Batch replace string in every subfolder?

Question

Is it possible to batch replace a text string inside a cmd file in every subfolder?

The folder structure is:

Root Folder (Batch script) > Several subfolders > job(folder number)_EncodeAudio.cmd > text string

The cmd file has the 128 string that should be replaced to 384 and each subfolder (job1, job2, job3) has the same job(folder number)_EncodeAudio.cmd file.

This is better explained in a single image:

Answer 1

Used Billy's script and a BAT to call the Powershell script.

BAT file:

CD /D %root% C:\Root Folder Location
powershell.exe -ExecutionPolicy ByPass -file batch.ps1

PS1 file:

Get-ChildItem *.cmd -Recurse | ForEach-Object { (Get-Content $_) | ForEach-Object { $_ -replace '128','384' } | Set-Content $_ }