FFmpeg jni cpp (WIP)

.gitignore

@@ -13,3 +13,4 @@ Gemfile
 Gemfile.lock
 /maintenance-tasks/build/
 /android/.cxx/Debug/5k2s1t1p/x86/
+/ffmpeg/ffmpeg-kit-android-lib/.cxx/Debug/

.gitmodules

@@ -1,6 +1,6 @@
 [submodule "spotiflyer-ios"]
 	path = spotiflyer-ios
 	url = https://github.com/Shabinder/spotiflyer-ios
-[submodule "ffmpeg-android-maker"]
+[submodule "ffmpeg/ffmpeg-android-maker"]
-	path = ffmpeg-android-maker
+	path = ffmpeg/ffmpeg-android-maker
 	url = https://github.com/Shabinder/ffmpeg-android-maker

android/build.gradle.kts

@@ -57,20 +57,6 @@ android {
         targetSdk = Versions.targetSdkVersion
         versionCode = Versions.versionCode
         versionName = Versions.versionName
-
-        ndk {
-            abiFilters.addAll(setOf("x86", "x86_64", "armeabi-v7a", "arm64-v8a"))
-        }
-    }
-    sourceSets {
-        named("main") {
-            jniLibs.srcDir("../ffmpeg-android-maker/output/lib")
-        }
-    }
-    externalNativeBuild {
-        cmake {
-            path("CMakeLists.txt")
-        }
     }
     buildTypes {
         getByName("release") {
@@ -103,16 +89,6 @@ android {
             exclude(group = "androidx.compose.ui")
         }
     }
-    packagingOptions {
-        resources {
-            excludes.apply {
-                add("META-INF/*")
-            }
-            jniLibs.pickFirsts.apply {
-                add("**/*.so")
-            }
-        }
-    }
 }
 dependencies {
     implementation(compose.material)

android/src/main/cpp/main.cpp

@@ -1,18 +0,0 @@
-#include <stdio.h>
-#include <stdlib.h>
-#include <jni.h>
-#include <string.h>
-#include <android/log.h>
-
-extern "C" {
-    #include <libavformat/avformat.h>
-    // #include <libavcodec/avcodec.h>
-    JNIEXPORT jint
-
-    JNICALL Java_com_shabinder_spotiflyer_ffmpeg_FFmpeg_testInit(JNIEnv *env, jclass c) {
-        __android_log_print(ANDROID_LOG_DEBUG, "FFmpeg", "%s", avcodec_configuration());
-        return (jint)
-        1;
-    }
-}
-

android/src/main/java/com/shabinder/spotiflyer/MainActivity.kt

@@ -54,10 +54,12 @@ import com.google.accompanist.insets.statusBarsPadding
 import com.shabinder.common.core_components.ConnectionLiveData
 import com.shabinder.common.core_components.analytics.AnalyticsManager
 import com.shabinder.common.core_components.file_manager.FileManager
+import com.shabinder.common.core_components.media_converter.AndroidMediaConverter
 import com.shabinder.common.core_components.preference_manager.PreferenceManager
 import com.shabinder.common.di.observeAsState
 import com.shabinder.common.models.*
 import com.shabinder.common.models.PlatformActions.Companion.SharedPreferencesKey
+import com.shabinder.common.models.event.coroutines.success
 import com.shabinder.common.providers.FetchPlatformQueryResult
 import com.shabinder.common.root.SpotiFlyerRoot
 import com.shabinder.common.root.callbacks.SpotiFlyerRootCallBacks
@@ -65,7 +67,6 @@ import com.shabinder.common.translations.Strings
 import com.shabinder.common.uikit.configurations.SpotiFlyerTheme
 import com.shabinder.common.uikit.configurations.colorOffWhite
 import com.shabinder.common.uikit.screens.SpotiFlyerRootContent
-import com.shabinder.spotiflyer.ffmpeg.FFmpeg
 import com.shabinder.spotiflyer.service.ForegroundService
 import com.shabinder.spotiflyer.ui.AnalyticsDialog
 import com.shabinder.spotiflyer.ui.NetworkDialog
@@ -106,8 +107,15 @@ class MainActivity : ComponentActivity() {
         // This app draws behind the system bars, so we want to handle fitting system windows
         WindowCompat.setDecorFitsSystemWindows(window, false)
         rootComponent = spotiFlyerRoot(defaultComponentContext())
-        Log.d("FFmpeg","init")
+        lifecycleScope.launch {
-        FFmpeg.testInit()
+            Log.d("FFmpeg", "init")
+            AndroidMediaConverter().convertAudioFile("/storage/emulated/0/Music/SpotiFlyer/Playlists/Sing-along_Punjabi/Kya_Baat_Ay.mp3","/storage/emulated/0/Music/SpotiFlyer/Playlists/Sing-along_Punjabi/Kya_Baat_Ay.temp.mp3").fold({
+                Log.d("FFmpeg Success",it)
+            }){
+                it.printStackTrace()
+            }
+        }
+        /*FFmpeg.testInit()*/
         setContent {
             SpotiFlyerTheme {
                 Surface(contentColor = colorOffWhite) {
@@ -246,7 +254,11 @@ class MainActivity : ComponentActivity() {
     }
 
     @Suppress("DEPRECATION")
-    override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<out String>, grantResults: IntArray) {
+    override fun onRequestPermissionsResult(
+        requestCode: Int,
+        permissions: Array<out String>,
+        grantResults: IntArray
+    ) {
         super.onRequestPermissionsResult(requestCode, permissions, grantResults)
         permissionGranted.value = checkPermissions()
     }
@@ -261,11 +273,13 @@ class MainActivity : ComponentActivity() {
                 override val fileManager: FileManager = this@MainActivity.fileManager
                 override val preferenceManager = this@MainActivity.preferenceManager
                 override val analyticsManager: AnalyticsManager = this@MainActivity.analyticsManager
-                override val downloadProgressFlow: MutableSharedFlow<HashMap<String, DownloadStatus>> = trackStatusFlow
+                override val downloadProgressFlow: MutableSharedFlow<HashMap<String, DownloadStatus>> =
+                    trackStatusFlow
                 override val actions = object : Actions {
 
                     override val platformActions = object : PlatformActions {
-                        override val imageCacheDir: String = applicationContext.cacheDir.absolutePath + File.separator
+                        override val imageCacheDir: String =
+                            applicationContext.cacheDir.absolutePath + File.separator
                         override val sharedPreferences = applicationContext.getSharedPreferences(
                             SharedPreferencesKey,
                             MODE_PRIVATE

