东源建设局网站,全自动建站系统源码,学做网站要什么基础,哪个平台可以免费卖货在Jetpack Compose中使用ExoPlayer实现直播流和音频均衡器
背景
ExoPlayer与Media3的能力结合#xff0c;为Android应用程序播放多媒体内容提供了强大的解决方案。在本教程中#xff0c;我们将介绍如何设置带有Media3的ExoPlayer来支持使用M3U8 URL进行直播流。此外#x…
在Jetpack Compose中使用ExoPlayer实现直播流和音频均衡器
背景
ExoPlayer与Media3的能力结合为Android应用程序播放多媒体内容提供了强大的解决方案。在本教程中我们将介绍如何设置带有Media3的ExoPlayer来支持使用M3U8 URL进行直播流。此外我们还将探讨如何集成音频均衡器为用户提供个性化的音频体验。
使用ExoPlayer进行直播流涉及到利用ExoPlayer库的强大能力在互联网上实时播放多媒体内容。
在这个探索中我们将深入了解ExoPlayer如何实现无缝播放直播流URL的复杂性为用户提供沉浸式体验。
ExoPlayer如何处理直播流
使用ExoPlayer进行直播流主要围绕着有效地处理音频和视频内容的实时传输。该过程包括几个关键阶段
内容源(Content Source)使用摄像机和麦克风捕获直播内容然后将此直播流可用于流媒体。编码(Encoding)捕获的内容被编码为适用于流媒体的数字格式。这涉及将原始音频和视频数据压缩并转换为与流媒体协议兼容的格式。流媒体服务器(Streaming Server)编码数据发送到充当中央枢纽的流媒体服务器。该服务器通过向用户设备发送数据包来管理多个观众的直播内容分发。ExoPlayer集成(ExoPlayer Integration)将具有强大能力的ExoPlayer集成到应用程序中以处理直播流的播放。应用程序获取直播流URL并配置ExoPlayer以处理流媒体协议例如HLS或DASH。观众设备(Viewer’s Device)用户通过各种设备访问直播流包括智能手机、平板电脑、计算机或智能电视。观众设备上的ExoPlayer实例解码接收到的数据使他们可以实时观看或收听直播内容。
设置ExoPlayer以进行直播流
要将ExoPlayer集成到我们的应用程序中以进行直播流我们需要遵循以下关键步骤
1.添加依赖项 在项目的build.gradle文件中包含必要的依赖项
// Exoplayer dependencies
implementation(androidx.media3:media3-exoplayer:1.2.0)
implementation(androidx.media3:media3-ui:1.2.0)
implementation(androidx.media3:media3-exoplayer-hls:1.2.0)这些依赖项确保应用程序可以利用ExoPlayer的功能进行直播流。
创建ExoPlayerManager 我们将创建一个管理器类来处理ExoPlayer实例。这可以确保应用程序的整个生命周期中只有一个播放器实例。
object ExoPlayerManager {private var exoPlayer: ExoPlayer? nullfun getExoPlayer(context: Context): ExoPlayer {if (exoPlayer null) {exoPlayer ExoPlayer.Builder(context).build()}return exoPlayer!!}fun releaseExoPlayer() {exoPlayer?.release()exoPlayer null}
}初始化ExoPlayer 在您的Composable函数中使用示例HLS流URL初始化ExoPlayer
Composable
fun LiveStreamingScreen() {// Obtain the current context and lifecycle owner using LocalContext and LocalLifecycleOwnerval context LocalContext.currentval lifecycleOwner LocalLifecycleOwner.current// Remember the ExoPlayer instance to persist across recompositionsval exoPlayer remember { ExoPlayerManager.getExoPlayer(context) }// Launch an effect to initialize ExoPlayer and set up the media sourceLaunchedEffect(key1 Unit) {// Create a data source factory for handling media requestsval dataSourceFactory DefaultHttpDataSource.Factory()// Define the URI for the sample HLS streamval uri Uri.Builder().encodedPath(http://sample.vodobox.net/skate_phantom_flex_4k/skate_phantom_flex_4k.m3u8).build()val mediaItem MediaItem.Builder().setUri(uri).build()// Create an HlsMediaSource from the media item for handling HTTP Live Streaming (HLS) content val internetVideoSource HlsMediaSource.Factory(dataSourceFactory).createMediaSource(mediaItem)exoPlayer.setMediaSource(internetVideoSource)exoPlayer.prepare()// Will be used in later implementation for EqualizerviewModel.onStart(exoPlayer.audioSessionId)}// ...
