Convert Side-by-Side 3D to Anaglyph with FFmpeg

This guide explains how to convert a side-by-side (SBS) 3D video into a red-cyan anaglyph video using FFmpeg’s powerful stereo3d video filter. You will learn the exact command-line syntax, understand the input and output parameters, and explore different anaglyph rendering styles, such as color, grayscale, and Dubois.

The Basic FFmpeg Command

To convert a standard side-by-side 3D video to a red-cyan anaglyph video, use the following FFmpeg command:

ffmpeg -i input_sbs.mp4 -vf "stereo3d=in=sbsl:out=arcd" -c:a copy output_anaglyph.mp4

Parameter Breakdown:

-i input_sbs.mp4: Specifies your input side-by-side 3D video file.
-vf "stereo3d=...": Calls the stereo 3D filter.
in=sbsl: Defines the input format. sbsl stands for “side-by-side left first” (full resolution). If your input is half-width SBS (the most common format for 3D torrents and media files), change this to sbs2l.
out=arcd: Defines the output format. arcd stands for “anaglyph red/cyan Dubois”, which is the highly recommended format as it uses a specialized algorithm to reduce ghosting and optimize colors.
-c:a copy: Copies the audio stream without re-encoding to save time and preserve quality.

Choosing Your Input Format (`in`)

You must match the in parameter to your source video’s specific layout:

Value	Description
`sbsl`	Side-by-side full width, left eye first.
`sbsr`	Side-by-side full width, right eye first.
`sbs2l`	Side-by-side half width (half resolution), left eye first.
`sbs2r`	Side-by-side half width (half resolution), right eye first.

For most downloaded 3D MKV or MP4 files, sbs2l is the correct choice.

Choosing Your Output Format (`out`)

FFmpeg supports several styles of red-cyan anaglyph. Choose the one that best fits your viewing preference:

1. Dubois Red/Cyan (Recommended)

This method uses a color-matching matrix to minimize eye strain and visual “ghosting.”

ffmpeg -i input.mp4 -vf "stereo3d=in=sbs2l:out=arcd" output.mp4

2. Full Color Red/Cyan

This preserves the original colors as much as possible, though it can cause more ghosting/crosstalk.

ffmpeg -i input.mp4 -vf "stereo3d=in=sbs2l:out=arcc" output.mp4

3. Grayscale (Monochrome) Red/Cyan

This removes all color, resulting in a black-and-white image that provides a very clean, high-contrast 3D depth effect with almost zero ghosting.

ffmpeg -i input.mp4 -vf "stereo3d=in=sbs2l:out=arbg" output.mp4

Advanced Example with Video Encoding

If you want to compress the final output and ensure compatibility with most media players, encode the video using the H.264 codec:

ffmpeg -i input_sbs.mp4 -vf "stereo3d=in=sbs2l:out=arcd" -c:v libx264 -crf 20 -preset fast -c:a aac -b:a 192k output_anaglyph.mp4

-c:v libx264: Encodes the video to H.264.
-crf 20: Controls quality (lower values mean higher quality; 18–22 is ideal).
-c:a aac -b:a 192k: Converts the audio to high-quality AAC at 192 kbps.