ffmpeg-360-3d

name	ffmpeg-360-3d
description	360° / VR and stereoscopic 3D video with ffmpeg: v360 filter (equirectangular, cubemap 3x2/6x1/1x6, fisheye, flat, hequirect, dfisheye, cylindrical, perspective, barrel, sinusoidal, half_equirectangular, stereographic, mercator, ball, hammer, pannini, eac, c3x2/c6x1/c1x6, rfish), stereo3d filter (SBS ↔ TAB ↔ interlaced ↔ anaglyph), framepack, spatial audio placeholder. Use when the user asks to convert 360 video projections, equirectangular to cubemap, unwrap fisheye, convert side-by-side 3D to top-bottom, make anaglyph 3D, reproject 360 video, or handle VR180/VR360 content.
argument-hint	[projection] [input]

Ffmpeg 360 3D

Context: $ARGUMENTS

Quick start

• Equirect → cubemap 3x2: → Step 3
• Dual fisheye → equirect: → Step 3 (dfisheye recipe)
• SBS 3D → TAB 3D: → Step 4
• SBS → anaglyph (red-cyan): → Step 4
• Virtual camera flat view from 360: → Step 3 (flat recipe)
• Frame-packed HDMI 3D: → Step 4 (framepack)

When to use

• Converting between 360 projections (equirect ↔ cubemap ↔ EAC ↔ fisheye).
• Unwrapping GoPro Max / Insta360 / Ricoh Theta dual-fisheye footage to equirect.
• Reprojecting VR content for different platforms (YouTube EAC vs Facebook equirect).
• Converting stereoscopic 3D layouts (SBS ↔ TAB ↔ interlaced ↔ anaglyph).
• Generating a "virtual camera" flat view from a 360 video (rectilinear crop).
• Packing SBS/TAB into HDMI 1.4a frame-packed output for 3D TVs.

Step 1 — Identify input projection

Before filtering, determine what you have:

• Equirectangular (e) — most common 360 format. 2:1 aspect ratio (e.g. 3840×1920, 4096×2048, 5760×2880). Looks like a stretched rectangular world map.
• Cubemap 3x2 (c3x2) — 6 cube faces in a 3-column, 2-row grid. 3:2 aspect. Common intermediate.
• Cubemap 6x1 (c6x1) or 1x6 (c1x6) — cube faces in a strip.
• Equi-Angular Cubemap (eac) — YouTube's 4K+ 360 format. Looks like a cubemap but with warped face geometry for higher quality at same bitrate.
• Dual fisheye (dfisheye) — two circular fisheye images side-by-side or stacked. Output from Insta360, GoPro Max, Ricoh Theta before stitching.
• Single fisheye (fisheye) — one circular fisheye lens image.
• Half equirect (hequirect) — half-sphere / VR180 format. 1:1 aspect per eye.

Run ffprobe -v error -select_streams v:0 -show_entries stream=width,height,side_data_list input.mp4 to inspect dimensions and any spherical metadata. Ratio 2:1 usually means equirect; 3:2 usually means cubemap 3×2; 1:1 per eye often means VR180 hequirect.

Step 2 — Pick output projection and interpolation

v360 grammar: v360=INPUT:OUTPUT:options. Interpolation choices:

• near — nearest neighbor (fastest, blocky).
• linear — default. Acceptable for preview.
• cubic — good quality/speed trade (RECOMMENDED for most conversions).
• lanczos — best quality, slowest.
• spline16, gaussian, mitchell — specialty choices.

Rule of thumb: always pass :cubic or :lanczos unless speed matters — default linear leaves visible artifacts at cube-face seams.

Step 3 — Run v360

Equirectangular → cubemap 3×2

ffmpeg -i equi.mp4 -vf "v360=e:c3x2:cubic" -c:v libx264 -crf 18 -c:a copy out.mp4

Cubemap 6×1 → equirectangular

ffmpeg -i cube.mp4 -vf "v360=c6x1:e:cubic" -c:v libx264 -crf 18 -c:a copy out.mp4

Dual fisheye → equirect (Insta360 / GoPro Max typical 190° lenses)

ffmpeg -i dual.mp4 -vf "v360=dfisheye:e:ih_fov=190:iv_fov=190:cubic" \
  -c:v libx264 -crf 18 -c:a copy out.mp4

ih_fov/iv_fov describe INPUT horizontal/vertical field-of-view of each fisheye circle. Typical consumer cams are 190°–200°.

Equirect → flat perspective (virtual camera)

ffmpeg -i equi.mp4 -vf "v360=e:flat:pitch=-15:yaw=30:h_fov=90:v_fov=60:cubic,scale=1920:1080" \
  -c:v libx264 -crf 18 -c:a copy view.mp4

yaw (left/right), pitch (up/down), roll (tilt) in degrees. h_fov/v_fov control output rectilinear FOV.