android/src/main/java/com/shabinder/spotiflyer/ffmpeg/FFmpeg.kt

@@ -1,9 +0,0 @@
-package com.shabinder.spotiflyer.ffmpeg
-
-object FFmpeg {
-    external fun testInit(): Long
-
-    init {
-        System.loadLibrary("spotiflyer-converter")
-    }
-}

common/core-components/build.gradle.kts

@@ -19,7 +19,8 @@ kotlin {
             dependencies {
                 implementation(Extras.mp3agic)
                 implementation(Extras.Android.countly)
-                implementation("com.arthenica:ffmpeg-kit-audio:4.4.LTS")
+                implementation(project(":ffmpeg:ffmpeg-kit-android-lib"))
+//                implementation("com.arthenica:ffmpeg-kit-audio:4.4.LTS")
                 //api(files("$rootDir/libs/mobile-ffmpeg.aar"))
             }
         }

common/core-components/src/androidMain/kotlin/com/shabinder/common/core_components/analytics/AndroidAnalyticsManager.kt

@@ -24,7 +24,7 @@ internal class AndroidAnalyticsManager(private val mainActivity: Activity) : Ana
                 setIdMode(DeviceId.Type.OPEN_UDID)
                 setViewTracking(true)
                 enableCrashReporting()
-                setLoggingEnabled(true)
+                setLoggingEnabled(false)
                 setRecordAllThreadsWithCrash()
                 setRequiresConsent(true)
                 setShouldIgnoreAppCrawlers(true)

common/core-components/src/androidMain/kotlin/com/shabinder/common/core_components/file_manager/AndroidFileManager.kt

@@ -152,7 +152,7 @@ class AndroidFileManager(
             SuspendableEvent.success(trackDetails.outputFilePath)
         } catch (e: Throwable) {
             e.printStackTrace()
-            if (songFile.exists()) songFile.delete()
+            //if (songFile.exists()) songFile.delete()
             logger.e { "${songFile.absolutePath} could not be created" }
             SuspendableEvent.error(e)
         }

common/core-components/src/androidMain/kotlin/com/shabinder/common/core_components/media_converter/AndroidMediaConverter.kt

@@ -1,17 +1,9 @@
 package com.shabinder.common.core_components.media_converter
 
-import android.util.Log
+import com.shabinder.spotiflyer.ffmpeg.AndroidFFmpeg.runTranscode
-import com.arthenica.ffmpegkit.FFmpegKit
-import com.arthenica.ffmpegkit.ReturnCode
 import com.shabinder.common.models.AudioQuality
-import com.shabinder.common.models.SpotiFlyerException
 import org.koin.dsl.bind
 import org.koin.dsl.module
-import com.arthenica.ffmpegkit.FFprobeKit
-
-import com.arthenica.ffmpegkit.MediaInformationSession
-import kotlin.math.ceil
-import kotlin.math.roundToInt
 
 
 class AndroidMediaConverter : MediaConverter() {
@@ -21,7 +13,10 @@ class AndroidMediaConverter : MediaConverter() {
         audioQuality: AudioQuality,
         progressCallbacks: (Long) -> Unit,
     ) = executeSafelyInPool {
-        val kbpsArg = if (audioQuality == AudioQuality.UNKNOWN) {
+        // 192 is Default
+        val audioBitrate = if (audioQuality == AudioQuality.UNKNOWN) 192 else audioQuality.kbps.toIntOrNull() ?: 192
+        runTranscode(inputFilePath,outputFilePath,audioBitrate).toString()
+        /*val kbpsArg = if (audioQuality == AudioQuality.UNKNOWN) {
             val mediaInformation = FFprobeKit.getMediaInformation(inputFilePath)
             val bitrate = ((mediaInformation.mediaInformation.bitrate).toFloat()/1000).roundToInt()
             Log.d("MEDIA-INPUT Bit", bitrate.toString())
@@ -41,7 +36,7 @@ class AndroidMediaConverter : MediaConverter() {
                 throw SpotiFlyerException.MP3ConversionFailed("FFmpeg Conversion Canceled for $inputFilePath")
             }
             else -> throw SpotiFlyerException.MP3ConversionFailed("FFmpeg Conversion Failed for $inputFilePath")
-        }
+        }*/
     }
 }
 

ffmpeg-android-maker

@@ -1 +0,0 @@
-Subproject commit b1dc4b643dc1c4015fc5f87075f9c135714def9e

ffmpeg/ffmpeg-kit-android-lib/CMakeLists.txt

@@ -9,7 +9,7 @@ set(
         # List variable name
         ffmpeg_libs_names
         # Values in the list
-        avutil avformat avcodec avresample swresample
+        avutil avformat avcodec swresample avdevice avfilter swscale
 )
 
 foreach (ffmpeg_lib_name ${ffmpeg_libs_names})
@@ -28,22 +28,29 @@ endforeach ()
 
 add_library(
         # Name for a library to build
-        spotiflyer-converter
+        spotiflyer-ffmpeg
         # Type of a library
         SHARED
         # All cpp files to compile
-        src/main/cpp/main.cpp
+        # mobile-ffmpeg
-        #        src/main/cpp/media_file_builder.cpp
+       src/main/cpp/doc_examples_transcode_aac.c
-        #        src/main/cpp/media_file_builder_jni.cpp
+
-        #        src/main/cpp/frame_loader_context.cpp
+        # ffmpeg-kit
-        #        src/main/cpp/frame_loader_context_jni.cpp
+#        src/main/cpp/ffmpegkit.c
-        #        src/main/cpp/frame_extractor.cpp
+#        src/main/cpp/ffprobekit.c
-        #        src/main/cpp/utils.cpp
+#        src/main/cpp/ffmpegkit_exception.c
+#        src/main/cpp/fftools_cmdutils.c
+#        src/main/cpp/fftools_ffmpeg.c
+#        src/main/cpp/fftools_ffprobe.c
+#        src/main/cpp/fftools_ffmpeg_opt.c
+#        src/main/cpp/fftools_ffmpeg_hw.c
+#        src/main/cpp/fftools_ffmpeg_filter.c
+#        src/main/cpp/saf_wrapper.c
 )
 
 target_link_libraries(
         # Library to link
-        spotiflyer-converter
+        spotiflyer-ffmpeg
         # List of libraries to link against:
         # Library for writing messages in LogCat
         log

