我有许多从各种数码相机格式转码的 MPEG-4 文件，这些文件系统的修改日期是正确的。我想将“媒体创建”标签设置为匹配。这可以通过“属性”窗口的“详细信息”选项卡在 Windows 资源管理器中手动完成。设置 Media Created 很有用，因为 Windows Live Photo Gallery 为它的 Date Taken 属性关闭此字段。不幸的是，文件的数量使得手动设置所有日期变得不切实际。
自动化的几种途径具有潜力。 TagLib# 似乎支持所有 MP4 标签，但获取更多基本标签的 API 尚不清楚。另一个角度是 Windows 外壳。据推测，Windows Explorer 正在使用它来编写标签。通过 shell 有一个example for reading，但似乎没有用于编写的 API。
【问题讨论】：
标签： tags taglib windows-shell mpeg-4 taglib-sharp
这是我编写的一个 PowerShell 脚本，用于使用 exiftool 批量解决这个问题。
它将所有 exiftool 命令写入 CMD 文件。 exiftool.exe 需要与文件和 exiftool.exe 位于同一位置
确保 Powershell ISE / PS1 文件与您正在处理文件的目录相同。 完成后，您可以在记事本中查看 CMD 文件。如果一切正常，请使用 CMD 运行它。 :)
$allFiles = Get-ChildItem -Filter * -Exclude *.exe
$exifFile = @()
$exifFile += "@echo off"
foreach($file in $allFiles)
{
$month = $file.CreationTime.Month
$day = $file.CreationTime.Day
$hour = $file.CreationTime.Hour
$min = $file.CreationTime.Minute
$sec = $file.CreationTime.Second
if($month -lt 10)
{
$month = "0$($file.CreationTime.Month)"
}
if($day -lt 10)
{
$day = "0$($file.CreationTime.Day)"
}
if($hour -lt 10)
{
$hour = "0$($file.CreationTime.Hour)"
}
if($min -lt 10)
{
$min = "0$($file.CreationTime.Minute)"
}
if($sec -lt 10)
{
$sec = "0$($file.CreationTime.Second)"
}
$exifFile += "exiftool.exe ^ -QuickTime:CreateDate=`"$($file.CreationTime.Year):$($month):$($day) $($hour):$($min):$($sec)`" ^ `"$($file.Name)`""
}
$exifFile | Out-File "MassCreateFix.cmd" -Encoding ascii -NoClobber
【讨论】：
我在exiftool 上取得了成功。以下是列出媒体文件中所有标签并更新选定标签的命令（也可以批量处理文件）：
C:\>exiftool.exe -short -groupNames test.mp4
[ExifTool] ExifToolVersion : 10.61
[File] FileName : test.mp4
[File] Directory : .
[File] FileSize : 91 MB
[File] FileModifyDate : 2018:06:30 19:25:34+05:00
[File] FileAccessDate : 2018:07:15 14:12:50+05:00
[File] FileCreateDate : 2018:07:15 14:12:50+05:00
[File] FilePermissions : rw-rw-rw-
[File] FileType : MP4
[File] FileTypeExtension : mp4
[File] MIMEType : video/mp4
[QuickTime] MajorBrand : MP4 v2 [ISO 14496-14]
[QuickTime] MinorVersion : 0.0.0
[QuickTime] CompatibleBrands : isom, mp42
[QuickTime] MovieDataSize : 95484206
[QuickTime] MovieDataOffset : 32
[QuickTime] MovieHeaderVersion : 0
[QuickTime] CreateDate : 2018:06:30 14:25:34
[QuickTime] ModifyDate : 2018:06:30 14:25:34
[QuickTime] TimeScale : 1000
[QuickTime] Duration : 0:01:02
-- snip --
[QuickTime] TrackCreateDate : 2018:06:30 14:25:34
[QuickTime] TrackModifyDate : 2018:06:30 14:25:34
-- snip --
[QuickTime] MediaCreateDate : 2018:06:30 14:25:34
[QuickTime] MediaModifyDate : 2018:06:30 14:25:34
-- snip --
C:\>exiftool.exe ^
-QuickTime:CreateDate="2018:07:15 13:15:00" ^
-QuickTime:ModifyDate="2018:07:15 13:15:00" ^
-QuickTime:TrackCreateDate="2018:07:15 13:15:00" ^
