[Core] Reference implementation for RGBtoNV12 and BGRtoNV12 operations

[mostafafaheem]

Details:

• Added 2 new operations to template plugin, RGBtoNV12 and BGRtoNV12, supporting single and two-plane conversion to NV12 format
• Integrated new operation into PostProcessing pipeline
• Added tests for operation and PostProcessing

Tickets:

• [Good First Issue] PostProcess supports RGB->NV12 color convert function #22985

AI Assistance:

• AI assistance used: yes
• AI was used to give in-depth guidance about operation enabling flow and help validating code changes. All code was thoroughly reviewed and tested

[mostafafaheem]

Hello @riverlijunjie and @praasz, sorry for the large PR, I thought that splitting it into smaller PRs would not be suitable for the granularity of this task, however, once this PR is merged, I will submit another PR containing CPU plugin reference implementation, and hopefully extend the operation to the GPU plugin.

[Copilot]

Pull request overview

Adds core ops and template-plugin reference support for RGB/BGR → NV12 conversion, and wires the conversion into the postprocessing pipeline (NV12 single-plane), with accompanying functional/type/visitor tests.

Changes:

• Introduce new opset16 operations RGBtoNV12 and BGRtoNV12 (single-plane and two-plane outputs) with shape inference and reference implementation.
• Enable evaluation/registration in the template plugin backend and add reference/functional tests.
• Extend postprocessing convert_color() to support RGB/BGR → NV12_SINGLE_PLANE, plus new preprocess/postprocess tests.

Reviewed changes

Copilot reviewed 22 out of 22 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/tests/test_utils/common_test_utils/include/common_test_utils/subgraph_builders/preprocess_builders.hpp	Adds postprocess subgraph builders for RGB/BGR → NV12 single-plane.
src/plugins/template/tests/functional/subgraph_reference/preprocess.cpp	Adds template-plugin reference preprocess tests for postprocess RGB/BGR → NV12.
src/plugins/template/tests/functional/op_reference/convert_color_to_nv12.cpp	Adds op-reference tests for RGBtoNV12/BGRtoNV12 (single/two-plane).
src/plugins/template/backend/opset_int_tbl.hpp	Registers new ops in the template plugin opset table.
src/plugins/template/backend/ops/ops_evaluates.hpp	Declares template-backend evaluate specializations for the new ops.
src/plugins/template/backend/ops/convert_color_to_nv12.cpp	Implements template-backend evaluation via the core reference function.
src/core/tests/visitors/op/convert_color_to_nv12.cpp	Adds visitor attribute tests for both ops and plane modes.
src/core/tests/type_prop/convert_color_to_nv12_base.hpp	Adds typed shape/type propagation tests for the new NV12 base op.
src/core/tests/type_prop/convert_color_to_nv12.cpp	Instantiates the new type-prop test suite for both ops.
src/core/tests/preprocess.cpp	Adds postprocess pipeline tests for RGB/BGR → NV12 single-plane and rejects two-plane.
src/core/src/preprocess/preprocess_steps_impl.cpp	Wires postprocess convert_color() to emit RGBtoNV12/BGRtoNV12 for NV12_SINGLE_PLANE.
src/core/src/op/util/convert_color_to_nv12_base.cpp	Implements validation/type inference for the NV12 base op.
src/core/src/op/rgb_to_nv12.cpp	Implements RGBtoNV12 op shell + cloning.
src/core/src/op/bgr_to_nv12.cpp	Implements BGRtoNV12 op shell + cloning.
src/core/shape_inference/include/rgb_bgr_to_nv12_shape_inference.hpp	Adds shape inference for RGB/BGR → NV12 (single/two-plane).
src/core/reference/include/openvino/reference/convert_color_to_nv12.hpp	Adds reference kernel for RGB/BGR → NV12 conversion.
src/core/include/openvino/opsets/opset16_tbl.hpp	Registers new ops in core opset16 table.
src/core/include/openvino/op/util/convert_color_to_nv12_base.hpp	Introduces the new base op API/attributes for RGB/BGR → NV12.
src/core/include/openvino/op/rgb_to_nv12.hpp	Adds public op header for RGBtoNV12.
src/core/include/openvino/op/ops.hpp	Exposes new op headers via umbrella include.
src/core/include/openvino/op/bgr_to_nv12.hpp	Adds public op header for BGRtoNV12.
src/core/docs/operation_enabling_flow.md	Updates documentation path for op implementation locations.

[Copilot]

Pull request overview

Copilot reviewed 22 out of 22 changed files in this pull request and generated 2 comments.

[p-wysocki]

Some builds are failing due to

/__w/openvino/openvino/openvino/src/core/reference/include/openvino/reference/convert_color_to_nv12.hpp:18:36: error: no member named 'min' in namespace 'std'; did you mean 'fmin'?
   18 |         return static_cast<T>(std::min(std::max(std::round(a), 0.0), 255.0));

Overall LGTM, thank you for your PR. Let's wait for more reviews, since this PR is quite big, I'm only covering a part of it. My approve is for the scope of shape infer, spec, type prop tests, reference tests and reference implementation.

@riverlijunjie do you know if there's a model we can use to test the changes?

[p-wysocki]

build_jenkins

[p-durandin]

build_jenkins

[p-durandin]

@mostafafaheem please check CI errors:

CMake Error at cmake/developer_package/add_target_helpers.cmake:627 (message):
[ov_core_unit_tests]
'C:/actions-runner/_work/openvino/openvino/openvino/src/core/tests/type_prop/convert_color_to_nv12.cpp'
exists on disk but is not listed in target sources and will not be
compiled. Add it to the appropriate CMakeLists.txt or sources.cmake.

[mostafafaheem]

@p-durandin Fixed, please check

[p-durandin]

build_jenkins

[Copilot]

Pull request overview

Copilot reviewed 34 out of 34 changed files in this pull request and generated 2 comments.

Suppressed comments (2)

src/core/include/openvino/op/rgb_to_nv12.hpp:33

• [HIGH] These new public opset17 operations have no Python factory/export or Python graph tests. Unlike the existing opset17 operations and the inverse NV12 conversion ops, users cannot construct rgb_to_nv12/bgr_to_nv12 through openvino.opset17. Add wrappers with the single_plane attribute, export them from openvino.opset17, and cover both output modes.

class OPENVINO_API RGBtoNV12 : public util::ConvertColorToNV12Base {
public:
    OPENVINO_OP("RGBtoNV12", "opset17", util::ConvertColorToNV12Base);

src/core/include/openvino/op/util/convert_color_to_nv12_base.hpp:49

• [MEDIUM] The base class registers itself as ConvertColorToRGBBase, which is unrelated to its class and direction of conversion. This exposes incorrect runtime type metadata and risks a future type-info name collision. Register it as ConvertColorToNV12Base, matching the class and established ConvertColorNV12Base/ConvertColorI420Base naming.

    OPENVINO_OP("ConvertColorToRGBBase", "util");

[p-durandin]

build_jenkins

[mostafafaheem]

@praasz @mitruska Can you please have a look at this? It should be ready to merge

[p-durandin]

build_jenkins