile.Close()

			pidFiles[d.PID] = bufio.NewWriter(pidFile)

			pidWriter = pidFiles[d.PID]
		}

		_, err = pidWriter.Write(d.PES.Data)
		if err != nil {
			panic(err)
		}
	}
}