mediamtx: add MediaMTX package

From the MediaMTX README:
MediaMTX (formerly rtsp-simple-server) is a ready-to-use and
zero-dependency real-time media server and media proxy that allows
to publish, read, proxy, record and playback video and audio streams.

It has been conceived as a "media router" that routes media streams
from one end to the other.

multimedia/mediamtx/Makefile

@@ -0,0 +1,70 @@
+#
+# Copyright 2023 Morse Micro
+#
+# This is free software, licensed under the Apache License, Version 2.0.
+#
+
+include $(TOPDIR)/rules.mk
+
+PKG_NAME:=mediamtx
+PKG_VERSION:=1.4.0
+PKG_RELEASE:=1
+
+PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
+PKG_SOURCE_URL:=https://codeload.github.com/bluenviron/mediamtx/tar.gz/v$(PKG_VERSION)?
+PKG_HASH:=8360d5e0337df599efb7a4200956caf59870965019140f976aba53673e81dc50
+
+PKG_BUILD_DEPENDS:=golang/host
+PKG_BUILD_PARALLEL:=1
+PKG_BUILD_FLAGS:=no-mips16
+
+GO_PKG:=github.com/bluenviron/mediamtx
+GO_PKG_LDFLAGS_X:=$(GO_PKG)/internal/core.version=$(PKG_VERSION)
+
+include $(INCLUDE_DIR)/package.mk
+include $(TOPDIR)/feeds/packages/lang/golang/golang-package.mk
+include $(INCLUDE_DIR)/nls.mk
+
+# Original Makefile had this, but the Golang in our version doesn't seem to support it.
+# GO_MOD_ARGS:=-buildvcs=false
+
+define Package/mediamtx
+  SECTION:=multimedia
+  CATEGORY:=Multimedia
+  TITLE:=MediaMTX
+  URL:=https://github.com/bluenviron/mediamtx
+  DEPENDS=$(GO_ARCH_DEPENDS) +PACKAGE_libcamera:libcamera +PACKAGE_libcamera:libfreetype $(INTL_DEPENDS)
+  MENU:=1
+endef
+
+# To support the rpicamera, there's a minimal binary that mediamtx spawns
+# to read the stream. For now, we equate 'rpicamera' with 'libcamera'.
+# Ideally, we'd have a separate config option, but if you define that option
+# inside this package we seem to end up with some kind of recursive dependency
+# issue as our dependencies are enabled by this as well.
+ifeq ($(CONFIG_PACKAGE_libcamera),y)
+GO_PKG_TAGS:=rpicamera
+MAKE_PATH=internal/protocols/rpicamera/exe
+
+define Build/Compile
+	$(call Build/Compile/Default)
+	$(call GoPackage/Build/Compile)
+endef
+endif
+
+define Package/mediamtx/install
+	$(call GoPackage/Package/Install/Bin,$(1))
+	$(INSTALL_DIR) $(1)/etc/init.d
+	$(INSTALL_BIN) files/mediamtx.init $(1)/etc/init.d/mediamtx
+	$(INSTALL_DIR) $(1)/etc/config
+	$(INSTALL_CONF) files/mediamtx.config $(1)/etc/config/mediamtx
+endef
+
+define Package/mediamtx/description
+  Ready-to-use server and proxy that allows users to publish, read and proxy live video and audio streams through various protocols.
+
+  If libcamera is enabled, it will try to build its rpicamera support.
+endef
+
+$(eval $(call GoBinPackage,mediamtx))
+$(eval $(call BuildPackage,mediamtx))

multimedia/mediamtx/files/mediamtx.config

@@ -0,0 +1,9 @@
+config mediamtx
+	# luci-app-camera and camera-onvif-server need to know about this port.
+	# By default, it's set to 9997.
+	option api_address '127.0.0.1:9997'
+	option webrtc_address ':8889'
+	option hls_address ':8888'
+	# This port is also in the camera-onvif-server configuration
+	# as it needs to return the correct stream URL.
+	option rtsp_address ':554'

