This script is designed for the broadcast of an event where the video and audio sources are included into a single mp4 file. I am not tested it. Please check it is works.

#! /bin/bash
 
VBR="1500k"
FPS="30"
QUAL="ultrafast"
YOUTUBE_URL=" rtmp://a.rtmp.youtube.com/live2"
YOUTUBE_KEY="XXXXXXXXXX"
VIDEO_SOURCE="sample.mp4"
AUDIO_ENCODER="aac"

$ ffmpeg 
  -re \
  -f lavfi \
  -i "$VIDEO_SOURCE" \
  -c:v libx264 -preset $QUAL -r $FPS -g $(($FPS *2)) -b:v $VBR \
  -c:a $AUDIO_ENCODER -threads 6 -ar 44100 -b:a 128k -bufsize 512k -pix_fmt yuv420p \
  -f $YOUTUBE_URL/$YOUTUBE_KEY