无法使用Python从视频文件中获取正确的Exif数据

Question

我无法找到使用Python从视频文件中获取Exif属性"DateEncoded“的方法。

我尝试过几个exif工具，但这个特定的mp4文件 (使用安卓应用程序FilmicPro录制)似乎是一个特例。

Windows在"Create“属性(参见图像)下显示正确的日期，该属性实际上是QuickTime exif键"Media_DateEncoded”。

Windows资源管理器上的正确日期

AdobeMediaEn编码器似乎还检索了正确的日期：

MediaEncoder元数据面板

但是，我尝试过的五种方法都无法以编程方式检索正确的日期:2019年1月6日。它总是在一月七号回来！

有谁能解释原因吗？

以下是代码：

import os
import re
import struct
import subprocess as sub
from datetime import datetime
from hachoir.parser import createParser
from hachoir.metadata import extractMetadata
from win32com.propsys import propsys, pscon

# Download ExifTool from https://exiftool.org/
EXIF_TOOL = "exiftool.exe"

def method_1(fpath):
    # On Windows ctime means "Creation time", on Linux "Changed time"
    ctime = os.path.getctime(fpath)
    dtime = datetime.fromtimestamp(ctime)
    return dtime.strftime("%Y:%m:%d %H:%M:%S")

def method_2(fpath):
    '''
    This requires Hachoir installed. For Python3 run:
        >> pip3 install hachoir==3.1.1
        >> pip3 install hachoir-parser
    The property key 'Creation date' is a filesystem metadata, but
    it was the only one returned by Hachoir. What I really need is
    the Quicktime key 'Media_DateEncoded', which Windows Explorer
    calls "Media Created"
    '''
    parser = createParser(fpath)
    with parser:
        metadata = extractMetadata(parser)
    exif_dict = metadata.exportDictionary()['Metadata']
    return exif_dict['Creation date']

def method_3(fpath):
    '''
    This executes this shell comand:
        >> exiftool.exe -h VID_20190106_162804.mp4
    ...which returns an HTML like string from stdout.
    So using regular expression, we look for this section:
        "Media Create Date</td><td>2019:01:07 00:28:08</td></tr>"
    '''
    p = sub.Popen(
        [EXIF_TOOL, '-h',fpath],
        stdout=sub.PIPE,
        encoding='utf8')
    res, err = p.communicate()
    pattern = re.compile(
        r'Media Create Date\</td\>\<td\>(\d{4}:\d{2}:\d{2}\s\d{2}:\d{2}:\d{2})'
    )
    match = re.findall(pattern, res)
    if match:
        return match[0]

def method_4(fpath):
    '''
    Here we look for the Quicktime property key: Media_DateEncoded, which
    Windows Explorer calls "Media Created"
    '''
    fpath = fpath.replace('/', '\\') # Windows api does not work with posix paths
    properties = propsys.SHGetPropertyStoreFromParsingName(fpath)
    dtime = properties.GetValue(pscon.PKEY_Media_DateEncoded).GetValue()
    return dtime.strftime("%Y:%m:%d %H:%M:%S")

def method_5(fpath):
    ATOM_HEADER_SIZE = 8

    # Difference between Unix epoch and QuickTime epoch, in seconds
    EPOCH_ADJUSTER = 2082844800

    # open file and search for moov item
    f = open(fpath, "rb")
    while 1:
        atom_header = f.read(ATOM_HEADER_SIZE)
        if atom_header[4:8] == b'moov':
            break
        atom_size = struct.unpack(">I", atom_header[0:4])[0]
        f.seek(atom_size - 8, 1)

    # found 'moov', look for 'mvhd' and timestamps
    atom_header = f.read(ATOM_HEADER_SIZE)
    if atom_header[4:8] == b'cmov':
        raise Exception("moov atom is compressed")
    elif atom_header[4:8] != b'mvhd':
        raise Exception("expected to find 'mvhd' header")
    else:
        f.seek(4, 1)
        creation_date = struct.unpack(">I", f.read(4))[0]
        dtime = datetime.utcfromtimestamp(creation_date - EPOCH_ADJUSTER)
        return dtime.strftime("%Y:%m:%d %H:%M:%S")

Python3.7.3 (v3.7.3:ef4ec6ed12) MSC v.1916 64位(AMD64) on win32

操作系统: Windows 10版本10.0.18362构建18362

Answer 1

您没有考虑的是，Quicktime元数据时间戳被保存为UTC，而不是本地时间。您需要根据时区调整存储时间。Windows理解这一点，并相应地显示校正时间，尽管并非所有程序都这样做。

使用exiftool提取时间戳时，可以添加选项，exiftool将自动调整计算机当前的时区。