Extract Left Eye from 3D Video Using FFmpeg Stereo3d

This article explains how to isolate and extract the left-eye view from a 3D stereoscopic video using the FFmpeg stereo3d filter. You will find direct, step-by-step instructions and command-line examples for converting common 3D formats—such as side-by-side (SBS) and top-and-bottom (TAB)—into standard 2D videos containing only the left-eye perspective.

Understanding the Stereo3D Filter Syntax

The stereo3d filter in FFmpeg converts stereoscopic 3D videos from one format to another. To extract the left eye, you must define the input format of your 3D video and set the output format to mono left (ml).

The basic syntax for the filter is:

-vf "stereo3d=input_format:ml"

Common Input Format Codes

• sbs2l: Side-by-side half resolution (left eye on the left, most common SBS format).
• sbsl: Side-by-side full resolution.
• tab2l: Top-and-bottom half resolution (left eye on top, most common TAB format).
• tabl: Top-and-bottom full resolution.

Command Examples

Example 1: Extracting Left Eye from Half Side-by-Side (SBS)

If your input video is a standard half-SBS 3D video, use the sbs2l input format. FFmpeg will extract the left half and automatically stretch the aspect ratio back to the correct dimensions:

ffmpeg -i input_3d_sbs.mp4 -vf "stereo3d=sbs2l:ml" -c:a copy output_left_eye.mp4

Example 2: Extracting Left Eye from Half Top-and-Bottom (TAB)

If your input video is a standard half top-and-bottom 3D video, use the tab2l input format. FFmpeg will extract the top half and scale it appropriately:

ffmpeg -i input_3d_tab.mp4 -vf "stereo3d=tab2l:ml" -c:a copy output_left_eye.mp4

Explanation of the Commands

• -i input_3d.mp4: Specifies the path to your source 3D video file.
• -vf "stereo3d=in:out": Applies the video filter. The first value defines the layout of your source file, and the second value (ml) tells FFmpeg to output only the mono left-eye channel.
• -c:a copy: Copies the audio stream directly without re-encoding, saving processing time and preserving original audio quality.
• output_left_eye.mp4: The filename for your newly created 2D video.