ffmpeg/ffmpeg-kit-android-lib/build.gradle.kts

@@ -0,0 +1,63 @@
+plugins {
+    id("com.android.library")
+    id("kotlin-android")
+}
+
+android {
+    //ndkVersion "22.0.7026061"
+    compileSdk = Versions.compileSdkVersion
+    buildToolsVersion = "30.0.3"
+
+    defaultConfig {
+        consumerProguardFile("proguard-rules.pro")
+
+        minSdk = Versions.minSdkVersion
+        targetSdk = Versions.targetSdkVersion
+
+        /*versionCode = Versions.versionCode
+        versionName = Versions.versionName*/
+
+        ndk {
+            abiFilters.addAll(setOf("x86", "x86_64", "armeabi-v7a", "arm64-v8a"))
+        }
+    }
+
+    sourceSets {
+        named("main") {
+            jniLibs.srcDir("../ffmpeg-android-maker/output/lib")
+        }
+    }
+    externalNativeBuild {
+        cmake {
+            path("CMakeLists.txt")
+        }
+    }
+
+    buildTypes {
+        getByName("release") {
+            isMinifyEnabled = false
+            proguardFiles(
+                getDefaultProguardFile("proguard-android.txt"),
+                "proguard-rules.pro"
+            )
+        }
+    }
+
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_1_8
+        targetCompatibility = JavaVersion.VERSION_1_8
+    }
+
+    packagingOptions {
+        resources {
+            excludes.apply {
+                add("META-INF/*")
+            }
+            jniLibs.pickFirsts.apply {
+                add("**/*.so")
+            }
+        }
+    }
+}
+
+dependencies { /**/ }

ffmpeg/ffmpeg-kit-android-lib/proguard-rules.pro

@@ -0,0 +1,17 @@
+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.kts.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+-keep class com.arthenica.ffmpegkit.FFmpegKitConfig {
+    native <methods>;
+    void log(long, int, byte[]);
+    void statistics(long, int, float, float, long , int, double, double);
+    void closeParcelFileDescriptor(int);
+}
+
+-keep class com.arthenica.ffmpegkit.AbiDetect {
+    native <methods>;
+}

ffmpeg/ffmpeg-kit-android-lib/src/main/AndroidManifest.xml

@@ -0,0 +1,4 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="com.shabinder.spotiflyer.ffmpeg">
+
+</manifest>