}显示ExoPlayer视图
将ExoPlayer视图集成到您的Composable函数中
// ...
Box(modifier Modifier.fillMaxSize()) {AndroidView(modifier Modifier.fillMaxWidth().aspectRatio(1.4f).padding(top 16.dp).background(Color.Black),factory {PlayerView(context).apply {// Connect the ExoPlayer instance to the PlayerViewplayer exoPlayer// Configure ExoPlayer settingsexoPlayer.repeatMode Player.REPEAT_MODE_ONEexoPlayer.playWhenReady falseuseController true}})
}
// ...
观察生命周期事件并释放资源 设置DisposableEffects来观察生命周期事件并在组合函数被释放时释放ExoPlayer
// ...
// Observe lifecycle events (e.g., app resume and pause)
// and adjust ExoPlayers playback state accordingly.
DisposableEffect(key1 lifecycleOwner) {val observer LifecycleEventObserver { _, event -if (event Lifecycle.Event.ON_RESUME) {exoPlayer.playWhenReady true} else if (event Lifecycle.Event.ON_PAUSE) {exoPlayer.playWhenReady false}}lifecycleOwner.lifecycle.addObserver(observer)onDispose {lifecycleOwner.lifecycle.removeObserver(observer)}
}// Release the ExoPlayer when the composable is disposed
// This helps in proper resource management
DisposableEffect(key1 Unit) {onDispose { ExoPlayerManager.releaseExoPlayer() }
}
// ...设置音频均衡器
现在让我们探讨如何在使用Jetpack Compose的Exoplayer设置中集成音频均衡器。这将允许用户通过调整预设均衡器设置或创建自定义均衡器配置来自定义音频体验。
音频均衡器通过提供对音频输出的细粒度控制来增强用户体验。
添加依赖项 在项目的build.gradle文件中包含必要的依赖项 implementation(com.google.dagger:hilt-android:2.48)kapt(com.google.dagger:hilt-android-compiler:2.47)implementation(androidx.hilt:hilt-navigation-compose:1.1.0)//Gsonimplementation(com.google.code.gson:gson:2.9.1)以上是示例依赖项您可以根据您的项目需要进行相应的更改。
这些依赖项确保您的应用程序可以利用Hilt进行依赖注入和Gson以高效地将复杂数据存储在首选项中。
定义均衡器预设和增益值 我们定义了一组预设例如Flat, Acoustic, 和 Rock每个预设都有相应的增益值来控制音频频率。这些预设将作为用户自定义其音频体验的起点。
// Equalizer presets and gain values
val effectType arrayListOf(Custom, Flat, Acoustic, Dance,Hip Hop, Jazz, Pop, Rock, Podcast
)// Constants for presets
const val PRESET_CUSTOM 0
const val PRESET_FLAT 1
const val PRESET_ACOUSTIC 2
const val PRESET_DANCE_LOUNGE 3
const val PRESET_HIP_HOP 4
const val PRESET_JAZZ_BLUES 5
const val PRESET_POP 6
const val PRESET_ROCK 7
const val PRESET_PODCAST 8// Gain values for each preset
val FLAT arrayListOf(0.0, 0.0, 0.0, 0.0, 0.0)
val ACOUSTIC arrayListOf(0.44, 0.12, 0.12, 0.34, 0.2)
val DANCE arrayListOf(0.52, 0.08, 0.28, 0.48, 0.06)
val HIP_HOPE arrayListOf(0.44, 0.06, -0.14, 0.1, 0.38)
val JAZZ arrayListOf(0.32, 0.0, 0.22, 0.1, 0.2)
val POP arrayListOf(-0.14, 0.28, 0.38, 0.22, -0.2)
val ROCK arrayListOf(0.38, 0.2, -0.04, 0.02, 0.34)
val PODCAST arrayListOf(-0.12, 0.26, 0.36, 0.16, -0.2)在上面的代码中我们定义了一个EqualizerConfiguration数据类它包含了预设设置和自定义频段设置的列表。EqualizerPreset类表示一个均衡器预设包括名称和增益值的列表。CustomEqualizerBand类表示自定义的均衡器频段包括频率和增益值。通过使用这些数据结构我们可以轻松地管理和应用均衡器配置。
创建音频效果数据类 音频效果数据类包含了关于所选效果类型及其相应增益值的重要信息。这个数据类充当用户偏好与音频均衡器实际实现之间的桥梁。
// 表示音频效果配置的数据类
data class AudioEffects(var selectedEffectType: Int 0,var gainValues: ArrayListDouble
)在这里selectedEffectType表示所选的音频预设而gainValues则存储了不同频段的自定义增益值。这个数据类封装了用户的音频偏好设置。
创建AppModule进行依赖注入 为了实现清晰模块化的依赖注入我们引入了AppModule。这个模块使用InstallIn(SingletonComponent::class)进行标注提供了诸如Gson和SharedPreferences等必要的依赖项。
Module
