Android SoundPool 最大同时播放音频量maxStreams简介

发表于 | 阅读次数：
| 本文字数： 2k | 阅读时长 ≈ 2 分钟

SoudPool的构造方法的第一个参数maxStreams表示当前SoundPool最大能够同时播放多少个音频，具体可以看如下SoudPool构造方法的源码

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
/**
 * Constructor. Constructs a SoundPool object with the following
 * characteristics:
 *
 * @param maxStreams the maximum number of simultaneous streams for this
 *                   SoundPool object
 * @param streamType the audio stream type as described in AudioManager 
 *                   For example, game applications will normally use
 *                   {@link AudioManager#STREAM_MUSIC}.
 * @param srcQuality the sample-rate converter quality. Currently has no
 *                   effect. Use 0 for the default.
 * @return a SoundPool object, or null if creation failed
 * @deprecated use {@link SoundPool.Builder} instead to create and configure a
 *     SoundPool instance
 */
public SoundPool(int maxStreams, int streamType, int srcQuality) {
    this(maxStreams,
            new AudioAttributes.Builder().setInternalLegacyStreamType(streamType).build());
    PlayerBase.deprecateStreamTypeForPlayback(streamType, "SoundPool", "SoundPool()");
}

Click and drag to move

在SoudPool源码里还有如下一段对maxStreams的说明，总结为如下几点

  • SoundPool能够管理同一时间内音频播放的数量
  • SoundPool跟踪当前播放的音频数量，若数量超了，会按一定规则停止先前播放的音频
  • 数量超过maxStreams停止播放的规则为，首先按音频的优先级，然后按音频已经播放的时长
  • 限制maxStreams的数量，减小对UI交互性能的影响
1
2
3
4
5
6
7
8
9
* <p>In addition to low-latency playback, SoundPool can also manage the number
* of audio streams being rendered at once. When the SoundPool object is
* constructed, the maxStreams parameter sets the maximum number of streams
* that can be played at a time from this single SoundPool. SoundPool tracks
* the number of active streams. If the maximum number of streams is exceeded,
* SoundPool will automatically stop a previously playing stream based first
* on priority and then by age within that priority. Limiting the maximum
* number of streams helps to cap CPU loading and reducing the likelihood that
* audio mixing will impact visuals or UI performance.</p>

Click and drag to move

maxStreams大小的设置应该根据具体需求具体场景来定，先预估同一时间最多可能有多少个音频同时播放，然后将maxStreams设置为该值，太小了容易出现有的音频没播放完就被停止，设置太大浪费CPU资源，影响性能。