Ffmpeg Ocio Colorpro

FFmpeg OCIO ColorPro

Context: $ARGUMENTS

Quick start

• Check OCIO support: → Step 1
• Apply ACES → Rec.709: → Step 2 + Step 3
• Bake OCIO transform to .cube (fallback when filter missing): → Gotchas + bake-lut
• Embed ICC profile: → Step 3 (attach-icc)

When to use

• You want Resolve-grade color fidelity through ffmpeg (ACES, LMTs, film emulation).
• You need to convert between ACES spaces (ACES2065-1, ACEScg, ACEScc, ACEScct) and a display space (Rec.709, sRGB, DCI-P3 D65, Rec.2020 PQ).
• You must embed/detect ICC profiles for downstream compositing/web delivery.
• You want to match a Resolve .cube/OCIO pipeline exactly, without re-grading.

Step 1 — Set OCIO config & check support

ffmpeg -hide_banner -filters | grep -i ocio   # expect "ocio" line if built with libOpenColorIO
export OCIO=/path/to/aces_1.3/config.ocio     # or ACES 2.0 studio-config

If ocio is missing from the filter list, jump to Gotchas → bake a .cube with ociobake and apply via the lut3d filter (see ffmpeg-lut-grade).

Step 2 — Pick the transform (pinput → poutput)

• pinput = source color space. Typical: ACES2065-1 (linear scene-referred, the ACES interchange), ACEScc / ACEScct (log grading spaces), ACEScg (rendering-linear for CGI), camera logs (Input - ARRI - V3 LogC (EI800), Input - Sony - S-Log3, Input - RED - Log3G10).
• poutput = target display/encoding. Typical: Output - Rec.709, Output - sRGB, Output - DCI-P3 D65, Output - Rec.2020 ST2084 (HDR10 PQ), Output - Rec.2100 HLG.

Names are config-dependent — run ociocheck --iconfig $OCIO or pyociotools to list exact strings.

Step 3 — Run

# ACES2065-1 → Rec.709 (SDR)
ffmpeg -i in.exr -vf "format=gbrpf32le,ocio=pinput=ACES2065-1:poutput=Output - Rec.709,format=yuv420p" \
  -c:v libx264 -crf 16 out.mp4

# ACEScc (log grading) → DCI-P3 D65 (DCDM proxy)
ffmpeg -i graded.mov -vf "format=gbrpf32le,ocio=pinput=ACEScc:poutput=Output - DCI-P3 D65" \
  -c:v prores_ks -profile:v 3 out_dcip3.mov

# Apply a CDL / Look (LMT) from config
ffmpeg -i in.mov -vf "ocio=pinput=ACEScc:poutput=Output - Rec.709:look=LMT_Analog_Exposure" out.mov

# Attach ICC profile (bt709 primaries + sRGB TRC) on output
ffmpeg -i in.mov -vf "iccgen=primaries=bt709:trc=iec61966-2-1" -c copy out_icc.mkv

# Detect ICC in source
ffmpeg -i src.mkv -vf "iccdetect=force=1" -f null -

Use scripts/colorpro.py for a guarded wrapper:

uv run ${CLAUDE_SKILL_DIR}/scripts/colorpro.py check
uv run ${CLAUDE_SKILL_DIR}/scripts/colorpro.py aces-to-rec709 --input in.exr --output out.mp4
uv run ${CLAUDE_SKILL_DIR}/scripts/colorpro.py transform --input in.mov --output out.mov \
  --pinput "ACEScc" --poutput "Output - Rec.709"
uv run ${CLAUDE_SKILL_DIR}/scripts/colorpro.py bake-lut --config $OCIO \
  --pinput "ACES2065-1" --poutput "Output - Rec.709" --output aces_to_709.cube
uv run ${CLAUDE_SKILL_DIR}/scripts/colorpro.py attach-icc --input in.mov --output out.mkv \
  --primaries bt709 --trc iec61966-2-1

Step 4 — Verify

• Visual QC with vectorscope/waveform via ffmpeg-playback:

  ffplay -vf "split=2[a][b];[a]vectorscope=m=color3[v];[b]waveform=m=1[w];[v][w]vstack" out.mp4
  

• Confirm container tags match the transform: primaries, transfer, matrix, range. Use ffmpeg-probe → -show_streams.
• For HDR/PQ delivery, cross-check with ffmpeg-hdr-color (MaxCLL/MaxFALL, mastering display metadata).
• For Netflix/studio IMF, audit with ffmpeg-mxf-imf.

