import subprocess
from pathlib import Path


def convert_to_h264(input_path: str, output_path: str = None) -> str:
    """
    将视频文件转码为 H.264 编码格式

    Args:
        input_path: 输入视频文件路径（相对或绝对路径）
        output_path: 输出视频文件路径（可选，默认为输入文件同名_h264.mp4）

    Returns:
        转码后的视频文件路径

    Raises:
        FileNotFoundError: 输入文件不存在
        subprocess.CalledProcessError: FFmpeg 转码失败
    """
    input_path_all = Path("input/" + input_path).resolve()
    output_path_all = Path("vid_h264/" + input_path).resolve()

    if not input_path_all.exists():
        raise FileNotFoundError(f"输入文件不存在：{input_path}")

    print(f"开始转码：{input_path_all}")
    # if output_path is None:
    output_path = str(output_path_all.with_name(f"{input_path_all.stem}_h264.mp4"))
    # else:
    #     output_path = Path(output_path).resolve()

    cmd = [
    "ffmpeg",
    "-i", str(input_path_all),
    "-c:v", "h264_nvenc",  # NVIDIA 硬件编码
    "-c:a", "aac",
    "-b:a", "128k",
    "-y",
    str(output_path)
]

    result = subprocess.run(cmd, capture_output=True, text=True)

    if result.returncode != 0:
        raise subprocess.CalledProcessError(
            result.returncode,
            cmd,
            result.stdout,
            result.stderr
        )
    print(f"转码完成：{output_path}")
    return str(output_path)

if __name__ == "__main__":
    convert_to_h264("VID_20251104_085655_024.AVI", "vid_h264/VID_20251104_085655_024_h264.mp4")
    # convert_to_h264("input/short.AVI", "vid_h264/short_h264.mp4")