
You might want to look into Tdarr. Configure it once and let your old computer transcode away automatically.
For audio stream replacement - if you get the exact same video (same intro length, same scene lengths, same total length, etc.), you can easily replace the audio streams and it should work out. ffmpeg is your friend to do it lossless.







It’s a mix of
--codec copyto not reencode the streams,--map 0:1to select the audio stream of the input file and for merging back you need multiple-iinput files and then--map 0:0to map the first input file’s video stream and--map 1to map the second input file (English audio stream). Mappings may vary - useffprobeto check your files.