Use ffmpeg to batch widen vertical videos with a blur effect (i.e. to upload vertical videos as non-shorts in Youtube)

batch-widen-vertical-videos-blur.sh

#!/bin/bash

# Target directory from the first argument, or current directory if none is provided
TARGET_DIR="${1:-.}"

# Define the complex filter as a variable to keep the code clean
FILTER='split[original][copy];[copy]scale=ih*16/9:-1,crop=h=iw*9/16,gblur=sigma=20[blurred];[blurred][original]overlay=(main_w-overlay_w)/2:(main_h-overlay_h)/2'

for input_file in "$TARGET_DIR"/*.[mM][pP]4 "$TARGET_DIR"/*.[mM][oO][vV]; do
    
    [ -e "$input_file" ] || continue
    
    if [[ "$input_file" == *-wide.* ]]; then
        echo "Skipping already processed file: $input_file"
        continue
    fi

    ext="${input_file##*.}"
    base="${input_file%.*}"
    output_file="${base}-wide.${ext}"

    echo "--------------------------------------------------------"
    echo "Processing: $input_file"
    echo "Outputting: $output_file"
    echo "--------------------------------------------------------"
    
    # 1. Attempt Hardware Acceleration (h264_videotoolbox)
    echo "Attempting hardware-accelerated encoding..."
    
    # Added -nostdin to prevent ffmpeg from interacting with the shell loop
    if ffmpeg -nostdin -i "$input_file" -vf "$FILTER" -c:v h264_videotoolbox -c:a copy "$output_file"; then
        echo "✅ Success: Hardware acceleration used."
    else
        echo "⚠️ Hardware acceleration failed. Falling back to standard software encoding..."
        
        # Remove the partially generated, broken file from the failed attempt
        rm -f "$output_file"
        
        # 2. Fallback to Standard Software Encoding (libx264 implicitly)
        if ffmpeg -nostdin -i "$input_file" -vf "$FILTER" -c:a copy "$output_file"; then
            echo "✅ Success: Software encoding used."
        else
            echo "❌ Error: Both hardware and software encoding failed for $input_file."
            # Clean up the broken file from the software attempt, if any
            rm -f "$output_file"
        fi
    fi
done

echo "Batch processing complete!"