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.

libavformat/dvbtxt.c

@@ -0,0 +1,50 @@
+/*
+ * RAW dvb teletext demuxer
+ * Copyright (c) 2016 Marton Balnt <cus@passwd.hu>
+ *
+ * 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
+ */
+
+#include "libavcodec/dvbtxt.h"
+
+#include "avformat.h"
+#include "rawdec.h"
+
+static int dvbtxt_probe(const AVProbeData *p)
+{
+    const uint8_t *end = p->buf + p->buf_size;
+    const uint8_t *buf;
+
+    /* The purpose of this is demuxer is to detect DVB teletext streams in
+     * mpegts, so we reject invalid buffer sizes */
+    if ((p->buf_size + 45) % 184 != 0)
+        return 0;
+
+    if (!ff_data_identifier_is_teletext(p->buf[0]))
+        return 0;
+
+    for (buf = p->buf + 1; buf < end; buf += 46) {
+        if (!ff_data_unit_id_is_teletext(buf[0]) && buf[0] != 0xff)
+            return 0;
+        if (buf[1] != 0x2c)     // data_unit_length
+            return 0;
+    }
+
+    return AVPROBE_SCORE_MAX / 2;
+}
+
+FF_DEF_RAWSUB_DEMUXER(dvbtxt, "dvbtxt", dvbtxt_probe, NULL, AV_CODEC_ID_DVB_TELETEXT, 0)