Create a thumbnail grid (8x5) with ffmpeg

Readme.md

thedava/thumbnail.sh

Create a thumbnail grid (8 cols, 5 rows) with additional meta data in the style of ezthumb but with ffmpeg.

Requirements

• ffmpeg
• imagemagick (montage & convert)
• bc
• fonts-dejavu-core

thumbnail.sh

#!/usr/bin/env bash

# Check if ffmpeg and imagemagick (montage) are installed
if ! command -v ffmpeg &> /dev/null; then
    echo "FFmpeg is not installed."
    exit 1
fi

if ! command -v montage &> /dev/null; then
    echo "ImageMagick is not installed."
    exit 1
fi

rows=5
columns=8
thumb_count=$((rows * columns))

function create_thumbnail {
    filename=$(basename -- "$1")
    filename_no_ext="${filename%.*}"
    output_dir=$(dirname "$1")
    output_thumbnail="${output_dir}/${filename_no_ext}_thumb.jpg"

    #rm -f "$output_thumbnail"
    if [[ -e "$output_thumbnail" ]]; then
        echo "Thumbnail for $filename already exists. Skipped creation."
        return 0
    fi

    # Extract metadata
    metadata=$(ffmpeg -i "$1" 2>&1 | grep -E "Duration|Video:|Audio:")
    duration=$(echo "$metadata" | grep "Duration" | awk '{print $2}' | tr -d ,)

    # Calculate thumbnail interval
    hours=$(echo "$duration" | cut -d: -f1 | sed 's/^0*//')
    minutes=$(echo "$duration" | cut -d: -f2 | sed 's/^0*//')
    seconds=$(echo "$duration" | cut -d: -f3 | cut -d. -f1 | sed 's/^0*//')
    total_seconds=$((hours * 3600 + minutes * 60 + seconds))
    interval=$((total_seconds / thumb_count))

    # Determine filesize (for header)
    file_size=$(stat -c%s "$1")
    if (( file_size >= 1073741824 )); then
        file_size_gb=$(echo "scale=2; $file_size / 1073741824" | bc)
        file_size_display="${file_size_gb} GB"
    else
        file_size_mb=$(echo "scale=2; $file_size / 1048576" | bc)
        file_size_display="${file_size_mb} MB"
    fi

    temp_dir=$(mktemp -d -t thumbnailer-XXXXXX)
    echo -n "Creating $thumb_count thumbnails now"
    for i in $(seq 0 $((thumb_count - 1))); do
        #echo "Creating thumbnail $((i + 1)) of $thumb_count..."
        timestamp=$((i * interval))
        timestamp_formatted=$(printf '%02d:%02d:%02d' $((timestamp/3600)) $(((timestamp%3600)/60)) $((timestamp%60)))
        
        (
            ffmpeg -hide_banner -loglevel error -ss "$timestamp_formatted" -i "$1" -vframes 1 "$temp_dir/thumb_$i.png"
            echo -n "."
        ) &
        
        if (( (i + 1) % columns == 0 )); then
            wait
        fi
    done
    wait
    echo

    montage "$temp_dir/thumb_*.png" -tile "${columns}x${rows}" -geometry 320x+2+2 "$temp_dir/grid.png"
    
    header_text=$(echo -e "Name: $filename\nSize: ${file_size_display}\n$metadata" | sed 's/^[[:space:]]*//gm')
    convert "$temp_dir/grid.png" \
        -gravity NorthWest -background White -splice 0x150 \
        -fill black -font "DejaVu-Sans-Mono" -pointsize 18 -annotate +10+10 "$header_text" \
        "$output_thumbnail"

    rm -rf "$temp_dir"

    echo "$output_thumbnail created!"
}

for input_video in "$@"; do
    # Check if input_video exists
    if [ ! -f "$input_video" ]; then
        echo "Input file not found: $input_video"
    else
        create_thumbnail "$input_video"
    fi
done

echo "done"