:television: screencast with ffmpeg

screencast_pulse.sh

#! /bin/bash
# getting started
# ================
# - install pavucontrol and make sure default input is set to desired input
# - sudo apt install pavucontrol
# - mpv /dev/video0 is the webcam (most likely)
# - for HD change resolution with xrandr -d :0 -s 1280x720 or another
#   youtube rec. resolution
# - If laptop is plugged into monitor and the excludsion of the laptop monitor is 
#   wanted then xrandr --output eDP-1 --off 
# note on codec
# ==============
# The VP9 codec was used because it is more free than H.265
# the video quality vs size tradoff maybe controlled with -crf
# crf ranges from 0-63 with 0 being highest quality
# -b:v 0 is a required flag and value.
# docs: https://trac.ffmpeg.org/wiki/Encode/VP9
# 
# note on container
# =================
# Matroska mkv file format is GPL/BSD licensed 
# Webm is built on top of mkv
# mkv is not a prefered format for some online video platforms
# mp4 is often prefered, but not free 
# webm is also prefered and more free
# webm was chosen because it is more free than mp4
# and is an acceptible format.
ffmpeg -y \
-video_size $(xdpyinfo | grep dimensions | awk '{print $2;}') \
-framerate 40 \
-f x11grab \
-i :0.0 \
-c:v libvpx-vp9 -crf 25 -b:v 0 \
~/videos/screen_recording_`date '+%Y-%m-%d_%H-%M-%S'.webm` \
-f alsa -i default