InstallIn(SingletonComponent::class)
class AppModule {ProvidesSingletonfun provideGson(): Gson {val gsonBuilder GsonBuilder()return gsonBuilder.create()}Named(AUDIO_EFFECT_PREFERENCES)Providesfun provideAudioEffectPreferences(application: Application): SharedPreferences {return application.getSharedPreferences(AUDIO_EFFECT_PREFERENCES, Context.MODE_PRIVATE)}
}在这个模块中provideGson提供了一个Gson的单例实例而provideAudioEffectPreferences则提供了一个特定用于音频效果偏好设置的SharedPreferences实例。这个模块对于管理整个应用程序的依赖项非常重要。
使用SharedPreferences和Gson实现均衡器偏好设置 为了提供无缝的用户体验我们将利用SharedPreferences来持久化与音频均衡器相关的用户偏好设置。此外我们使用Gson进行高效的数据序列化使我们能够将复杂的数据结构转换为易于存储和检索的格式。通过创建一个EqualizerPreferences类我们确保用户不必重复设置他们的均衡器偏好设置。
const val AUDIO_EFFECT_PREFERENCES audio_effect_preferencesprivate const val AUDIO_EFFECT_IS_EQUALIZER_ENABLED is_equalizer_enabled
private const val AUDIO_EFFECT_EQUALIZER_SETTING equalizer_audio_effect
private const val AUDIO_EFFECT_LOWEST_BAND_LEVEL equalizer_lowest_band_levelSingleton
class EqualizerPreferences
Inject constructor(param:Named(AUDIO_EFFECT_PREFERENCES) private val sharedPreferences: SharedPreferences,private val gson: Gson
) {var isEqualizerEnabled: Booleanget() sharedPreferences.getBoolean(AUDIO_EFFECT_IS_EQUALIZER_ENABLED, false)set(isEnable) sharedPreferences.edit().putBoolean(AUDIO_EFFECT_IS_EQUALIZER_ENABLED, isEnable).apply()// Getting and setting the users audio preferencesvar audioEffects: AudioEffects?get() {val json sharedPreferences.getString(AUDIO_EFFECT_EQUALIZER_SETTING, null)if (json ! null) {try {return gson.fromJson(json, AudioEffects::class.java)} catch (t: Throwable) {t.printStackTrace()}}return null}set(audioEffects) {var json: String? nullif (audioEffects ! null) {json gson.toJson(audioEffects)}sharedPreferences.edit().putString(AUDIO_EFFECT_EQUALIZER_SETTING, json).apply()}var lowestBandLevel: Intget() sharedPreferences.getInt(AUDIO_EFFECT_LOWEST_BAND_LEVEL, 0)set(value) sharedPreferences.edit().putInt(AUDIO_EFFECT_LOWEST_BAND_LEVEL, value).apply()
}上述代码展示了如何使用SharedPreferences和Gson来保存和加载音频效果配置。saveAudioEffects方法将AudioEffects对象转换为JSON字符串并将其保存在SharedPreferences中。loadAudioEffects方法从SharedPreferences中获取JSON字符串并将其转换回AudioEffects对象。通过使用EqualizerPreferences类我们可以方便地管理和访问均衡器偏好设置。
在这里Gson在将我们的AudioEffects数据类转换为JSON字符串以存储在SharedPreferences中方面起着至关重要的作用。这确保了一种无缝且高效的方式来存储和检索复杂的数据结构。
创建一个音频均衡器ViewModel 创建一个强大的AudioEqualizerViewModel负责管理音频均衡器逻辑。这个ViewModel初始化均衡器处理预设选择并根据用户交互更新设置。
HiltViewModel
class AudioEqualizerViewModel Inject constructor(private val equalizerPreferences: EqualizerPreferences
) : ViewModel() {// MutableStateFlow to observe and emit changes in audio effectsval audioEffects MutableStateFlowAudioEffects?