From 459a60927135d9aaa3d4a8bc2b46e36dbba6f7f2 Mon Sep 17 00:00:00 2001
From: Alexander Smorkalov <2536374+asmorkalov@users.noreply.github.com>
Date: Thu, 25 Dec 2025 15:43:38 +0300
Subject: [PATCH] Merge pull request #28283 from
 asmorkalov:as/ffmpeg_picture_leak

Fixed picture_sw object leak in ffmpeg backend with hardware codecs. #28283

Replacement for https://github.com/opencv/opencv/pull/28221

### Pull Request Readiness Checklist

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [ ] The PR is proposed to the proper branch
- [ ] There is a reference to the original bug report and related work
- [ ] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
      Patch to opencv_extra has the same branch name.
- [ ] The feature is well documented and sample code can be built with the project CMake
---
 modules/videoio/src/cap_ffmpeg_impl.hpp | 37 ++++++++++++++++++++++---
 1 file changed, 33 insertions(+), 4 deletions(-)

diff --git a/modules/videoio/src/cap_ffmpeg_impl.hpp b/modules/videoio/src/cap_ffmpeg_impl.hpp
index 26509a1a81..afd8fd4098 100644
--- a/modules/videoio/src/cap_ffmpeg_impl.hpp
+++ b/modules/videoio/src/cap_ffmpeg_impl.hpp
@@ -1845,16 +1845,28 @@ bool CvCapture_FFMPEG::retrieveFrame(int flag, unsigned char** data, int* step,
     // if hardware frame, copy it to system memory
     if (picture && picture->hw_frames_ctx) {
         sw_picture = av_frame_alloc();
+        if (!sw_picture) {
+            CV_LOG_ERROR(NULL, "av_frame_alloc failed");
+            return false;
+        }
         //if (av_hwframe_map(sw_picture, picture, AV_HWFRAME_MAP_READ) < 0) {
         if (av_hwframe_transfer_data(sw_picture, picture, 0) < 0) {
             CV_LOG_ERROR(NULL, "Error copying data from GPU to CPU (av_hwframe_transfer_data)");
+            av_frame_free(&sw_picture);
             return false;
         }
     }
 #endif
 
     if (!sw_picture || !sw_picture->data[0])
+    {
+#if USE_AV_HW_CODECS
+        if (sw_picture != picture)
+            av_frame_free(&sw_picture);
+#endif
+        CV_LOG_ERROR(NULL, "Picture does not contain data");
         return false;
+    }
 
 #if LIBAVUTIL_BUILD >= CALC_FFMPEG_VERSION(56, 72, 0)
     const char* color_space_name = av_color_space_name(sw_picture->colorspace);
@@ -1905,7 +1917,14 @@ bool CvCapture_FFMPEG::retrieveFrame(int flag, unsigned char** data, int* step,
 
         img_convert_ctx = sws_alloc_context();
         if (img_convert_ctx == NULL)
-            return false;//CV_Error(0, "Cannot initialize the conversion context!");
+        {
+            CV_LOG_ERROR(NULL, "Cannot initialize the conversion context!");
+#if USE_AV_HW_CODECS
+            if (sw_picture != picture)
+                av_frame_free(&sw_picture);
+#endif
+            return false;
+        }
 
         av_opt_set_int(img_convert_ctx, "sws_flags", SWS_BICUBIC, 0);
         av_opt_set_int(img_convert_ctx, "threads", requestedThreads, 0);
@@ -1946,8 +1965,14 @@ bool CvCapture_FFMPEG::retrieveFrame(int flag, unsigned char** data, int* step,
                 );
 #endif
 
-        if (img_convert_ctx == NULL)
-            return false;//CV_Error(0, "Cannot initialize the conversion context!");
+        if (img_convert_ctx == NULL) {
+            CV_LOG_ERROR(NULL, "Cannot initialize the conversion context!");
+#if USE_AV_HW_CODECS
+            if (sw_picture != picture)
+                av_frame_free(&sw_picture);
+#endif
+            return false;
+        }
 
 #if USE_AV_FRAME_GET_BUFFER
         av_frame_unref(&rgb_picture);
@@ -1956,7 +1981,11 @@ bool CvCapture_FFMPEG::retrieveFrame(int flag, unsigned char** data, int* step,
         rgb_picture.height = buffer_height;
         if (0 != av_frame_get_buffer(&rgb_picture, 32))
         {
-            CV_WARN("OutOfMemory");
+            CV_LOG_ERROR(NULL, "Out of memory issue on av_frame_get_buffer!");
+#if USE_AV_HW_CODECS
+            if (sw_picture != picture)
+                av_frame_free(&sw_picture);
+#endif
             return false;
         }
 #else