Slides for Streaming Service on Flex and Rails at Ruby Tuesday.

1. Streaming Service upon
Flex and Rails
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2. We work in Rhematech Inc.
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3. We provide live Streaming
service over Internet on web
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4. 100+ concurrent channels
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5. 50000+ concurrent audience
per channel
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6. Short demo
(todo)
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7. System Structure
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8. Encoder/Audience UI Flex
Event Management
System
Rails
Channel Management
System
Media Server Java/C++
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9. Main Challenges :
Cost and Scalability
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10. We choose Flex and Rails
because of
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11. COST
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12. We were used to be .NET
users
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13. We suffered from high
development and
deployment cost
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14. It fails to respond dynamic
requirements
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15. We did take Silverlight into
consideration
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16. Not popular enough
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17. Poor designer support
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18. No alternatives for media
server
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19. Flex and Rails save us
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20. Serve multimedia on web
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21. Rich user interaction
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22. Run over standard protocols
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23. Low development and
deployment cost
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24. Good looking
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25. Service on mobile device
(in the future)
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26. Lessons we learned
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27. #1. Be RESTful
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28. Consistent API design
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29. Consistent error handling
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30. Easier to extend and modify
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31. Always return errors in
JSON/XML with 200 Ok
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32. flash.net.URLLoader does not
handle HTTP error code well
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33. remove
protect_from_forgery
from environment.rb
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34. #2. Use JSON instead of XML
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35. Less Traffic
(quite important for large
service)
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36. Easier to parse complex
response
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37. Rails JSON Gotcha
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38. Rails does not unescape
unicode while decoding
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39. Fixed in Rails 2.3
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40. #3. Flash uses different
session for file uploading on
non-IE browsers
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41. Flash uses its http socket for
file uploading on non-IE
browsers
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42. Work Around -
Session Migration
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43. #4. Handle Browser
onbeforeunload event.
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44. Flash does not close
NetConnection until you
close all browser windows!
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45. #5. Create a controller to
deliver debug .swf file in
development mode.
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46. route.rb
map.connect '/encoder.swf',
:controller => “debugquot;,
:action => quot;encoderquot;
if RAILS_ENV == ‘development'
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47. debug_controller.rb
def encoder
send_file(path_to_debug_swf, options)
end
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48. Makes debug and trace with
rails much easier
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49. #6. Pick right video codec
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50. H263 vs. VP6 vs. H264
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51. H.263
Pros: Flash Player build-in
Cons: Poor quality
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52. VP6
Pros: Good video quality
Cons: Expensive
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53. H264
Pros: Good Quality
Cons: 2~6s more latency
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54. Questions?
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