Download and extract some background music from http://middle-earth.thehobbit.com/

get_middle-earth_music.ps1

<#
.SYNOPSIS
    Download and extract music from http://middle-earth.thehobbit.com/
#>

# Get dmaf JSON file
$dmaf_assets_url = 'http://middle-earth.thehobbit.com/stable.380729695375977266/assets/dmaf_assets/'
$data = Invoke-WebRequest -Uri ($dmaf_assets_url + 'json/dmaf_data.json') | ConvertFrom-Json

# Get the section of JSON that we're interested in
$webaudio_loader_json = ((
    $data.configs | Where-Object { $_.name -eq 'init_and_loading' }).actions |
                    Where-Object { $_.instanceId -eq 'webglmap_webaudio_loader' }).files |
                    Where-Object { $_.path -eq 'bin/webglmap_webaudio_loader' }

# Download the combined OGG file
$ogg_url = $dmaf_assets_url + $webaudio_loader_json.path + '.ogg.bin'
$ogg_filename = 'webglmap_webaudio_loader.ogg'
Invoke-WebRequest -Uri $ogg_url -OutFile $ogg_filename
$ogg_file = [System.IO.File]::ReadAllBytes($(Join-Path $PSScriptRoot $ogg_filename))

# Extract all the tracks from the OGG file
foreach ($track in $webaudio_loader_json.files) {
    # Extract the track to new file using the byte counts defined in ogg_start and ogg_end
    $track_filename = "$($track.name).ogg"
    Write-Output "Extracting $($track_filename)"

    # Extract the track to a new file (http://stackoverflow.com/a/24687573)
    $output_file = [System.IO.File]::OpenWrite($(Join-Path $PSScriptRoot $track_filename))
    $output_file.Write($ogg_file, $track.ogg.start, ($track.ogg.end - $track.ogg.start))
    $output_file.close()
}

Write-Output "Done! $($webaudio_loader_json.files.length) files produced."