如何在Android Exoplayer中实现质量控制功能？

Question

我想在我的Android应用程序的exoplayer中播放HLS视频。以下是代码-

    DefaultBandwidthMeter bandwidthMeter = new DefaultBandwidthMeter();

        //DefaultTrackSelector chooses tracks in the media item
        DefaultTrackSelector trackSelector = new DefaultTrackSelector(this);
        trackSelector.setParameters(trackSelector.buildUponParameters().setMaxVideoSizeSd());
        mPlayer = new SimpleExoPlayer.Builder(this).setTrackSelector(trackSelector).build();

        DataSource.Factory dataSourceFactory = new DefaultDataSourceFactory(this, Util.getUserAgent(this, "exoplayerapp"), bandwidthMeter);
        MediaSource mediaSource = new ProgressiveMediaSource.Factory(dataSourceFactory).createMediaSource(Uri.parse(url));

        mPlayer.prepare(mediaSource);

        playerView.setKeepScreenOn(true);
        playerView.requestFocus();
        playerView.setPlayer(mPlayer);
        mPlayer.setPlayWhenReady(true);

它工作得很好，但我无法添加质量控制。HSL流有不同的质量格式，如249p，360p，480p，但我无法选择曲目。我应该在哪里更改代码？

Answer 1

我做了一个回收站，你可以在那里找到我做的质量选择器，它可以在HLS流上帮助你。我正在试着用exoplayer版本更新它。

https://github.com/yoobi/exoplayer-kotlin/tree/master/qualityselector

exo_player_control_view.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- Copyright (C) 2016 The Android Open Source Project
     Licensed under the Apache License, Version 2.0 (the "License");
     you may not use this file except in compliance with the License.
     You may obtain a copy of the License at
          http://www.apache.org/licenses/LICENSE-2.0
     Unless required by applicable law or agreed to in writing, software
     distributed under the License is distributed on an "AS IS" BASIS,
     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     See the License for the specific language governing permissions and
     limitations under the License.
-->
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_gravity="bottom"
    android:layoutDirection="ltr"
    android:background="#CC000000"
    android:orientation="vertical">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:paddingTop="4dp"
        android:orientation="horizontal">

        <ImageButton android:id="@id/exo_rew"
            style="@style/ExoMediaButton.Rewind"/>

        <ImageButton android:id="@id/exo_play"
            style="@style/ExoMediaButton.Play"/>

        <ImageButton android:id="@id/exo_pause"
            style="@style/ExoMediaButton.Pause"/>

        <ImageButton android:id="@id/exo_ffwd"
            style="@style/ExoMediaButton.FastForward"/>

        <LinearLayout
            android:id="@+id/exo_quality_button"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content">

            <ImageButton
                android:id="@+id/exo_quality"
                app:srcCompat="@drawable/ic_settings"
                style="@style/ExoMediaButton"
                android:visibility="gone"/>

        </LinearLayout>

    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="4dp"
        android:gravity="center_vertical"
        android:orientation="horizontal">

        <TextView android:id="@id/exo_position"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="14sp"
            android:textStyle="bold"
            android:paddingLeft="4dp"
            android:paddingRight="4dp"
            android:includeFontPadding="false"
            android:textColor="#FFBEBEBE"/>

        <com.google.android.exoplayer2.ui.DefaultTimeBar
            android:id="@id/exo_progress"
            android:layout_width="0dp"
            android:layout_weight="1"
            android:layout_height="26dp"/>

        <TextView android:id="@id/exo_duration"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="14sp"
            android:textStyle="bold"
            android:paddingLeft="4dp"
            android:paddingRight="4dp"
            android:includeFontPadding="false"
            android:textColor="#FFBEBEBE"/>

    </LinearLayout>

</LinearLayout>

MainActivity

import android.app.Dialog
import android.os.Bundle
import android.view.View
import android.widget.FrameLayout
import android.widget.ImageButton
import android.widget.ImageView
import androidx.appcompat.app.AppCompatActivity
import com.google.android.exoplayer2.C
import com.google.android.exoplayer2.MediaItem
import com.google.android.exoplayer2.Player
import com.google.android.exoplayer2.SimpleExoPlayer
import com.google.android.exoplayer2.trackselection.DefaultTrackSelector
import com.google.android.exoplayer2.trackselection.MappingTrackSelector
import com.google.android.exoplayer2.ui.PlayerView
import com.google.android.exoplayer2.ui.TrackSelectionDialogBuilder
import com.google.android.exoplayer2.upstream.DataSource
import com.google.android.exoplayer2.upstream.DefaultDataSourceFactory
import com.google.android.exoplayer2.util.MimeTypes
import com.google.android.exoplayer2.util.Util

const val HLS_STATIC_URL = "https://bitdash-a.akamaihd.net/content/MI201109210084_1/m3u8s/f08e80da-bf1d-4e3d-8899-f0f6155f6efa.m3u8"
const val STATE_RESUME_WINDOW = "resumeWindow"
const val STATE_RESUME_POSITION = "resumePosition"
const val STATE_PLAYER_FULLSCREEN = "playerFullscreen"
const val STATE_PLAYER_PLAYING = "playerOnPlay"
const val MAX_HEIGHT = 539
const val MAX_WIDTH = 959

class MainActivity : AppCompatActivity() {

    private lateinit var exoPlayer: SimpleExoPlayer
    private lateinit var dataSourceFactory: DataSource.Factory
    private lateinit var trackSelector: DefaultTrackSelector
    private lateinit var playerView: PlayerView
    private lateinit var exoQuality: ImageButton

    private var currentWindow = 0
    private var playbackPosition: Long = 0
    private var isFullscreen = false
    private var isPlayerPlaying = true
    private var trackDialog: Dialog? = null
    private val mediaItem = MediaItem.Builder()
        .setUri(HLS_STATIC_URL)
        .setMimeType(MimeTypes.APPLICATION_M3U8)
        .build()

