Windows 10竟會損壞用戶文件？教你解決這個Bug
如果你是一名音樂發燒友，那么應該知道Flac這種常見的無損音樂格式。Flac音樂文件支持metadata，用戶可以編輯metadata，讓音樂文件帶有藝術家、所屬專輯、音軌等等信息。通常來說，metadata和音頻數據并不相關，修改metadata并不會影響音頻本身。但是，近日微軟官方公布了Windows 10中存在一個Bug，在Win10中用資源管理器修改Flac文件的metadata，竟會導致音頻的損壞!
根據Windows Latest的報道，微軟最新發布的一份支持文件披露，如果在Windows 10的2004或者更高版本中，使用文件資源管理器修改Flac音樂文件的metadata，就會損耗Flac音頻文件。這個Bug在Windows 10專業版、家庭版、企業版、工作站版乃至其他版本的Windows 10中均有出現。
根據微軟本月早些時候發布的支持文件，Windows 10的文件資源管理器導致了這個錯誤，它破壞了Flac文件頭包含的ID3框架也就是metadata，而這個ID3框架負責存儲音頻的注釋，例如音樂標題、藝術家、專輯、曲目編號等。在Windows 10上，Flac的處理程序忽視了ID3框架，該程序認為Flac文件在使用4字節的文件頭，當Flac文件被Windows 10編輯的時候，ID3框架被覆蓋了，導致沒有了開始代碼，導致了音樂播放器無法識別被修改后的文件。
因此，在Windows 10中，如果你直接用文件資源管理器修改Flac音樂文件的標題、藝術家等metadata，會導致該文件無法播放。
幸運的是，微軟已經確定了Bug的根本原因，用戶可以通過Windows Update升級KB5003214補丁進行修復。
在KB5003214補丁中，微軟確認了上文提到的錯誤已經被修復，修改了Flac的標題、藝術家等metadata后，Flac不會再變得無法播放。而對于已經損壞了的Flac文件，微軟則發布了一個PowerShell腳本來進行修復，運行該腳本后Flac文件即可重新播放，不過已經從ID3框架中丟失了的metadata信息并不能恢復。
下面是利用PowerShell腳本修復Flac文件的具體方法。
1、開啟記事本;
2、復制以下字符，粘貼到記事本中：
- # Copyright 2021 Microsoft
- # This script will repair a FLAC file that has been corrupted by Media Foundation in reference to KB5003430.
- # Refer to KB5003430 for further information
- param(
- [parameter(Mandatory=$true,
- HelpMessage="The path to the FLAC file that has been corrupted by Media Foundation",
- ValueFromRemainingArguments=$true)]
- [ValidateScript({ -not [String]::IsNullOrEmpty($_) -and (Test-Path $_) })]
- [String]$File
- )
- # We need to back up the current file incase we have any errors
- $FileDirectory = Split-Path -Resolve $File
- $Filename = Split-Path -Leaf -Resolve $File
- $FullPath = Join-Path -Resolve $FileDirectory $Filename
- $Filename = [String]::Format("Backup_{0:yyyyMMdd_hhmmss}_{1}", [DateTime]::Now, $Filename)
- $BackupLocation = Join-Path $FileDirectory $Filename
- Write-Output "Microsoft FLAC Repair Tool. This tool will repair a FLAC audio file that was corrupted when editing its details."
- Write-Output "Affected File: $FullPath"
- Write-Output "A backup of the file will be made: $BackupLocation"
- Write-Output "Do you wish to continue?"
