Web development requires more powerful and expensive system-on-chips (SoCs) than Qt development to achieve a good user experience. Specifically: - For a good user experience, the web requires a SoC with at least a quad-core ARM Cortex-A9 processor, which costs €21.15 per unit at a volume of 1 million units. Qt can achieve the same or better user experience on a single-core ARM Cortex-A8 SoC that costs €9.80 per unit. - Both Facebook and Netflix tried web-based approaches for embedded systems but abandoned them due to performance and user experience issues, ultimately adopting native approaches. - In contrast, Qt has many successful

1. Qt vs. Web – Total Cost of Ownership
Why Web is More Expensive than Qt
Burkhard Stubert – Solopreneur & Chief Engineer, Embedded Use

2. SoC Costs: Web Much Higher Than Qt
2
QML
Qt/C++
Linux
1-core Cortex-A8
AngularJS
Blink/C++
Linux
4-core Cortex-A9
€ 21.15
€ 9.80 + qt
Δ: € 11.35 - qt
Same Application
(e.g., appliance, printer, STB, TV, IFE, terminals)
Estimated prices per unit
at volume of 1 million
qt = 0 € for Qt LGPLv3
qt > 0 € for Qt Commercial

3. Outline – Why Web is More Expensive than Qt
• Recap of ARM SoCs: Devices and Costs
• For good UX: Web requires at least quad-core ARM Cortex-A9
• Qt achieves same or better UX on single-core ARM Cortex-A8 and ARM11
• Nothing will change any time soon
• Conclusion
4

4. Recap of ARM SoCs – Example Devices
Architecture Example Devices
Cortex-A57/53 IVI in premium cars (2015), Samsung GS6, Raspberry Pi 3
Cortex-A15 IVI in middle-class cars (2017), Samsung GS4
Cortex-A9 iPhone 4S, IVI in middle-class cars (2013), agricultural terminals
(2017)
Cortex-A8 Premium ovens (2013), Nest thermostat, iPhone 4, In-flight
entertainment (2014),
agricultural terminals (2013), Nokia N9
ARM11 Raspberry Pi 1, iPhone 3G, Nokia N8
ARM9 Nintendo DSi, Lego Mindstorm EV3, VoIP phones (2007)
5

5. Recap of ARM SoCs – Unit Costs in €
SoC Architecture Cores 1 100 10K 1M
R-CAR M3 Cortex-
A57/53
4/4 202.50 135.00 90.00 60.00
TI AM5728 Cortex-A15 2 124.00 82.65 55.10 36.75
NXP i.MX6 Cortex-A9 4 71.35 45.55 31.70 21.15
NXP i.MX53 Cortex-A8 1 33.05 22.05 14.70 9.80
NXP i.MX35 ARM11 1 16.00 10.65 7.10 4.75
NXP i.MX25 ARM9 1 11.30 7.55 5.05 3.35
6

6. Outline – Why Web is More Expensive than Qt
• Recap of ARM SoCs: Devices and Costs
• For good UX: Web requires at least quad-core ARM Cortex-A9
• Few high-profile Web applications on embedded systems
• Two cautionary stories: Facebook and Netflix
• Qt achieves same or better UX on single-core ARM Cortex-A8 and ARM11
• Nothing will change any time soon
• Conclusion
7

7. Few Embedded Web Applications
• No surprise: JavaScript frameworks
target mobile and desktop
8
Angular JS:
One framework. Mobile & desktop.
React Native:
Learn once, write anywhere:
Build mobile apps with React
Porsche
918 Spyder
3rd-party apps
Netflix
Orange Livebox
3rd-party apps

8. Facebook: Abandoning Web for Native
• iPhone 4S not good enough
• Dual-core Cortex-A9, 512MB RAM,
800 MHz, GPU
• Issues
• High memory consumption
• Inconsistent framerates: stuttering
during scrolling and animations
• Sluggish touch tracking
• Hard to find reasons because
debuggers and profilers missing or
wanting
9
The biggest mistake that we made
as a company is betting too much on
HTML5 as opposed to native.
We burned two years.
The mobile user experience is so good
that good enough is not good enough.
The only way we are going to get to
the highest quality level is by
going native.
September 2012

