WIP: Ffmpeg decoder, encoders and filters.

Kconfig

@@ -1,7 +1,112 @@
 # SPDX-License-Identifier: BSD-3-Clause
 
-mainmenu "SOF $(PROJECTVERSION) Configuration"
+config COMP_FFMPEG_DEC
+	tristate "FFmpeg (libavcodec) audio decoder"
+	select COMP_FFMPEG_DEC_STUB if COMP_STUBS
+	help
+	  Select to include the FFmpeg audio decoder module. It wraps
+	  libavcodec decoders behind the SOF module interface, decoding a
+	  compressed elementary stream to PCM. The real backend cross-builds
+	  libavcodec/libavutil/libswresample from the FFmpeg source pulled in
+	  by west (see west.yml), enabling only the decoders selected below.
+	  Without the source (or for CI) select COMP_FFMPEG_DEC_STUB to build
+	  the dependency-free passthrough stub.
 
-comment "Compiler: $(CC_VERSION_TEXT)"
+config COMP_FFMPEG_DEC_STUB
+	bool "FFmpeg decoder stub backend"
+	depends on COMP_FFMPEG_DEC
+	help
+	  Build the ffmpeg_dec module against a dependency-free passthrough
+	  backend instead of libavcodec. Intended for testing and CI so the
+	  SOF glue and LLEXT packaging can be validated without the FFmpeg
+	  source or a cross-built archive.
 
-source "Kconfig.sof"
+if COMP_FFMPEG_DEC && !COMP_FFMPEG_DEC_STUB
+
+comment "FFmpeg decoders to build (footprint scales with selection)"
+
+config FFMPEG_DEC_FLAC
+	bool "FLAC decoder"
+	default y
+	help
+	  Lossless integer decoder. Smallest footprint, no floating-point
+	  math. Enables --enable-decoder=flac in the libavcodec build.
+
+config FFMPEG_DEC_AAC
+	bool "AAC-LC decoder"
+	help
+	  AAC Low Complexity decoder. Pulls in the single-precision float
+	  math layer (see FFMPEG_DEC_FLOAT_MATH). Enables
+	  --enable-decoder=aac in the libavcodec build.
+
+config FFMPEG_DEC_OPUS
+	bool "Opus decoder"
+	help
+	  Opus (SILK+CELT) decoder. Pulls in the single-precision float math
+	  layer. Enables --enable-decoder=opus in the libavcodec build.
+
+config FFMPEG_DEC_MP3
+	bool "MP3 decoder"
+	help
+	  MPEG-1/2 Layer III decoder. Enables --enable-decoder=mp3 and the
+	  mpegaudio parser in the libavcodec build. Uses the float math layer.
+
+config FFMPEG_ENC_MP3
+	bool "MP3 encoder (libshine, fixed-point)"
+	help
+	  MPEG-1 Layer III encoder via libshine, a small fixed-point encoder
+	  (west-pinned; FFmpeg has no native MP3 encoder). Cross-builds libshine
+	  and enables --enable-libshine --enable-encoder=libshine. Fixed-point, so
+	  no float math dependency. The encoder is built into the archive; a module
+	  encode path (PCM->MP3) is a separate build mode.
+
+comment "FFmpeg audio filters (libavfilter; need the avfilter-graph backend to run)"
+
+config FFMPEG_FILTER_AFFTDN
+	bool "FFT noise reduction (afftdn)"
+	help
+	  Build FFmpeg's FFT-based denoiser (afftdn) into libavfilter. Pure DSP,
+	  no external model file (unlike arnndn). Enabling any filter turns on
+	  libavfilter in the cross-build. NOTE: a filter is only usable at runtime
+	  once the module gains an avfilter-graph backend; selecting it here just
+	  builds the filter into the archive.
+
+config FFMPEG_DEC_FILTER_MODE
+	bool "Build as a PCM filter effect instead of a decoder [EXPERIMENTAL]"
+	select FFMPEG_FILTER_AFFTDN
+	help
+	  Build the module as a PCM source->sink effect that runs an FFmpeg
+	  audio filter graph (default afftdn noise reduction) via the modern
+	  .process interface, instead of the compressed-stream decoder. Turns on
+	  libavfilter and the fast float math. Structurally complete and
+	  load-ready; real-time latency/format tuning needs on-hardware bring-up.
+
+# Turns on libavfilter in the FFmpeg cross-build when any filter is selected.
+config FFMPEG_BUILD_AVFILTER
+	bool
+	default y if FFMPEG_FILTER_AFFTDN
+
+# Selected automatically when a decoder or filter that needs IEEE float math is
+# built. Gates compilation of the fast single-precision libm (fastmathf.c).
+config FFMPEG_DEC_FLOAT_MATH
+	bool
+	default y if FFMPEG_DEC_AAC || FFMPEG_DEC_OPUS || FFMPEG_DEC_MP3 || FFMPEG_FILTER_AFFTDN
+
+config FFMPEG_DEC_COLD_SPLIT
+	bool "Place cold FFmpeg code (av_cold init/setup) in DRAM [EXPERIMENTAL]"
+	depends on COLD_STORE_EXECUTE_DRAM
+	default n
+	help
+	  EXPERIMENTAL. Build libavcodec with -mtext-section-literals and rename
+	  FFmpeg's cold functions (its av_cold init/table-generation code, which GCC
+	  emits into .text.unlikely) into SOF's .cold section so the LLEXT loader
+	  places them in DRAM, keeping the hot per-frame decode in fast SRAM.
+
+	  Measured cold code is small (~1 KB for FLAC, ~26 KB for AAC) because
+	  FFmpeg only marks init functions av_cold. Placing that much cold code in a
+	  -shared LLEXT currently hits Xtensa linker limits (cold->hot call8 range
+	  needs -mlongcalls; the orphan .cold lands at a bad LMA and overlaps .hash),
+	  so this is off by default pending proper cold-region placement in the LLEXT
+	  memory map. See git history / TESTING notes.
+
+endif # COMP_FFMPEG_DEC && !COMP_FFMPEG_DEC_STUB

