Openfx v3 by bmatherly · Pull Request #1204 · mltframework/mlt

bmatherly · 2026-02-23T04:02:02Z

Work on openfx module continued from this PR: #1186

… ends with other postfix

…ths from environment variable

…d widget '2dsize'

… implementation

- handle the Microsoft Visual C++ compiler in module CMakeLists.txt - Change every copyright to the year 2025 - Use C99 variables in the for loop initializer declare style - Clang format and include <stdbool.h> explicitly - specify which versions of OpenFX supported - mention OpenFX header files URL in mlt_openfx.c - using mlt_image and its functions in src/modules/openfx/filter_openfx.c

…sts.txt

…t frame to the suitable format

…escribe in context action required by some plugins such as net.sf.openfx.Mirror to function

…atherly

…atherly

…ion flow

src/modules/openfx/mlt_openfx.c

bmatherly · 2026-02-23T04:13:38Z

I still can not get the mirror filter to work:

Using a single parameter like this has no effect:
melt test.mp4 -filter openfx.net.sf.openfx.Mirror flop=1

Using two parameters crashes every time:
melt test.mp4 -filter openfx.net.sf.openfx.Mirror flop=1 flip=1

Copilot

Pull request overview

This PR adds OpenFX 1.5 plugin support to MLT, continuing work from PR #1186. It provides a module for processing videos using OpenFX plugins, filtering out unsupported plugins (draw suite, OpenGL) and handling plugin identifiers containing colons by replacing them with ^.

Changes:

Adds complete OpenFX module infrastructure including header files from the OpenFX specification
Implements MLT integration layer for OpenFX plugins with host suite implementations
Adds CMake build configuration with glib dependency and GPL licensing

Reviewed changes

Copilot reviewed 28 out of 28 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
CMakeLists.txt	Adds MOD_OPENFX option and glib dependency check
CMakePresets.json	Sets MOD_OPENFX to OFF by default
src/modules/CMakeLists.txt	Adds openfx subdirectory to build
src/modules/openfx/CMakeLists.txt	Defines mltopenfx module build configuration
src/modules/openfx/factory.c	Plugin discovery and registration from OFX_PLUGIN_PATH
src/modules/openfx/filter_openfx.c	Main filter implementation for OpenFX effects
src/modules/openfx/mlt_openfx.h	Common function declarations for OpenFX integration
src/modules/openfx/filter_openfx.yml	Metadata for the OpenFX filter
src/modules/openfx/openfx/LICENSE.md	BSD-3-Clause license for OpenFX headers
src/modules/openfx/openfx/include/*.h	OpenFX 1.5 API header files

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src/modules/openfx/filter_openfx.c

src/modules/openfx/factory.c

joinlaw · 2026-02-27T16:43:52Z

I built this branch and some plugins cause it to crash such as io.aswf.openfx.example.ColourspacePluginBasic because we didn't define kOfxImageEffectPropColourManagementStyle in the host properties although it come NULL with propGetString but the return status value of propGetString is kOfxStatOK which is not true it should return error status code because this property doesn't exists so:

diff --git a/src/modules/openfx/mlt_openfx.c b/src/modules/openfx/mlt_openfx.c
index 7dc6d8b9..d77ba9da 100644
--- a/src/modules/openfx/mlt_openfx.c
+++ b/src/modules/openfx/mlt_openfx.c
@@ -394,6 +394,10 @@ static OfxStatus propGetString(OfxPropertySetHandle properties,
     mlt_properties p = fetch_mlt_properties(properties, index);
     if (!p)
         return kOfxStatErrBadIndex;
+
+    if (!mlt_properties_exists(p, property))
+       return kOfxStatErrUnknown;
+
     *value = mlt_properties_get(p, property);
     return kOfxStatOK;
 }

And there will plugins that will use extensions that will come in the future and we don't support it yet so setting kOfxImageEffectPropColourManagementStyle alone in the host properties is not enough.

And this branch changed the way that filter metadata is formed so some video editors who parses mlt filter metada and generate the generic UIs such as kdenlive and others cannot render the interface anymore

---
schema_version: 7.0
type: filter
identifier: openfx.uk.co.thefoundry.BasicGainPlugin
title: openfx.uk.co.thefoundry.BasicGainPlugin
version: 1
license: GPLv2
language: en
url: "https://openeffects.org/"
creator: mr.fantastic <mrfantastic@firemail.cc>
tags:
  - Video
description: Process videos using OpenFX 1.5 plugins.
parameters:
  scale:
    type: double
    animation: no
  scaleComponents:
    type: boolean
    animation: no
  componentScales:
    type: group
    opened: 0
    animation: no
  scaleR:
    type: double
    animation: no
  scaleG:
    type: double
    animation: no
  scaleB:
    type: double
    animation: no
  scaleA:
    type: double
    animation: no
  Main:
    animation: no

joinlaw · 2026-02-27T16:59:46Z

The way I was saving properties internally as mlt_properties changed significantly it was (in pseudocode)

- Host Properties
  - kOfxImageEffectPropSupportedPixelDepths
    - t: mltofx_prop_string
    - v (length 2)
      - kOfxBitDepthByte
      - kOfxBitDepthShort
  - ...
    - ...
    - ...
      - ...
      - ...

And now it looks like

- Host Properties
 - 0
    - kOfxImageEffectPropContext: kOfxImageEffectContextFilter
    - kOfxImageEffectPropSupportedPixelDepths: kOfxBitDepthByte
 - 1
    - kOfxImageEffectPropSupportedPixelDepths: kOfxBitDepthShort
 - 2
    - ...
    - ...
 - 3
    - ...
    - ...

This resolves some review comments from Copilot about memory leaks and editing stings by index.