(null)// Instance of the Equalizer class from the Android system libraryprivate var equalizer: Equalizer? null// MutableStateFlow to observe and emit changes in the equalizers enable/disable stateval enableEqualizer MutableStateFlow(false)// Unique audio session ID associated with the Exoplayerprivate var audioSessionId 0init {// Retrieve and set the initial equalizer enable/disable state and audio effects from preferencesenableEqualizer.value equalizerPreferences.isEqualizerEnabledaudioEffects.tryEmit(equalizerPreferences.audioEffects)if (audioEffects.value null) {audioEffects.tryEmit(AudioEffects(PRESET_FLAT, FLAT))}}// Will be called when exoplayer instance is created and we have audioSessionIdfun onStart(sessionId: Int) {audioSessionId sessionIdequalizer?.enabled enableEqualizer.valueequalizer Equalizer(Int.MAX_VALUE, audioSessionId)// Set the lowest band level based on the equalizers capabilitiesequalizerPreferences.lowestBandLevel equalizer?.bandLevelRange?.get(0)?.toInt() ?: 0// Apply gain values to the equalizer based on the stored audio effectsaudioEffects.value?.gainValues?.forEachIndexed { index, value -val bandLevel (value * 1000).toInt().toShort()equalizer?.setBandLevel(index.toShort(), bandLevel)}}// Method called when a preset is selectedfun onSelectPreset(presetPosition: Int) {// Return if no audio effects are availableif (audioEffects.value null) return// Determine the gain values based on the selected presetval gain if (presetPosition PRESET_CUSTOM) {ArrayList(audioEffects.value!!.gainValues)} else {ArrayList(getPresetGainValue(presetPosition))}// Update the audio effects with the selected preset and gain valuesaudioEffects.tryEmit(AudioEffects(presetPosition, gain))equalizerPreferences.audioEffects audioEffects.value// Apply the gain values to the equalizerequalizer?.apply {gain.forEachIndexed { index, value -val bandLevel (value * 1000).toInt().toShort()setBandLevel(index.toShort(), bandLevel)}}}// Method called when a specific band level is changed by the userfun onBandLevelChanged(changedBand: Int, newGainValue: Int) {// Retrieve the lowest band level from preferencesval lowest equalizerPreferences.lowestBandLevel// Calculate the new band levelval bandLevel newGainValue.plus(lowest)// Apply the new band level to the equalizerequalizer?.setBandLevel(changedBand.toShort(), bandLevel.toShort())val list ArrayList(audioEffects.value!!.gainValues)list[changedBand] (newGainValue.toDouble() / 1000)audioEffects.tryEmit(AudioEffects(PRESET_CUSTOM,list))equalizerPreferences.audioEffects audioEffects.value}// Method called to toggle the equalizers enable/disable statefun toggleEqualizer() {enableEqualizer.tryEmit(!enableEqualizer.value)equalizer?.enabled enableEqualizer.valueequalizerPreferences.isEqualizerEnabled enableEqualizer.valueif (!enableEqualizer.value) {audioEffects.tryEmit(AudioEffects(PRESET_FLAT, FLAT))equalizerPreferences.audioEffects audioEffects.value}}// Method to retrieve gain values for a specific presetprivate fun getPresetGainValue(index: Int): ListDouble {return when (index) {PRESET_FLAT - FLATPRESET_ACOUSTIC - ACOUSTICPRESET_DANCE_LOUNGE - DANCEPRESET_HIP_HOP - HIP_HOPEPRESET_JAZZ_BLUES - JAZZPRESET_POP - POPPRESET_ROCK - ROCKPRESET_PODCAST - PODCASTelse - FLAT}}
}这个ViewModel高效地管理音频均衡器的状态处理用户交互并确保使用SharedPreferences持久化用户偏好设置。
开发均衡器开关视图、预设视图和均衡器视图组件 设计一个用户友好的均衡器开关、均衡器视图和预设视图组件让用户可以可视化和调整均衡器设置。开关允许用户使用均衡器启用/禁用音频设置而均衡器视图将包含不同频率带的滑块提供高度可定制的音频体验。预设视图将包含一些预定义的效果类型可以直接应用到均衡器上。
Switch View
