Subtitling Foreign Blu-ray Discs: A Challenge

My goal is to translate unsubtitled (domestic market only) Blu-ray discs into English subtitles and get them back into .MKV container for NAS storage accessible by Oppo BD player.

The process begins with MakeMKV, which rips the digital data and makes an MKV file. This file can contain multiple audio and subtitle tracks.

Next step import the .MKV file into DaVinci Resolve Studio, then have it analyze the audio and generate (in this case, Japanese) subtitles.

Then, I export the .SRT and send it over to ChatGPT with instructions to maintain the time code while making an English translation. Once done, (thank you, ChatGPT) I import the EN .srt file and make the English subtitles.

I tweak the color and outline (I wonder if there's a way to make my preferred yellow with black outline default style?)

Then render out to .MKV format with subtitles as embedded captions.

All of this seems to work if I transcode the ripped .MKV to Prores422, but the files are HUGE.
I tried importing the original ripped .MKV off a NAS drive, but my LAN is topping out at 60MB/s, so maybe the file being non-local is making playback very sluggish.

I wonder what the best and most compact intermediate file format I can use so these 50GB rips don't balloon into 2TB files?

I did a short sample about 2 mins and the Prores422 is over 3GB. But everything works! I was even able to save out to MKV with embedded subtitles for playback on BD player or VLC!

Resolve is a true miracle maker!

Screen shot with subtitles

Annotation 2025-04-16 174949.jpg (616.8 KiB) Viewed 229 times

If you only want to create the subtitles, why would convert into ProRes and then back?

There are tools to add new subtitle tracks back into a container format like mkv. No need to re-encode.

Since I am using Resolve's speech analysis to create subtitles, I needed to get the file into Resolve.
It CAN import the MKV file, but I didn't feel like pulling a 50GB file off the NAS and trying to fit it on a local drive to see if seek/scan performance was much better. I did a 2+ minute segment, exported to Prores422 just to test the concept (and it works).

How would another tool recognize the speech and create a subtitle track? I realize that an existing subtitle track could be added with some muxing tool, but to create that track with speech recognition is something I do not know outside of Resolve.

The test result:
https://drive.google.com/file/d/1kmjTpJ ... sp=sharing

You could use Shutter Encoder to demux the audio only and then after you got your subtitles you could use that to mux the subtitle back into your mkv.