Simplify Opus extension build process

Removed `Android.mk` and `Application.mk`, allowing `CMake` to run directly from the build.gradle file. Users no longer need to check out `NDK` or depend on it, simplifying the usage of the Opus extension.

PiperOrigin-RevId: 684489927

libraries/decoder_opus/README.md

@@ -1,7 +1,7 @@
 # Opus decoder module
 
-The Opus module provides `LibopusAudioRenderer`, which uses libopus (the Opus
+The Opus module provides `LibopusAudioRenderer`, which uses the libopus native
-decoding library) to decode Opus audio.
+library to decode Opus audio.
 
 ## License note
 
@@ -17,7 +17,7 @@ To use the module you need to clone this GitHub project and depend on its
 modules locally. Instructions for doing this can be found in the
 [top level README][].
 
-In addition, it's necessary to build the module's native components as follows:
+In addition, it's necessary to fetch libopus as follows:
 
 * Set the following environment variables:
 
@@ -26,13 +26,6 @@ cd "<path to project checkout>"
 OPUS_MODULE_PATH="$(pwd)/libraries/decoder_opus/src/main"
 ```
 
-* Download the [Android NDK][] and set its location in an environment variable.
-  This build configuration has been tested on NDK r21.
-
-```
-NDK_PATH="<path to Android NDK>"
-```
-
 * Fetch libopus:
 