-QuickTime:TrackModifyDate="2018:07:15 13:15:00" ^
-QuickTime:MediaCreateDate="2018:07:15 13:15:00" ^
-QuickTime:MediaModifyDate="2018:07:15 13:15:00" ^
test.mp4
C:\>exiftool.exe -short -groupNames test.mp4
-- snip --
[File] FileModifyDate : 2018:07:15 14:19:52+05:00
[File] FileAccessDate : 2018:07:15 14:19:51+05:00
[File] FileCreateDate : 2018:07:15 14:19:39+05:00
-- snip --
[QuickTime] CreateDate : 2018:07:15 13:15:00
[QuickTime] ModifyDate : 2018:07:15 13:15:00
-- snip --
[QuickTime] TrackCreateDate : 2018:07:15 13:15:00
[QuickTime] TrackModifyDate : 2018:07:15 13:15:00
-- snip --
[QuickTime] MediaCreateDate : 2018:07:15 13:15:00
[QuickTime] MediaModifyDate : 2018:07:15 13:15:00
-- snip --
【讨论】：
-d！）
我通过直接写读/写 MP4 文件格式解决了这个问题。这是VB中的代码：
Sub Main()
' Retrieve creation-time and modification-time, embedded inside the metadata of MP4 files
Dim ft = Mp4Times("a.mp4")
Console.WriteLine(ft.CreationTime)
Console.WriteLine(ft.ModificationTime)
' Update those times
Mp4Times("a.mp4", Date.Now, Date.Now)
End Sub
Class FileTimes
Public CreationTime As Date
Public ModificationTime As Date
End Class
Function Mp4Times(fn As String, Optional newCreationTime As Date? = Nothing, Optional newModificationTime As Date? = Nothing) As FileTimes
Dim ft As FileTimes
Using f = If(newCreationTime.HasValue OrElse newModificationTime.HasValue, IO.File.Open(fn, IO.FileMode.Open), IO.File.OpenRead(fn))
f.Seek(0, IO.SeekOrigin.End) : Dim fend = f.Position
' The file is made up of a sequence of boxes, with a standard way to find size and FourCC "kind" of each.
' Some box kinds contain a kind-specific blob of binary data. Other box kinds contain a sequence
' of sub-boxes. You need to look up the specs for each kind to know whether it has a blob or sub-boxes.
' We look for a top-level box of kind "moov", which contains sub-boxes, and then we look for its sub-box
' of kind "mvhd", which contains a binary blob. This is where Creation/ModificationTime are stored.
Dim pos = 0L, payloadStart = 0L, payloadEnd = 0L, boxKind = ""
While ReadNextBoxInfo(f, pos, fend, boxKind, payloadStart, payloadEnd) AndAlso boxKind <> "moov"
pos = payloadEnd
End While
If boxKind <> "moov" Then Return Nothing
pos = payloadStart : fend = payloadEnd
While ReadNextBoxInfo(f, pos, fend, boxKind, payloadStart, payloadEnd) AndAlso boxKind <> "mvhd"
pos = payloadEnd
End While
If boxKind <> "mvhd" Then Return Nothing
' The "mvhd" binary blob consists of 1byte (version, either 0 or 1), 3bytes (flags),
' and then either 4bytes (creation), 4bytes (modification)
' or 8bytes (creation), 8bytes (modification)
' If version=0 then it's the former, otherwise it's the later.