Gotchas

• ocio filter requires ffmpeg built with --enable-libocio. Most Homebrew/apt/chocolatey builds DO NOT include it — ffmpeg -filters | grep ocio tells the truth. If missing: (a) recompile ffmpeg against libOpenColorIO; (b) use ociobake --inputspace X --outputspace Y --format cinespace --lutsize 33 to emit a .cube, then apply with lut3d (see ffmpeg-lut-grade).
• $OCIO environment variable must point at a config.ocio file — ffmpeg reads it via getenv("OCIO") unless you pass config=/path.
• ACES config versions differ: 1.0.3 / 1.1 / 1.2 / 1.3 / 2.0 use different role names and transform catalogs. An ACES 1.x pipeline is NOT drop-in compatible with ACES 2.0 (new Output Transforms, different naming). Pin your config version in the project.
• ACES color-space glossary: ACES2065-1 = AP0 linear, interchange; ACEScg = AP1 linear, rendering/CGI; ACEScc = AP1 log, grading (pure log, no toe); ACEScct = AP1 log with a toe (closer to Cineon feel); ACESproxy = integer-quantized log for 10/12-bit transmission.
• Common ACES roles: scene_linear, compositing_linear, rendering, aces_interchange, cie_xyz_d65_interchange, color_timing, texture_paint, data, matte_paint.
• poutput spellings are literal & case-sensitive. Examples in ACES 1.3 studio-config: Output - sRGB, Output - Rec.709, Output - Rec.2020 ST2084, Output - DCI-P3 D65, Output - Rec.2100 HLG.
• ffmpeg's OCIO binding is more limited than Nuke/Resolve/Blender — some LMTs, display-referred looks, and GPU-only transforms may silently fall back or apply incorrectly. For deliveries, verify against a Resolve render.
• OCIO math is floating-point. Always bracket the filter with format=gbrpf32le on the input side and a target pixel format (e.g. format=yuv420p10le) on the output side to avoid quantization shocks.
• ICC profile embedding in MP4 is limited (iTunes-only colr atom semantics). Prefer MKV or MOV for ICC-tagged intermediates. iccgen builds an ICC from ffmpeg color tags (primaries, trc); iccdetect reads one from the input stream.
• Rec.709 ≠ sRGB. Same primaries, different transfer functions (Rec.709 is ~gamma 2.4 display; sRGB is piecewise linear + ~2.2). Don't swap them in web delivery.
• For HDR out of OCIO (e.g. ACES → HDR10 PQ BT.2020), set both the transform (poutput="Output - Rec.2020 ST2084") AND the container color tags (-colorspace bt2020nc -color_primaries bt2020 -color_trc smpte2084) via ffmpeg-hdr-color.
• DaVinci Resolve exports .cube LUTs at 17/33/65 cube sizes; reuse via lut3d filter. OCIO look sections map 1:1 to Resolve Color Space Transforms only in v2.0+.

Examples

Example 1: ARRI LogC EXR plates → Rec.709 proxy (VFX review)

ffmpeg -start_number 1001 -i plate_%04d.exr \
  -vf "format=gbrpf32le,ocio=pinput=Input - ARRI - V3 LogC (EI800):poutput=Output - Rec.709,format=yuv420p" \
  -c:v libx264 -crf 18 -pix_fmt yuv420p -colorspace bt709 -color_primaries bt709 -color_trc bt709 \
  review_proxy.mp4

Example 2: Graded ACEScc master → HDR10 deliverable

ffmpeg -i master_ACEScc.mov \
  -vf "format=gbrpf32le,ocio=pinput=ACEScc:poutput=Output - Rec.2020 ST2084,format=yuv420p10le" \
  -c:v libx265 -x265-params "hdr-opt=1:repeat-headers=1:colorprim=bt2020:transfer=smpte2084:colormatrix=bt2020nc:master-display=G(8500,39850)B(6550,2300)R(35400,14600)WP(15635,16450)L(10000000,50):max-cll=1000,400" \
  -pix_fmt yuv420p10le hdr10.mp4

Example 3: Film look via OCIO LMT

ffmpeg -i in.mov -vf "ocio=pinput=ACEScct:poutput=Output - Rec.709:look=Kodak_2383_D65" out_kodak2383.mov

Example 4: Fallback — bake .cube, apply with lut3d (no libocio build)

ociobake --iconfig $OCIO --inputspace "ACES2065-1" --outputspace "Output - Rec.709" \
  --format cinespace --lutsize 33 > aces_to_709.cube
ffmpeg -i in.exr -vf "format=gbrpf32le,lut3d=aces_to_709.cube,format=yuv420p" out.mp4

Troubleshooting

Error: No such filter: 'ocio'

Cause: ffmpeg built without libOpenColorIO. Solution: Rebuild with --enable-libocio, or bake the transform with ociobake and apply via lut3d.

Error: Could not find colorspace 'Output - Rec.709'

Cause: The active $OCIO config uses a different name (e.g. ACES 2.0 calls it Rec.709 - Display). Solution: ociocheck --iconfig $OCIO and list colorspaces; use the exact string.

Output looks washed out / over-saturated

Cause: Double display transform (e.g. applying ACES OutputTransform then also re-tagging as sRGB), or missing format=gbrpf32le stage causing int8 clipping before the transform. Solution: Ensure a single display transform; always bracket with float format; verify container tags are untouched.

ICC profile not honored in browser

Cause: MP4 container strips/ignores embedded ICC in most players. Solution: Deliver as MKV/MOV for ICC; for web, rely on colr primaries/trc tags and assume sRGB/Rec.709 rendering intent.

Reference docs

• references/ocio.md — ACES config version matrix, role names, colorspace catalog, ociobake usage, vendor log spaces, recipe book.

Related skills

• ffmpeg-lut-grade — lut3d/haldclut application, ideal fallback when libocio is absent.
• ffmpeg-hdr-color — HDR primaries/TRC tagging, tone-mapping.
• ffmpeg-playback — vectorscope/waveform QC.
• ffmpeg-probe — verify color tags on output.
• ffmpeg-mxf-imf — studio IMF deliverables.