 ```
@@ -40,21 +33,17 @@ cd "${OPUS_MODULE_PATH}/jni" && \
 git clone https://gitlab.xiph.org/xiph/opus.git libopus
 ```
 
-* Run the script to convert arm assembly to NDK compatible format:
+* [Install CMake][]
 
-```
+Having followed these steps, gradle will build the module automatically when run
-cd ${OPUS_MODULE_PATH}/jni && ./convert_android_asm.sh
+on the command line or via Android Studio, using [CMake][] and [Ninja][] to
-```
+configure and build libopus and the module's [JNI wrapper library][].
-
-* Build the JNI native libraries from the command line:
-
-```
-cd "${OPUS_MODULE_PATH}"/jni && \
-${NDK_PATH}/ndk-build APP_ABI=all -j4
-```
 
 [top level README]: ../../README.md
-[Android NDK]: https://developer.android.com/tools/sdk/ndk/index.html
+[Install CMake]: https://developer.android.com/studio/projects/install-ndk
+[CMake]: https://cmake.org/
+[Ninja]: https://ninja-build.org
+[JNI wrapper library]: src/main/jni/opus_jni.cc
 
 ## Build instructions (Windows)
 
@@ -63,14 +52,6 @@ be possible to follow the Linux instructions in [Windows PowerShell][].
 
 [Windows PowerShell]: https://docs.microsoft.com/en-us/powershell/scripting/getting-started/getting-started-with-windows-powershell
 
-## Notes
-
-* Every time there is a change to the libopus checkout:
-  * Arm assembly should be converted by running `convert_android_asm.sh`
-  * Clean and re-build the project.
-* If you want to use your own version of libopus, place it in
-  `${OPUS_MODULE_PATH}/jni/libopus`.
-
 ## Using the module with ExoPlayer
 
 Once you've followed the instructions above to check out, build and depend on

libraries/decoder_opus/build.gradle

@@ -17,13 +17,17 @@ android {
     namespace 'androidx.media3.decoder.opus'
 
     sourceSets {
-        main {
-            jniLibs.srcDir 'src/main/libs'
-            jni.srcDirs = [] // Disable the automatic ndk-build call by Android Studio.
-        }
         androidTest.assets.srcDir '../test_data/src/test/assets'
     }
 
+    defaultConfig {
+        externalNativeBuild {
+            cmake {
+                targets "opusV2JNI"
+            }
+        }
+    }
+
     // TODO(Internal: b/372449691): Remove packagingOptions once AGP is updated
     // to version 8.5.1 or higher.
     packagingOptions {
@@ -33,6 +37,22 @@ android {
     }
 }
 
+// Configure the native build only if libopus is present to avoid gradle sync
+// failures if libopus hasn't been built according to the README instructions.
+if (project.file('src/main/jni/libopus').exists()) {
+    android.externalNativeBuild.cmake {
+        path = 'src/main/jni/CMakeLists.txt'
+        version = '3.21.0+'
+        if (project.hasProperty('externalNativeBuildDir')) {
+            if (!new File(externalNativeBuildDir).isAbsolute()) {
+                ext.externalNativeBuildDir =
+                        new File(rootDir, it.externalNativeBuildDir)
+            }
+            buildStagingDirectory = "${externalNativeBuildDir}/${project.name}"
+        }
+    }
+}
+
 dependencies {
     implementation project(modulePrefix + 'lib-decoder')
     // TODO(b/203752526): Remove this dependency.

libraries/decoder_opus/src/main/jni/Android.mk

@@ -1,35 +0,0 @@
-#
-# Copyright (C) 2016 The Android Open Source Project
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#      http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-#
-
-WORKING_DIR := $(call my-dir)
-include $(CLEAR_VARS)
-
-# build libopus.a
-LOCAL_PATH := $(WORKING_DIR)
-include libopus.mk
-
-# build libopusV2JNI.so
-include $(CLEAR_VARS)
-LOCAL_PATH := $(WORKING_DIR)
-LOCAL_MODULE := libopusV2JNI
-LOCAL_ARM_MODE := arm
-LOCAL_CPP_EXTENSION := .cc
-LOCAL_SRC_FILES := opus_jni.cc
-LOCAL_LDLIBS := -llog -lz -lm
-LOCAL_STATIC_LIBRARIES := libopus
-# Enable 16 KB ELF alignment.
-LOCAL_LDFLAGS += "-Wl,-z,max-page-size=16384"
-include $(BUILD_SHARED_LIBRARY)

libraries/decoder_opus/src/main/jni/Application.mk

@@ -1,20 +0,0 @@
-#
-# Copyright (C) 2016 The Android Open Source Project
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#      http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-#
