python把ts文件合并成MP4失败，怎么弄？

python把ts文件合并成MP4失败，怎么弄？？

def merge_ts():
    lst = []
    with open("video/Homemade Christmas.m3u8", mode="r", encoding="utf-8") as f:
        for line in f:
            if line.startswith("#"):
                continue
            line = line.strip()
            lst.append(f"video/{line}")

    s = "+".join(lst)
    os.system(f"copy /b {s} Homemade Christmas.mp4")
    print("搞定！！!")