To start a stream on twitch with ffmpeg

twitch_ffmpeg.sh

# =========================================================
# Input resolution
# INRES="320x200"
INRES="640x360"
# INRES="1920x1080"
# =========================================================
# Output resolution
# OUTRES="320x200"
OUTRES="640x360"
# OUTRES="1920x1080"
# =========================================================
# Target FPS (but FFMEPG will choose one for you anyway)
TARGET_FPS="25"
# =========================================================
# One of the many FFMPEG preset
QUALITY="ultrafast"
# QUALITY="superfast"
# QUALITY="veryfast"
# QUALITY="fast"
# QUALITY="medium"
# =========================================================
# Max 6
THREADS="6"
# =========================================================
# constant bitrate (should be between 1000k - 3000k)
CBR="1000k"
# =========================================================
# Twitch STREAM KEY (go your account)
STREAM_KEY="live_xxxxxxxxxxxxxxxxxxxxxxxx"
# Twitch server (depend of your location)
SERVER="live-fra"
# =========================================================
# Output format
# ffmpeg -formats
OUTFORMAT=h264
# =========================================================
# Pixel format
# ffmpeg -h encoder=libx264 | grep "Supported pixel"
PIW_FMT=yuv420p
# PIW_FMT=gray
# =========================================================
ffmpeg \
    -s "$INRES" \
    -r "$TARGET_FPS" \
    -f v4l2 \
    -i /dev/video0 \
    \
    \
    -c:v $OUTFORMAT \
    -pix_fmt $PIW_FMT \
    -preset $QUALITY \
    -threads $THREADS \
    -s $OUTRES \
    -f flv \
    "rtmp://$SERVER.twitch.tv/app/$STREAM_KEY"
# =========================================================