278 lines
9.2 KiB
Bash
Executable File
278 lines
9.2 KiB
Bash
Executable File
#!/bin/bash
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# Script to extract first frame from WebM files and convert to WebP with alpha transparency
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# Usage: ./webm_to_webp.sh [directory_path] [background] [compression]
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# Function to display usage
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usage() {
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echo "Usage: $0 [directory_path] [background] [compression]"
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echo " directory_path: Path to directory containing WebM files (default: current directory)"
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echo " background: Background color for transparency (default: transparent)"
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echo " - 'transparent' for alpha transparency"
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echo " - Hex colors: '#000000', '#ffffff', '#ff0000', etc."
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echo " - Named colors: 'black', 'white', 'red', 'blue', etc."
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echo " compression: Compression level 1-5 (default: 3)"
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echo " - 1: Lossless, fast (largest files)"
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echo " - 2: Lossless, balanced"
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echo " - 3: Lossless, best compression (default)"
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echo " - 4: Lossy, high quality (quality 90)"
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echo " - 5: Lossy, maximum compression (quality 75)"
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echo ""
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echo "Examples:"
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echo " $0 # Current directory, transparent, lossless best"
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echo " $0 /path/to/files # Custom directory, defaults"
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echo " $0 /path/to/files black # Black background, lossless best"
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echo " $0 /path/to/files '#ff0000' 5 # Red background, maximum compression"
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echo ""
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echo "This script will:"
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echo " - Find all .webm files in the specified directory"
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echo " - Extract the frame with maximum coverage from each WebM file"
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echo " - Convert to WebP format maintaining alpha transparency"
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echo " - Save results in a 'webp' subdirectory"
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exit 1
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}
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# Check if ffmpeg is installed
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if ! command -v ffmpeg &> /dev/null; then
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echo "Error: ffmpeg is not installed or not in PATH"
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echo "Please install ffmpeg to use this script"
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exit 1
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fi
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# Set default values
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DIRECTORY="."
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BACKGROUND="transparent"
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COMPRESSION=3
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# Parse arguments
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if [ $# -eq 0 ]; then
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DIRECTORY="."
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elif [ $# -eq 1 ]; then
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DIRECTORY="$1"
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elif [ $# -eq 2 ]; then
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DIRECTORY="$1"
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BACKGROUND="$2"
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elif [ $# -eq 3 ]; then
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DIRECTORY="$1"
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BACKGROUND="$2"
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COMPRESSION="$3"
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else
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echo "Error: Too many arguments"
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usage
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fi
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# Validate background parameter
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if [ "$BACKGROUND" != "transparent" ]; then
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# Check if it's a valid hex color or named color
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if ! [[ "$BACKGROUND" =~ ^#[0-9a-fA-F]{6}$ ]] && ! [[ "$BACKGROUND" =~ ^[a-zA-Z]+$ ]]; then
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echo "Error: background must be 'transparent', a hex color (#000000), or a named color (black, white, etc.)"