ffmpeg/ffmpeg-kit-android-lib/src/main/cpp/.gitignore

@@ -0,0 +1,2 @@
+/android_lts_support.o
+/libandroidltssupport.a

ffmpeg/ffmpeg-kit-android-lib/src/main/cpp/doc_examples_transcode_aac.c

@@ -0,0 +1,915 @@
+/*
+ * Copyright (c) 2013-2018 Andreas Unterweger
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * Simple audio converter
+ *
+ * @example transcode_aac.c
+ * Convert an input audio file to AAC in an MP4 container using FFmpeg.
+ * Formats other than MP4 are supported based on the output file extension.
+ * @author Andreas Unterweger (dustsigns@gmail.com)
+ */
+
+#include <stdio.h>
+#include <jni.h>
+#include <android/log.h>
+
+#include "libavformat/avformat.h"
+#include "libavformat/avio.h"
+
+#include "libavcodec/avcodec.h"
+
+#include "libavutil/audio_fifo.h"
+#include "libavutil/avassert.h"
+#include "libavutil/avstring.h"
+#include "libavutil/frame.h"
+#include "libavutil/opt.h"
+
+#include "libswresample/swresample.h"
+#include <jni.h>
+
+/* The number of output channels */
+#define OUTPUT_CHANNELS 2
+/* The index of audio stream that will be transcoded */
+static int audio_stream_idx = -1;
+
+/**
+ * Open an input file and the required decoder.
+ * @param      filename             File to be opened
+ * @param[out] input_format_context Format context of opened file
+ * @param[out] input_codec_context  Codec context of opened file
+ * @return Error code (0 if successful)
+ */
+static int open_input_file(const char *filename,
+                           AVFormatContext **input_format_context,
+                           AVCodecContext **input_codec_context)
+{
+    AVCodecContext *avctx;
+    AVCodec *input_codec;
+    int error;
+
+    /* Open the input file to read from it. */
+    if ((error = avformat_open_input(input_format_context, filename, NULL,
+                                     NULL)) < 0) {
+        __android_log_print(ANDROID_LOG_ERROR, "transcode_aac", "Could not open input file '%s' (error '%s')\n",
+                filename, av_err2str(error));
+        *input_format_context = NULL;
+        return error;
+    }
+
+    /* Get information on the input file (number of streams etc.). */
+    if ((error = avformat_find_stream_info(*input_format_context, NULL)) < 0) {
+        __android_log_print(ANDROID_LOG_ERROR, "transcode_aac", "Could not open find stream info (error '%s')\n",
+                av_err2str(error));
+        avformat_close_input(input_format_context);
+        return error;
+    }
+
+    for (audio_stream_idx = 0; audio_stream_idx < (*input_format_context)->nb_streams; audio_stream_idx++) {
+        if ((*input_format_context)->streams[audio_stream_idx]->codecpar->codec_type == AVMEDIA_TYPE_AUDIO)
+            break;
+
+        __android_log_print(ANDROID_LOG_INFO, "transcode_aac", "Skip non-audio input stream %d\n", audio_stream_idx);
+    }
+
+    /* Make sure that there is at least one audio stream in the input file. */
+    if (audio_stream_idx >= (*input_format_context)->nb_streams) {
+        __android_log_print(ANDROID_LOG_ERROR, "transcode_aac", "Could not find an audio (error '%s')\n",
+                av_err2str(error));
+        avformat_close_input(input_format_context);
+        return AVERROR_EXIT;
+    }
+
+    /* Find a decoder for the audio stream. */
+    if (!(input_codec = avcodec_find_decoder((*input_format_context)->streams[audio_stream_idx]->codecpar->codec_id))) {
+        __android_log_print(ANDROID_LOG_ERROR, "transcode_aac", "Could not find input codec\n");
+        avformat_close_input(input_format_context);
+        return AVERROR_EXIT;
+    }
+
+    /* Allocate a new decoding context. */
+    avctx = avcodec_alloc_context3(input_codec);
+    if (!avctx) {
+        __android_log_print(ANDROID_LOG_ERROR, "transcode_aac", "Could not allocate a decoding context\n");
+        avformat_close_input(input_format_context);
+        return AVERROR(ENOMEM);
+    }
+
+    /* Initialize the stream parameters with demuxer information. */
+    error = avcodec_parameters_to_context(avctx, (*input_format_context)->streams[audio_stream_idx]->codecpar);
+    if (error < 0) {
+        avformat_close_input(input_format_context);
+        avcodec_free_context(&avctx);
+        return error;
+    }
+
+    /* Open the decoder for the audio stream to use it later. */
+    if ((error = avcodec_open2(avctx, input_codec, NULL)) < 0) {
+        __android_log_print(ANDROID_LOG_ERROR, "transcode_aac", "Could not open input codec (error '%s')\n",
+                av_err2str(error));
+        avcodec_free_context(&avctx);
+        avformat_close_input(input_format_context);
+        return error;
+    }
+
+    /* Save the decoder context for easier access later. */
+    *input_codec_context = avctx;
+
+    return 0;
+}
+
+/**
+ * Open an output file and the required encoder.
+ * Also set some basic encoder parameters.
+ * Some of these parameters are based on the input file's parameters.
+ * @param      filename              File to be opened
+ * @param      input_codec_context   Codec context of input file
+ * @param[out] output_format_context Format context of output file
+ * @param[out] output_codec_context  Codec context of output file
+ * @return Error code (0 if successful)
+ */
+static int open_output_file(const char *filename,
+                            AVCodecContext *input_codec_context,
+                            AVFormatContext **output_format_context,
+                            AVCodecContext **output_codec_context,
+                            int audioBitrate
+)
+{
+    AVCodecContext *avctx          = NULL;
+    AVIOContext *output_io_context = NULL;
+    AVStream *stream               = NULL;
+    AVCodec *output_codec          = NULL;
+    int error;
+
+    /* Open the output file to write to it. */
+    if ((error = avio_open(&output_io_context, filename,
+                           AVIO_FLAG_WRITE)) < 0) {
+        __android_log_print(ANDROID_LOG_ERROR, "transcode_aac", "Could not open output file '%s' (error '%s')\n",
+                filename, av_err2str(error));
+        return error;
+    }
+
+    /* Create a new format context for the output container format. */
+    if (!(*output_format_context = avformat_alloc_context())) {
+        __android_log_print(ANDROID_LOG_ERROR, "transcode_aac", "Could not allocate output format context\n");
+        return AVERROR(ENOMEM);
+    }
+
+    /* Associate the output file (pointer) with the container format context. */
+    (*output_format_context)->pb = output_io_context;
+
+    /* Guess the desired container format based on the file extension. */
+    if (!((*output_format_context)->oformat = av_guess_format(NULL, filename,
+                                                              NULL))) {
+        __android_log_print(ANDROID_LOG_ERROR, "transcode_aac", "Could not find output file format\n");
+        goto cleanup;
+    }
+
+    if (!((*output_format_context)->url = av_strdup(filename))) {
+        __android_log_print(ANDROID_LOG_ERROR, "transcode_aac", "Could not allocate url.\n");
+        error = AVERROR(ENOMEM);
+        goto cleanup;
+    }
+
+    /* Find the encoder to be used by its name. */
+    if (!(output_codec = avcodec_find_encoder((*output_format_context)->oformat->audio_codec))) {
+        __android_log_print(ANDROID_LOG_ERROR, "transcode_aac", "Could not find an encoder for %s(%d).\n",
+                            (*output_format_context)->oformat->long_name,
+                            (*output_format_context)->oformat->audio_codec);
+        goto cleanup;
+    }
+
+    /* Create a new audio stream in the output file container. */
+    if (!(stream = avformat_new_stream(*output_format_context, NULL))) {
+        __android_log_print(ANDROID_LOG_ERROR, "transcode_aac", "Could not create new stream\n");
+        error = AVERROR(ENOMEM);
+        goto cleanup;
+    }
+
+    avctx = avcodec_alloc_context3(output_codec);
+    if (!avctx) {
+        __android_log_print(ANDROID_LOG_ERROR, "transcode_aac", "Could not allocate an encoding context\n");
+        error = AVERROR(ENOMEM);
+        goto cleanup;
+    }
+
+    /* Set the basic encoder parameters.
+     * The input file's sample rate is used to avoid a sample rate conversion. */
+    avctx->channels       = OUTPUT_CHANNELS;
+    avctx->channel_layout = av_get_default_channel_layout(OUTPUT_CHANNELS);
+    avctx->sample_rate    = input_codec_context->sample_rate;
+    avctx->sample_fmt     = output_codec->sample_fmts[0];
+    avctx->bit_rate       = audioBitrate;
+
+    /* Allow the use of the experimental AAC encoder. */
+    avctx->strict_std_compliance = FF_COMPLIANCE_EXPERIMENTAL;
+
+    /* Set the sample rate for the container. */
+    stream->time_base.den = input_codec_context->sample_rate;
+    stream->time_base.num = 1;
+
+    /* Some container formats (like MP4) require global headers to be present.
+     * Mark the encoder so that it behaves accordingly. */
+    if ((*output_format_context)->oformat->flags & AVFMT_GLOBALHEADER)
+        avctx->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
+
+    /* Open the encoder for the audio stream to use it later. */
+    if ((error = avcodec_open2(avctx, output_codec, NULL)) < 0) {
+        __android_log_print(ANDROID_LOG_ERROR, "transcode_aac", "Could not open output codec (error '%s')\n",
+                av_err2str(error));
+        goto cleanup;
+    }
+
+    error = avcodec_parameters_from_context(stream->codecpar, avctx);
+    if (error < 0) {
