FFMPEG Screen capture/stream script

ffcapture

#!/bin/bash

#LICENSE
#To the extent possible under law, the author(s) have dedicated all 
#copyright and related and neighboring rights to this software to the
#public domain worldwide. This software is distributed without any warranty.
#See <http://creativecommons.org/publicdomain/zero/1.0/>.

# ffcapture, a hacky script to stream/capture your desktop or a window 
# REQUIRES ffmpeg, xwininfo and bc to be installed!
#
# Accepts a maximum of two parameters, from the following list:
# stream, window, composite, svideo.
#
# RUN THIS SCRIPT IN A CONSOLE because it uses prompts.
# I recommend invoking in a manner such as this (which I use in Openbox):
# urxvt -geometry 60x5+0+0 -e $HOME/bin/ffcapture stream window
#
# if "stream" is present, it will stream to your twitch.tv account.
# you can either replace the "$(cat ... /streamkey )" business below with your stream key, or put your key
# in a file called "streamkey" in the same directory as this script.
# if "stream" is absent, the default is to record the video to an .mkv container. You can tweak the settings below.
#
# if "window" is present, it will only stream/record the contents of a window (you'll be prompted to select the window).
# if "composite" is present, it will stream/record the v4l2 source specified by the COMPOSITE_SOURCE variable below.
# if "svideo" is present, it will stream/record the v4l2 source specified by the SVIDEO_SOURCE variable below.
#
# the default if invoked with no parameters is to record (not stream) the full desktop.
# RUN THIS SCRIPT IN A CONSOLE because it uses prompts.
# press 'q' in the console window to end capture/stream.


#--- Edit these default values.
OUTDIR=$HOME/Videos/GameFootage
TTV_STREAMKEY=$(cat "$(dirname "${BASH_SOURCE[0]}")"/streamkey )
COMPOSITE_SOURCE="-channel 0 -standard NTSC -i /dev/video1"
SVIDEO_SOURCE="-channel 1 -standard NTSC -i /dev/video1"

#--- Check for necessary utils
type xwininfo &> /dev/null || { echo "xwininfo not found! please install it."; exit 1; }
type ffmpeg &> /dev/null || { echo "ffmpeg not found! please install it."; exit 1; }
type bc &> /dev/null || { echo "bc not found! please install it."; exit 1; }

#--- Ahem... "parse" command line parameters
[[ "$1" = "stream" || "$2" = "stream" ]] && STREAMING=true
[[ "$1" = "window" || "$2" = "window" ]] && WINDOWED=true
[[ "$1" = "composite" || "$2" = "composite" ]] && COMPOSITE=true
[[ "$1" = "svideo" || "$2" = "svideo" ]] && SVIDEO=true

#--- Detect fullscreen size
FULLWIDTH=$(xrandr --current | grep '*' | uniq | awk '{print $1}' |  cut -d 'x' -f1)
FULLHEIGHT=$(xrandr --current | grep '*' | uniq | awk '{print $1}' |  cut -d 'x' -f2)
FULLRES="${FULLWIDTH}x$FULLHEIGHT"



#--- Change video settings below if you like

if [ "$STREAMING" = "true" ]; then

  #--- Video settings for streaming
  OUTHEIGHT=780
  FPS=30
  VBITRATE=1500k
  ABITRATE=96k
  
  ACODEC="libmp3lame -b:a $ABITRATE -ar 44100"
  VCODEC="libx264 -preset ultrafast -tune animation -b:v $VBITRATE"
  
  #--- File output settings  
  FILEOUT="-f flv rtmp://live.justin.tv/app/$TTV_STREAMKEY"
  
else

  #--- Timestamp format
  TIMESTAMP=$(date +%F-%R)
  
  #--- Video settings for recording
  OUTHEIGHT=$FULLHEIGHT
  FPS=60
  VBITRATE=8000k
  ABITRATE=96k
  
  ACODEC="libmp3lame -b:a $ABITRATE -ar 44100"
  VCODEC="libx264 -preset ultrafast -tune animation -b:v $VBITRATE"
  

