I need to create a simple application where I have to stream a video and convert the video to hls and save it in aws s3 while the video is streaming (I cannot wait till the entire video is downloaded and also I cannot wait till ffmpeg fnishes the conversion to upload it to S3) the below is the code of what I attempted

import (
    "bytes"
    "io"
    "net/http"
    "os"
    "os/exec"

    "github.com/VinukaThejana/go-utils/logger"
)

func main() {
    res, err := http.Get("http://localhost/video.mp4")
    if err != nil {
        logger.Errorf(err)
    }
    payload, err := io.ReadAll(res.Body)
    if err != nil {
        logger.Errorf(err)
    }

    cmd := exec.Command("ffmpeg", "-i", "pipe:0", "-c:v", "libx264", "-preset", "ultrafast", "-tune", "zerolatency", "-f", "flv", "pipe:1")
    buffer := bytes.NewBuffer(make([]byte, 5*1024*1024))

    cmd.Stderr = os.Stderr
    cmd.Stdout = buffer

    stdin, err := cmd.StdinPipe()
    if err != nil {
        logger.Errorf(err)
    }

    err = cmd.Start()
    if err != nil {
        logger.Errorf(err)
    }

    _, err = stdin.Write(payload)
    if err != nil {
        logger.Errorf(err)
    }

    err = stdin.Close()
    if err != nil {
        logger.Errorf(err)
    }

    err = cmd.Wait()
    if err != nil {
        logger.Errorf(err)
    }

    output, err := os.Create("output.mp4")
    if err != nil {
        logger.Errorf(err)
    }
    defer output.Close()

    _, err = output.Write(buffer.Bytes())
    if err != nil {
        logger.Errorf(err)
    }
}

(the ffmpeg command given above is not correct for converting the video to hls I just put it there just to get things working)

The thing that I don’t understand it how am I able to get the video stream as it being downloaded and save it in s3 whilst converting it with ffmpeg in real time