JSON Powershell memory issue - json

Question

I use a command to read a JSON file, this all works perfectly, until the file becomes large.
I currently have a JSON file of about 1.5GB. I read the file using Powershell using the following command:
get-content -Path C:\TEMP\largefile.json | out-string | ConvertFrom-Json
It returns the following error:
out-string : Exception of type 'System.OutOfMemoryException' was thrown.
+ ... oices = get-content -Path C:\TEMP\largefile.json | out-string | Conve ...
+ ~~~~~~~~~~
+ CategoryInfo : NotSpecified: (:) [Out-String], OutOfMemoryException
+ FullyQualifiedErrorId : System.OutOfMemoryException,Microsoft.PowerShell.Commands.OutStringCommand
I've increased the memory as shown here:
get-item wsman:localhost\Shell\MaxMemoryPerShellMB
WSManConfig: Microsoft.WSMan.Management\WSMan::localhost\Shell
Type Name SourceOfValue Value
---- ---- ------------- -----
System.String MaxMemoryPerShellMB 8096
Any ideas on how to process this?
Edit (additions based on comments):
When I remove the out-string I get this error:
ConvertFrom-Json : Exception of type 'System.OutOfMemoryException' was thrown.
+ ... oices = get-content -Path C:\TEMP\largefile.json | ConvertFrom-Json ...
+ ~~~~~~~~~~~~~~~~
+ CategoryInfo : NotSpecified: (:) [Out-String], OutOfMemoryException
+ FullyQualifiedErrorId : System.OutOfMemoryException,Microsoft.PowerShell.Commands.OutStringCommand
The Powershell version that I have is: 5.1.17763.1490
The file contains multiple columns regarding PDF files. These files are exported via an API into a JSON so it contains the file metadata such as owner and when it was created but also the actual PDF file in the column Body which later will be decoded to an actual PDF file. The structure is as followed:
[{"Id":"ID","ParentId":"parent","Name":"filename","OwnerId":"owner","CreatedDate":"date","Body":"*******"}
{"Id":"ID","ParentId":"parent","Name":"filename","OwnerId":"owner","CreatedDate":"date","Body":"*******"}
{"Id":"ID","ParentId":"parent","Name":"filename","OwnerId":"owner","CreatedDate":"date","Body":"*******"}
{"Id":"ID","ParentId":"parent","Name":"filename","OwnerId":"owner","CreatedDate":"date","Body":"*******"}
{"Id":"ID","ParentId":"parent","Name":"filename","OwnerId":"owner","CreatedDate":"date","Body":"*******"}
]

Answer 1

Thank for the details.
For this issue I would try to convert each line separately and stream that through your process:
Get-Content C:\TEMP\largefile.json | ForEach-Object {
$_ = $_.Trim().TrimStart('[').TrimEnd(']')
if ($_) { $_ | ConvertFrom-Json }
}
As already suggested, I wouldn't be surprised if these memory issues wouldn't appear in PowerShell core. if possible, I recommend you to also give that a try.