MediaCodec

areRenderMetricsEnabled()

1. server_configurable_flags::GetServerConfigurableFlag 函数的本质：
   把参数_1和参数_2和 “persist.device_config” 拼接到一块，当做property的key值，获取其value，如果没有，就获取默认值

"persist.device_config.${param_1_string}.${param_2_string}"

2. areRenderMetricsEnabled 获取 persist.device_config.media_native.render_metrics_enabled 属性值，返回值如下：
   a. Pixel 8a 返回 false;
   b. XiaoMi 13 Ultra 返回空，故也是false

VideoRenderQualityTracker::Configuration::getFromServerConfigurableFlags(GetServerConfigurableFlag)

![在这里插入图片描述](https://i-blog.csdnimg.cn/direct/386962ba13d1496a96e3bb0e3312d44f.png

getFlag的本质是，获取 persist.device_config.media_native.render_metrics_xxx 存放到 c.xxx变量中
如果找不到对应的属性值，c.xxx的值不变

而执行命令 adb shell getprop | findstr persist.device_config.media_native ，获得结果如下：
Pixel 8a

C:\Users\Liming>adb shell getprop | findstr persist.device_config.media_native
[persist.device_config.media_native.render_metrics_are_skipped_frames_dropped]: [true]
[persist.device_config.media_native.render_metrics_enable]: [true]
[persist.device_config.media_native.render_metrics_enabled]: [false]
[persist.device_config.media_native.render_metrics_frame_detection_tolerance_us]: [2000]
[persist.device_config.media_native.render_metrics_freeze_distance_ms_histogram_buckets]: [0,20,100,400,1000,2000,3000,4000,8000,15000,30000,60000]
[persist.device_config.media_native.render_metrics_freeze_duration_ms_histogram_buckets]: [0,20,40,60,80,100,120,150,175,225,300,400,500]
[persist.device_config.media_native.render_metrics_freeze_duration_ms_histogram_to_score]: [1,1,50,50,100,100,100,100,100,100,250,250,500]
[persist.device_config.media_native.render_metrics_freeze_event_details_max]: [20]
[persist.device_config.media_native.render_metrics_freeze_event_distance_ms_max]: [60000]
[persist.device_config.media_native.render_metrics_freeze_event_max]: [0]
[persist.device_config.media_native.render_metrics_judder_error_tolerance_us]: [2000]
[persist.device_config.media_native.render_metrics_judder_event_details_max]: [20]
[persist.device_config.media_native.render_metrics_judder_event_distance_ms_max]: [5000]
[persist.device_config.media_native.render_metrics_judder_event_max]: [0]
[persist.device_config.media_native.render_metrics_judder_score_histogram_buckets]: [0,4,5,9,11,20,30,40,50,60,70,80]
[persist.device_config.media_native.render_metrics_judder_score_histogram_to_score]: [1,1,1,1,1,1,1,1,1,1,1,1]
[persist.device_config.media_native.render_metrics_live_content_frame_drop_tolerance_us]: [200000]
[persist.device_config.media_native.render_metrics_max_expected_content_frame_duration_us]: [400000]
[persist.device_config.media_native.render_metrics_trace_maximum_freeze_duration_ms]: [1500]
[persist.device_config.media_native.render_metrics_trace_minimum_freeze_duration_ms]: [400]
[persist.device_config.media_native.render_metrics_trace_trigger_enabled]: [false]
[persist.device_config.media_native.render_metrics_trace_trigger_throttle_ms]: [300000]

故 VideoRenderQualityTracker::Configuration c 的一些变量如下：

enabled: false
areSkippedFramesDropped: true
maxExpectedContentFrameDurationUs: 400000
frameRateDetectionToleranceUs: 2000
liveContentFrameDropToleranceUs: 200000
freezeDurationMsHistogramBuckets:[0,20,40,60,80,100,120,150,175,225,300,400,500]
freezeDurationMsHistogramToScore:[1,1,50,50,100,100,100,100,100,100,250,250,500]
freezeDistanceMsHistogramBuckets: [0,20,100,400,1000,2000,3000,4000,8000,15000,30000,60000]
freezeEventMax: 0
freezeEventDetailsMax: 20
freezeEventDistanceToleranceMs: 原始值, 60000
judderErrorToleranceUs: 2000
judderScoreHistogramBuckets: [0,4,5,9,11,20,30,40,50,60,70,80]
judderScoreHistogramToScore: [1,1,1,1,1,1,1,1,1,1,1,1]
judderEventMax: 0
judderEventDetailsMax: 20
judderEventDistanceToleranceMs: 原始值, 5000

XiaoMi 13 Ultra上返回空, 故 VideoRenderQualityTracker::Configuration c 仍然采用代码中默认的值
而 MediaCodec与 VideoRenderQualityTracker 以及 VideoRenderQualityTracker::Configuration 的关系如下：