streaming script for Twitch and YouTube

streaming

#!/bin/bash
# Written by Yu-Jie Lin in 2016
# Adopted from
#   https://wiki.archlinux.org/index.php/Streaming_using_twitch.tv
# With guides
#   http://help.twitch.tv/customer/portal/articles/1253460-broadcast-requirements
#   https://trac.ffmpeg.org/wiki/StreamingGuide
#   https://support.google.com/youtube/answer/2853702

LOG_OPTS='-loglevel warning -stats'

SIZE=1280x720 # input resolution
FPS=10 # target FPS
PRESET=ultrafast  # one of the many FFMPEG preset
THREADS=0 # max 6
CBR=2500k # constant bitrate (should be between 1000k - 3000k)

AUDIO_RATE=48000
AUDIO_BR=128k

GOP=$((2 * FPS)) # i-frame interval, should be double of FPS, 
GOPMIN="$FPS" # min i-frame interval, should be equal to fps, 

VINPUT="-f x11grab -s $SIZE -r $FPS -i :0.0"
AINPUT="-f alsa -i pulse -f flv -ac 2 -ar $AUDIO_RATE"

VRATES="-b:v $CBR -minrate $CBR -maxrate $CBR -bufsize $CBR"
VCODEC="-vcodec libx264 -preset $PRESET -g $GOP -keyint_min $GOPMIN $VRATES -pix_fmt yuv420p"
ACODEC="-acodec libfdk_aac -b:a $AUDIO_BR"

case "$1" in
  twitch)
    SERVER=live-tpe
    #SERVER="live-fra" # twitch server in frankfurt, see http://bashtech.net/twitch/ingest.php for list
    STREAM_KEY="$(<$XDG_CONFIG_HOME/twitch-key)"

    OUTPUT="rtmp://$SERVER.twitch.tv/app/$STREAM_KEY"
    ;;
  youtube)
    STREAM_KEY="$(<$XDG_CONFIG_HOME/youtube-key)"

    OUTPUT="rtmp://a.rtmp.youtube.com/live2/$STREAM_KEY"
    ;;
  null)
    OUTPUT=/dev/null
    ;;
  test)
    OUTPUT=/tmp/test.mp4
    ;;
  *)
    echo 'no service specified.' >&2
    exit 1
esac

ffmpeg          \
  $LOG_OPTS     \
  $VINPUT       \
  $AINPUT       \
  $VCODEC       \
  $ACODEC       \
  "$OUTPUT"