- $choice=$host.ui.PromptForChoice("Fixing FLAC Script", "Do you wish to continue", ('&Yes', '&No'), 1)
- function ParseStreamInfoMetadataBlock([System.IO.FileStream]$stream)
- {
- $blockType = $stream.ReadByte()
- $lastBlock = ($blockType -shr 7) -ne 0
- $blockType = $blockType -band 0x7F
- if ($blockType -ne 0)
- {
- return $false
- }
- $blockSize = (($stream.ReadByte() -shl 16) -bor ($stream.ReadByte() -shl 8) -bor $stream.ReadByte())
- if ($blockSize -lt 34)
- {
- return $false
- }
- $minAudioBlockSize = ($stream.ReadByte() -shl 8) -bor $stream.ReadByte()
- $maxAudioBlockSize = ($stream.ReadByte() -shl 8) -bor $stream.ReadByte()
- if ($minAudioBlockSize -lt 16 -or $maxAudioBlockSize -lt 16)
- {
- return $false
- }
- $minFrameSize = (($stream.ReadByte() -shl 16) -bor ($stream.ReadByte() -shl 8) -bor $stream.ReadByte())
- $maxFrameSize = (($stream.ReadByte() -shl 16) -bor ($stream.ReadByte() -shl 8) -bor $stream.ReadByte())
- $sampleInfo = (($stream.ReadByte() -shl 24) -bor ($stream.ReadByte() -shl 16) -bor ($stream.ReadByte() -shl 8) -bor $stream.ReadByte())
- $sampleRate = $sampleInfo -shr 12
- $channelCount = (($sampleInfo -shr 9) -band 0x7) + 1
- $bitsPerSample = (($sampleInfo -shr 4) -band 0x1F) + 1
- [UInt64]$sampleCount = (($stream.ReadByte() -shl 24) -bor ($stream.ReadByte() -shl 16) -bor ($stream.ReadByte() -shl 8) -bor $stream.ReadByte())
- $sampleCount = (([UInt64]$sampleInfo -band 0xF) -shl 32) -bor $sampleCount
- $MD5HashBytes = New-Object byte[] 16
- $stream.Read($MD5HashBytes, 0, $MD5HashBytes.Length)
- $MD5Hash = [Guid]($MD5HashBytes)
- if ($sampleRate -eq 0)
- {
- return $false
- }
- # Passing these checks means that we likely have a stream info header and can rebuild the file
- Write-Output "File Stream Information"
- Write-Output "Sample Rate: $sampleRate"
- Write-Output "Audio Channels: $channelCount"
- Write-Output "Sample Depth: $bitsPerSample"
- Write-Output "MD5 Audio Sample Hash: $MD5Hash"
- return $true
- }
- if ($choice -eq 0)
- {
- Copy-Item $FullPath -Destination $BackupLocation -Force
- $stream = [System.IO.File]::Open($FullPath, [System.IO.FileMode]::Open)
- $stream.Seek(4, [System.IO.SeekOrigin]::Begin)
- while ($stream.ReadByte() -eq 0) {}
- # We now need to figure out where a valid FLAC metadata frame begins
- # We are likely pointing to the last byte of the size member so we'll seek back 4 bytes and retry
- $flacDataStartPosition = $stream.Position - 4
- $stream.Seek($flacDataStartPosition, [System.IO.SeekOrigin]::Begin)
- while (-not(ParseStreamInfoMetadataBlock($stream)))
- {
- $flacDataStartPosition = $flacDataStartPosition + 1
- $stream.Seek($flacDataStartPosition, [System.IO.SeekOrigin]::Begin)
- }
- # Insert the start code
- $stream.Seek($flacDataStartPosition, [System.IO.SeekOrigin]::Begin)
- if (Test-Path "$FullPath.tmp")
- {
- Remove-Item "$FullPath.tmp"
- }
- $fixedStream = [System.IO.File]::Open("$FullPath.tmp", [System.IO.FileMode]::CreateNew)
- [byte[]]$startCode = [char[]]('f', 'L', 'a', 'C');
- $fixedStream.Write($startCode, 0, $startCode.Length)
- $stream.CopyTo($fixedStream)
- $stream.Close()
- $fixedStream.Close()
- Move-Item -Force "$FullPath.tmp" $FullPath
- }
3、保存文件，在“另存為”對話框中，將目錄定位到你想要保存PowerShell腳本的位置;
4、在文件名輸入框中，輸入“FixFlacFiles.ps1”，將另存為文件的類型更改為Text Documents (*.txt);
5、進入到你保存該PowerShell腳本的目錄;
6、右鍵點擊剛剛保存的腳本，然后選擇“使用PowerShell運行”;
7、出現提示時，輸入無法播放的Flac文件的文件名，然后按下回車鍵。
微軟建議大家安裝本月推送的可選累積更新，以避免修改Flac文件metadata出現的問題。
