vb.net 解析视频文件的元数据 gps

在 VB.NET 中解析视频元数据和 GPS 数据，可以使用一些第三方库，比如 FFmpeg 和 Exiftool。以下是使用 FFmpeg 和 Exiftool 的示例代码：

1. 解析视频元数据

使用 FFmpeg 库可以解析视频文件的元数据，可以使用 NuGet 来安装 FFmpeg 库。以下是示例代码：

Imports FFmpeg.AutoGen

' 初始化 FFmpeg 库
FFmpegBinariesHelper.RegisterFFmpegBinaries()

' 打开视频文件
Dim inputFile As String = "path/to/video.mp4"
Dim inputFormatContext As AVFormatContext = Nothing
FFmpegInvoke.avformat_open_input(inputFormatContext, inputFile, Nothing, Nothing)

' 读取视频流信息
FFmpegInvoke.avformat_find_stream_info(inputFormatContext, Nothing)

' 获取视频元数据
Dim metadata As Dictionary(Of String, String) = New Dictionary(Of String, String)()
For i As Integer = 0 To inputFormatContext.nb_streams - 1
    Dim streamMetadata As AVDictionary = inputFormatContext.streams(i).metadata
    While streamMetadata IsNot Nothing
        Dim key As String = FFmpegInvoke.av_dict_get_key(streamMetadata)
        Dim value As String = FFmpegInvoke.av_dict_get(streamMetadata, key, Nothing, 0)
        metadata.Add(key, value)
        streamMetadata = streamMetadata.Next
    End While
Next

' 关闭视频文件
FFmpegInvoke.avformat_close_input(inputFormatContext)

' 输出视频元数据
For Each pair As KeyValuePair(Of String, String) In metadata
    Console.WriteLine("{0}: {1}", pair.Key, pair.Value)
Next

2. 解析 GPS 数据

使用 Exiftool 库可以解析视频文件中的 GPS 数据，可以使用 NuGet 来安装 Exiftool 库。以下是示例代码：

Imports PhilHarvey.ExifToolLib

' 打开视频文件
Dim inputFile As String = "path/to/video.mp4"
Dim exiftool As ExifTool = New ExifTool()
Dim tags As String = exiftool.GetTags(inputFile)

' 解析 GPS 数据
Dim gps As String = ""
If tags.Contains("GPS Latitude") AndAlso tags.Contains("GPS Longitude") Then
    Dim latitude As Double = GetGpsCoordinate(tags, "GPS Latitude")
    Dim longitude As Double = GetGpsCoordinate(tags, "GPS Longitude")
    Dim latitudeRef As String = GetGpsRef(tags, "GPS Latitude Ref")
    Dim longitudeRef As String = GetGpsRef(tags, "GPS Longitude Ref")
    gps = String.Format("{0} {1}, {2} {3}", latitude, latitudeRef, longitude, longitudeRef)
End If

' 关闭视频文件
exiftool.Dispose()

' 输出 GPS 数据
Console.WriteLine("GPS: {0}", gps)

' 获取 GPS 坐标
Private Function GetGpsCoordinate(tags As String, tagName As String) As Double
    Dim coordinate As Double = 0
    Dim parts As String() = tags.Split(New String() {tagName & " : "}, StringSplitOptions.None)
    If parts.Length > 1 Then
        Dim coordinateParts As String() = parts(1).Split(New Char() {","c, " "c}, StringSplitOptions.RemoveEmptyEntries)
        If coordinateParts.Length = 3 Then
            Dim degrees As Double = Double.Parse(coordinateParts(0))
            Dim minutes As Double = Double.Parse(coordinateParts(1))
            Dim seconds As Double = Double.Parse(coordinateParts(2))
            coordinate = degrees + (minutes / 60) + (seconds / 3600)
        End If
    End If
    Return coordinate
End Function

' 获取 GPS 参考方向
Private Function GetGpsRef(tags As String, tagName As String) As String
    Dim ref As String = ""
    Dim parts As String() = tags.Split(New String() {tagName & " : "}, StringSplitOptions.None)
    If parts.Length > 1 Then
        ref = parts(1).Trim()
    End If
    Return ref
End Function