Row(modifier Modifier.fillMaxWidth(),horizontalArrangement Arrangement.SpaceBetween,verticalAlignment Alignment.CenterVertically
) {Text(text stringResource(R.string.equalizer_title_text),fontSize MaterialTheme.typography.titleLarge.fontSize,fontWeight FontWeight.SemiBold,color Color.White)Switch(checked enableEqualizer,onCheckedChange { // Toggle the equalizers enable/disable stateviewModel.toggleEqualizer() },colors SwitchDefaults.colors(checkedTrackColor Color.Black,checkedIconColor Color.Black,uncheckedTrackColor Color.White,uncheckedBorderColor Color.Black,))
}EqualizerView
OptIn(ExperimentalMaterial3Api::class)
Composable
fun EqualizerView(viewModel: AudioEqualizerViewModel) {// Frequency labels for the equalizer bandsval xAxisLabels listOf(60Hz, 230Hz, 910Hz, 3kHz, 14kHz)// Collect the current state of audio effects from the ViewModelval audioEffects by viewModel.audioEffects.collectAsState()// Column layout to arrange UI elements verticallyColumn(modifier Modifier.fillMaxWidth().fillMaxHeight().graphicsLayer {// Rotate the entire column to display frequency labels/sliders verticallyrotationZ 270f},verticalArrangement Arrangement.SpaceEvenly,horizontalAlignment Alignment.CenterHorizontally) {// Iterate through frequency labels and create corresponding UI elementsfor (index in xAxisLabels.indices) {Row(modifier Modifier.padding(top 20.dp).width(220.dp)) {// Each frequency label and its corresponding slider are placed in a BoxBox {// Display the frequency label with rotationText(text xAxisLabels[index],modifier Modifier.wrapContentWidth().align(Alignment.CenterStart).rotate(90f),color Color.White,fontSize 8.sp,textAlign TextAlign.Start)// Slider component for adjusting the gain value of each frequency bandSlider(modifier Modifier.offset(x 20.dp),// Bind the slider value to the corresponding gain value from the ViewModelvalue audioEffects!!.gainValues[index].times(1000f).toFloat().coerceIn(-3000f, 3000f),onValueChange {// Notify the ViewModel when a slider value changesviewModel.onBandLevelChanged(index, it.toInt())},valueRange -3000f..3000f,colors SliderDefaults.colors(thumbColor Color.Black,activeTrackColor Color.Black,inactiveTrackColor Color.White),thumb {// Customized appearance of the sliders thumbBox(modifier Modifier.size(20.dp).border(1.dp,Color.White,CircleShape).clip(CircleShape).background(Color.Black, CircleShape))})}}}}
}PresetsView
Composable
fun PresetsView(viewModel: AudioEqualizerViewModel) {// Collect the current state of audio effects from the ViewModelval audioEffects by viewModel.audioEffects.collectAsState()// Group the effect types into chunks of 4 for layoutval groupedList effectType.chunked(4)// Row containing the title and dividersRow(verticalAlignment Alignment.CenterVertically) {Divider(modifier Modifier.weight(1f).height(4.dp).clip(RoundedCornerShape(4.dp)),color Color.White,thickness 1.dp)// Title textText(text stringResource(R.string.presets_title_text),fontSize MaterialTheme.typography.titleMedium.fontSize,fontWeight FontWeight.Medium,color Color.White,modifier