RK Android7.1 音频播放 Standby

 

一.Standby

当使用MediaPlayer停止本地播放后，如果切换我们自定义的音频通道（线路输入，只有模拟通道，数字通道没有工作），开始正常但隔几秒钟后就会没声音输出

Android系统默认播放停止后3秒（默认）会进入Standby模式来降低功耗

1.1.frameworks\av\services\audioflinger\AudioFlinger.cpp

ro.audio.flinger_standbytime_ms=2592000000

standby时间  由ro.audio.flinger_standbytime_ms控制  如果没有 这个属性 则默认是3秒

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void AudioFlinger::onFirstRef() {     Mutex::Autolock _l(mLock);       /* TODO: move all this work into an Init() function */     char val_str[PROPERTY_VALUE_MAX] = { 0 };     if (property_get("ro.audio.flinger_standbytime_ms", val_str, NULL) >= 0) {         uint32_t int_val;         if (1 == sscanf(val_str, "%u", &int_val)) {             mStandbyTimeInNsecs = milliseconds(int_val);             ALOGI("Using %u mSec as standby time.", int_val);         } else {             mStandbyTimeInNsecs = kDefaultStandbyTimeInNsecs;             ALOGI("Using default %u mSec as standby time.",                     (uint32_t)(mStandbyTimeInNsecs / 1000000));         }     }       mPatchPanel = new PatchPanel(this);       mMode = AUDIO_MODE_NORMAL; }

1.2.\frameworks\av\services\audioflinger\AudioFlinger.h

      Android系统默认播放停止后3秒会进入Standby模式以节省电源

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// ----------------------------------------------------------------------------   static const nsecs_t kDefaultStandbyTimeInNsecs = seconds(3);

1.3.进入Standby 之前关闭 Speak 功放

hardware/rockchip/audio/tinyalsa_hal/audio_hw.c

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--- a/hardware/rockchip/audio/tinyalsa_hal/audio_hw.c +++ b/hardware/rockchip/audio/tinyalsa_hal/audio_hw.c @@ -1162,6 +1162,11 @@ static void do_out_standby(struct stream_out *out)          }          out->standby = true;          out->nframes = 0; +       speaker_mute(1);         property_set("media.audio.slice", "0");          if (out == adev->outputs[OUTPUT_HDMI_MULTI]) {              /* force standby on low latency output stream so that it can reuse HDMI driver if     static void speaker_mute(int mute) {         int ret=0;     int fdp =0;           fdp= open("/sys/class/xh_custom/xh_custom_gpio/device/speaker_en",O_RDWR);           if(fdp > 0)     {                           if(mute==1)             {                 ALOGD("MUTE speaker");                 ret= write(fdp,"0",1);             }             else             {                 ALOGD("UNMUTE speaker");                 ret= write(fdp,"1",1);             }                    if(ret != 1)         {             ALOGD("MUTE speaker FAILED");             close(fdp);         }         close(fdp);     } }