字幕组成品列表（Beta）
  • 写在前面
  • Android 平台
    • Game On! 游戏开发系列 - 031
      • Pie Noon - 1503060393
      • The Death of Base Game Activity - 1504030543
      • Surviving OpenGL Context Loss - 1504030546
      • WebP for Game Devs - 1504030547
      • Saved Games In-Depth (Part 1) - 1504070556
      • Saved Games In-Depth (Part 2) - 1504030548
      • Smaller Flipbook Textures with CRABBY - 1504030544
      • Google Tag Manager - 1504030545
      • Flatbuffers - 1505050794
      • Achievement Point Pointers - 1505050796
      • Frequency Scaling - 1505050797
      • Meet the Management APIs - 1501140367
      • Y U Ship Broken Games - 1505050795
    • Android 性能优化 - 088
      • Garbage Collection in Android - 1503170425
      • Performance Cost of Memory Leaks - 1503170424
      • Rendering Performance 101 - 1501130351
      • Understanding Overdraw - 1501130352
      • Understanding VSYNC - 1501130353
      • Tool - Profile GPU Rendering - 1501130354
      • Why 60fps? - 1501130355
      • Android UI and the GPU - 1501130356
      • Invalidations, Layouts, and Performance - 1501130357
      • Overdraw, Cliprect, QuickReject - 1501130358
      • Tool - Memory Monitor - 1501130363
      • Battery Performance 101 - 1501130364
      • Understanding Battery Drain on Android - 1501130365
      • Battery Drain and WakeLocks - 1501130366
      • Memory Performance 101 - 1504170661
    • I/O 2014 Android 开发专题 - 089
      • Activity Transitions - 1504020505
      • Building Apps For Android TV - 1504020520
      • Building great Android media experiences - 1504020510
      • Building a quality app from start to finish - 1504020515
      • App Indexing API - 1504020507
      • What's new in WebView - 1504010484
      • Bluetooth Low Energy - 1504010486
      • Building impressive Android media experiences - 1504010493
      • The next Generation of Authentication - 1504020497
      • Don't Alpha That Pixel! - 1504020523
      • NFC + HCE Your phone in an interactive world - 1504020509
      • Demystifying encodes and decodes of WebM - 1504020521
      • Google Cloud Messaging - 1504020524
      • Getting your Game on the Big Screen - 1504020518
      • I hear you like realtime memes - 1504020511
      • Offerize your App - 1504020506
      • Using the Android Job Scheduler - 1504020504
      • From Holo to Material - 1504020526
      • Under the Hood of Android Auto - 1504020501
      • Isolation for Android App Developers - 1504020498
      • Android Work - 1504010496
      • ExoPlayer: Adaptive video streaming on Android - 1504010489
      • Sample rates and resampling: Why can't we all just agree? - 1504010488
      • Drive Android API - 1504010485
    • Android Studio - 004
      • Layout Editor (Ep 3, Android Studio) - 1503290479
      • Introducing Gradle (Ep 2, Android Studio) - 1503170426
    • I/O 2014 Android 分发主题 - 091
      • Introduction to Google Play - 1504030534
      • Google Play: building your user community - 1504030535
      • Optimizing Apps for Education - 1504030536
      • Succeeding in Education Technology - 1504030530
      • Subscriptions Made Easy with Google Play - 1504030531
      • The world is your playground - go global with Google - 1504030533
      • Maximizing discoverability on Google Play - 1504030538
    • Android Auto - 003
      • Introduction to Android Auto - 1504130615
      • Android Auto Messaging - 1504130617
      • Android Auto Audio - 1504130616
    • Android Wear - 006
      • Designing for Android Wear - 1503210448
      • How We Customized Google Apps for Android Wear - 1503210450
      • Fullscreen apps for Android Wear - 1503210445
      • New Notification Features for Android Wear - 1503210446
      • Building Cloud-powered wearable Apps - 1503210449
      • An Introduction to Android Wear - 1503190435
      • Google I/O 2014 - Android Wear: The developer's perspective - 1503210442
      • Devoxx 2014 Interviews: Android Wear - 1503210440
      • DevBytes: Watch Faces for Android Wear - 1503210439
    • Android TV - 005
      • Using the Leanback library - 1504080588
      • Beach Buggy Racing Multiplayer with Nearby Connections (Play Services) - 1503060387
    • Android for Work - 106
