Stream history: in-memory H.264+AAC ring via ffmpeg (opt-in CMake toggle)

.github/workflows/cpp-ci-serial-programs-base.yml

@@ -97,6 +97,7 @@ jobs:
           cd Arduino-Source
           sudo apt update
           sudo apt install ccache clang-tools libopencv-dev libsystemd-dev
+          sudo apt install libavcodec-dev libavformat-dev libavutil-dev libswscale-dev libswresample-dev
 
           sudo apt install ./3rdPartyBinaries/libdpp-10.1.5-linux-x64.deb
 
@@ -106,7 +107,7 @@ jobs:
           cd Arduino-Source
           # libsodium, openssl@3, opus and pkgconf are libdpp's dependencies, installed here so
           # their versions can go into the libdpp cache key below.
-          brew install opencv@4 onnxruntime ccache libsodium openssl@3 opus pkgconf
+          brew install opencv@4 onnxruntime ccache libsodium openssl@3 opus pkgconf ffmpeg
 
           brew tap-new --no-git PA/libdpp
           brew trust PA/libdpp

3rdParty/ffmpeg/README.txt

@@ -0,0 +1,4 @@
+LGPL build taken from:
+https://github.com/btbn/ffmpeg-builds/releases/tag/autobuild-2026-10-13-13-05
+version: "n9.0.2-27-g7e93014c5b-20261013"
+ffmpeg-n9.0.2-27-g7e93014c5b-win64-lgpl-shared-9.0.zip

3rdParty/ffmpeg/libavcodec/ac3_parser.h

@@ -0,0 +1,36 @@
+/*
+ * AC-3 parser prototypes
+ * Copyright (c) 2003 Fabrice Bellard
+ * Copyright (c) 2003 Michael Niedermayer
+ *
+ * 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_AC3_PARSER_H
+#define AVCODEC_AC3_PARSER_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+/**
+ * Extract the bitstream ID and the frame size from AC-3 data.
+ */
+int av_ac3_parse_header(const uint8_t *buf, size_t size,
+                        uint8_t *bitstream_id, uint16_t *frame_size);
+
+
+#endif /* AVCODEC_AC3_PARSER_H */

3rdParty/ffmpeg/libavcodec/adts_parser.h

@@ -0,0 +1,37 @@
+/*
+ * 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_ADTS_PARSER_H
+#define AVCODEC_ADTS_PARSER_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+#define AV_AAC_ADTS_HEADER_SIZE 7
+
+/**
+ * Extract the number of samples and frames from AAC data.
+ * @param[in]  buf     pointer to AAC data buffer
+ * @param[out] samples Pointer to where number of samples is written
+ * @param[out] frames  Pointer to where number of frames is written
+ * @return Returns 0 on success, error code on failure.
+ */
+int av_adts_header_parse(const uint8_t *buf, uint32_t *samples,
+                         uint8_t *frames);
+
+#endif /* AVCODEC_ADTS_PARSER_H */