yangkang2021.github.io

点播、直播、视频会议中，在软件内做卡顿率统计

一. 问题引出

• 最近看了几场视频号的会议直播，常常出现其中有一两个人声音卡顿。
• 大概每隔10-20秒卡一次，卡的时候声音会丢失，说话句子不完整，体验极差。
• 可见【卡顿率统计】对发现、分析、解决问题及其重要。
• 卡顿率：单位时间内，卡顿时间所占的百分比。

二. 卡顿原因

1. 网络抖动幅度大
2. 网络丢包率高
3. cpu等资源不够用
4. 软件自身问题

三. 【音频】的卡顿率统计

sampleRate  = 48000      //采样率
period      = 2          //周期：秒
playSample  = 据实统计    //1个周期内，给扬声器播放声音的样本数

卡顿率百分比 = [1 - playSample*1.0f / (sampleRate * period) ] * 100

四. 【视频】的卡顿率统计

fps          = 20        //帧率
period       = 5         //周期：秒
renderFrames = 渲染帧数   //1个周期内，发起视频渲染的帧数

卡顿率百分比 = [1 - renderFrames*1.0f / (fps * period) ] * 100 //在一个浮动范围更好

//这里可能忽略了渲染的平滑程度，只考虑丢帧，平滑渲染需要软件自己做好

五. webrtc内怎么计算

从stats里面获取totalSamplesReceived和framesReceived计算

{
		"type": "track",
		"id": "RTCMediaStreamTrack_receiver_3",
		"timestamp": 1622995437355000,
		"trackIdentifier": "824ad06d-6253-407f-9bf8-cd90ee438133",
		"remoteSource": true,
		"ended": false,
		"detached": false,
		"kind": "audio",
		"jitterBufferDelay": 5596.8,
		"jitterBufferEmittedCount": 148800,
		"audioLevel": 0.00006103701895199438,
		"totalAudioEnergy": 1.085988404462192e-8,
		"totalSamplesReceived": 151040,
		"totalSamplesDuration": 3.179999999999976,
		"concealedSamples": 800,
		"silentConcealedSamples": 280,
		"concealmentEvents": 1,
		"insertedSamplesForDeceleration": 1489,
		"removedSamplesForAcceleration": 0,
		"jitterBufferFlushes": 0,
		"delayedPacketOutageSamples": 0,
		"relativePacketArrivalDelay": 1.63,
		"interruptionCount": 0,
		"totalInterruptionDuration": 0
	},
	{
		"type": "track",
		"id": "RTCMediaStreamTrack_receiver_4",
		"timestamp": 1622995437355000,
		"trackIdentifier": "07a99ef3-314c-4629-b326-1022e6fa7058",
		"remoteSource": true,
		"ended": false,
		"detached": false,
		"kind": "video",
		"jitterBufferDelay": 2.206,
		"jitterBufferEmittedCount": 60,
		"frameWidth": 640,
		"frameHeight": 480,
		"framesReceived": 61,
		"framesDecoded": 61,
		"framesDropped": 0,
		"freezeCount": 0,
		"pauseCount": 0,
		"totalFreezesDuration": 0,
		"totalPausesDuration": 0,
		"totalFramesDuration": 2.977,
		"sumOfSquaredFramesDuration": 0.151969
	}