      • Android for Work for Developers - 1503060390
      • App Configurations, Testing and Launchers - 1504110590
    • IO Bytes 2014 - Android - 066
      • Chrome Apps on Android and iOS - 1501080014
      • Perf Primer CPU, GPU and your Android game - 1501080017
  • Chrome 平台
    • IO Bytes 2014 - Chrome and Web - 067
      • Using the PageSpeed API - 1505070815
      • Fabulous Forms for the multi-device web - 1505070816
      • Testing multi-screen web pages - 1505070817
      • Responsive images today - 1505070819
      • Web Performance Testing at YouTube - 1505070828
      • Building sites for the multi-device web - 1505070820
      • Deep dive: Google Cloud Messaging for Chrome - 1505070827
  • Google 创业者资源
    • Coffee with a Googler - 012
      • Chat with Allen Huang of AndroidTV - 1503040384
      • Chat with Fred Chung about developer advocacy - 1503070395
      • Google Fit platform with Michelle Haq - 1503210443
      • Android Auto Product Manager Andrew Brenner - 1501120027
      • Chat with Francis Ma about Google Play services - 1501120028
    • Root Access For Startups - 077
      • What we learned building plug-ins for Android, with startup Magnet - 1503230453
      • How to use crowdfunding to your advantage, with startup Hale Devices - 1503280462
      • How to overcome customer objections when selling tech, with startup Guesswork - 1503280458
    • First Things First - 029
      • Getting started with Android: A crash-course in developing for Android - 1504120601
      • How to ask a question: conducting research for your startup - 1504120603
      • MVP Design Hacks: transform your hot idea into a validated prototype - 1504120602
      • Build something people want: Solving real problems - 1504120605
    • How I - 061
      • Use BigQuery to find my most valuable customers - 1504070573
      • Manage beta testing communities using Google Play - 1504070572
      • Use paper wireframing to build native prototypes - 1504070570
      • Used social media and $0 marketing to get 68 million users - 1504070568
      • Prep to fundraise with four questions - 1504070564
      • Validated my idea in 2 days (with no code) - 1504070562
      • Build open platforms on Android - 1504120596
      • Get cheap, automatic analytics for my business using BigQuery - 1504070571
      • Write press releases to get international media coverage - 1504070569
      • Test beta-product features using Google Apps - 1504070563
      • Use URL builder to measure ROI on social media - 1504070561
      • Use events to build DeadSocial's brand - 1504070557
      • Use BigQuery to visualize streaming data - 1503220452
      • Find, screen, and hire developers - 1503120406
      • Drive engagement with social challenges - 1504070558
  • 设计
    • DesignBytes - 017
      • Paper and Ink: The Materials that Matter - 1505050793
  • 云计算
    • DevBytes: Google Cloud Platform - 021
      • Powering the next killer app with the Google Cloud Platform - 1504210672
      • Introduction to Google Cloud Endpoints - 1504210675
      • The Beauty of Scale with Google Cloud Platform - 1504210678
    • Google Cloud Platform - Big Data - 105
      • GDELT & BigQuery: Understand the world - 1502200379
    • Uncategorized - 999
      • Introducing Google Cloud Platform Resources - 1501190370
  • Google 应用开发
    • Launchpad Online - 072
      • The Setup: Creating new apps using Google APIs - 1503190428
      • Listing your files in Google Drive - 1503190429
      • Customizing Google Analytics for your startup - 1503290473
      • The Launchpad Online series - 1503190427
      • Getting started with Google Analytics - 1503290472
      • Accessing Google Maps from a spreadsheet?!? - 1502220381
      • Change the world in 10 lines of code - 1503080398
    • Google Play Services - 054
      • Google Play services 6.1 - 1503290481
      • Google Play Services 7.0 - 1503200437
      • Google Play Services 6.5 - 1501080015
    • 谷歌地图 iOS SDK - 053
      • Maps Live: New Features in the Google Maps Mobile APIs for Android and iOS - 1504300777
    • Google 移动搜索开发 - 055
      • Is your app in the Google index? - 1504120598
      • Get more engaged users with Google Search for Developers - 1503070397
