transcode-scripts/transcode at main · kaerumy/transcode-scripts · GitHub

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#!/bin/bash

# Usage: ./transcode -i <input_file> [-codec av1|h265] <bitrate>

# Parse arguments
INPUT=""
CODEC=""
BITRATE_CHOICE=""

while [[ $# -gt 0 ]]; do
    case $1 in
        -i)
            INPUT="$2"
            shift 2
            ;;
        -codec)
            CODEC="$2"
            shift 2
            ;;
        *)
            BITRATE_CHOICE="$1"
            shift
            ;;
    esac
done

# Validate required arguments
if [[ -z "$INPUT" || -z "$BITRATE_CHOICE" ]]; then
    echo "Usage: $0 -i <input_file> [-codec av1|h265] <bitrate>"
    echo ""
    echo "AV1/H265 bitrate options: 1M, 5M, 20M, 40M, 100M"
    exit 1
fi

# Validate codec
if [[ "$CODEC" != "av1" && "$CODEC" != "h265" ]]; then
    echo "Error: Invalid codec. Use 'av1' or 'h265'."
    exit 1
fi

# Map Bitrate Selection to Numeric Values
case "$BITRATE_CHOICE" in
    "1M")
        BV="1000000"
        MAX="2000000"
        ;;
    "5M")
        BV="5000000"
        MAX="10000000"
        ;;
    "20M")
        BV="20000000"
        MAX="50000000"
        ;;
    "40M")
        BV="40000000"
        MAX="80000000"
        ;;
    "100M")
        BV="100000000"
        MAX="200000000"
        ;;
    *)
        echo "Error: Invalid bitrate. Choose 1M, 5M, 20M, 40M, or 100M."
        exit 1
        ;;
esac

# Get current working directory for output
SCRIPT_DIR="$(pwd)"

# Extract just filename (handles relative or absolute input paths)
BASENAME=$(basename "$INPUT")
BASE="${BASENAME%.*}"

# Build output filename
OUTPUT="${SCRIPT_DIR}/${BASE}_${CODEC}_${BITRATE_CHOICE}.mp4"

# Overwrite Protection: Increment suffix if file already exists
COUNTER=1
while [[ -f "$OUTPUT" ]]; do
    OUTPUT="${SCRIPT_DIR}/${BASE}_${CODEC}_${BITRATE_CHOICE}-${COUNTER}.mp4"
    ((COUNTER++))
done

# Run FFmpeg
if [[ "$CODEC" == "av1" ]]; then
    # AV1 codec with scaling filter to ensure even resolution
    ffmpeg -i "$INPUT" \
        -vf "scale='trunc(iw/2)*2':'trunc(ih/2)*2',format=nv12" \
        -c:v av1_amf \
        -preset quality \
        -rc vbr_peak \
        -b:v "$BV" \
        -maxrate "$MAX" \
        -bufsize "$MAX" \
        "$OUTPUT"
else
    # H265 codec
    ffmpeg -i "$INPUT" \
        -vf "scale='trunc(iw/2)*2':'trunc(ih/2)*2',format=nv12" \
        -c:v hevc_amf \
        -preset quality \
        -rc vbr_peak \
        -b:v "$BV" \
        -maxrate "$MAX" \
        "$OUTPUT"
fi

echo "Encoding complete: $OUTPUT"