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

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

// ----------------------------------------------------------------------------

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

--- 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);
    }
}