    • DevBytes: Google Cast - 020
      • Google Cast SDK for Android - 1504180666
      • Media Router Framework - Part 1 - Media Router API - 1504180667
      • Overview for Google Cast Receivers - 1504180664
      • Google Cast SDK for iOS - 1504180663
    • Getting Started with the Google Maps SDK for iOS - 035
      • Getting started with the Google Maps SDK for iOS, Part 1 - 1504270757
    • IO Bytes 2014 - Wearables - 070
      • Voice Driven GDK Glassware - 1505280836
    • Route 85 - 078
      • Introducing Route 85 - 1501120022
      • Quick Tip: Don't Default that Switch! - 1501190371
      • OpenInChrome on iOS, Part 1 - 1501120023
      • OpenInChrome on iOS, Part 2 - 1501120024
      • OpenInChrome on iOS, Part 3 - 1501120025
      • OpenInChrome on iOS, Part 4 - 1501120026
    • DevBytes 2014 - 019
      • Web Components - Template - 1505040789
      • Wearable DataLayer API - 1505050792
      • Using srcset for responsive images - 1505050790
      • The picture element for art direction - 1505050791
    • Uncategorized - 999
      • Sun Surveyor brings augmented reality to photographers using Google Maps APIs - 1504200668
      • Snappy travels with the Roads API - 1503060392
      • Easy Maps Apps in Java and Python - 1501140030
  • Google 广告平台
  • Polymer
    • Polycasts - 076
      • The Awesome Power of Auto-Binding Templates -- Polycasts #08 - 1502220382
      • Content Switcheroo with Core-Pages -- Polycasts #09 - 1502200380
      • Core Iconset -- Polycasts #02 - 1505040788
  • Web 平台
    • HTTP 203 - 062
      • Gotchas - 1501140368
      • Font Rendering - 1501080016
    • Web Components - 081
      • DevBytes: Web Components - Overview - 1504250709
  • 宣传视频
    • Uncategorized - 999
      • Google Developers - 1501150369
      • I/O Extended 2014 - Join me - 1502220383
  • Google 各类开发者会议
    • 2014 Chrome 开发者高峰会议 - 009
      • Keynote - Chrome Dev Summit 2014 (Darin Fisher) - 1503120407
      • TLS All the Things! - Security with Performance(Chris Palmer) - 1503140412
      • Let’s build some apps with Polymer!(Rob Dodson) - 1503150415
      • Day One Closing Remarks(Sundar Pichai) - 1503150417
      • Chrome Leadership panel - 1503160422
      • Fundamentals of Mobile Web Development(Matt Gaunt) - 1503150416
    • 2015 游戏开发者大会中 - 039
      • FlatBuffers - 1504150640
      • Games for Google Cast - 1504150637
      • Top 10 Things Android Game Developers Should Know v 3.0 - 1504150643
      • Automate Publishing for Google Play APIs - 1504150639
      • 3 Game Design Mistakes You're Making - 1504150636
      • Android TV - 1504150638
      • How to Go Viral Without Really Trying - 1504150641
    • Devoxx 2014 Interviews - 024
      • What's new in Android 5.0 Lollipop - 1504260740
      • Android Tools - 1504260743
      • BigQuery and user-defined functions - 1504260744
    • IO Bytes 2014 - 065
      • Dart in Google Cloud - 1505070810
      • Big genomic data on Google Cloud Platform - 1505070811
      • Easy International Checkout with Chrome - 1505070802
      • Google developer tools and APIs for iOS - 1503190436
      • Whet your appetite with IO Bytes - 1501080021
    • PlayTime@Shanghai - 095
      • 主题演讲 Chris Yerga - 1504060549
      • 如何成功地开发你的应用 Ellie Powers - 1504060550
      • 在Google上营利 Brahim Elbouchikhi - 1504060551
      • Playtime Shanghai event sizzle reel - 1504070552
    • Project Google I/O 2015 - 098
      • Project Tango Mobile 3D tracking and perception - 1506120857
      • Democratizing Education - 1506120868
      • Improve your Android app’s accessibility - 1506120864
      • Google Cloud Messaging 3.0 - 1506120844
      • Developers connecting the world through Google Play - 1506120862
  • 开源开放技术
    • Compressor Head - 013
      • The Trailer, Season 2 - 1503060385
      • Behind the Scenes - 1503210441
      • Arithmetic Compression (Ep 5, Compressor Head) Google - 1503070394
      • Introducing Compressor Head - 1502120372
      • Episode 1 (Variable Length Codes) - 1502120373
      • Episode 2 (The LZ77 Compression Family) - 1502120374
      • Episode 3 (Markov Chain Compression) - 1502120375
Powered by GitBook
On this page
  • 译者信息
  • 解说词中文版：