+        __android_log_print(ANDROID_LOG_ERROR, "transcode_aac", "Could not initialize stream parameters\n");
+        goto cleanup;
+    }
+
+    /* Save the encoder context for easier access later. */
+    *output_codec_context = avctx;
+
+    return 0;
+
+cleanup:
+    avcodec_free_context(&avctx);
+    avio_closep(&(*output_format_context)->pb);
+    avformat_free_context(*output_format_context);
+    *output_format_context = NULL;
+    return error < 0 ? error : AVERROR_EXIT;
+}
+
+/**
+ * Initialize one data packet for reading or writing.
+ * @param packet Packet to be initialized
+ */
+static void init_packet(AVPacket *packet)
+{
+    av_init_packet(packet);
+    /* Set the packet data and size so that it is recognized as being empty. */
+    packet->data = NULL;
+    packet->size = 0;
+}
+
+/**
+ * Initialize one audio frame for reading from the input file.
+ * @param[out] frame Frame to be initialized
+ * @return Error code (0 if successful)
+ */
+static int init_input_frame(AVFrame **frame)
+{
+    if (!(*frame = av_frame_alloc())) {
+        __android_log_print(ANDROID_LOG_ERROR, "transcode_aac", "Could not allocate input frame\n");
+        return AVERROR(ENOMEM);
+    }
+    return 0;
+}
+
+/**
+ * Initialize the audio resampler based on the input and output codec settings.
+ * If the input and output sample formats differ, a conversion is required
+ * libswresample takes care of this, but requires initialization.
+ * @param      input_codec_context  Codec context of the input file
+ * @param      output_codec_context Codec context of the output file
+ * @param[out] resample_context     Resample context for the required conversion
+ * @return Error code (0 if successful)
+ */
+static int init_resampler(AVCodecContext *input_codec_context,
+                          AVCodecContext *output_codec_context,
+                          SwrContext **resample_context)
+{
+        int error;
+
+        /*
+         * Create a resampler context for the conversion.
+         * Set the conversion parameters.
+         * Default channel layouts based on the number of channels
+         * are assumed for simplicity (they are sometimes not detected
+         * properly by the demuxer and/or decoder).
+         */
+        *resample_context = swr_alloc_set_opts(NULL,
+                                              av_get_default_channel_layout(output_codec_context->channels),
+                                              output_codec_context->sample_fmt,
+                                              output_codec_context->sample_rate,
+                                              av_get_default_channel_layout(input_codec_context->channels),
+                                              input_codec_context->sample_fmt,
+                                              input_codec_context->sample_rate,
+                                              0, NULL);
+        if (!*resample_context) {
+            __android_log_print(ANDROID_LOG_ERROR, "transcode_aac", "Could not allocate resample context\n");
+            return AVERROR(ENOMEM);
+        }
+        /*
+        * Perform a sanity check so that the number of converted samples is
+        * not greater than the number of samples to be converted.
+        * If the sample rates differ, this case has to be handled differently
+        */
+        av_assert0(output_codec_context->sample_rate == input_codec_context->sample_rate);
+
+        /* Open the resampler with the specified parameters. */
+        if ((error = swr_init(*resample_context)) < 0) {
+            __android_log_print(ANDROID_LOG_ERROR, "transcode_aac", "Could not open resample context\n");
+            swr_free(resample_context);
+            return error;
+        }
+    return 0;
+}
+
+/**
+ * Initialize a FIFO buffer for the audio samples to be encoded.
+ * @param[out] fifo                 Sample buffer
+ * @param      output_codec_context Codec context of the output file
+ * @return Error code (0 if successful)
+ */
+static int init_fifo(AVAudioFifo **fifo, AVCodecContext *output_codec_context)
+{
+    /* Create the FIFO buffer based on the specified output sample format. */
+    if (!(*fifo = av_audio_fifo_alloc(output_codec_context->sample_fmt,
+                                      output_codec_context->channels, 1))) {
+        __android_log_print(ANDROID_LOG_ERROR, "transcode_aac", "Could not allocate FIFO\n");
+        return AVERROR(ENOMEM);
+    }
+    return 0;
+}
+
+/**
+ * Write the header of the output file container.
+ * @param output_format_context Format context of the output file
+ * @return Error code (0 if successful)
+ */
+static int write_output_file_header(AVFormatContext *output_format_context)
+{
+    int error;
+    if ((error = avformat_write_header(output_format_context, NULL)) < 0) {
+        __android_log_print(ANDROID_LOG_ERROR, "transcode_aac", "Could not write output file header (error '%s')\n",
+                av_err2str(error));
+        return error;
+    }
+    return 0;
+}
+
+/**
+ * Decode one audio frame from the input file.
+ * @param      frame                Audio frame to be decoded
+ * @param      input_format_context Format context of the input file
+ * @param      input_codec_context  Codec context of the input file
+ * @param[out] data_present         Indicates whether data has been decoded
+ * @param[out] finished             Indicates whether the end of file has
+ *                                  been reached and all data has been
+ *                                  decoded. If this flag is false, there
+ *                                  is more data to be decoded, i.e., this
+ *                                  function has to be called again.
+ * @return Error code (0 if successful)
+ */
+static int decode_audio_frame(AVFrame *frame,
+                              AVFormatContext *input_format_context,
+                              AVCodecContext *input_codec_context,
+                              int *data_present, int *finished)
+{
+    /* Packet used for temporary storage. */
+    AVPacket input_packet;
+    int error;
+    init_packet(&input_packet);
+
+    /* Read one audio frame from the input file into a temporary packet. */
+    if ((error = av_read_frame(input_format_context, &input_packet)) < 0) {
+        /* If we are at the end of the file, flush the decoder below. */
+        if (error == AVERROR_EOF)
+            *finished = 1;
+        else {
+            __android_log_print(ANDROID_LOG_WARN, "transcode_aac", "Could not read frame (error '%s')\n",
+                    av_err2str(error));
+            return error;
+        }
+    }
+
+    if (error != AVERROR_EOF && input_packet.stream_index != audio_stream_idx) {
+        goto cleanup;
+    }
+
+    /* Send the audio frame stored in the temporary packet to the decoder.
+     * The input audio stream decoder is used to do this. */
+    if ((error = avcodec_send_packet(input_codec_context, &input_packet)) < 0) {
+        __android_log_print(ANDROID_LOG_ERROR, "transcode_aac", "Could not send packet for decoding (error '%s')\n",
+                av_err2str(error));
+        return error;
+    }
+
+    /* Receive one frame from the decoder. */
+    error = avcodec_receive_frame(input_codec_context, frame);
+    /* If the decoder asks for more data to be able to decode a frame,
+     * return indicating that no data is present. */
+    if (error == AVERROR(EAGAIN)) {
+        error = 0;
+        goto cleanup;
+    /* If the end of the input file is reached, stop decoding. */
+    } else if (error == AVERROR_EOF) {
+        *finished = 1;
+        error = 0;
+        goto cleanup;
+    } else if (error < 0) {
+        __android_log_print(ANDROID_LOG_WARN, "transcode_aac", "Could not decode frame (error '%s')\n",
+                av_err2str(error));
+        goto cleanup;
+    /* Default case: Return decoded data. */
+    } else {
+        *data_present = 1;
+        goto cleanup;
+    }
+
+cleanup:
+    av_packet_unref(&input_packet);
+    return error;
+}
+
+/**
+ * Initialize a temporary storage for the specified number of audio samples.
+ * The conversion requires temporary storage due to the different format.
+ * The number of audio samples to be allocated is specified in frame_size.
+ * @param[out] converted_input_samples Array of converted samples. The
+ *                                     dimensions are reference, channel
+ *                                     (for multi-channel audio), sample.
+ * @param      output_codec_context    Codec context of the output file
+ * @param      frame_size              Number of samples to be converted in
+ *                                     each round
+ * @return Error code (0 if successful)
+ */
+static int init_converted_samples(uint8_t ***converted_input_samples,
+                                  AVCodecContext *output_codec_context,
+                                  int frame_size)
+{
+    int error;
+
+    /* Allocate as many pointers as there are audio channels.
+     * Each pointer will later point to the audio samples of the corresponding
+     * channels (although it may be NULL for interleaved formats).
+     */
+    if (!(*converted_input_samples = calloc(output_codec_context->channels,
+                                            sizeof(**converted_input_samples)))) {
+        __android_log_print(ANDROID_LOG_ERROR, "transcode_aac", "Could not allocate converted input sample pointers\n");
