core: support parsing null in json parser in FileStorage #27579
Fixes https://github.com/opencv/opencv/issues/27578
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This is a useful property for modularized libraries and applications to be able to use OpenCV
A full module-info.java file for true compatibility with the Java module system would require compiling with Java 9+ and either use a multi-release JAR (which can be tricky to maintain) or compile the entire library with Java 9+ (which would break Android consumers on older SDK versions). In the interest of causing the least disruption, only an automatic module name is set so that modular Java 9+ consumers can use OpenCV but not break anybody else.
Fixed build issue with some old GCC versions #27569
Fixes build for GCC 4.8.5 at least. Looks like the method default signature differs cross GCC versions or newer version has softer checker.
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[GSOC 2025] PNG&WebP Metadata Reading Writing Improvements #27503
Merge with https://github.com/opencv/opencv_extra/pull/1271
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G-API: Implement cfgEnsureNamedTensors option to OpenVINO Params #27549
Added the option cfgEnsureNamedTensors to be applied on OpenVINO models with nameless tensors. If a tensor doesn't have a name, it sets a default one. The default name is created using OpenVINO's standard `make_default_tensor_name` . `make_default_tensor_name` had to be rewritten because it is only available in OpenVINO's dev_api.
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Add enum IMWRITE_PNG_ZLIBBUFFER_SIZE #27551
### Pull Request Readiness Checklist
This patch enables users to set the internal zlib compression buffer size for PNG encoding
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Add Raspberry Pi 4 and 5 V4L2 Stateless HEVC Hardware Acceleration with FFmpeg #27453
This PR enables V4L2 stateless HEVC hardware acceleration for Raspberry Pi 5 within OpenCV's videoio module. It leverages FFmpeg's drm acceleration ([FFmpeg API changes](https://github.com/FFmpeg/FFmpeg/blob/ee1f79b0fa4c82da9c19328b049b593c71611402/doc/APIchanges#L1529)), significantly improving HEVC decoding performance on RPi5 for robotics and embedded vision applications.
I have a working proof-of-concept with local benchmarks showing clear gains.
Checklist Status:
Ready: License, branch (4.x), FFmpeg reference, and (linked) related issue (#27452).
Seeking Guidance: Need help with formal C++ performance/accuracy tests, opencv_extra integration, and full documentation/examples.
As a Python developer, I welcome C++ best practice feedback and assistance with testing setup.
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imgcodecs: OpenEXR multispectral read/write support #27485
OpenCV Extra: https://github.com/opencv/opencv_extra/pull/1262/
Adds capability to read and write multispectral (>4 channels) images in OpenEXR format.
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FIX: CvCapture_FFMPEG::setProperty(CAP_PROP_POS_*) followed by getProperty #27523
Partially fixes#23088 and #23472. This PR fixes `get(CAP_PROP_POS_MSEC)` calls after a `set(CAP_PROP_POS_*)` without calling `read` first.
Since `seek` calls `grabFrame` which already sets `picture_pts`, manually setting `picture_pts` anywhere else in the call stack should not be necessary (except for the special case of seeking to frame 0).
Minimal example from #23088
```cpp
for(int i = 0; i < 3; i++) cap.read(img);
printf("at: %f frames, %f msec\n", cap.get(CAP_PROP_POS_FRAMES), cap.get(CAP_PROP_POS_MSEC));
cap.set(CAP_PROP_POS_FRAMES, 3);
printf("at: %f frames, %f msec\n", cap.get(CAP_PROP_POS_FRAMES), cap.get(CAP_PROP_POS_MSEC));
```
Current
```txt
at: 3.000000 frames, 80.000000 msec
at: 3.000000 frames, 0.234375 msec
```
PR
```txt
at: 3.000000 frames, 80.000000 msec
at: 3.000000 frames, 80.000000 msec
```
It similarly helps with `CAP_PROP_POS_MSEC`:
Current
```txt
at: 3.000000 frames, 80.000000 msec
at: 2.000000 frames, 6.250000 msec
```
PR
```txt
at: 3.000000 frames, 80.000000 msec
at: 2.000000 frames, 40.000000 msec
```
Note the seek operation is still inconsistent between the `CAP_PROP_POS_*` options as mentioned by #23088, and VFR video seeking has issues discussed in #9053. For fixed-frame rate video, we could change 0.5 to 1 in `void CvCapture_FFMPEG::seek(double sec);` to align `CAP_PROP_POS_MSEC` with `CAP_PROP_POS_FRAMES`, but `CAP_POS_AVI_RATIO` and VFR video would still be broken.
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In my configuration with bazel, when building the Java bindings,
it is not like building C++ and including videio/videoio.hpp
triggers:
error this is a compatibility header which should not be used inside the OpenCV library
Extend image I/O API with metadata support #27499
Covered with the PR:
* AVIF encoder can write exif, xmp, icc
* AVIF decoder can read exif
* JPEG encoder can write exif
* JPEG decoder can read exif
* PNG encoder can write exif
* PNG decoder can read exif
This PR is a sort of preamble for #27488. I suggest to merge this one first to OpenCV 4.x, then promote this change to OpenCV 5.x and then provide extra API to read and write metadata in 5.x (or maybe 4.x) in a style similar to #27488. Maybe in that PR exif packing/unpacking should be done using a separate external API. That is, metadata reading and writing can/should be done in 2 steps:
* [1] pack and then [2] embed exif into image at the encoding stage.
* [1] extract and then [2] unpack exif at the decoding stage.
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Issue 26972: Proper treatment of float values in intersectConvexConvex #26974
As outlined in https://github.com/opencv/opencv/issues/26972 the function `intersectConvexConvex()` may not work as expected in the corner case, where two polygons intersect at a corner. A concrete example is given that I added as unit test. The unit test would fail without the proposed bug fix. I recommend porting the fix to all versions.
Now concerning the fix: When digging into the implementation I found, that when the line intersections are computed, openCV currently does not apply floating point comparison syntax, but pretends that line end points are exact. Instead I replaced the formulation using the eps that is already used in another component of the function in line.277: `epx=1e-5`. IMO that is solid enough, definitely better than assuming an exact floating point comparison is possible.
As a follow up I would suggest to use a scalable eps, s.t. also cases with high floating point numbers would be less error prone. However that would need to be done in all relevant sub steps, not just the line intersection code. So for me outside the scope of this fix.
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Alexander Smorkalov
Yuantao Feng
Sam Carlberg
Suleyman TURKMEN
pratham-mcw
Andrei Tamas
Yan Wen
Vincent Rabaud
inventshah
xaos-cz
Dmytro Dadyka
ekharkov
Kumataro
eplankin
Alexander Smorkalov
Vadim Pisarevsky
Martin
Martin Valgur
Maksim Shabunin
Alexander Alekhin
Souriya Trinh