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exit 1
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fi
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fi
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# Validate compression parameter
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if ! [[ "$COMPRESSION" =~ ^[1-5]$ ]]; then
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echo "Error: compression must be between 1-5"
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exit 1
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fi
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# Set compression values based on level
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case $COMPRESSION in
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1) WEBP_LOSSLESS=1; WEBP_COMP_LEVEL=0; WEBP_QUALITY=100; WEBP_METHOD=0; COMP_DESC="Lossless, fast" ;;
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2) WEBP_LOSSLESS=1; WEBP_COMP_LEVEL=3; WEBP_QUALITY=100; WEBP_METHOD=0; COMP_DESC="Lossless, balanced" ;;
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3) WEBP_LOSSLESS=1; WEBP_COMP_LEVEL=6; WEBP_QUALITY=100; WEBP_METHOD=0; COMP_DESC="Lossless, best compression" ;;
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4) WEBP_LOSSLESS=0; WEBP_COMP_LEVEL=4; WEBP_QUALITY=90; WEBP_METHOD=4; COMP_DESC="Lossy, high quality (q90)" ;;
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5) WEBP_LOSSLESS=0; WEBP_COMP_LEVEL=4; WEBP_QUALITY=75; WEBP_METHOD=6; COMP_DESC="Lossy, maximum compression (q75)" ;;
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esac
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# Check if directory exists
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if [ ! -d "$DIRECTORY" ]; then
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echo "Error: Directory '$DIRECTORY' does not exist"
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exit 1
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fi
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# Convert to absolute path
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DIRECTORY=$(realpath "$DIRECTORY")
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echo "Processing WebM files in: $DIRECTORY"
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echo "Background: $BACKGROUND"
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echo "Compression: Level $COMPRESSION ($COMP_DESC)"
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# Create webp output directory
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WEBP_DIR="$DIRECTORY/webp"
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if [ ! -d "$WEBP_DIR" ]; then
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mkdir -p "$WEBP_DIR"
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echo "Created output directory: $WEBP_DIR"
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else
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echo "Using existing output directory: $WEBP_DIR"
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fi
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# Find all WebM files in the directory
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WEBM_FILES=($(find "$DIRECTORY" -maxdepth 1 -name "*.webm" -type f))
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# Check if any WebM files were found
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if [ ${#WEBM_FILES[@]} -eq 0 ]; then
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echo "No WebM files found in '$DIRECTORY'"
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exit 0
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fi
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echo "Found ${#WEBM_FILES[@]} WebM file(s)"
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echo "Note: Existing WebP files will be overwritten to ensure proper transparency"
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echo ""
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# Counter for processed files
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PROCESSED=0
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FAILED=0
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OVERWRITTEN=0
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NEW_FILES=0
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# Process each WebM file
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for webm_file in "${WEBM_FILES[@]}"; do
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# Get the base filename without path and extension
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base_name=$(basename "$webm_file" .webm)
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# Output WebP file path
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webp_output="$WEBP_DIR/${base_name}.webp"
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echo "Processing: $(basename "$webm_file")"
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# Check if output file already exists
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FILE_EXISTS=false
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if [ -f "$webp_output" ]; then
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echo " → Overwriting existing file: ${base_name}.webp"
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FILE_EXISTS=true
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fi
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# Detect codec type (VP8 or VP9) to use correct decoder
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CODEC_INFO=$(ffprobe -v quiet -select_streams v:0 -show_entries stream=codec_name -of csv=p=0 "$webm_file" 2>/dev/null)
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# Set appropriate decoder based on codec
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if [ "$CODEC_INFO" = "vp9" ]; then
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DECODER="libvpx-vp9"
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echo " → Using VP9 decoder (optimal for alpha preservation)"
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else
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DECODER="libvpx" # Default to VP8 decoder
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echo " → Using VP8 decoder"
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fi
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echo " → Finding frame with maximum coverage..."
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# Get total frame count and duration
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FRAME_COUNT=$(ffprobe -v quiet -select_streams v:0 -count_frames -show_entries stream=nb_read_frames -of csv=p=0 "$webm_file" 2>/dev/null)
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if [ -z "$FRAME_COUNT" ] || [ "$FRAME_COUNT" -eq 0 ]; then
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echo " ✗ Could not determine frame count"
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((FAILED++))
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continue
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fi
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# Sample 10 frames evenly distributed throughout the video
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SAMPLE_COUNT=10
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if [ "$FRAME_COUNT" -lt "$SAMPLE_COUNT" ]; then
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SAMPLE_COUNT=$FRAME_COUNT
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fi
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MAX_SIZE=0
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BEST_FRAME=0
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TEMP_DIR=$(mktemp -d)
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echo " → Analyzing $SAMPLE_COUNT sample frames from $FRAME_COUNT total frames..."
