encode-for-yt.ps1

Param(
  [Parameter(Mandatory=$true)] [string]$path
)

$raw_fps = ffprobe -v 0 -of csv=p=0 -select_streams 0 -show_entries stream=r_frame_rate $path
if ($raw_fps -eq $null) {
  Write-Host -ForegroundColor red "Invalid video format: '$path'"
  exit 1
}
$parts = $raw_fps.Split('/')
[int]$fps = [double]$parts[0] / [double]$parts[1]
[int]$resolution = ffprobe -v 0 -select_streams v:0 -show_entries stream=height -of csv=s=x:p=0 $path

Write-Output "Video: $($resolution)p$($fps)"

if ($fps -le 30) {
  $br = switch ($resolution) {
    360 { 1 }
    480 { 2.5 }
    720 { 5 }
    1080 { 8 }
    1440 { 16 }
    2160 { 35 }
    2880 { 80 }
  }
} elseif ($fps -le 60) {
  $br = switch ($resolution) {
    360 { 1.5 }
    480 { 4 }
    720 { 7.5 }
    1080 { 12 }
    1440 { 24 }
    2160 { 53 }
    2880 { 120 }
  }
}

if ($br -eq $null) {
  Write-Host -ForegroundColor red "Invalid video resolution or fps: '$($resolution)p$($fps)'"
  exit 2
}

$brs = "$($br)M"
$brm = "$($br * 1.5)M"
$brb = "$($br * 2)M"
Write-Host "Bitrate: $brs, $brm, $brb"

ffmpeg -hwaccel cuda -hwaccel_output_format cuda `
  -hide_banner `
  -i $path `
  -c:v h264_nvenc `
    -preset p7 -profile:v high -tune hq -multipass fullres `
    -pix_fmt yuv420p `
    -rc vbr -cq 19 -b:v $brs -maxrate $brm -bufsize $brb `
    -rc-lookahead 32 -spatial-aq 1 `
    -r $fps -g $($fps / 2) -bf 2 `
    -colorspace bt709 -color_primaries bt709 -color_trc bt709 `
  -c:a aac -b:a 384k -ar 48000 -ac 2 `
  -movflags +faststart `
  output.mp4