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.

libavcodec/threadframe.h

@@ -0,0 +1,87 @@
+/*
+ * Copyright (c) 2022 Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
+ *
+ * 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 AVCODEC_THREADFRAME_H
+#define AVCODEC_THREADFRAME_H
+
+#include "libavutil/frame.h"
+#include "avcodec.h"
+
+typedef struct ThreadFrame {
+    AVFrame *f;
+    AVCodecContext *owner[2];
+    struct ThreadFrameProgress *progress;
+} ThreadFrame;
+
+/**
+ * Notify later decoding threads when part of their reference picture is ready.
+ * Call this when some part of the picture is finished decoding.
+ * Later calls with lower values of progress have no effect.
+ *
+ * @param f The picture being decoded.
+ * @param progress Value, in arbitrary units, of how much of the picture has decoded.
+ * @param field The field being decoded, for field-picture codecs.
+ * 0 for top field or frame pictures, 1 for bottom field.
+ */
+void ff_thread_report_progress(ThreadFrame *f, int progress, int field);
+
+/**
+ * Wait for earlier decoding threads to finish reference pictures.
+ * Call this before accessing some part of a picture, with a given
+ * value for progress, and it will return after the responsible decoding
+ * thread calls ff_thread_report_progress() with the same or
+ * higher value for progress.
+ *
+ * @param f The picture being referenced.
+ * @param progress Value, in arbitrary units, to wait for.
+ * @param field The field being referenced, for field-picture codecs.
+ * 0 for top field or frame pictures, 1 for bottom field.
+ */
+void ff_thread_await_progress(const ThreadFrame *f, int progress, int field);
+
+/**
+ * Wrapper around ff_get_buffer() for frame-multithreaded codecs.
+ * Call this function instead of ff_get_buffer() if you might need
+ * to wait for progress on this frame.
+ * Cannot be called after the codec has called ff_thread_finish_setup().
+ *
+ * @param avctx The current context.
+ * @param f The frame to write into.
+ * @note: It is fine to call this with codecs that do not support
+ *        frame threading.
+ */
+int ff_thread_get_ext_buffer(AVCodecContext *avctx, ThreadFrame *f, int flags);
+
+/**
+ * Unref a ThreadFrame.
+ *
+ * This is basically a wrapper around av_frame_unref() and should
+ * be called instead of it.
+ *
+ * @param avctx The current context.
+ * @param f The picture being released.
+ */
+void ff_thread_release_ext_buffer(ThreadFrame *f);
+
+int ff_thread_ref_frame(ThreadFrame *dst, const ThreadFrame *src);
+
+int ff_thread_replace_frame(ThreadFrame *dst, const ThreadFrame *src);
+
+#endif