4. 0.5
0.6
0.7
0.8
0.9
Standing in Line Standing on the
edge of a virtual
cliff
Experiencing
Mobile Delays
Solving a Math
Problem
https://www.ericsson.com/res/docs/2016/mobility-report/emr-feb-2016-the-stress-of-steaming-delays.pdf
Stress
5. Large Downloads Induce Delays in Rendering
3s: 53% of Users Abandon Mobile Sites
500ms: 26% Frustration
8% Engagement
100ms: 1% Revenue Walmart & Amazon (Desktop 2001)
4% Mobile Users Throw Their Phones
https://www.doubleclickbygoogle.com/articles/mobile-speed-matters
http://bit.ly/mobileWebStress
http://www.globaldots.com/how-website-speed-affects-conversion-rates/
https://www.mobilejoomla.com/blog/172-responsive-design-vs-server-side-solutions-infographic.html
6. Fast is a Human Perception
• 100ms:
• 1s:
• 10s:
https://www.nngroup.com/articles/response-times-3-important-limits/
Perceived as instantaneous
Limit for uninterrupted train of thought: Delay is
noticed, but generally accepted
Limit for keeping focus
7. Images & Video make up 75% of Web Content
HTTPArchive mobile websites 15/02/18
61. Animated GIFs
Video Tags:
<video loop autoplay muted playsinline controls = "false” src="goats.mp4”/>
Video is not pre-loaded, will be last to download
Img tags are fast!
<picture>
<source type="video/mp4" srcset=”goats.mp4">
<source type="image/webp" srcset=”goats.webp">
<img src=”goats.gif">
</picture>
https://calendar.perfplanet.com/2017/animated-gif-without-the-gif/
70. Video Background
Video (as Downloaded): 5.3 MB
Video 5 MB
Audio 250 KB 5% of file
Best Practice:
To save bandwidth, remove the audio stream from videos that
are played silently.
81. Conclusion
Optimize Image:
Quality
Format
Sizing
Lazy Load if Possible
Only download Video when displayed
Strip audio if silent
Resize Videos for Mobile
Audit 3rd Party Videos
Streaming: Start with lower bitrates to speed video playback
Streaming: Conservative bitrates *may* reduce stalls, but will lower quality
Images
Video