+        return AVERROR(ENOMEM);
+    }
+
+    /* Allocate memory for the samples of all channels in one consecutive
+     * block for convenience. */
+    if ((error = av_samples_alloc(*converted_input_samples, NULL,
+                                  output_codec_context->channels,
+                                  frame_size,
+                                  output_codec_context->sample_fmt, 0)) < 0) {
+        __android_log_print(ANDROID_LOG_ERROR, "transcode_aac",
+                "Could not allocate converted input samples (error '%s')\n",
+                av_err2str(error));
+        av_freep(&(*converted_input_samples)[0]);
+        free(*converted_input_samples);
+        return error;
+    }
+    return 0;
+}
+
+/**
+ * Convert the input audio samples into the output sample format.
+ * The conversion happens on a per-frame basis, the size of which is
+ * specified by frame_size.
+ * @param      input_data       Samples to be decoded. The dimensions are
+ *                              channel (for multi-channel audio), sample.
+ * @param[out] converted_data   Converted samples. The dimensions are channel
+ *                              (for multi-channel audio), sample.
+ * @param      frame_size       Number of samples to be converted
+ * @param      resample_context Resample context for the conversion
+ * @return Error code (0 if successful)
+ */
+static int convert_samples(const uint8_t **input_data,
+                           uint8_t **converted_data, const int frame_size,
+                           SwrContext *resample_context)
+{
+    int error;
+
+    /* Convert the samples using the resampler. */
+    if ((error = swr_convert(resample_context,
+                             converted_data, frame_size,
+                             input_data    , frame_size)) < 0) {
+        __android_log_print(ANDROID_LOG_ERROR, "transcode_aac", "Could not convert input samples (error '%s')\n",
+                av_err2str(error));
+        return error;
+    }
+
+    return 0;
+}
+
+/**
+ * Add converted input audio samples to the FIFO buffer for later processing.
+ * @param fifo                    Buffer to add the samples to
+ * @param converted_input_samples Samples to be added. The dimensions are channel
+ *                                (for multi-channel audio), sample.
+ * @param frame_size              Number of samples to be converted
+ * @return Error code (0 if successful)
+ */
+static int add_samples_to_fifo(AVAudioFifo *fifo,
+                               uint8_t **converted_input_samples,
+                               const int frame_size)
+{
+    int error;
+
+    /* Make the FIFO as large as it needs to be to hold both,
+     * the old and the new samples. */
+    if ((error = av_audio_fifo_realloc(fifo, av_audio_fifo_size(fifo) + frame_size)) < 0) {
+        __android_log_print(ANDROID_LOG_ERROR, "transcode_aac", "Could not reallocate FIFO\n");
+        return error;
+    }
+
+    /* Store the new samples in the FIFO buffer. */
+    if (av_audio_fifo_write(fifo, (void **)converted_input_samples,
+                            frame_size) < frame_size) {
+        __android_log_print(ANDROID_LOG_ERROR, "transcode_aac", "Could not write data to FIFO\n");
+        return AVERROR_EXIT;
+    }
+    return 0;
+}
+
+/**
+ * Read one audio frame from the input file, decode, convert and store
+ * it in the FIFO buffer.
+ * @param      fifo                 Buffer used for temporary storage
+ * @param      input_format_context Format context of the input file
+ * @param      input_codec_context  Codec context of the input file
+ * @param      output_codec_context Codec context of the output file
+ * @param      resampler_context    Resample context for the conversion
+ * @param[out] finished             Indicates whether the end of file has
+ *                                  been reached and all data has been
+ *                                  decoded. If this flag is false,
+ *                                  there is more data to be decoded,
+ *                                  i.e., this function has to be called
+ *                                  again.
+ * @return Error code (0 if successful)
+ */
+static int read_decode_convert_and_store(AVAudioFifo *fifo,
+                                         AVFormatContext *input_format_context,
+                                         AVCodecContext *input_codec_context,
+                                         AVCodecContext *output_codec_context,
+                                         SwrContext *resampler_context,
+                                         int *finished)
+{
+    /* Temporary storage of the input samples of the frame read from the file. */
+    AVFrame *input_frame = NULL;
+    /* Temporary storage for the converted input samples. */
+    uint8_t **converted_input_samples = NULL;
+    int data_present = 0;
+    int ret = AVERROR_EXIT;
+
+    /* Initialize temporary storage for one input frame. */
+    if (init_input_frame(&input_frame))
+        goto cleanup;
+    /* Decode one frame worth of audio samples. */
+    if (decode_audio_frame(input_frame, input_format_context,
+                           input_codec_context, &data_present, finished))
+        goto cleanup;
+    /* If we are at the end of the file and there are no more samples
+     * in the decoder which are delayed, we are actually finished.
+     * This must not be treated as an error. */
+    if (*finished) {
+        ret = 0;
+        goto cleanup;
+    }
+    /* If there is decoded data, convert and store it. */
+    if (data_present) {
+        /* Initialize the temporary storage for the converted input samples. */
+        if (init_converted_samples(&converted_input_samples, output_codec_context,
+                                   input_frame->nb_samples))
+            goto cleanup;
+
+        /* Convert the input samples to the desired output sample format.
+         * This requires a temporary storage provided by converted_input_samples. */
+        if (convert_samples((const uint8_t**)input_frame->extended_data, converted_input_samples,
+                            input_frame->nb_samples, resampler_context))
+            goto cleanup;
+
+        /* Add the converted input samples to the FIFO buffer for later processing. */
+        if (add_samples_to_fifo(fifo, converted_input_samples,
+                                input_frame->nb_samples))
+            goto cleanup;
+        ret = 0;
+    }
+    ret = 0;
+
+cleanup:
+    if (converted_input_samples) {
+        av_freep(&converted_input_samples[0]);
+        free(converted_input_samples);
+    }
+    av_frame_free(&input_frame);
+
+    return ret;
+}
+
+/**
+ * Initialize one input frame for writing to the output file.
+ * The frame will be exactly frame_size samples large.
+ * @param[out] frame                Frame to be initialized
+ * @param      output_codec_context Codec context of the output file
+ * @param      frame_size           Size of the frame
+ * @return Error code (0 if successful)
+ */
+static int init_output_frame(AVFrame **frame,
+                             AVCodecContext *output_codec_context,
+                             int frame_size)
+{
+    int error;
+
+    /* Create a new frame to store the audio samples. */
+    if (!(*frame = av_frame_alloc())) {
+        __android_log_print(ANDROID_LOG_WARN, "transcode_aac", "Could not allocate output frame\n");
+        return AVERROR_EXIT;
+    }
+
+    /* Set the frame's parameters, especially its size and format.
+     * av_frame_get_buffer needs this to allocate memory for the
+     * audio samples of the frame.
+     * Default channel layouts based on the number of channels
+     * are assumed for simplicity. */
+    (*frame)->nb_samples     = frame_size;
+    (*frame)->channel_layout = output_codec_context->channel_layout;
+    (*frame)->format         = output_codec_context->sample_fmt;
+    (*frame)->sample_rate    = output_codec_context->sample_rate;
+
+    /* Allocate the samples of the created frame. This call will make
+     * sure that the audio frame can hold as many samples as specified. */
+    if ((error = av_frame_get_buffer(*frame, 0)) < 0) {
+        __android_log_print(ANDROID_LOG_WARN, "transcode_aac", "Could not allocate output frame samples (error '%s')\n",
+                av_err2str(error));
+        av_frame_free(frame);
+        return error;
+    }
+
+    return 0;
+}
+
+/* Global timestamp for the audio frames. */
+static int64_t pts = 0;
+
+/**
+ * Encode one frame worth of audio to the output file.
+ * @param      frame                 Samples to be encoded
+ * @param      output_format_context Format context of the output file
+ * @param      output_codec_context  Codec context of the output file
+ * @param[out] data_present          Indicates whether data has been
+ *                                   encoded
+ * @return Error code (0 if successful)
+ */
+static int encode_audio_frame(AVFrame *frame,
+                              AVFormatContext *output_format_context,
+                              AVCodecContext *output_codec_context,
+                              int *data_present)
+{
+    /* Packet used for temporary storage. */
+    AVPacket output_packet;
+    int error;
+    init_packet(&output_packet);
+
+    /* Set a timestamp based on the sample rate for the container. */
+    if (frame) {
+        frame->pts = pts;
+        pts += frame->nb_samples;
+    }
+