Modifier.wrapContentWidth().weight(0.5f).padding(4.dp).zIndex(1f),textAlign TextAlign.Center)Divider(modifier Modifier.weight(1f).height(4.dp).clip(RoundedCornerShape(4.dp)),color Color.White,thickness 1.dp)}Spacer(modifier Modifier.height(20.dp))// Iterate through grouped effect types and create UI elementsfor (itemList in groupedList) {BoxWithConstraints(modifier Modifier.fillMaxWidth()) {// Calculate padding and spacing based on screen widthval horizontalPadding if (maxWidth 320.dp) 8.dp else if (maxWidth 400.dp) 40.dp else 20.dpval horizontalSpacing if (maxWidth 400.dp) 24.dp else 16.dp// Row containing individual preset itemsRow(modifier Modifier.fillMaxWidth().padding(vertical 8.dp),horizontalArrangement Arrangement.spacedBy(space horizontalSpacing,alignment Alignment.CenterHorizontally),verticalAlignment Alignment.CenterVertically) {for (item in itemList) {// Get the index of the current itemval index by remember {mutableIntStateOf(effectType.indexOf(item))}// Create a clickable preset itemBoxWithConstraints(modifier Modifier.wrapContentSize().border(1.dp,if (index audioEffects?.selectedEffectType) Color.White else Color.Black,RoundedCornerShape(40.dp)).clip(RoundedCornerShape(40.dp)).clickable {// Notify the ViewModel when a preset is selectedviewModel.onSelectPreset(index)}.background(if (index audioEffects?.selectedEffectType) Color.Black else Color.White),contentAlignment Alignment.Center) {// Display the preset item textText(text item,style MaterialTheme.typography.bodySmall,modifier Modifier.padding(horizontal horizontalPadding,vertical 12.dp),fontSize 14.sp,color if (index audioEffects?.selectedEffectType) Color.White else Color.Black,maxLines 1,overflow TextOverflow.Ellipsis)}}}}}
}现在让我们使用AnimatedVisibility从父组件中调用上述函数
Composable
fun AudioEqualizerScreen() {val viewModel hiltViewModelAudioEqualizerViewModel()val enableEqualizer by viewModel.enableEqualizer.collectAsState()Column {Row(modifier Modifier.fillMaxWidth(),horizontalArrangement Arrangement.SpaceBetween,verticalAlignment Alignment.CenterVertically) {Text(text stringResource(R.string.equalizer_title_text),fontSize MaterialTheme.typography.titleLarge.fontSize,fontWeight FontWeight.SemiBold,color Color.White)Switch(checked enableEqualizer,onCheckedChange { viewModel.toggleEqualizer() },colors SwitchDefaults.colors(checkedTrackColor Color.Black,checkedIconColor Color.Black,uncheckedTrackColor Color.White,uncheckedBorderColor Color.Black,))}AnimatedVisibility(visible enableEqualizer,enter fadeIn() slideInVertically { fullHeight - -fullHeight / 2 },exit fadeOut() slideOutVertically { fullHeight - -fullHeight / 3 }) {EqualizerView(viewModel viewModel)}AnimatedVisibility(visible enableEqualizer,enter fadeIn() slideInVertically { fullHeight - -fullHeight / 2 },exit fadeOut() slideOutVertically { fullHeight - -fullHeight / 2 }) {PresetsView(viewModel)}}
}结论
在本篇博客中我们为在Jetpack Compose应用程序中设置ExoPlayer进行实时流式传输和集成音频均衡器打下了基础。这个组合为带有可定制均衡器设置的音频流提供了无缝的用户体验。
Github https://github.com/cp-megh-l/audio-equalizer-compose
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