If newCreationTime.HasValue Then IO.File.SetCreationTime(fn, newCreationTime.Value)
ModificationTime = If(version = 0, ReadNext4byteDate(f), ReadNext8byteDate(f))įt = New FileTimes With If version = 0 Then Write4byteDate(f, modificationTime) Else Write8byteDate(f, modificationTime) ModificationTime = newModificationTime.Value If version = 0 Then Write4byteDate(f, creationTime) Else Write8byteDate(f, creationTime)ĬreationTime = If(version = 0, ReadNext4byteDate(f), ReadNext8byteDate(f)) ' In both cases "creation" and "modification" are big-endian number of seconds since 1st Jan 1904 UTCį.Seek(pos + 8, IO.SeekOrigin.Begin) : Dim version = f.ReadByte()ĭim creationTime As Date, modificationTime As Date ' If version=0 then it's the former, otherwise it's the later. ' or 8bytes (creation), 8bytes (modification) ' and then either 4bytes (creation), 4bytes (modification) ' The "mvhd" binary blob consists of 1byte (version, either 0 or 1), 3bytes (flags), While ReadNextBoxInfo(f, pos, fend, boxKind, payloadStart, payloadEnd) AndAlso boxKind "mvhd" While ReadNextBoxInfo(f, pos, fend, boxKind, payloadStart, payloadEnd) AndAlso boxKind "moov" This is where Creation/ModificationTime are stored.ĭim pos = 0L, payloadStart = 0L, payloadEnd = 0L, boxKind = "" ' of kind "mvhd", which contains a binary blob. ' We look for a top-level box of kind "moov", which contains sub-boxes, and then we look for its sub-box You need to look up the specs for each kind to know whether it has a blob or sub-boxes. ' Some box kinds contain a kind-specific blob of binary data. ' The file is made up of a sequence of boxes, with a standard way to find size and FourCC "kind" of each. Using f = If(newCreationTime.HasValue OrElse newModificationTime.HasValue, IO.File.Open(fn, IO.FileMode.Open), IO.File.OpenRead(fn))į.Seek(0, IO.SeekOrigin.End) : Dim fend = f.Position
Mp4 file properties editor mp4#
' Retrieve creation-time and modification-time, embedded inside the metadata of MP4 filesįunction Mp4Times(fn As String, Optional newCreationTime As Date? = Nothing, Optional newModificationTime As Date? = Nothing) As FileTimes I solved this by writing reading/writing the MP4 file format directly.
Mp4 file properties editor update#
Here are the commands to list all tags in a media file and update selected tags (batch processing of files is also possible): C:\>exiftool.exe -short -groupNames test.mp4
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