ffmpeg.cmake

@@ -0,0 +1,199 @@
+# SPDX-License-Identifier: BSD-3-Clause
+#
+# Cross-build decoder-only FFmpeg static libraries for the ffmpeg_dec module.
+#
+# Invokes FFmpeg's autotools build as an ExternalProject, cross-compiled with the
+# Zephyr target toolchain, enabling only the decoders selected in Kconfig. The
+# source comes from the west-pinned FFmpeg project (see west.yml). Produces
+# libavcodec/libavutil/libswresample .a under ${FFMPEG_INSTALL_DIR} for the LLEXT
+# to link, and defines the 'ffmpeg_ext' target it must depend on.
+
+include(ExternalProject)
+
+# --- 1. Locate the FFmpeg source (west module), overridable for local trees ---
+if(NOT DEFINED SOF_FFMPEG_SRC_DIR)
+	set(SOF_FFMPEG_SRC_DIR "${sof_top_dir}/../modules/audio/ffmpeg"
+	    CACHE PATH "FFmpeg source tree (west-pinned)")
+endif()
+cmake_path(NORMAL_PATH SOF_FFMPEG_SRC_DIR)
+if(NOT EXISTS "${SOF_FFMPEG_SRC_DIR}/configure")
+	message(FATAL_ERROR
+		"ffmpeg_dec: FFmpeg source not found at '${SOF_FFMPEG_SRC_DIR}'.\n"
+		"Run 'west update' (FFmpeg is pinned in west.yml) or pass "
+		"-DSOF_FFMPEG_SRC_DIR=<path-to-clean-ffmpeg-checkout>.")
+endif()
+
+# --- 2. Kconfig -> --enable-decoder / --enable-parser lists ---
+set(_ff_decoders "")
+set(_ff_parsers "")
+if(CONFIG_FFMPEG_DEC_FLAC)
+	list(APPEND _ff_decoders flac)
+	list(APPEND _ff_parsers  flac)
+endif()
+if(CONFIG_FFMPEG_DEC_AAC)
+	list(APPEND _ff_decoders aac aac_latm)
+	list(APPEND _ff_parsers  aac aac_latm)
+endif()
+if(CONFIG_FFMPEG_DEC_OPUS)
+	list(APPEND _ff_decoders opus)
+	list(APPEND _ff_parsers  opus)
+endif()
+if(CONFIG_FFMPEG_DEC_MP3)
+	list(APPEND _ff_decoders mp3)
+	list(APPEND _ff_parsers  mpegaudio)
+endif()
+if(NOT _ff_decoders)
+	message(FATAL_ERROR "ffmpeg_dec: no decoder selected (Kconfig FFMPEG_DEC_*)")
+endif()
+list(JOIN _ff_decoders "," _ff_dec_csv)
+list(JOIN _ff_parsers  "," _ff_par_csv)
+
+# --- 2b. Kconfig -> libavfilter audio filters (off unless a filter is chosen) ---
+set(_ff_avfilter_cfg --disable-avfilter)
+if(CONFIG_FFMPEG_BUILD_AVFILTER)
+	set(_ff_filters "")
+	if(CONFIG_FFMPEG_FILTER_AFFTDN)
+		list(APPEND _ff_filters afftdn)
+	endif()
+	list(JOIN _ff_filters "," _ff_filt_csv)
+	# abuffer/abuffersink feed/drain a filter graph; aformat negotiates format.
+	set(_ff_avfilter_cfg
+		--enable-avfilter
+		--enable-filter=abuffer,abuffersink,aformat,${_ff_filt_csv})
+	message(STATUS "ffmpeg_dec: enabling avfilter, filters [${_ff_filt_csv}]")
+endif()
+
+# --- 3. Derive the cross toolchain prefix from the Zephyr target compiler ---
+# e.g. .../bin/xtensa-intel_ace30_ptl_zephyr-elf-gcc
+#   -> prefix .../bin/xtensa-intel_ace30_ptl_zephyr-elf-
+get_filename_component(_tc_dir  "${CMAKE_C_COMPILER}" DIRECTORY)
+get_filename_component(_tc_name "${CMAKE_C_COMPILER}" NAME)
+string(REGEX REPLACE "gcc$" "" _tc_prefix_name "${_tc_name}")
+set(_ff_cross_prefix "${_tc_dir}/${_tc_prefix_name}")
+
+# GCC 14 (Zephyr SDK) promotes these to errors; FFmpeg 7.x trips them.
+set(_ff_extra_cflags "-fPIC -Wno-error=incompatible-pointer-types -Wno-error=implicit-function-declaration")