Was this helpful?

  1. Android 平台
  2. Android 性能优化 - 088

Understanding VSYNC - 1501130353

PreviousUnderstanding Overdraw - 1501130352NextTool - Profile GPU Rendering - 1501130354

Last updated 5 years ago

Was this helpful?

视频发布时间

2015年1月6日

视频介绍

Unbeknown to most developers, there’s a simple hardware design that defines everything about how fast your application can draw things to the screen.

视频推介语

暂无，待补充。

译者信息

翻译

润稿

终审

原始链接

中文字幕

翻译流水号

加入字幕组

高洁

高洁、Kesen

——

1501130353

解说词中文版：

想要开发一个高性能的应用程序

首先你得了解它的硬件工作原理

那么 最好的办法就是去使用它

应用程序运行速度的快慢

很容易被人误解为是硬件进程的控制问题

然而这最主要根源都应归于渲染性能

我的名字是Colt McAnlis

如果你想要提高你的应用程序的渲染性能

就必须理解什么是VSYNC

但首先 让我们退一步

在讲解VSYNC之前

我们需要了解两个相关的概念

第一个是刷新率

它代表屏幕在一秒内刷新屏幕的次数

这个值被规定在赫兹里 取决于硬件的固定参数

第二个是帧速率

代表了GPU在一秒内绘制操作的帧数

例如30fps 60fps

在这种情况下 高点总是好的

现在 刷新频率和帧率需要一起合作

才能让你的内容呈现到屏幕上

GPU会获取图形数据进行绘制

然后硬件负责把内容呈现到屏幕上

这将在您应用程序的生命周期中

一遍又一遍的发生

不幸的是 刷新频率和帧率

并不是总能够保持相同的节奏

如果你的帧速率实际上比刷新率快

那么将会出现一些视觉问题

举个栗子 你先拍了一张照片

然后旋转相机大约5度再拍了第二张张照片

现在 将第二张照片剪切一半

并把它粘在第一张的上半部分

两个图片是相似的

但是在沿切缝的地方上半部分

和下半部分有明显的区别

这称为撕裂 是应用程序中

帧率与刷新频率不一致的情况导致

问题是 当你的显卡正在使用

一个内存区域写入帧数据

从顶部开始 新一帧覆盖前一帧

并立刻输出一行内容

现在 当你屏幕刷新时

实际上并不知道缓冲区是什么状态

因此 它从GPU中抓住的帧并不是完全完整的

这也就是说它有一半的前一帧和一半当前帧

这种解决方案被称为双缓冲

这是非常有效的 当GPU将帧写进存储器

被称为后缓冲

而存储器中的次级区域被称为帧缓冲

当写入下一帧时 它会开始填充后缓冲

而帧缓冲保持不变

现在 我们刷新屏幕

它将使用帧缓冲

而不是在绘制操作过程中

这就是VSYNC用武之地

如果屏幕在刷新中 VSYNC 垂直同步

将会在后缓冲到帧缓冲

这里基本上保持同样的复制操作

帧速率比刷新率高是合理的

因为你的GPU刷新会比屏幕读取快

在这种情况下 当屏幕刷新成功

你的GPU将等待垂直同步 直到下一次屏幕刷新

这时 你的帧速率将有效的

达到设备的刷新率上限

但是如果你的屏幕刷新比GPU写录快两倍

会发生什么呢

例如 当GPU以每秒30帧的速度输出

而屏幕实际上以每秒60帧的速度刷新

这意味着 每次刷新都将从相同的帧采样

或者更确切地说

屏幕会在一排显示两次相同的GPU帧

当这种断断续续的情况发生 你就遇到麻烦了

例如 当你的帧速率比刷新率高时

突然骤降

那么用户将会看到一个顺畅的动画卡住了

然后剩余部分又能顺畅播出

这种不流畅的用户观赏体验

这通常被描述为闪屏 跳顿 延迟或者卡屏

相信我 这些你肯定都不想遇到

您的应用程序应避免这些帧速率突降的情况

确保GPU迅速获取数据

并在屏幕再次刷新之前写录内容

这才是你对VSYNC理解开始

当你开发高性能的应用程序时

你需要知道Android设备的底层工作原理

并确保在Android Performance Patterns页面中

查看其它的视频

哦 别忘了加入我们的Google+社区

开启神奇之旅

代码分析 你值得拥有 性能问题 永不能忘

Youtube
Youtube
加入 GDG 字幕组
video_screenshot