-
-APP_OPTIM := release
-APP_STL := c++_static
-APP_CPPFLAGS := -frtti
-APP_PLATFORM := android-9

libraries/decoder_opus/src/main/jni/CMakeLists.txt

@@ -0,0 +1,51 @@
+#
+# Copyright 2024 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+cmake_minimum_required(VERSION 3.21.0 FATAL_ERROR)
+
+# Enable C++11 features.
+set(CMAKE_CXX_STANDARD 11)
+
+# Define project name for your JNI module
+project(libopusJNI C CXX)
+
+set(libopus_jni_root "${CMAKE_CURRENT_SOURCE_DIR}")
+
+# Build libopus.
+add_subdirectory("${libopus_jni_root}/libopus"
+                 EXCLUDE_FROM_ALL)
+
+# Add the include directory from libopus.
+include_directories ("${libopus_jni_root}/libopus/include")
+
+# Build libopusJNI.
+add_library(opusV2JNI
+            SHARED
+            opus_jni.cc)
+
+# Locate NDK log library.
+find_library(android_log_lib log)
+
+# Link libgav1JNI against used libraries.
+target_link_libraries(opusV2JNI
+                      PRIVATE android
+                      PRIVATE opus
+                      PRIVATE ${android_log_lib})
+
+# Enable 16 KB ELF alignment.
+target_link_options(opusV2JNI
+                    PRIVATE "-Wl,-z,max-page-size=16384")
+

libraries/decoder_opus/src/main/jni/convert_android_asm.sh

@@ -1,47 +0,0 @@
-#!/bin/bash
-#
-# Copyright (C) 2016 The Android Open Source Project
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#      http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-#
-
-set -eu
-ASM_CONVERTER="./libopus/celt/arm/arm2gnu.pl"
-
-if [[ ! -x "${ASM_CONVERTER}" ]]; then
-  echo "Please make sure you have checked out libopus."
-  exit
-fi
-
-while read file; do
-  # This check is required because the ASM conversion script doesn't seem to be
-  # idempotent.
-  if [[ ! "${file}" =~ .*_gnu\.s$ ]]; then
-    gnu_file="${file%.s}_gnu.s"
-    ${ASM_CONVERTER} "${file}" > "${gnu_file}"
-    # The ASM conversion script replaces includes with *_gnu.S. So, replace
-    # occurences of "*-gnu.S" with "*_gnu.s".
-    perl -pi -e "s/-gnu\.S/_gnu\.s/g" "${gnu_file}"
-    rm -f "${file}"
-  fi
-done < <(find -L . -iname '*.s')
-
-# Generate armopts.s from armopts.s.in
-sed \
-  -e "s/@OPUS_ARM_MAY_HAVE_EDSP@/1/g" \
-  -e "s/@OPUS_ARM_MAY_HAVE_MEDIA@/1/g" \
-  -e "s/@OPUS_ARM_MAY_HAVE_NEON@/1/g" \
-  libopus/celt/arm/armopts.s.in > libopus/celt/arm/armopts.s.temp
-${ASM_CONVERTER} "libopus/celt/arm/armopts.s.temp" > "libopus/celt/arm/armopts_gnu.s"
-rm "libopus/celt/arm/armopts.s.temp"
-echo "Converted all ASM files and generated armopts.s successfully."

libraries/decoder_opus/src/main/jni/libopus.mk

@@ -1,50 +0,0 @@
-#
-# Copyright (C) 2016 The Android Open Source Project
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#      http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-#
-
-LOCAL_PATH := $(call my-dir)/libopus
-
-include $(CLEAR_VARS)
-
-include $(LOCAL_PATH)/celt_headers.mk
-include $(LOCAL_PATH)/celt_sources.mk
-include $(LOCAL_PATH)/opus_headers.mk
-include $(LOCAL_PATH)/opus_sources.mk
-include $(LOCAL_PATH)/silk_headers.mk
-include $(LOCAL_PATH)/silk_sources.mk
-
-LOCAL_MODULE := libopus
-LOCAL_ARM_MODE := arm
-LOCAL_CFLAGS := -DOPUS_BUILD -DFIXED_POINT -DUSE_ALLOCA -DHAVE_LRINT \
-                -DHAVE_LRINTF
-LOCAL_C_INCLUDES := $(LOCAL_PATH)/include $(LOCAL_PATH)/src \
-                    $(LOCAL_PATH)/silk $(LOCAL_PATH)/celt \
-                    $(LOCAL_PATH)/silk/fixed
-LOCAL_SRC_FILES := $(CELT_SOURCES) $(OPUS_SOURCES) $(OPUS_SOURCES_FLOAT) \
-                   $(SILK_SOURCES) $(SILK_SOURCES_FIXED)
-
-ifneq ($(findstring armeabi-v7a, $(TARGET_ARCH_ABI)),)
-LOCAL_SRC_FILES += $(CELT_SOURCES_ARM)
-LOCAL_SRC_FILES += celt/arm/armopts_gnu.s.neon
-LOCAL_SRC_FILES += $(subst .s,_gnu.s.neon,$(CELT_SOURCES_ARM_ASM))
-LOCAL_CFLAGS += -DOPUS_ARM_ASM -DOPUS_ARM_INLINE_ASM -DOPUS_ARM_INLINE_EDSP \
-                -DOPUS_ARM_INLINE_MEDIA -DOPUS_ARM_INLINE_NEON \
-                -DOPUS_ARM_MAY_HAVE_NEON -DOPUS_ARM_MAY_HAVE_MEDIA \
-                -DOPUS_ARM_MAY_HAVE_EDSP
-endif
-
-LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)/include
-
-include $(BUILD_STATIC_LIBRARY)