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        playerView = findViewById(R.id.player_view)
        exoQuality = playerView.findViewById(R.id.exo_quality)

        dataSourceFactory = DefaultDataSourceFactory(this,
            Util.getUserAgent(this, "testapp"))

        exoQuality.setOnClickListener{
            if(trackDialog == null){
                initPopupQuality()
            }
            trackDialog?.show()
        }

        if (savedInstanceState != null) {
            currentWindow = savedInstanceState.getInt(STATE_RESUME_WINDOW)
            playbackPosition = savedInstanceState.getLong(STATE_RESUME_POSITION)
            isFullscreen = savedInstanceState.getBoolean(STATE_PLAYER_FULLSCREEN)
            isPlayerPlaying = savedInstanceState.getBoolean(STATE_PLAYER_PLAYING)
        }
    }

    private fun initPlayer(){

        trackSelector = DefaultTrackSelector(this)
        // When player is initialized it'll be played with a quality of MaxVideoSize to prevent loading in 1080p from the start
        trackSelector.setParameters(trackSelector.buildUponParameters().setMaxVideoSize(MAX_WIDTH,MAX_HEIGHT))
        exoPlayer = SimpleExoPlayer.Builder(this).setTrackSelector(trackSelector).build().apply {
            playWhenReady = isPlayerPlaying
            seekTo(currentWindow, playbackPosition)
            setMediaItem(mediaItem)
            prepare()
        }
        playerView.player = exoPlayer

        //Listener on player
        exoPlayer.addListener(object: Player.Listener{
            override fun onPlayerStateChanged(playWhenReady: Boolean, playbackState: Int) {
                if(playbackState == Player.STATE_READY){
                    exoQuality.visibility = View.VISIBLE
                }
            }
        })
    }

    private fun releasePlayer(){
        isPlayerPlaying = exoPlayer.playWhenReady
        playbackPosition = exoPlayer.currentPosition
        currentWindow = exoPlayer.currentWindowIndex
        exoPlayer.release()
    }

    override fun onSaveInstanceState(outState: Bundle) {
        outState.putInt(STATE_RESUME_WINDOW, exoPlayer.currentWindowIndex)
        outState.putLong(STATE_RESUME_POSITION, exoPlayer.currentPosition)
        outState.putBoolean(STATE_PLAYER_FULLSCREEN, isFullscreen)
        outState.putBoolean(STATE_PLAYER_PLAYING, isPlayerPlaying)
        super.onSaveInstanceState(outState)
    }

    override fun onStart() {
        super.onStart()
        if (Util.SDK_INT > 23) {
            initPlayer()
            playerView.onResume()
        }
    }

    override fun onResume() {
        super.onResume()
        if (Util.SDK_INT <= 23) {
            initPlayer()
            playerView.onResume()
        }
    }

    override fun onPause() {
        super.onPause()
        if (Util.SDK_INT <= 23) {
            playerView.onPause()
            releasePlayer()
        }
    }

    override fun onStop() {
        super.onStop()
        if (Util.SDK_INT > 23) {
            playerView.onPause()
            releasePlayer()
        }
    }

    // QUALITY SELECTOR

    private fun initPopupQuality() {
        val mappedTrackInfo = trackSelector.currentMappedTrackInfo
        var videoRenderer : Int? = null

        if(mappedTrackInfo == null) return else exoQuality.visibility = View.VISIBLE

        for(i in 0 until mappedTrackInfo.rendererCount){
            if(isVideoRenderer(mappedTrackInfo, i)){
                videoRenderer = i
            }
        }

        if(videoRenderer == null){
            exoQuality.visibility = View.GONE
            return
        }

        val trackSelectionDialogBuilder = TrackSelectionDialogBuilder(this, getString(R.string.qualitySelector), trackSelector, videoRenderer)
        trackSelectionDialogBuilder.setTrackNameProvider{
            // Override function getTrackName
            getString(R.string.exo_track_resolution_pixel, it.height)
        }
        trackDialog = trackSelectionDialogBuilder.build()
    }

    private fun isVideoRenderer(mappedTrackInfo: MappingTrackSelector.MappedTrackInfo, rendererIndex: Int): Boolean {
        val trackGroupArray = mappedTrackInfo.getTrackGroups(rendererIndex)
        if (trackGroupArray.length == 0) {
            return false
        }
        val trackType = mappedTrackInfo.getRendererType(rendererIndex)
        return C.TRACK_TYPE_VIDEO == trackType
    }

}