  #--- File output settings
  mkdir -p $OUTDIR
  FILEOUT="-y $OUTDIR/capture.mkv"
  
fi



#--- Calculate in/out resolutions, grab source window size if necessary

if [ "$WINDOWED" = "true" ]; then

  echo Select the target window.
  unset x y w h
  eval $(xwininfo |
    sed -n -e "s/^ \+Absolute upper-left X: \+\([0-9]\+\).*/x=\1/p" \
        -e "s/^ \+Absolute upper-left Y: \+\([0-9]\+\).*/y=\1/p" \
        -e "s/^ \+Width: \+\([0-9]\+\).*/w=\1/p" \
        -e "s/^ \+Height: \+\([0-9]\+\).*/h=\1/p" )
    
  INRES=$(echo "-s ${w}x$h -r $FPS -i :0.0+$x,$y")
  if [ "$h" -lt "$OUTHEIGHT" ]; then 
    OUTHEIGHT=$h
  fi
  OUTHEIGHT=$(echo "scale=0;$OUTHEIGHT/2*2" | bc)
  OUTWIDTH=$(echo "scale=1;$OUTHEIGHT/$h*$w" | bc)
  OUTWIDTH=$(echo "scale=0;$OUTWIDTH/2*2" | bc)
  
  VIDEOSRC="-f x11grab"
  OUTRES="-s ${OUTWIDTH}x${OUTHEIGHT}"
  
elif [ "$COMPOSITE" = "true" ]; then

  VIDEOSRC="-f video4linux2 $COMPOSITE_SOURCE"
  OUTRES=

elif [ "$SVIDEO" = "true" ]; then

  VIDEOSRC="-f video4linux2 $SVIDEO_SOURCE"
  OUTRES=
  
else #No Parameter = fullscreen capture.

  INRES=$(echo "-s $FULLRES -r $FPS -i :0.0")
  OUTHEIGHT=$(echo "scale=0;$OUTHEIGHT/2*2" | bc)
  OUTWIDTH=$(echo "scale=1;$OUTHEIGHT/${FULLHEIGHT}*${FULLWIDTH}" | bc)
  OUTWIDTH=$(echo "scale=0;$OUTWIDTH/2*2" | bc)
  
  VIDEOSRC="-f x11grab"
  OUTRES="-s ${OUTWIDTH}x${OUTHEIGHT}"
  
fi



#--- Figure out a reasonable audio source
# IMPORTANT: I recommend running Pulse or Jack as your audio
# server. Personally I use Jack and have Qjackctl's patchbay
# set-up to automatically connect ffmpeg to ALSA-Jack plugin clients.
# If you're running Pulse (e.g. Ubuntu), you might need to play around
# with Pavucontrol to capture your outgoing audio.
# If you're only using ALSA, it will use the default capture
# interface, meaning your sound card's inputs, not the sound
# being played back by apps.

AUDIOSRC="-f alsa -ac 2 -i default"
ps ax | grep pulseaudio | grep -v grep > /dev/null
if [ "$?" = "0" ]; then
  AUDIOSRC="-f alsa -ac 2 -i pulse"
fi

ps ax | grep jackd | grep -v grep > /dev/null
if [ "$?" = "0" ]; then
  #AUDIOSRC="-f alsa -ac 2 -i jackplug"
  AUDIOSRC="-f jack -ac 2 -i ffmpeg"
fi





#NOW THE FUN BEGINS ==========================================================================
ffmpeg \
 $VIDEOSRC $INRES \
 $AUDIOSRC \
 -acodec $ACODEC -threads auto \
 -vcodec $VCODEC $OUTRES -threads auto \
 $FILEOUT
 
#exit 0

#--- rename the resulting capture file if applicable

if [ "$STREAMING" != "true" ]; then
  echo "Please type a name for the recording."
  read RENAMETO
  [[ "$RENAMETO" = "" ]] && RENAMETO=capture
  mv "$OUTDIR/capture.mkv" "$OUTDIR/$RENAMETO-$TIMESTAMP.mkv"
fi

This is super useful, thanks! I've been using obs for this sort of thing but needed more control over the number of audio channels that were captured etc.

Do you have a particular license for this?

I'm glad you've found this to be useful... I added a public domain notice to it, please use as you like.

@seanbutnotheard thanks again