' In both cases "creation" and "modification" are big-endian number of seconds since 1st Jan 1904 UTC
f.Seek(pos + 8, IO.SeekOrigin.Begin) : Dim version = f.ReadByte()
f.Seek(pos + 12, IO.SeekOrigin.Begin)
Dim creationTime As Date, modificationTime As Date
'
If newCreationTime.HasValue Then
creationTime = newCreationTime.Value
If version = 0 Then Write4byteDate(f, creationTime) Else Write8byteDate(f, creationTime)
Else
creationTime = If(version = 0, ReadNext4byteDate(f), ReadNext8byteDate(f))
End If
'
If newModificationTime.HasValue Then
modificationTime = newModificationTime.Value
If version = 0 Then Write4byteDate(f, modificationTime) Else Write8byteDate(f, modificationTime)
Else
modificationTime = If(version = 0, ReadNext4byteDate(f), ReadNext8byteDate(f))
End If
ft = New FileTimes With {.CreationTime = creationTime, .ModificationTime = modificationTime}
End Using
If newCreationTime.HasValue Then IO.File.SetCreationTime(fn, newCreationTime.Value)
If newModificationTime.HasValue Then IO.File.SetLastWriteTime(fn, newModificationTime.Value)
Return ft
End Function
Function ReadNextBoxInfo(f As IO.Stream, pos As Long, fend As Long, ByRef boxKind As String, ByRef payloadStart As Long, ByRef payloadEnd As Long) As Boolean
boxKind = "" : payloadStart = 0 : payloadEnd = 0
If pos + 8 > fend Then Return False
Dim b(3) As Byte
f.Seek(pos, IO.SeekOrigin.Begin)
f.Read(b, 0, 4) : If BitConverter.IsLittleEndian Then Array.Reverse(b)
Dim size = BitConverter.ToUInt32(b, 0)
f.Read(b, 0, 4)
Dim kind = ChrW(b(0)) & ChrW(b(1)) & ChrW(b(2)) & ChrW(b(3))
If size <> 1 Then
If pos + size > fend Then Return False
boxKind = kind : payloadStart = pos + 8 : payloadEnd = payloadStart + size - 8 : Return True
End If
If size = 1 AndAlso pos + 16 <= fend Then
ReDim b(7)
f.Read(b, 0, 8) : If BitConverter.IsLittleEndian Then Array.Reverse(b)
Dim size2 = CLng(BitConverter.ToUInt64(b, 0))
If pos + size2 > fend Then Return False
boxKind = kind : payloadStart = pos + 16 : payloadEnd = payloadStart + size2 - 16 : Return True
End If
Return False
End Function
ReadOnly TZERO As Date = New Date(1904, 1, 1, 0, 0, 0, DateTimeKind.Utc)
Function ReadNext4byteDate(f As IO.Stream) As Date
Dim b(3) As Byte
f.Read(b, 0, 4) : If BitConverter.IsLittleEndian Then Array.Reverse(b)
Dim secs = BitConverter.ToUInt32(b, 0)
Return TZERO.AddSeconds(secs)
End Function
Function ReadNext8byteDate(f As IO.Stream) As Date
Dim b(7) As Byte
f.Read(b, 0, 8) : If BitConverter.IsLittleEndian Then Array.Reverse(b)
Dim secs = BitConverter.ToUInt64(b, 0)
Return TZERO.AddSeconds(secs)
End Function
Sub Write4byteDate(f As IO.Stream, d As Date)
Dim secs = CUInt((d - TZERO).TotalSeconds)
Dim b = BitConverter.GetBytes(secs) : If BitConverter.IsLittleEndian Then Array.Reverse(b)
f.Write(b, 0, 4)
End Sub
Sub Write8byteDate(f As IO.Stream, d As Date)
Dim secs = CULng((d - TZERO).TotalSeconds)
Dim b = BitConverter.GetBytes(secs) : If BitConverter.IsLittleEndian Then Array.Reverse(b)
f.Write(b, 0, 8)
End Sub
【讨论】：
使用Windows Property System。请参阅Property Edit Sample 以开始使用。设置这些属性：
【讨论】：