9. Netflix: Going All In with Web
10
Huge Fragmentation problem:
Wide-range of SoCs for TVs, STBs,
DB/DVD players, smartphones,
tablets, PCs
2009 – 2014:
Mediocre UX with hybrid
QtWebkit approach
From 2014 – Proprietary solution:
• Gibbon rendering engine in JS
• HMI in JS similar to ReactNative
(highly optimised for domain)
Results on SoCs >= Cortex-A8:
• 30fps refresh rate
• 110ms response time
• Not quite a good UX!
Netflix spent
millions of dollars!
With Qt: Better UX
for less dollars!

10. Outline – Why Web is More Expensive than Qt
• Recap of ARM SoCs: Devices and Costs
• For good UX: Web requires at least quad-core ARM Cortex-A9
• Qt achieves same or better UX on single-core ARM Cortex-A8 and ARM11
• Many high-profile Qt applications on embedded systems
• Nothing will change any time soon
• Conclusion
11

11. Many Embedded Qt Applications
12
1 of Top-3
ROPA
More...
Krone
2 of Top-3 OEMs incl.
Panasonic
Electrolux
eGym
e-bikes
CCI
HAM
7 of Top-15 OEMs
2 EV OEMs
More...
12+ tier1 suppliers
Precor

12. Outline – Why Web is More Expensive than Qt
• Recap of ARM SoCs: Devices and Costs
• For good UX: Web requires at least quad-core ARM Cortex-A9
• Qt achieves same or better UX on single-core ARM Cortex-A8 and ARM11
• Nothing will change any time soon
• Web requires more RAM, flash memory and power
• Web's JIT compilation no match for QML's native compilation
• Web rendering flow badly suited for graphics acceleration
• Conclusion
13

13. No Changes Soon: RAM, Flash, Power, Startup
• Size of Qt5WebEngineCore: 103MB
• Size of Chromium browser: 42 MB
• Startup time of Chromium browser
on Raspberry Pi 3: 6 seconds
• Power consumption on Macbook
Pro. Time battery lasts when reading
Web pages:
• Safari: 5:30h
• Chrome: 3:40h
• Size of Q5Quick and Qt5Qml: 8MB
• Startup time of Linux and QML
application on iMX6: 1.25s
14

14. No Changes Soon: Compilation
• Web
• Just-in-time compilation saw huge
speed-ups over last years
• Qt Commercial
• QML compiled into C++ and then into
machine code
• For example: 30% faster startup times
of QML application
• Qt LGPLv3
• Cache compilation of QML/JS in one
run and use in next run
15

15. No Changes Soon: Rendering Flows
16
Style Rules
HTML CSS
DOM Tree
Render Tree
Layout Tree
Display
QML
QML Scene Graph
Display
OpenGL Scene Graph

16. Outline – Why Web is More Expensive than Qt
• Recap of ARM SoCs: Devices and Costs
• For good UX: Web requires at least quad-core ARM Cortex-A9
• Qt achieves same or better UX on single-core ARM Cortex-A8 and ARM11
• Nothing will change any time soon
• Conclusion
17

17. SoC Costs: Web Much Higher Than Qt
18
QML
Qt/C++
Linux
1-core Cortex-A8
AngularJS
Blink/C++
Linux
4-core Cortex-A9
€ 21.15
€ 9.80 + qt
Δ: € 11.35 - qt
Same Application
(e.g., appliance, printer, STB, TV, IFE, terminals)
Estimated prices per unit
at volume of 1 million
qt = 0 € for Qt LGPLv3
qt > 0 € for Qt Commercial

18. Soon to come: Whitepaper on qt.io
Thank you 
Mail: burkhard.stubert@embeddeduse.com
Web: http://www.embeddeduse.com