YouTube EAC → standard equirect

ffmpeg -i youtube_eac.mp4 -vf "v360=eac:e:cubic" -c:v libx264 -crf 18 -c:a copy equi.mp4

Rotate / re-orient an equirect (keep projection, change heading)

ffmpeg -i equi.mp4 -vf "v360=e:e:yaw=90:pitch=0:roll=0:cubic" \
  -c:v libx264 -crf 18 -c:a copy rotated.mp4

Step 4 — Handle stereoscopic 3D (stereo3d / framepack)

SBS (left-first) → TAB (left-first)

ffmpeg -i sbs.mp4 -vf "stereo3d=sbsl:tbl" -c:v libx264 -crf 18 -c:a copy tab.mp4

SBS → anaglyph red-cyan grayscale

ffmpeg -i sbs.mp4 -vf "stereo3d=sbsl:arcg" -c:v libx264 -crf 18 -c:a copy anaglyph.mp4

Use arcc for color anaglyph, arch for half-color, arcd for Dubois.

SBS → mono left eye only

ffmpeg -i sbs.mp4 -vf "stereo3d=sbsl:ml" -c:v libx264 -crf 18 -c:a copy mono.mp4

HDMI 1.4a frame packing (for 3D TVs)

ffmpeg -i input.mp4 -vf "framepack=sbs" -c:v libx264 -crf 18 -c:a copy packed.mp4
# modes: sbs | tab | frameseq | lines | columns

Spherical metadata (OUT OF FFMPEG SCOPE)

ffmpeg writes pixels but cannot inject the Google / 360 MP4/MOV SphericalVideo box. After rendering, use Google's spatial-media tool:

python spatialmedia -i --stereo=none video.mp4 video_360.mp4
# VR180 / SBS:
python spatialmedia -i --stereo=left-right --projection=equirectangular video.mp4 out.mp4

Without this metadata box, YouTube / Facebook / Oculus will play the file as a flat 2D video rather than 360.

Available scripts

• scripts/immersive.py — stdlib argparse wrapper with subcommands: project, flat-view, stereo3d, anaglyph, framepack. Supports --dry-run and --verbose.

Workflow

# Project conversion (any supported v360 type pair)
uv run ${CLAUDE_SKILL_DIR}/scripts/immersive.py project \
  --input equi.mp4 --output cube.mp4 --from equirect --to cubemap3x2 --interp cubic

# Virtual camera flat view from equirect
uv run ${CLAUDE_SKILL_DIR}/scripts/immersive.py flat-view \
  --input equi.mp4 --output view.mp4 --from equirect \
  --yaw 30 --pitch -15 --h-fov 90 --v-fov 60 --size 1920x1080

# Stereoscopic layout conversion
uv run ${CLAUDE_SKILL_DIR}/scripts/immersive.py stereo3d \
  --input sbs.mp4 --output tab.mp4 --from sbsl --to tbl

# Anaglyph
uv run ${CLAUDE_SKILL_DIR}/scripts/immersive.py anaglyph \
  --input sbs.mp4 --output ana.mp4 --from sbsl --mode arcg

# HDMI frame packing
uv run ${CLAUDE_SKILL_DIR}/scripts/immersive.py framepack \
  --input in.mp4 --output packed.mp4 --mode sbs

Reference docs

• Read references/projections.md for the full v360 type table, stereo3d code table, framepack options, and VR platform compatibility matrix.

