Audio capture and streaming app for webOS 5/6

Captures the TV's audio and sends it out over several transports. The
primary one is HyperHDR: RTP/L16 to a host-side loopback device, since
HyperHDR has no network audio input of its own. A second route renders
the spectrum on the TV and sends FlatBuffers images to port 19400
instead, for setups where touching the host's sound config is not an
option.

  native/       the service: capture backends (PulseAudio, ALSA, exec,
                test tone, all dlopen-based), DSP, and one file per sink
  frontend/     D-pad driven UI at a fixed 1920x1080
  servicefiles/ native service manifest plus the boot script
  host/         RTP receiver and the loopback installer for the HyperHDR
                machine
  tools/        build/package, asset generation, Homebrew Channel
                manifest, on-TV probe
  test/         host-side suites: FlatBuffers and RTP verified against
                real decoders, the engine end to end, the page in jsdom

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

native/CMakeLists.txt

@@ -0,0 +1,110 @@
+cmake_minimum_required(VERSION 3.5)
+project(lgtv-audio-cap C)
+
+# Built with the openlgtv arm-webos-linux-gnueabi buildroot SDK:
+#
+#   source /path/to/arm-webos-linux-gnueabi_sdk-buildroot/environment-setup
+#   cmake -B build -DCMAKE_BUILD_TYPE=Release native
+#   cmake --build build
+#
+# The SDK's environment-setup exports CC/SYSROOT and puts its pkg-config in
+# front, so luna-service2 and glib resolve to the TV's versions rather than the
+# host's.
+
+set(CMAKE_C_STANDARD 11)
+set(CMAKE_C_STANDARD_REQUIRED ON)
+
+if(NOT CMAKE_BUILD_TYPE)
+  set(CMAKE_BUILD_TYPE Release)
+endif()
+
+find_package(PkgConfig REQUIRED)
+pkg_check_modules(LUNASERVICE REQUIRED luna-service2)
+pkg_check_modules(GLIB REQUIRED glib-2.0)
+pkg_check_modules(GTHREAD REQUIRED gthread-2.0)
+# PmLogLib is how webOS services normally reach the system log. It is optional
+# here: the logger writes to stderr, which the service launcher captures.
+pkg_check_modules(PMLOG PmLogLib)
+
+add_executable(audiocap-service
+  src/main.c
+  src/service.c
+  src/engine.c
+  src/config.c
+  src/dsp.c
+  src/common/log.c
+  src/common/json.c
+  src/common/ringbuf.c
+  src/capture/capture.c
+  src/capture/cap_pulse.c
+  src/capture/cap_alsa.c
+  src/capture/cap_exec.c
+  src/capture/cap_tone.c
+  src/net/flatbuf.c
+  src/net/hyperion.c
+  src/net/streamserv.c
+  src/sinks/sink.c
+  src/sinks/sink_hyperhdr.c
+  src/sinks/sink_hyperhdr_viz.c
+  src/sinks/sink_udp.c
+  src/sinks/sink_tcp.c
+  src/sinks/sink_http.c
+)
+
+target_include_directories(audiocap-service PRIVATE
+  src
+  ${LUNASERVICE_INCLUDE_DIRS}
+  ${GLIB_INCLUDE_DIRS}
+  ${GTHREAD_INCLUDE_DIRS}
+  ${PMLOG_INCLUDE_DIRS}
+)
+
+target_compile_options(audiocap-service PRIVATE
+  -Wall -Wextra -Wno-unused-parameter
+  ${LUNASERVICE_CFLAGS_OTHER}
+  ${GLIB_CFLAGS_OTHER}
+)
+
+target_compile_definitions(audiocap-service PRIVATE
+  _GNU_SOURCE
+  # Lets LSRegisterPubPriv resolve on firmware older than 3.5 without making
+  # the symbol mandatory on newer builds.
+  SECURITY_COMPATIBILITY
+)
+
+# The audio backends are dlopen'd at runtime, so libpulse and libasound are
+# deliberately absent from this list: the service has to start on a TV that has
+# neither, report that in the diagnostics, and let the user pick another path.
+target_link_libraries(audiocap-service PRIVATE
+  ${LUNASERVICE_LIBRARIES}
+  ${GLIB_LIBRARIES}
+  ${GTHREAD_LIBRARIES}
+  ${PMLOG_LIBRARIES}
+  pthread
+  dl
+  m
+)
+
+target_link_directories(audiocap-service PRIVATE
+  ${LUNASERVICE_LIBRARY_DIRS}
+  ${GLIB_LIBRARY_DIRS}
+  ${GTHREAD_LIBRARY_DIRS}
+  ${PMLOG_LIBRARY_DIRS}
+)
+
+if(CMAKE_C_COMPILER_ID STREQUAL "GNU" AND CMAKE_SYSTEM_PROCESSOR MATCHES "arm")
+  # webOS 5/6 TVs are Cortex-A9 (and A53 on later chassis, which runs A9 code
+  # fine). softfp matches the SDK's ABI.
+  target_compile_options(audiocap-service PRIVATE
+    -mcpu=cortex-a9 -mfloat-abi=softfp -mfpu=neon -ffast-math
+  )
+endif()
+
+# Homebrew services are unpacked to an arbitrary directory, so anything we ship
+# alongside the binary has to be found relative to it.
+set_target_properties(audiocap-service PROPERTIES
+  BUILD_RPATH "$ORIGIN"
+  INSTALL_RPATH "$ORIGIN"
+)
+
+install(TARGETS audiocap-service RUNTIME DESTINATION .)