Implement skeleton of native litr-muxers module

litr-demo/build.gradle

@@ -40,6 +40,7 @@ android {
 dependencies {
     implementation project(':litr')
     implementation project(':litr-filters')
+    implementation project(':litr-muxers')
 
     implementation 'androidx.appcompat:appcompat:1.2.0'
     implementation 'androidx.recyclerview:recyclerview:1.2.0'

litr-demo/src/main/java/com/linkedin/android/litr/demo/data/SharedMediaStoragePublisher.kt

@@ -10,6 +10,7 @@ import android.os.Handler
 import android.os.Looper
 import android.provider.MediaStore
 import android.util.Log
+import android.webkit.MimeTypeMap
 import androidx.annotation.ChecksSdkIntAtLeast
 import androidx.annotation.WorkerThread
 import java.io.File
@@ -49,9 +50,11 @@ class SharedMediaStoragePublisher @JvmOverloads constructor(
         if (!file.exists()) return null
 
         val newFileName = file.name
+        val extension = MimeTypeMap.getFileExtensionFromUrl(newFileName)
+        val mimeType = MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension) ?: MIME_TYPE_MPEG_4
 
         val values = ContentValues().apply {
-            put(MediaStore.Video.Media.MIME_TYPE, MIME_TYPE_MPEG_4)
+            put(MediaStore.Video.Media.MIME_TYPE, mimeType)
             put(MediaStore.Video.Media.TITLE, newFileName)
             put(MediaStore.Video.Media.DISPLAY_NAME, newFileName)
             put(MediaStore.Video.Media.DATE_TAKEN, System.currentTimeMillis())

litr-muxers/.gitignore

@@ -0,0 +1,4 @@
+/build
+
+# FFmpeg symlink
+src/main/cpp/ffmpeg

litr-muxers/README.md

@@ -0,0 +1,58 @@
+# Litr Muxers module
+
+The Litr Muxers module provides `NativeMediaMuxerMediaTarget`, which uses FFmpeg for muxing 
+individual streams into a target file container.
+
+## Build instructions (Linux, macOS)
+
+It is necessary to manually build the FFmpeg library, so that gradle  can bundle the FFmpeg binaries
+in the APK:
+
+* Set the following shell variable:
+
+```
+cd "<path to project checkout>"
+FFMPEG_MODULE_PATH="$(pwd)/litr-muxers/src/main"
+```
+
+* Download the [Android NDK][] and set its location in a shell variable.
+  This build configuration has been tested on NDK r22b.
+
+```
+NDK_PATH="<path to Android NDK>"
+```
+
+* Set the host platform (use "darwin-x86_64" for Mac OS X):
+
+```
+HOST_PLATFORM="linux-x86_64"
+```
+
+* Fetch FFmpeg and checkout an appropriate branch. We cannot guarantee
+  compatibility with all versions of FFmpeg. We currently recommend version 4.2:
+
+```
+cd "<preferred location for ffmpeg>" && \
+git clone git://source.ffmpeg.org/ffmpeg && \
+cd ffmpeg && \
+git checkout release/4.2 && \
+FFMPEG_PATH="$(pwd)"
+```
+
+*   Add a link to the FFmpeg source code in the FFmpeg module `cpp` directory.
+
+```
+cd "${FFMPEG_MODULE_PATH}/cpp" && \
+ln -s "$FFMPEG_PATH" ffmpeg
+```
+
+* Execute `build_ffmpeg.sh` to build FFmpeg for `armeabi-v7a`, `arm64-v8a`,
+  `x86` and `x86_64`. The script can be edited if you need to build for
+  different architectures:
+
+```
+cd "${FFMPEG_MODULE_PATH}/cpp" && \
+chmod +x build_ffmpeg.sh && \
+./build_ffmpeg.sh \
+  "${FFMPEG_MODULE_PATH}" "${NDK_PATH}" "${HOST_PLATFORM}"
+```

litr-muxers/build.gradle

@@ -0,0 +1,36 @@
+plugins {
+    id 'com.android.library'
+    id 'org.jetbrains.kotlin.android'
+}
+
+android {
+    namespace 'com.linkedin.android.litr.muxers'
+
+    compileSdkVersion rootProject.ext.compileSdkVersion
+    buildToolsVersion rootProject.ext.buildToolsVersion
+
+    defaultConfig {
+        minSdkVersion rootProject.ext.minSdkVersion
+        targetSdkVersion rootProject.ext.targetSdkVersion
+    }
+
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
+
+    kotlinOptions {
+        freeCompilerArgs += "-Xopt-in=kotlin.RequiresOptIn"
+    }
+
+    externalNativeBuild {
+        cmake {
+            path file('src/main/cpp/CMakeLists.txt')
+            version '3.10.2'
+        }
+    }
+}
+
+dependencies {
+    implementation project(':litr')
+}

