Use FFmpeg shared libraries & Update build instructions

README.md

@@ -75,7 +75,10 @@ DroidFS need some permissions to work properly. Here is why:
   Required to encrypt/decrypt password hashes using a fingerprint protected key.
   </li>
   <li><h4>Camera:</h4>
-  Needed to take photos directly from DroidFS to import them securely. You can deny this permission if you don't want to use it.
+  Needed to take photos & videos directly encrypted inside DroidFS. You can deny this permission if you don't want to use it.
+  </li>
+  <li><h4>Record audio:</h4>
+  Required if you want sound on video recorded with DroidFS.
   </li>
 </ul>
 
@@ -114,6 +117,11 @@ Continue **ONLY** if the signature is **VALID**.
 ```
 $ tar -xvzf openssl-1.1.1l.tar.gz
 ```
+DroidFS also need [FFmpeg](https://ffmpeg.org) to record encrypted video:
+```
+$ cd app/ffmpeg
+$ git clone --depth=1 https://git.ffmpeg.org/ffmpeg.git
+```
 
 #### Build
 First, we need to install some dependencies:
@@ -129,6 +137,11 @@ Then, retrieve your Android NDK installation path, usually someting like "/home/
 $ cd DroidFS/app/libgocryptfs
 $ env ANDROID_NDK_HOME="<your ndk path>" OPENSSL_PATH="./openssl-1.1.1l" ./build.sh
  ```
+And also FFmpeg:
+```
+$ cd app/ffmpeg
+$ env ANDROID_NDK_HOME="<your ndk path>" ./build.sh ffmpeg
+```
 Then, open the DroidFS project with Android Studio. \
 If a device (virtual or physical) is connected, just click on "Run". \
 If you want to generate a signed APK, you can follow this [post](https://stackoverflow.com/a/28938286).

app/CMakeLists.txt

@@ -25,38 +25,38 @@ target_link_libraries(
 
 add_library(
         avformat
-        STATIC
+        SHARED
         IMPORTED
 )
 
 set_target_properties(
         avformat
         PROPERTIES IMPORTED_LOCATION
-        ${PROJECT_SOURCE_DIR}/ffmpeg/build/${ANDROID_ABI}/libavformat/libavformat.a
+        ${PROJECT_SOURCE_DIR}/ffmpeg/build/${ANDROID_ABI}/libavformat/libavformat.so
 )
 
 add_library(
         avcodec
-        STATIC
+        SHARED
         IMPORTED
 )
 
 set_target_properties(
         avcodec
         PROPERTIES IMPORTED_LOCATION
-        ${PROJECT_SOURCE_DIR}/ffmpeg/build/${ANDROID_ABI}/libavcodec/libavcodec.a
+        ${PROJECT_SOURCE_DIR}/ffmpeg/build/${ANDROID_ABI}/libavcodec/libavcodec.so
 )
 
 add_library(
         avutil
-        STATIC
+        SHARED
         IMPORTED
 )
 
 set_target_properties(
         avutil
         PROPERTIES IMPORTED_LOCATION
-        ${PROJECT_SOURCE_DIR}/ffmpeg/build/${ANDROID_ABI}/libavutil/libavutil.a
+        ${PROJECT_SOURCE_DIR}/ffmpeg/build/${ANDROID_ABI}/libavutil/libavutil.so
 )
 
 add_library(

app/build.gradle

@@ -4,7 +4,7 @@ apply plugin: 'kotlin-android'
 android {
     compileSdkVersion 31
     buildToolsVersion "31"
-    ndkVersion "21.4.7075529"
+    ndkVersion "23.0.7599858"
 
     compileOptions {
         targetCompatibility JavaVersion.VERSION_1_8

app/ffmpeg/build.sh

@@ -2,8 +2,12 @@
 
 if [ -z ${ANDROID_NDK_HOME+x} ]; then
 	echo "Error: \$ANDROID_NDK_HOME is not defined."
+elif [ $# -lt 1 ]; then
+	echo "Usage: $0 <FFmpeg source directory> [<ABI>]"
 else
+	FFMPEG_DIR=$1
 	compile_for_arch() {
+		echo "Compiling for $1..."
 		case $1 in
 			"x86_64")
 				CFN="x86_64-linux-android21-clang"
@@ -12,6 +16,7 @@ else
 			"x86")
 				CFN="i686-linux-android21-clang"
 				ARCH="i686"
+				EXTRA_FLAGS="--disable-asm"
 				;;
 			"arm64-v8a")
 				CFN="aarch64-linux-android21-clang"
@@ -22,19 +27,26 @@ else
 				ARCH="arm"
 				;;
 		esac
-		cd ffmpeg && make clean &&
+		(cd $FFMPEG_DIR && make clean;
 		./configure \
 			--cc="$CFN" \
 			--cxx="$CFN++" \
 			--arch="$ARCH" \
+			$EXTRA_FLAGS \
 			--target-os=android \
 			--enable-cross-compile \
 			--enable-version3 \
 			--disable-programs \
+			--disable-static \
+			--enable-shared \
 			--disable-bsfs \
 			--disable-parsers \
 			--disable-demuxers \
+			--disable-muxers \
+			--enable-muxer="mp4" \
 			--disable-decoders \
+			--disable-encoders \
+			--enable-encoder="aac" \
 			--disable-avdevice \
 			--disable-swresample \
 			--disable-swscale \
@@ -60,21 +72,19 @@ else
 			--disable-alsa \
 			--disable-debug \
 			>/dev/null &&
-			make -j 8 >/dev/null &&
+		make -j $(nproc --all) >/dev/null) &&
-			mkdir -p ../build/$1/libavformat ../build/$1/libavcodec ../build/$1/libavutil &&
+		mkdir -p build/$1/libavformat build/$1/libavcodec build/$1/libavutil &&
-			cp libavformat/*.h libavformat/libavformat.a ../build/$1/libavformat &&
+		cp $FFMPEG_DIR/libavformat/*.h $FFMPEG_DIR/libavformat/libavformat.so build/$1/libavformat &&
-			cp libavcodec/*.h libavcodec/libavcodec.a ../build/$1/libavcodec &&
+		cp $FFMPEG_DIR/libavcodec/*.h $FFMPEG_DIR/libavcodec/libavcodec.so build/$1/libavcodec &&
-			cp libavutil/*.h libavutil/libavutil.a ../build/$1/libavutil &&
+		cp $FFMPEG_DIR/libavutil/*.h $FFMPEG_DIR/libavutil/libavutil.so build/$1/libavutil
-			cd ..
 	}
 
 	export PATH=$ANDROID_NDK_HOME/toolchains/llvm/prebuilt/linux-x86_64/bin:$PATH
-	if [ "$#" -eq 1 ]; then
+	if [ $# -eq 2 ]; then
-		compile_for_arch $1
+		compile_for_arch $2
 	else
 		declare -a ABIs=("x86_64" "x86" "arm64-v8a" "armeabi-v7a")
 		for abi in ${ABIs[@]}; do
-			echo "Compiling for $abi..."
 			compile_for_arch $abi
 		done
 	fi