+    /* Send the audio frame stored in the temporary packet to the encoder.
+     * The output audio stream encoder is used to do this. */
+    error = avcodec_send_frame(output_codec_context, frame);
+    /* The encoder signals that it has nothing more to encode. */
+    if (error == AVERROR_EOF) {
+        error = 0;
+        goto cleanup;
+    } else if (error < 0) {
+        __android_log_print(ANDROID_LOG_WARN, "transcode_aac", "Could not send packet for encoding (error '%s')\n",
+                av_err2str(error));
+        return error;
+    }
+
+    /* Receive one encoded frame from the encoder. */
+    error = avcodec_receive_packet(output_codec_context, &output_packet);
+    /* If the encoder asks for more data to be able to provide an
+     * encoded frame, return indicating that no data is present. */
+    if (error == AVERROR(EAGAIN)) {
+        error = 0;
+        goto cleanup;
+    /* If the last frame has been encoded, stop encoding. */
+    } else if (error == AVERROR_EOF) {
+        error = 0;
+        goto cleanup;
+    } else if (error < 0) {
+        __android_log_print(ANDROID_LOG_ERROR, "transcode_aac", "Could not encode frame (error '%s')\n",
+                av_err2str(error));
+        goto cleanup;
+    /* Default case: Return encoded data. */
+    } else {
+        *data_present = 1;
+    }
+
+    /* Write one audio frame from the temporary packet to the output file. */
+    if (*data_present &&
+        (error = av_write_frame(output_format_context, &output_packet)) < 0) {
+        __android_log_print(ANDROID_LOG_ERROR, "transcode_aac", "Could not write frame (error '%s')\n",
+                av_err2str(error));
+        goto cleanup;
+    }
+
+cleanup:
+    av_packet_unref(&output_packet);
+    return error;
+}
+
+/**
+ * Load one audio frame from the FIFO buffer, encode and write it to the
+ * output file.
+ * @param fifo                  Buffer used for temporary storage
+ * @param output_format_context Format context of the output file
+ * @param output_codec_context  Codec context of the output file
+ * @return Error code (0 if successful)
+ */
+static int load_encode_and_write(AVAudioFifo *fifo,
+                                 AVFormatContext *output_format_context,
+                                 AVCodecContext *output_codec_context)
+{
+    /* Temporary storage of the output samples of the frame written to the file. */
+    AVFrame *output_frame;
+    /* Use the maximum number of possible samples per frame.
+     * If there is less than the maximum possible frame size in the FIFO
+     * buffer use this number. Otherwise, use the maximum possible frame size. */
+    const int frame_size = FFMIN(av_audio_fifo_size(fifo),
+                                 output_codec_context->frame_size);
+    int data_written;
+
+    /* Initialize temporary storage for one output frame. */
+    if (init_output_frame(&output_frame, output_codec_context, frame_size))
+        return AVERROR_EXIT;
+
+    /* Read as many samples from the FIFO buffer as required to fill the frame.
+     * The samples are stored in the frame temporarily. */
+    if (av_audio_fifo_read(fifo, (void **)output_frame->data, frame_size) < frame_size) {
+        __android_log_print(ANDROID_LOG_WARN, "transcode_aac", "Could not read data from FIFO\n");
+        av_frame_free(&output_frame);
+        return AVERROR_EXIT;
+    }
+
+    /* Encode one frame worth of audio samples. */
+    if (encode_audio_frame(output_frame, output_format_context,
+                           output_codec_context, &data_written)) {
+        av_frame_free(&output_frame);
+        return AVERROR_EXIT;
+    }
+    av_frame_free(&output_frame);
+    return 0;
+}
+
+/**
+ * Write the trailer of the output file container.
+ * @param output_format_context Format context of the output file
+ * @return Error code (0 if successful)
+ */
+static int write_output_file_trailer(AVFormatContext *output_format_context)
+{
+    int error;
+    if ((error = av_write_trailer(output_format_context)) < 0) {
+        __android_log_print(ANDROID_LOG_ERROR, "transcode_aac", "Could not write output file trailer (error '%s')\n",
+                av_err2str(error));
+        return error;
+    }
+    return 0;
+}
+
+JNIEXPORT jint JNICALL Java_com_shabinder_spotiflyer_ffmpeg_AndroidFFmpeg_runTranscode(
+        JNIEnv *env, jobject c,
+        jstring inFilename,
+        jstring outFilename,
+        jint audioBitrate
+) {
+    AVFormatContext *input_format_context = NULL, *output_format_context = NULL;
+    AVCodecContext *input_codec_context = NULL, *output_codec_context = NULL;
+    SwrContext *resample_context = NULL;
+    AVAudioFifo *fifo = NULL;
+    int ret = AVERROR_EXIT;
+
+    const char *in_filename = (*env)->GetStringUTFChars(env, inFilename, 0);
+    const char *out_filename = (*env)->GetStringUTFChars(env, outFilename, 0);
+
+    __android_log_print(ANDROID_LOG_INFO, "transcode_aac", "Bitrate:%d :: %s -> %s\n", audioBitrate, in_filename, out_filename);
+
+    /* Open the input file for reading. */
+    if (open_input_file(in_filename, &input_format_context,
+                        &input_codec_context))
+        goto cleanup;
+
+    __android_log_print(ANDROID_LOG_INFO, "transcode_aac", "Input format: %s.\n",
+                        input_format_context->iformat->long_name);
+
+    /* Open the output file for writing. */
+    if (open_output_file(out_filename, input_codec_context,
+                         &output_format_context, &output_codec_context, (audioBitrate*1000)))
+        goto cleanup;
+
+    __android_log_print(ANDROID_LOG_INFO, "transcode_aac", "Output format: %s.\n",
+                        output_format_context->oformat->long_name);
+
+    /* Initialize the resampler to be able to convert audio sample formats. */
+    if (init_resampler(input_codec_context, output_codec_context,
+                       &resample_context))
+        goto cleanup;
+    /* Initialize the FIFO buffer to store audio samples to be encoded. */
+    if (init_fifo(&fifo, output_codec_context))
+        goto cleanup;
+    /* Write the header of the output file container. */
+    if (write_output_file_header(output_format_context))
+        goto cleanup;
+
+    /* Loop as long as we have input samples to read or output samples
+     * to write; abort as soon as we have neither. */
+    while (1) {
+        /* Use the encoder's desired frame size for processing. */
+        const int output_frame_size = output_codec_context->frame_size;
+        int finished                = 0;
+
+        /* Make sure that there is one frame worth of samples in the FIFO
+         * buffer so that the encoder can do its work.
+         * Since the decoder's and the encoder's frame size may differ, we
+         * need to FIFO buffer to store as many frames worth of input samples
+         * that they make up at least one frame worth of output samples. */
+        while (av_audio_fifo_size(fifo) < output_frame_size) {
+            /* Decode one frame worth of audio samples, convert it to the
+             * output sample format and put it into the FIFO buffer. */
+            if (read_decode_convert_and_store(fifo, input_format_context,
+                                              input_codec_context,
+                                              output_codec_context,
+                                              resample_context, &finished))
+                goto cleanup;
+
+            /* If we are at the end of the input file, we continue
+             * encoding the remaining audio samples to the output file. */
+            if (finished)
+                break;
+        }
+
+        /* If we have enough samples for the encoder, we encode them.
+         * At the end of the file, we pass the remaining samples to
+         * the encoder. */
+        while (av_audio_fifo_size(fifo) >= output_frame_size ||
+               (finished && av_audio_fifo_size(fifo) > 0))
+            /* Take one frame worth of audio samples from the FIFO buffer,
+             * encode it and write it to the output file. */
+            if (load_encode_and_write(fifo, output_format_context,
+                                      output_codec_context))
+                goto cleanup;
+
+        /* If we are at the end of the input file and have encoded
+         * all remaining samples, we can exit this loop and finish. */
+        if (finished) {
+            int data_written;
+            /* Flush the encoder as it may have delayed frames. */
+            do {
+                data_written = 0;
+                if (encode_audio_frame(NULL, output_format_context,
+                                       output_codec_context, &data_written))
+                    goto cleanup;
+            } while (data_written);
+            break;
+        }
+    }
+
+    /* Write the trailer of the output file container. */
+    if (write_output_file_trailer(output_format_context))
+        goto cleanup;
+    ret = 0;
+
+cleanup:
+    if (fifo)
+        av_audio_fifo_free(fifo);
+    swr_free(&resample_context);
+    if (output_codec_context)
+        avcodec_free_context(&output_codec_context);
+    if (output_format_context) {
+        avio_closep(&output_format_context->pb);
+        avformat_free_context(output_format_context);
+    }
+    if (input_codec_context)
+        avcodec_free_context(&input_codec_context);
+    if (input_format_context)
+        avformat_close_input(&input_format_context);
+
+    return ret;
+}

