The Concept

We are taking a single "Full SBS" file (which contains both eyes side-by-side in one wide frame) and slicing it down the middle. Because your source might be a cinema-style "Ultrawide" format (like 3840x800), we must also add black bars (padding) to the top and bottom to reach the mandatory Blu-ray height of 1080 pixels.

Figure 1: Visual process of splitting Full SBS into two 1080p streams with padding.

The Command

Run this in your terminal:

ffmpeg -i input.mkv -filter_complex "[0:v]split=2[l_raw][r_raw]; \
 [l_raw]crop=1920:ih:0:0,pad=1920:1080:0:(1080-ih)/2:black[leftout]; \
 [r_raw]crop=1920:ih:1920:0,pad=1920:1080:0:(1080-ih)/2:black[rightout]" \
-map "[leftout]" -c:v libx264 -crf 16 -preset slow -r 23.976 -pix_fmt yuv420p left_eye.mkv \
-map "[rightout]" -c:v libx264 -crf 16 -preset slow -r 23.976 -pix_fmt yuv420p right_eye.mkv

You want to use the command in 1 line when using command prompt instead:

ffmpeg -i input.mkv -filter_complex "[0:v]split=2[l_raw][r_raw];[l_raw]crop=1920:ih:0:0,pad=1920:1080:0:(1080-ih)/2:black[leftout];[r_raw]crop=1920:ih:1920:0,pad=1920:1080:0:(1080-ih)/2:black[rightout]" -map "[leftout]" -c:v libx264 -crf 16 -preset slow -r 23.976 -vsync cfr -pix_fmt yuv420p left_eye.mkv -map "[rightout]" -c:v libx264 -crf 16 -preset slow -r 23.976 -vsync cfr -pix_fmt yuv420p right_eye.mkv

Command Breakdown

Verification: The "Perfect Sync" Check

Ensure both files have the exact same number of frames to prevent player crashes.

ffprobe -v error -select_streams v:0 -show_entries stream=nb_frames -of default=nokey=1:noprint_wrappers=1 left_eye.mkv
ffprobe -v error -select_streams v:0 -show_entries stream=nb_frames -of default=nokey=1:noprint_wrappers=1 right_eye.mkv

Why this ensures 100% Compatibility

• Resolution: Satisfies the BD-ROM physical specification.
• Timing: Eliminates "drift" between eyes.
• Bitstream: Standard x264 inside mkv is the preferred input for Cinevision.

Part A: The MakeMKV Pull

Extract the data off the physical disc without changing a single bit of quality.

1. Open the Disc: Launch MakeMKV and click the Optical Drive icon.
2. Select the Title: Find the largest Title (main movie).
3. Uncheck Video: You handled this in Step 1.
4. Select Audio: Check high-definition tracks (DTS-HD MA, TrueHD, etc.).
5. Output: Click "Make MKV" to create your backup.mkv.

Figure 2: Selecting only the HD audio tracks in MakeMKV.

Part B: Extracting the Audio with FFmpeg

Professional authoring tools are extremely picky—they cannot read an MKV file directly. We need to perform "surgery" to pull out the raw audio data. Before we do that, we must identify exactly which audio track we want to grab.

1. Preliminary: Find your Track Number

Movies often have multiple audio tracks (different languages or commentary). We need to find the Stream Index of the one you want. Run this command:

ffprobe -v error -show_streams -select_streams a backup.mkv

Look at the results and find the language you need. The "Index" number determines your -map setting:

• If your track is the first one listed: Use -map 0:a:0
• If your track is the second one listed: Use -map 0:a:1
• (And so on...)

2. Run the Extraction Command

Choose the command below that matches the type of audio you selected in MakeMKV. If your track index wasn't 0, remember to update the -map part!

ffmpeg -i backup.mkv -map 0:a:0 -c copy movie.mlp -map 0:a:0 -c copy movie.ac3

ffmpeg -i backup.mkv -map 0:a:0 -c copy movie.dts

ffmpeg -i backup.mkv -map 0:a:0 -c copy movie.ec3

ffmpeg -i backup.mkv -map 0:a:0 -c copy movie.ac3

Technical Cheat Sheet

Part C: The MUI Generator (The "Scenarist Bridge")

Once you have extracted your files, you need to prepare the high-definition tracks. While standard AC3 files can be imported into Scenarist directly, Lossless HD formats (TrueHD/Atmos and DTS-HD MA) must be processed through the MUI Generator to create a "VES" (Video Elementary Stream) asset.