A function expanded a given audio/video up to 2 hours using FFMPEG

expand-clip.sh

expand() {
    local file="$1"
    local filename="${file%.*}"
    local extension="${file##*.}"
    # Convert extension to lowercase using 'tr' (works on Mac & Linux)
    local ext_lower=$(echo "$extension" | tr '[:upper:]' '[:lower:]')
    local duration
    local loops

    # 1. Get duration in seconds
    duration=$(ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 "$file")
    
    # 2. Calculate loops needed to exceed 2 hours (7200 seconds)
    loops=$(echo "$duration" | awk '{print int(7200/$1) + 1}')

    echo "Input length: $duration sec | Loops: $loops"

    # 3. Logic check: wav/mp3 -> flac, others -> copy original
    if [[ "$ext_lower" == "wav" || "$ext_lower" == "mp3" ]]; then
        # Audio Mode: Convert to FLAC (48kHz)
        ffmpeg -stream_loop "$loops" -i "$file" -c:a flac -ar 48000 "${filename}-expanded.flac"
    else
        # Video/Other Mode: Stream copy
        ffmpeg -stream_loop "$loops" -i "$file" -c copy "${filename}-expanded.${extension}"
    fi
}