Convert media file to a chromecast compatible

chromecast-compatible.ps1

# PowerShell version 7 and higher, the default intalled on Windows is 5.1
# https://docs.microsoft.com/en-us/powershell/scripting/install/installing-powershell?view=powershell-7.1
# on Windows Terminal a profiles for PowerShell 7 is directly created.
# ffmpeg and ffprobe must be on PATH.

<#
        .DESCRIPTION
        Convert a media file to format compatible with chromecast.
        PowerShell version 7 and higher is needed, the default intalled on Windows is 5.1.
        .PARAMETER i
        Input file to be converted.
        .PARAMETER remove-karaoke
        Remove karaoke effect from subtitle
        .PARAMETER burn-sub
        Burn subtitle on video stream.
        .PARAMETER force-search-replace
        Force srt subtitle. If a subtitle is already compatible with Chromecast, convert it to srt.
        .PARAMETER search
        Search a text in subtitle.
        .PARAMETER replace
        Replace search text by replace text.
        .EXAMPLE 
        chromecast.ps1 -i test.mp4 -remove-karaoke
        .LINK
        Install powershell 7: https://docs.microsoft.com/en-us/powershell/scripting/install/installing-powershell?view=powershell-7.1
#>
param (
    [Alias('input')] 
    # Validate file path
    [ValidateScript({
            if (-Not ($_ | Test-Path) ) {
                throw "File or folder does not exist" 
            }
            if (-Not ($_ | Test-Path -PathType Leaf) ) {
                throw "The Path argument must be a file. Folder paths are not allowed."
            }
            return $true
        })] [string] $i, 
    [switch]${remove-karaoke} = $false,
    [switch]${burn-sub} = $false,
    [string[]] $search = @(),
    [string[]] $replace = @()
)

function Write-ColorOutput($ForegroundColor) {
    # Save the current color
    $fc = $host.UI.RawUI.ForegroundColor

    # Set the new color
    $host.UI.RawUI.ForegroundColor = $ForegroundColor

    # Output
    if ($args) {
        Write-Output $args
    }
    else {
        $input | Write-Output
    }

    # restore the original color
    $host.UI.RawUI.ForegroundColor = $fc
}


#####################################
#  Check ffmpeg and ffprobe available
#####################################
ffprobe.exe
if ($LastExitCode -ne 0) { 
    Write-ColorOutput red ("ffprobe error.Maybe the executable is not on path")
}
ffmpeg.exe
if ($LastExitCode -ne 0) { 
    Write-ColorOutput red ("ffprobe error.Maybe the executable is not on path")
}

#######################
#  Check nvenc available
#######################
$hwaccel_available = $false
# $list = "encoders","decoders","filters"
$list = "encoders"
foreach ($i in $list) {
    $output = ffmpeg -hide_banner -$i
    if ($output -match "nvenc") {
        $hwaccel_available = $true
    }
}


$filename = Convert-Path $i
if (Test-Path -Path $filename) {
    Write-ColorOutput red ("No file provided")
    Exit
}

if($search.length -ne $replace.length) {
    Write-ColorOutput red ("No search/replace arguments have not the same length")
    Exit
}   


# Final ffmpeg cmd
$ffmpeg_input = ""
$pre_input = "" # Pre input cmd
$post_input = "" # Post input cmd
$remux = $false

# Move flag value to better variable name
$burn_sub = ${burn-sub}
$remove_karaoke = ${remove-karaoke}

# The reaseon of 2>&1 in ffprobe cmd it's because ffprobe and ffmpeg
# output on stderr and not stdout. The 2>&1 operator redirect stderr to stdout.

#######################
#  Check subtitle codec
#######################
# Select first subtitle stream
$subtitle_probe = ffprobe.exe -v error -show_format -show_streams -select_streams s:0 $filename 2>&1
# Test ffprobe error 
if ($LastExitCode -ne 0) { 
    Write-Output "ffprobe error: $audio_probe. Error code: $LastExitCode"
    Exit
}

# Codec name 
$subtile_name = ($subtitle_probe[2] -split "=")[1]
$supported_subtitle = "ttml", "webvtt", "srt", "wav", "vorbis"

# TODO Check more sub codec
if ($subtile_name -ne "srt") {
    $remux = $true

    # The subtitle codec might be not work for chromecast 
    Write-Output $subtitle_probe[2]
    # Get subtitle stream index
    $index = ($subtitle_probe[1] -split "=")[1]
    # Extract subtitle 
    ffmpeg -y -i $filename -map 0:$index original.$subtile_name

