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/encode.h

@@ -0,0 +1,99 @@
+/*
+ * generic encoding-related code
+ *
+ * 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_ENCODE_H
+#define AVCODEC_ENCODE_H
+
+#include "libavutil/frame.h"
+
+#include "avcodec.h"
+#include "packet.h"
+
+/**
+ * Used by some encoders as upper bound for the length of headers.
+ * TODO: Use proper codec-specific upper bounds.
+ */
+#define FF_INPUT_BUFFER_MIN_SIZE 16384
+
+/**
+ * Called by encoders to get the next frame for encoding.
+ *
+ * @param frame An empty frame to be filled with data.
+ * @return 0 if a new reference has been successfully written to frame
+ *         AVERROR(EAGAIN) if no data is currently available
+ *         AVERROR_EOF if end of stream has been reached, so no more data
+ *                     will be available
+ */
+int ff_encode_get_frame(AVCodecContext *avctx, AVFrame *frame);
+
+/**
+ * Get a buffer for a packet. This is a wrapper around
+ * AVCodecContext.get_encode_buffer() and should be used instead calling get_encode_buffer()
+ * directly.
+ */
+int ff_get_encode_buffer(AVCodecContext *avctx, AVPacket *avpkt, int64_t size, int flags);
+
+/**
+ * Allocate buffers for a frame. Encoder equivalent to ff_get_buffer().
+ */
+int ff_encode_alloc_frame(AVCodecContext *avctx, AVFrame *frame);
+
+/**
+ * Check AVPacket size and allocate data.
+ *
+ * Encoders of type FF_CODEC_CB_TYPE_ENCODE can use this as a convenience to
+ * obtain a big enough buffer for the encoded bitstream.
+ *
+ * @param avctx   the AVCodecContext of the encoder
+ * @param avpkt   The AVPacket: on success, avpkt->data will point to a buffer
+ *                of size at least `size`; the packet will not be refcounted.
+ *                This packet must be initially blank.
+ * @param size    an upper bound of the size of the packet to encode
+ * @return        non negative on success, negative error code on failure
+ */
+int ff_alloc_packet(AVCodecContext *avctx, AVPacket *avpkt, int64_t size);
+
+/**
+ * Propagate user opaque values from the frame to avctx/pkt as needed.
+ */
+int ff_encode_reordered_opaque(AVCodecContext *avctx,
+                               AVPacket *pkt, const AVFrame *frame);
+
+int ff_encode_encode_cb(AVCodecContext *avctx, AVPacket *avpkt,
+                        AVFrame *frame, int *got_packet);
+
+/**
+ * Add a CPB properties side data to an encoding context.
+ */
+AVCPBProperties *ff_encode_add_cpb_side_data(AVCodecContext *avctx);
+
+/**
+ * Rescale from sample rate to AVCodecContext.time_base.
+ */
+static av_always_inline int64_t ff_samples_to_time_base(const AVCodecContext *avctx,
+                                                        int64_t samples)
+{
+    if (samples == AV_NOPTS_VALUE)
+        return AV_NOPTS_VALUE;
+    return av_rescale_q(samples, (AVRational){ 1, avctx->sample_rate },
+                        avctx->time_base);
+}
+
+#endif /* AVCODEC_ENCODE_H */