process_video.sh

#!/bin/bash
# A simple script to overlay audio over a video lowering the original video's volume by 80%
# FFMPEG is awesome! 

video="$1"
audio="$2"

if [[ "$video" != *".webm"* ]]; then
	echo "Please input a video file as a first argument"
	exit 1
fi

if [[ "$audio" != *".mp3"* ]]; then
	echo "Please input an audio file as a second argument"
	exit 1
fi

ffmpeg \
	-i "$video" \
	-i "$audio" \
	-filter_complex \
	"[1:a]apad[A];[0:a]volume=0.20,[A]amerge[out]" \
	-c:v copy -map 0:v -map [out] -y \
	"processed_${video:0:10}.mp4"



# Concat multiple videos into one, listed in a file
# $ cat mylist.txt
# file '/path/to/file1'
# file '/path/to/file2'
# file '/path/to/file3'

ffmpeg -f concat -safe 0 -i mylist.txt -c copy output.mp4

# Split a video given two timestamps
# Time in form Hh:Mm:Ss
video="$1"
timestamp="$2"

ffmpeg -i "$video" -to "$timestamp" -c copy first.mp4
ffmpeg -i "$video" -ss "$timestamp" -c copy second.mp4

# Trim a video
video="$1"
time="$2"
ffmpeg -i "$video" -vcodec copy -c:a copy -map 0 -ss "$time" trimmed.webm

# Make a video from a single image
image="$1"
audio="$2"
length="$3" #Hh:Mm:Ss
ffmpeg \
    -r 0.01 -loop 1 -i "$image" \
    -i "$audio" -c:v libx264 \
    -tune stillimage -preset ultrafast \
    -ss 00:00:00 -t "$length" \
    -c:a aac -b:a 96k -pix_fmt yuv420p \
    -shortest out.mp4 -y