makewebm

#!/bin/bash
# Simple wrapper for creating a webm from a video using ffmpeg
# https://wiki.installgentoo.com/index.php/WebM#Converting_with_ffmpeg
# https://superuser.com/questions/556463/converting-video-to-webm-with-ffmpeg-avconv

# TODO if ever use this again
# ffmpeg -i %1 -r 30 -c:v libvpx-vp9 -pass 1 -b:v 1500K -threads 4 -speed 4 -tile-columns 6 -frame-parallel 1 -an -f webm -y NUL
# ffmpeg -i %1 -r 30 -c:v libvpx-vp9 -pass 2 -b:v 1500K -threads 4 -speed 1 -tile-columns 6 -frame-parallel 1 -auto-alt-ref 1 -lag-in-frames 25 -c:a libopus -b:a 64k -f webm -y "%~n1.webm"
# shift
# >add -f 1, -f 2 as a flag for your two passes
# ffmpeg -ss <start_time> -i <source> -an -t <length> -b:v <24/length>M -vf "scale=-1:480" <destination_path>

function print_help() {
	echo "
$ makewebm /path/to/video

Creates a webm from  a video.

-w <width>     specify a width for the webm
               (default: not scaled to any specific width)
-o <filename>  specify an output name (default: output.webm)
-d <dir>       specify the dir to create the frames and output webm in
               (default: ~/move/gif)
-q <crf>       specify the crf value from 4-63; lower is higher quality
               (default: 10)
-a             include audio in webm (default: false)
-h             print help and exit
"

	if [[ $1 == illegal_opt ]]; then
		exit 1
	else
		exit 0
	fi
}

# default values
cur_time=$(date +%Y.%m.%d_%H:%M:%S)
outfile=${cur_time}_output.webm
outdir=$HOME/move/gif
quality=10
audio=false
while getopts :w:o:d:q:ah opt
do
	case $opt in
	w) width=$OPTARG;;
	o) outfile="$OPTARG";;
	d) outdir="$OPTARG";;
	q) quality="$OPTARG";;
	a) audio=true;;
	h) print_help;;
	*) print_help illegal_opt;;
    esac
done
infile=${!#}
infile=$(readlink -f "$infile")

mkdir -p "$outdir"
cd "$outdir"

# max video bit rate of 3M
ffmpeg_command="ffmpeg -i \"$infile\" -c:v libvpx -crf $quality -b:v 3M"

if [[ -n $width ]]; then
	ffmpeg_command="$ffmpeg_command -vf scale=$width:-1"
fi

if $audio; then
	ffmpeg_command="$ffmpeg_command -c:a libvorbis -q:a 4"
else
	ffmpeg_command="$ffmpeg_command -an"
fi

ffmpeg_command="$ffmpeg_command \"$outfile\""

eval "$ffmpeg_command"