build and link ffmpeg

Author: tckmn

.gitignore

@@ -1,3 +1,4 @@
 build
+shared
 .externalNativeBuild
 .gradle

CMakeLists.txt

@@ -1,6 +1,25 @@
-cmake_minimum_required(VERSION 3.4.1)
-add_library (semitone-native SHARED src/main/cpp/semitone-native.cpp src/main/cpp/PianoEngine.cpp src/main/cpp/Tone.cpp src/main/cpp/Sound.cpp)
+cmake_minimum_required (VERSION 3.4.1)
+
+add_library (semitone-native SHARED
+    src/main/cpp/semitone-native.cpp
+    src/main/cpp/PianoEngine.cpp
+    src/main/cpp/Tone.cpp
+    src/main/cpp/Sound.cpp)
+
 find_library (android-lib android)
-target_link_libraries (semitone-native oboe ${android-lib})
-add_subdirectory (./lib/oboe ./lib/oboe)
-include_directories (./lib/oboe/include)
+
+add_subdirectory (lib/oboe lib/oboe)
+include_directories (lib/oboe/include)
+
+set (FFMPEG_DIR ${PROJECT_SOURCE_DIR}/lib/ffmpeg/build/${ANDROID_ABI})
+include_directories (${FFMPEG_DIR}/include)
+add_library (avcodec SHARED IMPORTED)
+set_target_properties (avcodec PROPERTIES IMPORTED_LOCATION ${FFMPEG_DIR}/lib/libavcodec.so)
+add_library (avformat SHARED IMPORTED)
+set_target_properties (avformat PROPERTIES IMPORTED_LOCATION ${FFMPEG_DIR}/lib/libavformat.so)
+add_library (avutil SHARED IMPORTED)
+set_target_properties (avutil PROPERTIES IMPORTED_LOCATION ${FFMPEG_DIR}/lib/libavutil.so)
+add_library (swresample SHARED IMPORTED)
+set_target_properties (swresample PROPERTIES IMPORTED_LOCATION ${FFMPEG_DIR}/lib/libswresample.so)
+
+target_link_libraries (semitone-native ${android-lib} oboe avcodec avformat avutil swresample)

build.gradle

@@ -41,6 +41,12 @@ android {
             path "CMakeLists.txt"
         }
     }
+
+    sourceSets {
+        main {
+            jniLibs.srcDirs = ["shared"]
+        }
+    }
 }
 
 gradle.projectsEvaluated {

tools/build_ffmpeg.sh

@@ -0,0 +1,40 @@
+#!/bin/bash
+
+# NOTE: run this from project root
+
+set -e
+cd lib/ffmpeg
+
+[ -n "$ANDROID_NDK" ] || { echo >&2 no ndk; exit 1; }
+HOST_ARCH=${HOST_ARCH:-linux-x86_64}
+
+TOOLCHAIN="$ANDROID_NDK/toolchains/llvm/prebuilt/$HOST_ARCH/bin"
+[ -d "$TOOLCHAIN" ] || { echo >&2 no toolchain; exit 1; }
+
+while read ABI ARCH CC_CMD STRIP_CMD FLAGS
+do
+
+    [ -f "$TOOLCHAIN/$CC_CMD" ] || { echo >&2 "no cc for $ABI"; exit 1; }
+    [ -f "$TOOLCHAIN/$STRIP_CMD" ] || { echo >&2 "no strip for $ABI"; exit 1; }
+
+    ./configure \
+        --prefix="build/$ABI" \
+        --arch="$ARCH" \
+        --cc="$TOOLCHAIN/$CC_CMD" \
+        --strip="$TOOLCHAIN/$STRIP_CMD" \
+        $FLAGS \
+        --target-os=android \
+        --enable-cross-compile --enable-small --enable-shared \
+        --disable-programs --disable-doc --disable-static --disable-everything \
+        --enable-decoder=mp3 --enable-demuxer=mp3
+
+    make clean
+    make -j3
+    make install
+
+done <<x
+armeabi-v7a armv7-a armv7a-linux-androideabi16-clang arm-linux-androideabi-strip
+arm64-v8a   aarch64 aarch64-linux-android21-clang    aarch64-linux-android-strip
+x86         x86     i686-linux-android16-clang       i686-linux-android-strip    --disable-asm
+x86_64      x86_64  x86_64-linux-android21-clang     x86_64-linux-android-strip  --disable-asm
+x

tools/copy_ffmpeg.sh

@@ -0,0 +1,11 @@
+#!/bin/bash
+
+set -e
+
+rm -rf shared
+mkdir shared
+for ABI in armeabi-v7a arm64-v8a x86 x86_64
+do
+    mkdir "shared/$ABI"
+    cp lib/ffmpeg/build/"$ABI"/lib/lib{avcodec,avformat,avutil,swresample}.so "shared/$ABI"
+done