hangouts-screencast.sh

#!/bin/bash

# Used to cast screen with camera feed ttached + recording this stream along with audio mixed from both mic and speakers.
# For hangouts one should share gst-launch window (the window itself can then be minimized)
# Tested on Ubuntu 16.04

PIP_WIDTH=320
PIP_HEIGHT=240
SCREEN_WIDTH=1920
SCREEN_HEIGHT=1200

SCREEN_RIGHT=$((SCREEN_WIDTH-1))
SCREEN_BOTTOM=$((SCREEN_HEIGHT-1))
PIP_LEFT=$((SCREEN_WIDTH-PIP_WIDTH))
PIP_TOP=$((SCREEN_HEIGHT-PIP_HEIGHT))

FILE="screencast_$(date '+%Y%m%d_%H%M%S')"

# use `LC_ALL="EN_us" pactl list | grep -A2 'Source' | grep -P 'input|monitor'` to find out names for this section
MIC_DEVICE="alsa_input.usb-046d_0819_2455EEA0-02.analog-mono"
SPEAKER_DEVICE="alsa_output.pci-0000_01_00.1.hdmi-stereo.monitor"

 
gst-launch-1.0 -e \
v4l2src \
    ! "video/x-raw,framerate=25/1,width=${PIP_WIDTH},height=${PIP_HEIGHT}"\
    ! queue \
    ! vmix.sink_0 \
ximagesrc use-damage=0 startx=0 endx=${SCREEN_RIGHT} endy=${SCREEN_BOTTOM} \
    ! 'video/x-raw,framerate=25/1' \
    ! queue \
    ! vmix.sink_1 \
videomixer name=vmix \
  sink_0::xpos=${PIP_LEFT} sink_0::ypos=${PIP_TOP} sink_0::zorder=1 \
  sink_1::xpos=0 sink_1::ypos=0 sink_1::zorder=0 \
    ! tee name=t \
    ! queue \
    ! xvimagesink sync=false \
t.  ! queue \
    ! x264enc speed-preset=ultrafast tune=zerolatency byte-stream=true threads=1 key-int-max=15 intra-refresh=true \
    ! h264parse \
    ! out.video_0 \
pulsesrc device="${MIC_DEVICE}" \
    ! queue \
    ! amix. \
pulsesrc device="${SPEAKER_DEVICE}" \
    ! queue \
    ! amix. \
adder name=amix \
    ! queue \
    ! lamemp3enc encoding-engine-quality=fast target=bitrate bitrate=128 cbr=true mono=true \
    ! out.audio_0 \
avimux name=out ! filesink sync=false location="${FILE}.avi"