Takes thirty random images from a directory and makes an mp4 video

ffmpeg_script.sh

#!/bin/bash
#----------------------------------------------------------------
# SETTINGS

#input_dir="/mnt/HDD500/collections/newdownloads/512x512"  # Replace this by a path to your folder /path/to/your/folder
input_dir="$(pwd)"  #use the current directory the script can be copied to and run from /usr/local/bin run from 
n_files=30                        # Replace this by a number of images
#files=`ls ${input_dir}/*.jpg | head -${n_files}`  # Change the file type to the correct type of your images
files=$(ls -1 "${input_dir}"/*.jpg | shuf -n ${n_files})  # pick thirty random *.jpg
#output_file="video.mp4"           # Name of output video
output_file="$(date +%s).mp4" # Use a date_file_name to keep from overwriting names

crossfade=0.9                     # Crossfade duration between two images
#----------------------------------------------------------------

# Making an ffmpeg script...
input=""
filters=""
output="[0:v]"

i=0

for f in ${files}; do
  input+=" -loop 1 -t 1 -i $f"

  next=$((i+1))
  if [ "${i}" -ne "$((n_files-1))" ]; then
    filters+=" [${next}:v][${i}:v]blend=all_expr='A*(if(gte(T,${crossfade}),1,T/${crossfade}))+B*(1-(if(gte(T,${crossfade}),1,T/${crossfade})))'[b${next}v];"
  fi

  if [ "${i}" -gt "0" ]; then
    output+="[b${i}v][${i}:v]"
  fi

  i=$((i+1))
done

output+="concat=n=$((i * 2 - 1)):v=1:a=0,format=yuv420p10le[v]\" -map \"[v]\" ${output_file}"

script="ffmpeg ${input} -filter_complex \"${filters} ${output}"

echo ${script}

# Run it
eval "${script}"