anime_audio_encoder.py is a comprehensive batch-processing script for MKV files, specifically tailored for modern anime encoding workflows. It automates the entire pipeline, including advanced video encoding with AV1 (via av1an), sophisticated audio conversion to Opus, and intelligent handling of both Variable Frame Rate (VFR) and Constant Frame Rate (CFR) sources. To ensure transparency and aid in debugging, the script also preserves detailed, per-file logs of the entire conversion process.

Features

Advanced Video Encoding: Uses a robust VapourSynth-based pipeline with av1an and SVT-AV1 for efficient, high-quality AV1 video encoding.
VFR Handling: Automatically detects Variable Frame Rate (VFR) sources using mediainfo and converts them to Constant Frame Rate (CFR) with HandBrakeCLI before encoding, ensuring broader playback compatibility.
Detailed Logging: Creates a separate, detailed log file for each processed MKV in the conv_logs/ directory, capturing the full terminal output for easy review.
Sophisticated Audio Processing: Converts common audio formats to normalized Opus files. It provides an option to downmix surround sound to stereo or preserve the original channel layout.
File Organization: Keeps your workspace tidy by automatically moving original files to original/ and completed encodes to completed/.
Resumable & Efficient: The script processes files one by one and uses av1an's resume feature, making it easy to continue an encoding batch if it's interrupted.

Requirements

The following command-line tools must be installed and available in your system's PATH:

ffmpeg
ffprobe
mkvmerge
mkvpropedit
sox
opusenc
mediainfo
av1an
HandBrakeCLI

Usage

Place your .mkv files in the same directory as the script.
Make the script executable by running chmod +x anime_audio_encoder.py.
Execute the script from your terminal:

./anime_audio_encoder.py

Optional Arguments

--no-downmix: By default, the script downmixes surround sound audio (e.g., 5.1) to stereo. Use this flag to preserve the original audio channel layout.

Example:

./anime_audio_encoder.py --no-downmix

Output

Processed files are moved to the completed/ directory.
Original files are moved to the original/ directory.
Per-file logs are saved in the conv_logs/ directory.

Notes

The script will check if a file can be decoded by ffmpeg before processing and will skip corrupted or unsupported files.
The entire process, especially scene detection and AV1 encoding, can be very time-consuming and CPU-intensive.