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# Sample frames evenly throughout the video
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for ((i=0; i<SAMPLE_COUNT; i++)); do
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# Calculate frame position (evenly distributed)
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FRAME_POS=$((i * FRAME_COUNT / SAMPLE_COUNT))
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# Extract single frame as WebP to temp location
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TEMP_FRAME="$TEMP_DIR/frame_${FRAME_POS}.webp"
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ffmpeg -c:v "$DECODER" \
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-i "$webm_file" \
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-vf "select=eq(n\\,$FRAME_POS)" \
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-vframes 1 \
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-c:v libwebp \
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-lossless 1 \
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-y \
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"$TEMP_FRAME" \
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-v quiet 2>/dev/null
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if [ -f "$TEMP_FRAME" ]; then
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# Use file size as coverage indicator (larger = more content)
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FRAME_SIZE=$(stat -f%z "$TEMP_FRAME" 2>/dev/null || stat -c%s "$TEMP_FRAME" 2>/dev/null)
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if [ -n "$FRAME_SIZE" ] && [ "$FRAME_SIZE" -gt "$MAX_SIZE" ]; then
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MAX_SIZE=$FRAME_SIZE
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BEST_FRAME=$FRAME_POS
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fi
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fi
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done
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# Clean up temp directory
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rm -rf "$TEMP_DIR"
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echo " → Best frame: #$BEST_FRAME (size: $MAX_SIZE bytes)"
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# Set up filter chain based on background setting
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if [ "$BACKGROUND" = "transparent" ]; then
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FILTER_CHAIN="select=eq(n\\,$BEST_FRAME)"
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echo " → Extracting frame with alpha transparency preserved"
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else
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FILTER_CHAIN="select=eq(n\\,$BEST_FRAME),split[a][b];[a]geq=r=0:g=0:b=0:a=255,drawbox=color=$BACKGROUND@1.0:replace=1:t=fill[bg];[bg][b]overlay=format=auto"
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echo " → Extracting frame with background color: $BACKGROUND"
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fi
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# Build WebP encoding parameters based on compression level
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if [ "$WEBP_LOSSLESS" -eq 1 ]; then
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WEBP_PARAMS="-c:v libwebp -lossless 1 -compression_level $WEBP_COMP_LEVEL"
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else
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WEBP_PARAMS="-c:v libwebp -lossless 0 -quality $WEBP_QUALITY -method $WEBP_METHOD -compression_level $WEBP_COMP_LEVEL"
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fi
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# Extract the frame with maximum coverage
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if ffmpeg -c:v "$DECODER" \
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-i "$webm_file" \
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-vf "$FILTER_CHAIN" \
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-vframes 1 \
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$WEBP_PARAMS \
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-an \
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-y \
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"$webp_output" \
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-v quiet -stats; then
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if [ "$FILE_EXISTS" = true ]; then
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echo " ✓ Successfully overwritten: ${base_name}.webp"
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((OVERWRITTEN++))
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else
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echo " ✓ Successfully created: ${base_name}.webp"
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((NEW_FILES++))
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fi
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((PROCESSED++))
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else
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echo " ✗ Failed to process: $(basename "$webm_file")"
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((FAILED++))
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fi
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echo ""
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done
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# Summary
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echo "=== Processing Complete ==="
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echo "Total files processed: $PROCESSED"
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if [ $NEW_FILES -gt 0 ]; then
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echo "New files created: $NEW_FILES"
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fi
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if [ $OVERWRITTEN -gt 0 ]; then
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echo "Existing files overwritten: $OVERWRITTEN"
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fi
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if [ $FAILED -gt 0 ]; then
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echo "Failed to process: $FAILED files"
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fi
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echo "Output directory: $WEBP_DIR"
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echo "Settings used - Background: $BACKGROUND, Compression: Level $COMPRESSION ($COMP_DESC)"
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echo ""
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# List generated files
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if [ $PROCESSED -gt 0 ]; then
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echo "Generated WebP files:"
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ls -la "$WEBP_DIR"/*.webp 2>/dev/null | while read -r line; do
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echo " $line"
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done
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fi
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