multimedia/mediamtx/files/mediamtx.init

@@ -0,0 +1,87 @@
+#!/bin/sh /etc/rc.common
+
+START=90
+STOP=10
+
+USE_PROCD=1
+
+SERVICE=mediamtx
+
+error() {
+	logger -t "$SERVICE" "$@"
+}
+
+start_instance() {
+	local s="$1"
+	local conffile="/var/run/$SERVICE-$s.json"
+
+	# get options
+	# Having a port option enables that ability.
+	config_get api_address "$s" 'api_address' ''
+	config_get rtsp_address "$s" 'rtsp_address' ''
+	config_get webrtc_address "$s" 'webrtc_address' ''
+	config_get hls_address "$s" 'hls_address' ''
+	config_get rtmp_address "$s" 'rtmp_address' ''
+	config_get log_level "$s" 'log_level' 'info'
+
+	# Generate config file from options.
+	json_init
+
+	if [ -n "$api_address" ];  then
+		json_add_boolean "api" 1
+		json_add_string "apiAddress" "$api_address"
+	else
+		json_add_boolean "api" 0
+	fi
+
+	json_add_string "logLevel" "$log_level"
+
+	if [ -n "$rtsp_address" ];  then
+		json_add_boolean "rtsp" 1
+		json_add_string "rtspAddress" "$rtsp_address"
+	else
+		json_add_boolean "rtsp" 0
+	fi
+
+	if [ -n "$webrtc_address" ];  then
+		json_add_boolean "webrtc" 1
+		json_add_string "webrtcAddress" "$webrtc_address"
+	else
+		json_add_boolean "webrtc" 0
+	fi
+
+	if [ -n "$hls_address" ];  then
+		json_add_boolean "hls" 1
+		json_add_string "hlsAddress" "$hls_address"
+	else
+		json_add_boolean "hls" 0
+	fi
+
+	if [ -n "$rtmp_address" ];  then
+		json_add_boolean "rtmp" 1
+		json_add_string "rtmpAddress" "$rtmp_address"
+	else
+		json_add_boolean "rtmp" 0
+	fi
+
+	json_dump > "$conffile"
+
+	# procd stuff
+	procd_open_instance
+	# We don't need to watch the conffile, since mediamtx does that for us
+	# (and reloads when it changes).
+	procd_set_param command mediamtx "$conffile"
+	procd_set_param stdout 1
+	procd_set_param stderr 1
+	procd_set_param respawn
+	procd_close_instance
+}
+
+start_service() {
+	config_load "$SERVICE"
+	config_foreach start_instance "$SERVICE"
+}
+
+service_triggers() {
+	procd_add_reload_trigger "$SERVICE"
+}

multimedia/mediamtx/patches/000-simplify-xxd-usage.patch

@@ -0,0 +1,16 @@
+OpenWrt replaces xxd with a simple perl implementation that doesn't
+understand longopts.
+
+diff --git a/internal/protocols/rpicamera/exe/Makefile b/internal/protocols/rpicamera/exe/Makefile
+index d2a1901..987d87f 100644
+--- a/internal/protocols/rpicamera/exe/Makefile
++++ b/internal/protocols/rpicamera/exe/Makefile
+@@ -37,7 +37,7 @@ OBJS = \
+ all: exe
+ 
+ text_font.h: text_font.ttf
+-	xxd --include $< > text_font.h
++	xxd -i $< > text_font.h
+ 
+ %.o: %.c text_font.h
+ 	$(CC) $(CFLAGS) -c $< -o $@

multimedia/mediamtx/patches/001-allow-copts-overrides.patch

@@ -0,0 +1,28 @@
+diff --git a/internal/protocols/rpicamera/exe/Makefile b/internal/protocols/rpicamera/exe/Makefile
+index d2a1901..16fbf3b 100644
+--- a/internal/protocols/rpicamera/exe/Makefile
++++ b/internal/protocols/rpicamera/exe/Makefile
+@@ -1,4 +1,4 @@
+-CFLAGS = \
++CFLAGS += \
+ 	-Ofast \
+ 	-Werror \
+ 	-Wall \
+@@ -7,7 +7,7 @@ CFLAGS = \
+ 	-Wno-unused-result \
+ 	$$(pkg-config --cflags freetype2)
+ 
+-CXXFLAGS = \
++CXXFLAGS += \
+ 	-Ofast \
+ 	-Werror \
+ 	-Wall \
+@@ -17,7 +17,7 @@ CXXFLAGS = \
+ 	-std=c++17 \
+ 	$$(pkg-config --cflags libcamera)
+ 
+-LDFLAGS = \
++LDFLAGS += \
+ 	-s \
+ 	-pthread \
+ 	$$(pkg-config --libs freetype2) \