Gotchas

• v360 grammar: v360=INPUT_TYPE:OUTPUT_TYPE:opt=val:opt=val. Input and output types are positional — colon-separated — not in=/out=.
• pitch / yaw / roll rotate the view in degrees. Defaults 0. Only affect output sampling, not input parsing.
• h_fov / v_fov are OUTPUT field-of-view; only meaningful for rectilinear outputs (flat, perspective). Ignored for e, c3x2, etc.
• ih_fov / iv_fov are INPUT field-of-view; required for fisheye / dfisheye inputs because the filter cannot infer lens FOV from pixels.
• YouTube 360 at 4K+ uses EAC (equi-angular cubemap), not standard cubemap. Upload equirect and YouTube transcodes to EAC server-side — but if you receive an EAC source, decode with v360=eac:e.
• Facebook 360 uses equirect. Oculus/Quest plays both equirect and EAC. VR180 uses hequirect with SBS stereo pair.
• stereo3d codes: sbsl/sbsr (SBS left-first / right-first), tbl/tbr (top-bottom), al/ar (above-below alt), ml/mr (mono L/R), abl/abr (above-below), arbg (red-blue gray), arcg (red-cyan gray), arcc (red-cyan color), arch (red-cyan half-color), arcd (red-cyan Dubois), aybd (yellow-blue Dubois), agmd/agmg/agmh (green-magenta Dubois/gray/half), irl/irr (interleaved rows), icl/icr (interleaved cols), hdmi (HDMI frame-packed).
• stereo3d cannot increase resolution. Converting TAB → SBS keeps dimensions; each eye stays at half-resolution. To get full-res per eye you need two separate mono sources, not a stereo3d conversion.
• Anaglyph: prefer arcg for grayscale-friendly content, arcc for color (watch for retinal rivalry), arcd (Dubois) for best color quality on modern displays.
• framepack outputs a packed single frame at roughly 2× dimensions — intended for HDMI 1.4a 3D sinks, not playback in standard players.
• Interpolation: pass :cubic or :lanczos. Default linear produces visible seams at cube-face boundaries.
• Verify by uploading to YouTube (unlisted) or playing in VLC 3.x (supports 360 mouse-look), or in a headset.
• Spherical metadata box is a MP4/MOV sidecar. ffmpeg does NOT write it. Use Google's spatial-media Python tool on the rendered output.

Examples

Example 1: Insta360 dual-fisheye to YouTube-ready equirect

Input: insta360.mp4 — 3840×1920 dual fisheye, 2 circles 190°, side by side.

ffmpeg -i insta360.mp4 \
  -vf "v360=dfisheye:e:ih_fov=190:iv_fov=190:cubic,scale=3840:1920" \
  -c:v libx264 -crf 18 -preset slow -c:a aac -b:a 192k equi.mp4

# then inject spherical metadata (external tool):
python spatialmedia -i --stereo=none equi.mp4 equi_spherical.mp4

Upload equi_spherical.mp4 to YouTube — it will detect 360 and serve as EAC.

Example 2: Virtual cinematographer crop from 360

Input: equi.mp4 4K equirect. Want a 1080p "flat" view facing 45° right, 10° down.

ffmpeg -i equi.mp4 \
  -vf "v360=e:flat:yaw=45:pitch=-10:roll=0:h_fov=85:v_fov=55:cubic,scale=1920:1080" \
  -c:v libx264 -crf 18 -c:a aac -b:a 160k flat_cam.mp4

Example 3: 3D Blu-ray rip (SBS) → anaglyph for monitor playback

ffmpeg -i movie_sbs.mkv -vf "stereo3d=sbsl:arcd" \
  -c:v libx264 -crf 18 -c:a copy movie_anaglyph.mkv

arcd (Dubois red-cyan) has the best color fidelity; viewer needs red-cyan glasses.

Example 4: VR180 SBS equirect → flat single-eye view

ffmpeg -i vr180_sbs.mp4 \
  -vf "v360=hequirect:flat:in_stereo=sbs:out_stereo=mono:yaw=0:pitch=0:h_fov=90:v_fov=60:cubic" \
  -c:v libx264 -crf 18 -c:a copy left_eye_flat.mp4

Troubleshooting

Error: [Parsed_v360_0 @ ...] Specified input format is not accurate.

Cause: Input type (e.g. e) doesn't match actual pixel layout (content is 3×2 cubemap). Solution: Re-inspect aspect ratio; pick correct input type (c3x2, eac, etc.).

Output has visible seams at cube edges

Cause: default linear interpolation. Solution: Add :cubic or :lanczos to the filter: v360=e:c3x2:lanczos.

Fisheye unwrap looks squeezed or shows black wedges

Cause: wrong ih_fov/iv_fov. 190° lens treated as 180° leaves unused area; 180° lens forced to 220° stretches pixels. Solution: check camera spec — Insta360 ONE / GoPro Max ≈ 190°–200°. Try ih_fov=190:iv_fov=190 first, adjust ±5° until horizon is straight.

YouTube plays my output as flat 2D, not 360

Cause: missing SphericalVideo metadata box. ffmpeg cannot write it. Solution: run Google's spatialmedia tool on the rendered file to inject the box.

stereo3d SBS → TAB output is squashed

Cause: stereo3d preserves total frame dimensions. Input 1920×1080 SBS (960×1080 per eye) → TAB becomes 1920×1080 with 1920×540 per eye. Each eye is still half-resolution; that is expected. Solution: accept the halved resolution, or source full-resolution per-eye and encode mono streams separately.

Anaglyph looks washed out / ghosted

Cause: using arcc (color) on high-contrast content; retinal rivalry. Solution: try arcd (Dubois) or arcg (grayscale) — both reduce ghosting.