[Audio+VIdeo merge] lossless #ffmpeg #audio #video #cli #bash

dynamic-fade.sh

ffmpeg -i input.mp4 -i soundtrack.mp3 -filter_complex "[1:a]afade=t=out:st=$(bc <<< "$duration-$fade"):d=$fade[a]" -map 0:v:0 -map "[a]" -c:v copy -c:a aac -shortest with_audio.mp4

get-length.sh

ffprobe -v error -select_streams v:0 -show_entries stream=duration -of csv=p=0 input.mp4

leet-fade.sh

#!/bin/bash

f="$*" # all args
p="${f##*/}" # file
fn="${p%.*}" # name only
e="${p##*.}" # extension

echo
echo $f
echo $p
echo $fn
echo $e
echo

read -e -p "Number of seconds of fade-out: " -i 1 sec # prompt for fade duration in seconds

r=$(ffprobe -show_streams "$f" 2> /dev/null | grep r_frame_rate | head -1 | cut -d \= -f 2) # frame rate
let "frames = $r * $sec" # duration of fade as number of frames
echo $r
echo $sec
echo $frames
lf=$(ffprobe -show_streams "$f" 2> /dev/null | grep nb_frames | head -1 | cut -d \= -f 2) # total number of frames
let "lf = $lf - $frames" # initial frame to start fade at

ffmpeg -loglevel quiet -i "$f" -vf fade=out:$lf:$frames -r $r -vcodec libx264 -preset slow -crf 12 -bf 2 -flags +cgop -pix_fmt yuv420p -acodec copy "$fn $sec sec fade-out.$e"
open "$fn $sec sec fade-out.$e"

merge-media.sh

ffmpeg -i video.mp4 -i audio.wav -codec copy -shortest output.mov