    # If ass, ssa format and burn flag write to video stream
    if ($burn_sub) {
        $ffmpeg_input = "-i original.$subtile_name" # Set subtitle input
        $post_input = "-vf subtitles=original.$subtile_name" # Flag to burn on video
    }
    else {
        # Remove karaoke
        if ($remove_karaoke) {
            # TODO Search/Replace 
            # Improve subs rewriting 
            $PSDefaultParameterValues['Out-File:Encoding'] = 'utf8'
            $replace = @()
            $remove_style = "karaoke"
            foreach ($line in Get-Content .\original.$subtile_name) { 

                if (-Not ($line | Select-String -pattern $remove_style)) {
                    $replace += $line
                }
            }
            
            
            $replace | Out-File -Append ./out.ass -Encoding utf8
            # Convert to new format
            ffmpeg -y -i out.ass -scodec srt cache.srt
        }
        else {
            # Convert to new format
            ffmpeg -y -i original.$subtile_name -scodec srt cache.srt
        }

        $ffmpeg_input = "-i cache.srt"
        $post_input = "-scodec srt"
    }

}
else {
    # Placeholder for encode audio or video (maybe not needed)
    $post_input = "-scodec copy"
}


#######################
#  Check audio codec
#######################
# Select first audio stream
$audio_probe = ffprobe.exe -v error -show_format -show_streams -select_streams a:0 $filename 2>&1
# Test ffprobe error 
if ($LastExitCode -ne 0) { 
    Write-Output "ffprobe error: $audio_probe. Error code: $LastExitCode"
    Exit
}

# Codec name 
$codec_name = ($audio_probe[2] -split "=")[1]

# Chromecast supported codec
# https://support.google.com/chromecast/answer/6279377?hl=en 
$supported_codec = "flac", "aac", "mp3", "wav", "vorbis"

# Wrong codec for chromecast
if (-Not $supported_codec.Contains($codec_name)) {
    $remux = $true
    $post_input = "$post_input -acodec mp3"  # Set to mp3 by default
}
else {
    # In case of flac
    if ($codec_name -eq "flac") {
        $sample_rate = [int]($audio_probe[9] -split "=")[1]
        $bits_per_raw_sample = [int]($audio_probe[23] -split "=")[1]

        # Set max sample rate
        if (($sample_rate -ne -1) -and ($sample_rate -gt 96000)) {
            $post_input = "$post_input -sample_rate 96000"  
        }

        # Set bits per raw sample
        if ($bits_per_raw_sample -gt 24) {
            $post_input = "$post_input -bits_per_raw_sample 24"  
        }
    }
}



#######################
#  Check video codec
#######################

$video_probe = ffprobe.exe -v error -show_format -show_streams -select_streams v:0 $filename 2>&1

# Test ffprobe error 
if ($LastExitCode -ne 0) { 
    Write-Output "ffprobe error: $video_probe. Error code: $LastExitCode"
    Exit
}

# Codec name 
$codec_name = ($video_probe[2] -split "=")[1]

# Chrome cast support only h264 or vp8
# vp8 is ignored in this case
# https://developers.google.com/cast/docs/media

if ($codec_name -ne "h264") {
    $remux = $true

    $post_input = $post_input + $(if ($hwaccel_available) { " -vcodec h264_nvenc" } else { " -vcodec h264" })
    $post_input = "$post_input -pix_fmt yuv420p"

}
else {

    # TODO Check if it's needed
    $bad_fmt = ($video_probe[17] -split "=")[1] -ne "yuv420p"
    
    $codec = if ($hwaccel_available) { " -vcodec h264_nvenc" } else { " -vcodec h264" }

    # Encode must needed for burn sub or bad fmt
    $post_input = $post_input + $(if ($burn_sub) { $codec } else { " -vcodec copy" })

    # Check pix fmt
    if ($bad_fmt) {
        $post_input = "$post_input -pix_fmt yuv420p"
    }
    
}


#######################
#  Final cmd
#######################

if ($remux) {
    $file = [System.IO.Path]::GetFileNameWithoutExtension($filename)
    $ext = [System.IO.Path]::GetExtension($filename)


    # Add flag for harware acceleration
    if ($hwaccel_available) {
        $pre_input = "-init_hw_device cuda=cuda:0 -hwaccel cuda -filter_hw_device cuda"
    }

    $ffmpeg_input = "$ffmpeg_input -i $filename" # Add video file to input



    $directory = [System.IO.Path]::GetDirectoryName($filename)
    $output_file = "$directory/$($file)_converted$($ext)" # Concat filename converted and extension

    $cmd_str = "ffmpeg $pre_input $ffmpeg_input $post_input $output_file"

    Invoke-Expression $cmd_str
    if ($LastExitCode -ne 0) { 
        Write-Output "ffmpeg error: $out. Error code: $LastExitCode"
        Write-Output "Maybe ffmpeg nvenc is enable but you doesn't have a nvidia gpu"
        Exit
    }
}


Remove-Item -Path ./out.ass
Remove-Item -Path ./cache.srt
Remove-Item -Path "original.$subtile_name"