FFmpeg 7.1 + cuframes input demuxer

Snapshot FFmpeg n7.1 (release tag) с применённым patch'ем для cuframes
input format. Используется как FFMPEG_REPO_OVERRIDE в NickM-27/FFmpeg-Builds
fork для статической сборки patched binary под Frigate (Debian 12 / glibc 2.36).

Apply changes:
  + libavformat/cuframesdec.c (новый — реализация демуксера)
  M libavformat/Makefile (CONFIG_CUFRAMES_DEMUXER target)
  M libavformat/allformats.c (extern declaration)
  M configure (--enable-libcuframes option + dep check)

Patch source: https://git.goldix.org/gx/cuframes (filter/ffmpeg-7.1-cuframes-demuxer.patch)

History сброшена (snapshot вместо fork) потому что upstream shallow clone
не позволял push в gitea. Полная история FFmpeg — на github.com/FFmpeg/FFmpeg n7.1.

libavfilter/bbox.h

@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2005 Robert Edele <yartrebo@earthlink.net>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVFILTER_BBOX_H
+#define AVFILTER_BBOX_H
+
+#include <stdint.h>
+
+typedef struct FFBoundingBox {
+    int x1, x2, y1, y2;
+} FFBoundingBox;
+
+/**
+ * Calculate the smallest rectangle that will encompass the
+ * region with values > min_val.
+ *
+ * @param bbox bounding box structure which is updated with the found values.
+ *             If no pixels could be found with value > min_val, the
+ *             structure is not modified.
+ * @return 1 in case at least one pixel with value > min_val was found,
+ *         0 otherwise
+ */
+int ff_calculate_bounding_box(FFBoundingBox *bbox,
+                              const uint8_t *data, int linesize,
+                              int w, int h, int min_val, int depth);
+
+#endif /* AVFILTER_BBOX_H */