litr-muxers/src/main/AndroidManifest.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+
+</manifest>

litr-muxers/src/main/cpp/CMakeLists.txt

@@ -0,0 +1,52 @@
+cmake_minimum_required(VERSION 3.10.2)
+
+# Enable C++11 features.
+set(CMAKE_CXX_STANDARD 11)
+
+project(LiTrMuxers C CXX)
+
+# Additional flags needed for "arm64-v8a" from NDK 23.1.7779620 and above.
+if(${ANDROID_ABI} MATCHES "arm64-v8a")
+    set(CMAKE_CXX_FLAGS "-Wl,-Bsymbolic")
+endif()
+
+# If locally built ffmpeg binaries are available, we will prioritise these. This is preferable as
+# ensures they are built to match exactly what the consumer requires. However, we will allow the
+# build to fallback to those bundled with the repository.
+if(EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/ffmpeg")
+    set(ffmpeg_location "${CMAKE_CURRENT_SOURCE_DIR}/ffmpeg")
+    set(ffmpeg_binaries "${ffmpeg_location}/android-libs/${ANDROID_ABI}")
+else()
+    set(ffmpeg_location "${CMAKE_CURRENT_SOURCE_DIR}/ffmpeg_bundled")
+    set(ffmpeg_binaries "${ffmpeg_location}/${ANDROID_ABI}")
+endif()
+
+foreach(ffmpeg_lib avutil avcodec avformat)
+    set(ffmpeg_lib_filename lib${ffmpeg_lib}.so)
+    set(ffmpeg_lib_file_path ${ffmpeg_binaries}/${ffmpeg_lib_filename})
+    add_library(
+            ${ffmpeg_lib}
+            SHARED
+            IMPORTED)
+    set_target_properties(
+            ${ffmpeg_lib} PROPERTIES
+            IMPORTED_LOCATION
+            ${ffmpeg_lib_file_path})
+endforeach()
+
+include_directories(${ffmpeg_location})
+find_library(log-lib log)
+
+add_library(litr-muxers SHARED
+        FFmpeg.h
+        Logging.h
+        )
+
+target_link_libraries(litr-muxers
+        PRIVATE android
+        PRIVATE avcodec
+        PRIVATE avutil
+        PRIVATE avformat
+        PRIVATE ${log-lib})
+
+set_property(TARGET litr-muxers PROPERTY LINKER_LANGUAGE CXX)

litr-muxers/src/main/cpp/FFmpeg.h

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2022 LinkedIn Corporation
+ * All Rights Reserved.
+ *
+ * Licensed under the BSD 2-Clause License (the "License").  See License in the project root for
+ * license information.
+ *
+ * Author: Ian Bird
+ */
+
+#ifndef LITR_FFMPEG_H
+#define LITR_FFMPEG_H
+
+extern "C" {
+#include "libavutil/log.h"
+#include "libavformat/avformat.h"
+}
+
+#endif //LITR_FFMPEG_H

litr-muxers/src/main/cpp/Logging.h

@@ -0,0 +1,22 @@
+/*
+ * Copyright 2022 LinkedIn Corporation
+ * All Rights Reserved.
+ *
+ * Licensed under the BSD 2-Clause License (the "License").  See License in the project root for
+ * license information.
+ *
+ * Author: Ian Bird
+ */
+
+#ifndef LITR_LOGGING_H
+#define LITR_LOGGING_H
+
+#include <android/log.h>
+
+#define LOG_TAG "LiTrMuxers_JNI"
+#define LOGD(...) ((void)__android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, __VA_ARGS__))
+#define LOGI(...) ((void)__android_log_print(ANDROID_LOG_INFO, LOG_TAG, __VA_ARGS__))
+#define LOGW(...) ((void)__android_log_print(ANDROID_LOG_WARN, LOG_TAG, __VA_ARGS__))
+#define LOGE(...) ((void)__android_log_print(ANDROID_LOG_ERROR, LOG_TAG, __VA_ARGS__))
+
+#endif //LITR_LOGGING_H

