frame_extractor.sh

gistfile1.txt

#!/bin/bash

# Check if enough arguments are passed
if [ "$#" -ne 3 ]; then
    echo "Usage: $0 <source_video> <frame_interval> <change_percentage>"
    exit 1
fi

# Assign the arguments to variables
SOURCE_VIDEO="$1"
FRAME_INTERVAL="$2"
CHANGE_PERCENTAGE="$3"

# Directory for extracted frames
mkdir -p frames
mkdir -p diff_frames

# Check if the frames directory is empty
if [ -z "$(ls -A frames)" ]; then
    # Extract frames from the video and get the total number of frames
    total_frames=$(ffmpeg -i "$SOURCE_VIDEO" -vf "select=not(mod(n\,$FRAME_INTERVAL))" -vsync vfr frames/frame_%04d.png |& grep -oP 'frame=\s*\K\d+' | tail -1)
else
    echo "Frames already extracted. Skipping extraction..."
    total_frames=$(ls frames | wc -l)
fi

# Initialize variables
previous_frame=""
current_frame=""
frame_count=0

# Function to update progress bar
update_progress_bar() {
    local current=$1
    local total=$2
    local percent=$((200*$current/$total % 2 + 100*$current/$total))
    local progress_bar=$(printf "[%-${total}s]" $(for i in $(seq 1 $((percent/2))); do printf "#"; done))
    printf "\r$progress_bar %d%%" $percent
}

# Iterate over extracted frames
for frame in frames/*.png; do
    current_frame=$frame
    if [ ! -z "$previous_frame" ]; then
        # Compare the current frame with the previous frame
        difference=$(compare -metric MAE "$previous_frame" "$current_frame" null: 2>&1 | awk '{print $1}')
        echo "$previous_frame to $current_frame = $difference vs $CHANGE_PERCENTAGE"
        change_ratio=$(echo "$difference $FRAME_INTERVAL" | awk '{print ($1 * 100) / ($2 * 2)}')
        echo "$change_ratio > $CHANGE_PERCENTAGE"
        # Check if the change is significant
        if [ $(echo "$change_ratio > $CHANGE_PERCENTAGE" | bc) -eq 1 ]; then
            
            cp "$current_frame" diff_frames/
        fi
    fi
    previous_frame=$current_frame
    ((frame_count++))
    update_progress_bar $frame_count $total_frames
done

echo -e "\nSignificant frames saved in diff_frames directory."