+
+set(FFMPEG_INSTALL_DIR "${CMAKE_CURRENT_BINARY_DIR}/ffmpeg-install" CACHE INTERNAL "ffmpeg_dec libs")
+
+# Hot/cold split: GCC emits av_cold (init/setup) functions into .text.unlikely.
+# We rename that to SOF's .cold (post-install, below) so the LLEXT loader places
+# it in DRAM. -mtext-section-literals interleaves each function's Xtensa L32R
+# literals into its text section (as SOF does for LLEXT module code) so the
+# renamed section carries its literals and L32R stays in range. We deliberately
+# do NOT use -ffunction-sections: keeping one .text.unlikely per object lets a
+# single objcopy --rename-section catch it, and lets .cold be placed by SOF's
+# existing orphan .cold handling (a hand-written linker script that forces .cold
+# ahead of .text overruns the SRAM budget and overlaps .rodata for big codecs).
+if(CONFIG_FFMPEG_DEC_COLD_SPLIT)
+	# -mlongcalls: cold code lives in DRAM (.cold, relocated by the loader) far
+	# from the hot SRAM .text, so calls between them exceed call8 range; longcalls
+	# emit an indirect L32R+CALLX with unlimited range. -mtext-section-literals
+	# keeps each function's literals in its own text section so the rename carries
+	# them. Coarse split: rename the whole FFmpeg .text (not just av_cold) into
+	# .cold so essentially all of libav* executes from DRAM, freeing SRAM.
+	set(_ff_extra_cflags "${_ff_extra_cflags} -mtext-section-literals -mlongcalls")
+	set(_ff_objcopy "${_ff_cross_prefix}objcopy")
+	set(_ff_cold_rename
+		COMMAND ${_ff_objcopy} --rename-section .text=.cold
+			${FFMPEG_INSTALL_DIR}/lib/libavcodec.a
+		COMMAND ${_ff_objcopy} --rename-section .text=.cold
+			${FFMPEG_INSTALL_DIR}/lib/libavutil.a
+		COMMAND ${_ff_objcopy} --rename-section .text=.cold
+			${FFMPEG_INSTALL_DIR}/lib/libswresample.a)
+endif()
+
+# --- 3b. MP3 encoder via libshine (fixed-point; FFmpeg has no native one) ---
+set(_ff_cfg_env "PATH=${_tc_dir}:$ENV{PATH}")
+set(_ff_shine_cfg "")
+set(_ff_shine_dep "")
+if(CONFIG_FFMPEG_ENC_MP3)
+	set(SHINE_SRC "${sof_top_dir}/../modules/audio/shine")
+	if(NOT EXISTS "${SHINE_SRC}/src/lib/layer3.h")
+		message(FATAL_ERROR "ffmpeg_dec: libshine source not at '${SHINE_SRC}'; run 'west update'")
+	endif()
+	set(SHINE_INSTALL "${CMAKE_CURRENT_BINARY_DIR}/shine-install")
+	file(MAKE_DIRECTORY "${SHINE_INSTALL}/lib/pkgconfig" "${SHINE_INSTALL}/include/shine")
+	# pkg-config file for FFmpeg's require_pkg_config libshine.
+	file(WRITE "${SHINE_INSTALL}/lib/pkgconfig/shine.pc"
+"prefix=${SHINE_INSTALL}
+libdir=\${prefix}/lib
+includedir=\${prefix}/include
+Name: shine
+Description: Shine fixed-point MP3 encoder
+Version: 3.1.1
+Libs: -L\${libdir} -lshine
+Cflags: -I\${includedir}
+")
+	# FFmpeg's -lshine link *test* pulls newlib malloc -> Zephyr runtime syms
+	# (z_errno_wrap, ...) that only exist at module load. Provide dummies so the
+	# configure test links; --extra-ldflags only affects tests, not the .a build.
+	file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/shine_cfgstub.c"