ffmpeg/ffmpeg-kit-android-lib/src/main/java/com/shabinder/spotiflyer/ffmpeg/AndroidFFmpeg.kt

@@ -0,0 +1,27 @@
+package com.shabinder.spotiflyer.ffmpeg
+
+import android.util.Log
+
+object AndroidFFmpeg {
+    /**
+     *
+     * Run transcode_aac from doc/examples.
+     *
+     * @return zero if transcoding was successful
+     */
+    @JvmStatic
+    external fun runTranscode(inFilename: String?, outFilename: String?, audioBitrate: Int): Int
+
+    init {
+        Log.i("FFmpeg", "Loading mobile-ffmpeg.")
+        System.loadLibrary("avutil")
+        System.loadLibrary("swscale")
+        System.loadLibrary("swresample")
+        System.loadLibrary("avcodec")
+        System.loadLibrary("avformat")
+        System.loadLibrary("avfilter")
+        System.loadLibrary("avdevice")
+        //System.loadLibrary("avresample")
+        System.loadLibrary("spotiflyer-ffmpeg")
+    }
+}

settings.gradle.kts

@@ -27,6 +27,7 @@ include(
     ":common:providers",
     ":common:core-components",
     ":common:dependency-injection",
+    ":ffmpeg:ffmpeg-kit-android-lib",
     ":android",
     ":desktop",
     ":web-app",