utils.py

# convert from mkv to mp4 using ffmpeg
import subprocess
import os
import pandas as pd


def mkv_to_mp4(video_path, converted_video_path):
    """将 MKV 视频转换为 MP4 (H.264 + AAC)"""
    if not os.path.exists(converted_video_path):
        print(f"🎬 转换 {video_path} 为 {converted_video_path} (H.264)...")
        cmd = [
            "ffmpeg", "-y", "-i", video_path,
            "-c:v", "libx264", "-preset", "fast", "-crf", "23",
            "-c:a", "aac", "-b:a", "128k",
            converted_video_path
        ]
        subprocess.run(cmd, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
        print("✅ 视频转换完成！")

def extract_audio(video_path, audio_output_path):
    """从 MKV 文件提取音频，并转换为 MP3"""
    if not os.path.exists(audio_output_path):
        print(f"🎵 提取音频到 {audio_output_path}...")
        cmd = [
            "ffmpeg", "-y", "-i", video_path,  # 输入 MKV 文件
            "-vn",  # 不处理视频
            "-acodec", "mp3",  # 输出 MP3 音频
            "-b:a", "192k",  # 保持较好的音质
            audio_output_path
        ]
        subprocess.run(cmd, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
        print("✅ 音频提取完成！")

def convert_video(video_path, converted_video_path):
    """使用 FFmpeg 转换 AV1 视频为 H.264 (如果需要)"""
    if not os.path.exists(converted_video_path):
        print(f"转换 {video_path} 为 {converted_video_path} (H.264)...")
        cmd = [
            "ffmpeg", "-y", "-i", video_path,
            "-c:v", "libx264", "-preset", "fast", "-crf", "23",
            "-c:a", "aac", "-b:a", "128k",
            converted_video_path
        ]
        subprocess.run(cmd, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
        print("视频转换完成！")

def get_unique_filename(filename):
    """如果文件存在，则生成一个不重名的文件名"""
    base, ext = os.path.splitext(filename)
    counter = 1
    while os.path.exists(filename):
        filename = f"{base}_{counter}{ext}"
        counter += 1
    return filename