+"int z_errno_wrap(void){return 0;}
+void *stdout;
+int open(const char *p, int f, ...){return -1;}
+void *sbrk(int i){return (void *)-1;}
+")
+	# libshine's lib needs no config.h; build the objects directly and archive
+	# (its autotools CLI/shared link cannot work bare-metal).
+	file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/shine-build.sh"
+"#!/bin/sh
+set -e
+export PATH=${_tc_dir}:\$PATH
+mkdir -p ${CMAKE_CURRENT_BINARY_DIR}/shine-obj
+for f in ${SHINE_SRC}/src/lib/*.c; do
+	${CMAKE_C_COMPILER} -O2 -fPIC -mtext-section-literals -DSHINE_HAVE_BSWAP_H \\
+		-I${SHINE_SRC}/src/lib -c \"\$f\" \\
+		-o ${CMAKE_CURRENT_BINARY_DIR}/shine-obj/\$(basename \"\$f\").o
+done
+${_ff_cross_prefix}ar rcs ${SHINE_INSTALL}/lib/libshine.a ${CMAKE_CURRENT_BINARY_DIR}/shine-obj/*.o
+cp ${SHINE_SRC}/src/lib/layer3.h ${SHINE_INSTALL}/include/shine/layer3.h
+${CMAKE_C_COMPILER} -fPIC -c ${CMAKE_CURRENT_BINARY_DIR}/shine_cfgstub.c \\
+	-o ${CMAKE_CURRENT_BINARY_DIR}/shine_cfgstub.o
+")
+	add_custom_command(
+		OUTPUT "${SHINE_INSTALL}/lib/libshine.a" "${CMAKE_CURRENT_BINARY_DIR}/shine_cfgstub.o"
+		COMMAND sh "${CMAKE_CURRENT_BINARY_DIR}/shine-build.sh"
+		VERBATIM)
+	add_custom_target(shine_ext DEPENDS "${SHINE_INSTALL}/lib/libshine.a")
+
+	set(_ff_cfg_env "PATH=${_tc_dir}:$ENV{PATH}" "PKG_CONFIG_PATH=${SHINE_INSTALL}/lib/pkgconfig")
+	set(_ff_shine_cfg --enable-libshine --enable-encoder=libshine --pkg-config=pkg-config
+		"--extra-ldflags=${CMAKE_CURRENT_BINARY_DIR}/shine_cfgstub.o")
+	set(_ff_shine_dep shine_ext)
+	message(STATUS "ffmpeg_dec: enabling MP3 encoder via libshine (${SHINE_SRC})")
+endif()
+
+# --- 4. Configure + make + install (out-of-tree; source must be clean) ---
+ExternalProject_Add(ffmpeg_ext
+	DEPENDS ${_ff_shine_dep}
+	SOURCE_DIR      "${SOF_FFMPEG_SRC_DIR}"
+	BUILD_IN_SOURCE 0
+	CONFIGURE_COMMAND
+		${CMAKE_COMMAND} -E env ${_ff_cfg_env}
+		<SOURCE_DIR>/configure
+			--prefix=${FFMPEG_INSTALL_DIR}
+			--enable-cross-compile --target-os=none --arch=xtensa
+			--cross-prefix=${_ff_cross_prefix} --cc=${CMAKE_C_COMPILER}
+			--disable-asm --disable-all --disable-everything --disable-autodetect
+			--disable-programs --disable-doc --disable-network
+			--disable-avformat --disable-avdevice ${_ff_avfilter_cfg}
+			--disable-swscale --disable-postproc
+			--disable-pthreads --disable-w32threads --disable-os2threads
+			--disable-runtime-cpudetect --disable-debug
+			--enable-avcodec --enable-avutil --enable-swresample
+			--enable-decoder=${_ff_dec_csv} --enable-parser=${_ff_par_csv}
+			${_ff_shine_cfg}
+			--enable-small --enable-pic
+			"--extra-cflags=${_ff_extra_cflags}"
+	BUILD_COMMAND
+		${CMAKE_COMMAND} -E env "PATH=${_tc_dir}:$ENV{PATH}" make -j 8
+	INSTALL_COMMAND make install
+		${_ff_cold_rename}
+	BUILD_BYPRODUCTS
+		${FFMPEG_INSTALL_DIR}/lib/libavcodec.a
+		${FFMPEG_INSTALL_DIR}/lib/libavutil.a
+		${FFMPEG_INSTALL_DIR}/lib/libswresample.a
+)
+
+message(STATUS "ffmpeg_dec: cross-building FFmpeg decoders [${_ff_dec_csv}] from ${SOF_FFMPEG_SRC_DIR}")