The plugin might try to use the null pointer

bmatherly · 2026-02-27T23:45:59Z

@joinlaw - Thanks for testing!!

I built this branch and some plugins cause it to crash

I applied your patch for propGetString. I think that makes sense since we do not want the plugin to use a null pointer. Should we also do that for other data types (double, int, pointer)?

And this branch changed the way that filter metadata

I will look into that

The way I was saving properties internally

The first digit is the dimension index. I decided to structure the dimensions this way to resolve the memory leaks caused by the calls to realloc() to create arrays. Let me know if this causes problems.

Copilot

Pull request overview

Copilot reviewed 27 out of 28 changed files in this pull request and generated 7 comments.

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src/modules/openfx/filter_openfx.c

src/modules/openfx/factory.c

src/modules/openfx/CMakeLists.txt

src/modules/openfx/openfx/include/ofxTimeLine.h

src/modules/openfx/openfx/include/ofxProgress.h

src/modules/openfx/filter_openfx.c

Mostly related to: * Prefer mlt_properties_get_properties() to nest properties * NULL pointer checking * whitespace

bmatherly · 2026-03-02T01:58:40Z

@joinlaw I think I have resolved our comments. Feel free to give it another try.

My only remaining issue is that I still get crashes when I run:

melt test.mp4 -filter openfx.net.sf.openfx.Mirror flop=1

If I can figure that out, this branch should be ready to merge.

bmatherly · 2026-03-03T03:15:02Z

@joinlaw , I have not fixed the flip crash yet. But in the meantime, can you test this branch with your working copy? Thanks!

joinlaw · 2026-03-03T20:18:34Z

@joinlaw , I have not fixed the flip crash yet. But in the meantime, can you test this branch with your working copy? Thanks!

Nice. I will try it once I have free time an I will debug the mirror plugin also to see if I can find anything to deal with this crashes.

mr.fantastic and others added 30 commits February 22, 2026 15:13

Initial work on OpenFX module support

f4ca385

Making yml files explicit in openfx module CMakeLists

a13af15

clang-format openfx module source files

6915f71

OpenFX module: adding TODO to incompleted code

7feec02

reordering functions in src/modules/openfx/mlt_openfx.c|h

a2473bd

openfx module: avoid reading directories that contain .ofx.bundle but…

4118811

… ends with other postfix

openfx module: using typedefs for shared object symbols

42c173e

openfx module: replace strtok with strtok_r to parse openfx plugin pa…

4a24c27

…ths from environment variable

closedir after parsing openfx plugins

96e2c59

openfx module support more parameters types

6acbf6f

openfx module fix plugin parameter not passed correctly form the host

f1fa437

openfx module adding support for color parameters

a180f22

openfx module: add support for double 2d point

5dd30f1

filter_openfx.c set default value for parameter with type 'double' an…

308c2f3

…d widget '2dsize'

openfx module: progress on kOfxImageEffectActionGetRegionOfDefinition…

81190a1

… implementation

openfx module: avoid adding unsupported plugins as filters

b678494

Fix openfx module build issue with mingw/msys2

d9f06be

Make sure that OpenFX module have the imported target glib in CMakeLi…

144ed62

…sts.txt

Turn off openfx module on msvc CI/CD build

a2e23aa

openfx module: when plugin support RGBA64 or RGBA color format conver…

a5e3923

…t frame to the suitable format

clang-format src/modules/openfx/filter_openfx.c

7ab8bb2

openfx module extract plugin description into mlt filter metadata

b003c7d

clang-format src/modules/openfx/filter_openfx.c

fee354f

OpenFX module: setting some standard Source/Output properties after d…

02e052e

…escribe in context action required by some plugins such as net.sf.openfx.Mirror to function

openfx module: Quiet warnings from plugins that use OCIO patch by @bm…

048578a

…atherly

openfx module: applying @bmatherly suggested changes in plugin detect…

93cae7c

…ion flow

Move third-party openfx files into a subdirector

ceecdad

Update copyright dates in openfx module

ef9ee93

Update comment styles and consistency

160106a

bmatherly added 2 commits February 22, 2026 20:09

Fix apparent copy/paste typo

f8814c8

Flag another TODO

6fb5b52

bmatherly commented Feb 23, 2026

View reviewed changes

bmatherly mentioned this pull request Feb 23, 2026

OpenFX Module #1186

Closed

bmatherly requested a review from Copilot February 23, 2026 04:15

Copilot started reviewing on behalf of bmatherly February 23, 2026 04:16 View session

Copilot AI reviewed Feb 23, 2026

View reviewed changes

src/modules/openfx/filter_openfx.c Outdated Show resolved Hide resolved

src/modules/openfx/factory.c Outdated Show resolved Hide resolved

src/modules/openfx/factory.c Outdated Show resolved Hide resolved

Fix memory leaks in property storage.

f967618

bmatherly added 3 commits February 27, 2026 16:25

Fix destructors for dynamic library handles

9759bac

Refactor some dynamic library handle management.

0e6f6f6

This resolves some review comments from Copilot about memory leaks and editing stings by index.

Do not return status OK if the property does not exist

eb04489

The plugin might try to use the null pointer

bmatherly requested a review from Copilot February 27, 2026 23:54

bmatherly marked this pull request as draft February 27, 2026 23:54

Copilot started reviewing on behalf of bmatherly February 27, 2026 23:54 View session

Copilot AI reviewed Feb 27, 2026

View reviewed changes

bmatherly added 2 commits March 1, 2026 15:26

Consistency changes

07474b5

Mostly related to: * Prefer mlt_properties_get_properties() to nest properties * NULL pointer checking * whitespace

Fix metadata formatting

c4914a1

Add additional handling for unknown properties

6e586f6

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joinlaw commented Feb 27, 2026

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