litr-muxers/src/main/cpp/build_ffmpeg.sh

@@ -0,0 +1,86 @@
+#!/bin/bash
+
+FFMPEG_MODULE_PATH=$1
+NDK_PATH=$2
+HOST_PLATFORM=$3
+ENABLED_DECODERS=("${@:4}")
+JOBS=$(nproc 2> /dev/null || sysctl -n hw.ncpu 2> /dev/null || echo 4)
+echo "Using $JOBS jobs for make"
+COMMON_OPTIONS="
+    --target-os=android
+    --enable-shared
+    --disable-static
+    --disable-doc
+    --disable-all
+    --enable-avcodec
+    --enable-avformat
+    --enable-protocol=file
+    --enable-protocol=hls
+    --enable-muxer=mp4
+    --enable-muxer=matroska
+    --enable-muxer=hls
+    --enable-muxer=stream_segment
+    --enable-parser=aac
+    --enable-parser=aac_latm
+    --enable-parser=h264
+    --enable-parser=hevc
+    --extra-ldexeflags=-pie
+    "
+TOOLCHAIN_PREFIX="${NDK_PATH}/toolchains/llvm/prebuilt/${HOST_PLATFORM}/bin"
+cd "${FFMPEG_MODULE_PATH}/cpp/ffmpeg"
+./configure \
+    --libdir=android-libs/armeabi-v7a \
+    --arch=arm \
+    --cpu=armv7-a \
+    --cross-prefix="${TOOLCHAIN_PREFIX}/armv7a-linux-androideabi16-" \
+    --nm="${TOOLCHAIN_PREFIX}/llvm-nm" \
+    --ar="${TOOLCHAIN_PREFIX}/llvm-ar" \
+    --ranlib="${TOOLCHAIN_PREFIX}/llvm-ranlib" \
+    --strip="${TOOLCHAIN_PREFIX}/llvm-strip" \
+    --extra-cflags="-march=armv7-a -mfloat-abi=softfp" \
+    --extra-ldflags="-Wl,--fix-cortex-a8" \
+    ${COMMON_OPTIONS}
+make -j$JOBS
+make install-libs
+make clean
+./configure \
+    --libdir=android-libs/arm64-v8a \
+    --arch=aarch64 \
+    --cpu=armv8-a \
+    --cross-prefix="${TOOLCHAIN_PREFIX}/aarch64-linux-android21-" \
+    --nm="${TOOLCHAIN_PREFIX}/llvm-nm" \
+    --ar="${TOOLCHAIN_PREFIX}/llvm-ar" \
+    --ranlib="${TOOLCHAIN_PREFIX}/llvm-ranlib" \
+    --strip="${TOOLCHAIN_PREFIX}/llvm-strip" \
+    ${COMMON_OPTIONS}
+make -j$JOBS
+make install-libs
+make clean
+./configure \
+    --libdir=android-libs/x86 \
+    --arch=x86 \
+    --cpu=i686 \
+    --cross-prefix="${TOOLCHAIN_PREFIX}/i686-linux-android16-" \
+    --nm="${TOOLCHAIN_PREFIX}/llvm-nm" \
+    --ar="${TOOLCHAIN_PREFIX}/llvm-ar" \
+    --ranlib="${TOOLCHAIN_PREFIX}/llvm-ranlib" \
+    --strip="${TOOLCHAIN_PREFIX}/llvm-strip" \
+    --disable-asm \
+    ${COMMON_OPTIONS}
+make -j$JOBS
+make install-libs
+make clean
+./configure \
+    --libdir=android-libs/x86_64 \
+    --arch=x86_64 \
+    --cpu=x86_64 \
+    --cross-prefix="${TOOLCHAIN_PREFIX}/x86_64-linux-android21-" \
+    --nm="${TOOLCHAIN_PREFIX}/llvm-nm" \
+    --ar="${TOOLCHAIN_PREFIX}/llvm-ar" \
+    --ranlib="${TOOLCHAIN_PREFIX}/llvm-ranlib" \
+    --strip="${TOOLCHAIN_PREFIX}/llvm-strip" \
+    --disable-asm \
+    ${COMMON_OPTIONS}
+make -j$JOBS
+make install-libs
+make clean

settings.gradle

@@ -1 +1 @@
-include ':litr-demo', ':litr', ':litr-filters'
+include ':litr-demo', ':litr', ':litr-filters', ':litr-muxers'