src/audio/CMakeLists.txt

@@ -41,6 +41,9 @@ if(NOT CONFIG_COMP_MODULE_SHARED_LIBRARY_BUILD)
 	if(CONFIG_COMP_DRC)
 		add_subdirectory(drc)
 	endif()
+	if(CONFIG_COMP_FFMPEG_DEC)
+		add_subdirectory(ffmpeg_dec)
+	endif()
 	if(CONFIG_COMP_FIR)
 		add_subdirectory(eq_fir)
 	endif()
@@ -107,6 +110,18 @@ if(NOT CONFIG_COMP_MODULE_SHARED_LIBRARY_BUILD)
 	if(CONFIG_COMP_VOLUME)
 		add_subdirectory(volume)
 	endif()
+	if(CONFIG_COMP_WEBRTC_VAD)
+		add_subdirectory(webrtc_vad)
+	endif()
+	if(CONFIG_COMP_WEBRTC_NS)
+		add_subdirectory(webrtc_ns)
+	endif()
+	if(CONFIG_COMP_WEBRTC_AEC)
+		add_subdirectory(webrtc_aec)
+	endif()
+	if(CONFIG_COMP_WEBRTC_NS2)
+		add_subdirectory(webrtc_ns2)
+	endif()
 	if(CONFIG_DTS_CODEC)
 		add_subdirectory(codec)
 	endif()

src/audio/Kconfig

@@ -139,6 +139,7 @@ rsource "dcblock/Kconfig"
 rsource "drc/Kconfig"
 rsource "eq_fir/Kconfig"
 rsource "eq_iir/Kconfig"
+rsource "ffmpeg_dec/Kconfig"
 rsource "google/Kconfig"
 rsource "igo_nr/Kconfig"
 rsource "mfcc/Kconfig"
@@ -161,6 +162,10 @@ rsource "tensorflow/Kconfig"
 rsource "tone/Kconfig"
 rsource "up_down_mixer/Kconfig"
 rsource "volume/Kconfig"
+rsource "webrtc_vad/Kconfig"
+rsource "webrtc_ns/Kconfig"
+rsource "webrtc_aec/Kconfig"
+rsource "webrtc_ns2/Kconfig"
 # --- End Kconfig Sources (alphabetical order) ---
 
 rsource "level_multiplier/Kconfig"

src/audio/ffmpeg_dec/CMakeLists.txt

@@ -0,0 +1,18 @@
+# SPDX-License-Identifier: BSD-3-Clause
+
+if(CONFIG_COMP_FFMPEG_DEC STREQUAL "m" AND DEFINED CONFIG_LLEXT)
+  add_subdirectory(llext ${PROJECT_BINARY_DIR}/ffmpeg_dec_llext)
+  add_dependencies(app ffmpeg_dec)
+else()
+  add_local_sources(sof ffmpeg_dec.c)
+
+  if(CONFIG_COMP_FFMPEG_DEC_STUB)
+    add_local_sources(sof ffmpeg_dec-stub.c)
+  else()
+    add_local_sources(sof ffmpeg_dec-ffmpeg.c)
+    # NOTE: ffmpeg_dec-shims.c / ffmpeg_dec-alloc.c are LLEXT-only (see
+    # llext/CMakeLists.txt). They provide libc/libm symbols the isolated LLEXT
+    # cannot import; in a built-in (=y) or native/testbench build the real libc
+    # provides those, so including them here would multiply-define malloc etc.
+  endif()
+endif()