影音檔 Whisper 轉逐字稿之檔案批次處理工具

function Resolve-AbsPath($relPath) {
    return $ExecutionContext.SessionState.Path.GetUnresolvedProviderPathFromPSPath($relPath)
}

function Az-MergeMp4s(
    [Parameter(Mandatory=$true)][string[]]$mp4Paths, 
    [Parameter(Mandatory=$true)][string]$outPath) {
    # 寫入檔案清單暫存檔
    $tmpListPath = [IO.Path]::GetTempFileName() + '.txt'
    $mp4Paths | ForEach-Object { "file '$(Resolve-Path $_)'" } | Set-Content -Path $tmpListPath
    # 將路徑解析成絕對路徑 https://blog.darkthread.net/blog/ps-resolve-non-existing-path/
    $outPath = Resolve-AbsPath $outPath
    & ffmpeg -f concat -safe 0 -i $tmpListPath -c copy  -hide_banner -stats -v warning $outPath
    Remove-Item -Path $tmpListPath    
    Write-Host "$outPath created." -ForegroundColor Green
}

function Az-ConvertMp4ToMp3($mp4Path, $outDir = '.') {
    $mp4Path = Resolve-Path $mp4Path
    $outDir = Resolve-AbsPath $outDir
    [IO.Directory]::CreateDirectory($outDir) | Out-Null
    $mp3Path = [System.IO.Path]::ChangeExtension($mp4Path, '.mp3')
    & ffmpeg -i $mp4Path -hide_banner -stats -v warning $mp3Path
    Write-Host "$mp3Path created." -ForegroundColor Green
}

function Az-SplitMp3($mp3Path, $outDir = '.', $sliceLen = 1200, $overlap = 60)
{
    $mp3Path = Resolve-Path $mp3Path
    [int]$duration = & ffprobe -i $mp3Path -show_entries "format=duration" -v quiet -of "csv=p=0"
    $count = [math]::Ceiling($duration / $sliceLen)
    for ($i = 0; $i -lt $count; $i++) {
        $start = $i * $sliceLen
        $timeSpan = [TimeSpan]::FromSeconds($start)
        $outFile = [System.IO.Path]::Combine($outDir, [System.IO.Path]::GetFileNameWithoutExtension($mp3Path) + "-$($i+1).mp3")
        & ffmpeg -i $mp3Path -ss $start -t ($sliceLen + $overlap) -hide_banner -stats -v warning -c copy $outFile
        Write-Host "Split $timeSpan to $outFile" -ForegroundColor Cyan
    }
}

function Az-TranscibeLongMp3(
    [Parameter(Mandatory=$true)]$mp3Path, 
    [Parameter(Mandatory=$true)]$prompt, 
    $outDir = '.\temp', $sliceLen = 1200, 
    $whisperDelpoy = $whisperDeployName, 
    $gptDeploy = $gptDeployName
    )
{    
    $outDir = Resolve-AbsPath $outDir
    [IO.Directory]::CreateDirectory($outDir) | Out-Null
    $mp3Path = Resolve-Path $mp3Path
    Az-SplitMp3 $mp3Path $outDir $sliceLen
    $files = Get-ChildItem -Path $outDir -Filter '*.mp3'
    $transcripts = @()
    $toRemove = @()
    foreach ($file in $files) {
        $transcripts += "==== $($file.Name) ===="
        $transcript = Az-WhisperTranscribe $file.FullName -language 'zh' -prompt $prompt -deployName $whisperDelpoy
        $transcriptPath = [System.IO.Path]::ChangeExtension($file.FullName, '.txt')
        $transcript | Out-File -Path $transcriptPath -Encoding utf8 # backup
        $transcripts += $transcript
        $toRemove += $file.FullName
        $toRemove += $transcriptPath
    }
    $txtPath = [System.IO.Path]::ChangeExtension($mp3Path, '.txt')
    $transcripts | Out-File -Path $txtPath -Encoding utf8
    $toRemove | ForEach-Object { Remove-Item -Path $_ -Force }
    Write-Host "Transcript saved. [$txtPath]" -ForegroundColor Green
}