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. How Much Do Customers Hate Delays?
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
7. Cellular Networks Are High Latency Environments
• Connection Establishment 500-2500ms 50-250ms 1-10ms
• Round Trip Time (RTT) 200ms 100ms 8-50ms
3G 4G Wi-Fi
8. Today’s Goals
Test where your app/site is today
Common Tools
Learn best practices for speed
Learn from existing tests
See the results of performance
fixes
9. Testing Your Mobile Performance
Native Web
Free & Open Source Tools
Video Optimizer
https://developer.att.com/
Video-Optimizer
WebPageTest
https://www.webpagetest.org
https://webspeed.cloudinary.com
10. Testing With Video Optimizer
Run network traces on your
phone
1. Pick device
2. Collector type
3. Set network conditions
4. Decrypt HTTPS
5. Record screen?
6. Name
7. GO!
11. Video Optimizer
Video Optimizer
establishes a VPN
connection on Device
Collects all Traffic in/out
Device screen displayed
on your computer
Click Stop to end trace.
Files copied over to
computer for analysis.
54. Video Tags are slow:
Video is not pre-loaded, will be last to download
<video autoplay loop muted playsinline controls = "false” src="goats.mp4" />
Img tags are fast!
<picture>
<source type="video/mp4" srcset=”goats.mp4">
<source type="image/webp" srcset=”goats.webp">
<img src=”goats.gif">
</picture>
Optimizing Content Delivery
Animated GIFs
https://calendar.perfplanet.com/2017/animated-gif-without-the-gif/
56. 56
Buffer Rage
a state of uncontrollable fury or violent
anger induced by delayed or interrupted
streaming video content
http://www.ineoquest.com/press-releases/new-research-reveals-buffer-rage-as-techs-newest-epidemic
64. Video Startup Delay
After 2 seconds,
every additional
second corresponds
to 5.8% increase in
abandonment
https://www.akamai.com/kr/ko/multimedia/documents/technical-publication/video-stream-quality-impacts-viewer-behavior-inferring-causality-using-quasi-experimental-designs-technical-publication.pdf
72. 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.
83. 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
84. Video Streaming
Manifest File:
List of Available
Streams
Player Chooses a Stream Stream Manifest:
List of Video Segments
Player Downloads
Segments into buffer
Video Plays
85. Video Plays
Optimizing Video Delivery
Video Streaming
Player can estimate
network throughput
Optimal video Bitrate
HTTPArchive
Mobile: 1.6 MBPS
Desktop 5 MBPS
86. Video Streaming: Manifest File
https://hls.ted.com/talks/2208.m3u8
Video Tracks
Video Tracks (iFrames)
Audio Tracks &
Subtitles
89. Optimizing Video Delivery
Video Streaming
Manifest File:
List of Available
Streams
Player selects high
bitrate stream Stream Manifest:
List of Video Segments
Buffer takes a long
time to fill
Video Does Not Play
Player chooses low
bitrate
Buffer Fills Quickly
Video Plays
93. Video Startup
4k Low->High:
4K Middle
(Goldilocks):
4k:High->Low:
PROs: CONS:
Fast Startup Initial Quality: Low
Other Connections:
Initial Quality: Low
Very slow startup
Fast Connections:
Initial Quality: High
Initial Quality: Good
Initial Startup: Not
fast, but not slow