utils.py

import hashlib
import logging
import platform
import subprocess

import numpy as np

from config import LOG_LEVEL

logging.basicConfig(level=LOG_LEVEL, format='%(asctime)s %(name)s %(levelname)s %(message)s')
logger = logging.getLogger(__name__)


def get_file_hash(path):
    """
    计算文件hash
    :param path: string, 文件路径
    :return: string, 十六进制字符串
    """
    _hash = hashlib.sha1()
    try:
        with open(path, "rb") as f:
            while True:
                data = f.read(1048576)
                if not data:
                    break
                _hash.update(data)
    except Exception as e:
        logger.error(f"计算hash出错：{path} {repr(e)}")
        return None
    return _hash.hexdigest()


def get_string_hash(string):
    """
    计算字符串hash
    :param string: string, 字符串
    :return: string, 十六进制字符串
    """
    _hash = hashlib.sha1()
    _hash.update(string.encode("utf8"))
    return _hash.hexdigest()


def softmax(x):
    """
    计算softmax，使得每一个元素的范围都在(0,1)之间，并且所有元素的和为1。
    softmax其实还有个temperature参数，目前暂时不用。
    :param x: [float]
    :return: [float]
    """
    exp_scores = np.exp(x)
    return exp_scores / np.sum(exp_scores)


def format_seconds(seconds):
    """
    将秒数转成时分秒格式
    :param seconds: int, 秒数
    :return: "时:分:秒"
    """
    minutes, seconds = divmod(seconds, 60)
    hours, minutes = divmod(minutes, 60)
    return f"{hours:02d}:{minutes:02d}:{seconds:02d}"


def crop_video(input_file, output_file, start_time, end_time):
    """
    调用ffmpeg截取视频片段
    :param input_file: 要截取的文件路径
    :param output_file: 保存文件路径
    :param start_time: int, 开始时间，单位为秒
    :param end_time: int, 结束时间，单位为秒
    :return: None
    """
    cmd = 'ffmpeg'
    if platform.system() == 'Windows':
        cmd += ".exe"
    command = [
        cmd,
        '-i', input_file,
        '-ss', format_seconds(start_time),
        '-to', format_seconds(end_time),
        '-c:v', 'copy',
        '-c:a', 'copy',
        output_file
    ]
    subprocess.run(command)