Transcript Helix On The OLPC

Helix On The OLPC
Python Extensions of Helix
Helix Summit 2007
Introductions
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We support open software, open communities, and an open world
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Peter Krenesky
• Lead Software Engineer
• Tech Lead for OLPC projects @ OSL
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Summary
• Python API Overview
• Helix Player On the OLPC:
• Watch & Listen
• ProducerSDK On the OLPC:
• Produce
• Teleconference
• Future Plans:
• Audio Presentations Via Producer
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Pykit - Overview
• Python Modules
• HxPlay
• HxRecord
• Capture
• Editing
• Encoding
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Pykit - Design Goals
• Simplify the interface
• Hide engine initialization
• Hide initialization of components
• Resizing
• Seeking
• Reuse as much as possible
• Start from pyplayer
• Feature implementations borrowed from splay
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HxPlay - Overview
• Ported to atlas
• Target: player_kit_python
• Code cleanup
• Added new features
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QuickSeek
Video Site Resizing
Playlist support
Color Controls
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HxPlay - Player sample
Import hxplay
hxplay.init()
player = hxplay.open(“foo.mp3”)
player.start()
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HxPlay – Incomplete Features
• Support other than Linux
• Support for Multiple Players
• Audio Formatting
• Audio Visualization
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HxRecord - Overview
• New Python Bindings Around ProducerSDK
• Target: player_kit_python_hxrecord
• ProducerSDK modifications
• Porting to atlas
• Adding features
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HxRecord - Design Goals
• Match ProducerSDK workflow
• Full featured
• Simplicity
• Merger with hxplay
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HxRecord - Code Sample
dictionary = {
‘pluginType’ : ’avFileInput’
, ’filename’ : ’foo.avi’
}
input = hxrecord.createInput(dictionary)
encodingjob.setInput(input)
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HxRecord – Roadmap
• Bindings Mostly Complete
• Debug Ported ProducerSDK
• Merge ProducerSDK components with Atlas
• Merge HxRecord and HxPlay
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ProducerSDK - Current Hierarchy
Atlas
ProducerSDK
Media
Playback
EncodeSVC
Class Factory
Class Factory
Video Output (sites)
Video Output (sites)
Container Classes
Container Classes
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ProducerSDK – Intermediate Step
Atlas
Media
Playback
EncodeSVC
Class Factory
Class Factory
Video Output (sites)
Video Output (sites)
Container Classes
Container Classes
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ProducerSDK - Planned Hierarchy
Atlas
Media
Playback
EncodeSVC
Class Factory
Video Output (sites)
Container Classes
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PyKit - Current Hierarchy
HxPlay
HxRecord
Engine
Initialization
Engine
Initialization
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PyKit - Planned Hierarchy
PyKit
HxPlay
HxRecord
HxEngine
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Helix Player on the OLPC
• Named “Watch and Listen” after the activity
that children are doing.
• Lots of possible features but need to keep it
simple
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Watch & Listen - Screenshot
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Watch & Listen - Features
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Standard Playback Buttons
Seeking via slider
Screen size toggles
Metadata display
Playlist Support
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The OLPC Journal
• Stores a history of what a child has done
• Activities can be resumed
• Files have a mime-type
• Only place where Watch & Listen can be
launched
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Journal - Screenshot
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W & L - Features We’d Like to Add
• Visualizations for audio Playback
• Keyboard Shortcuts
• Sharing - Collaboration among children
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Sharing - Overview
• It’s a collaboration tool not just a laptop!
• Shared learning experiences
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Watch & Listen - Multicasting
• Positives
• Scales very well for 1:M
transmission
• Negatives
• Server is a large image
• Simultaneous multicasts may
degrade mesh
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W & L - Synchronized Viewing
• Positives
• Doesn’t require a much
larger image
Server
• Negatives
• Limited Scaling
• Must all have access to
video
• Keeping video
synchronized is difficult
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Produce - Overview
• Capture - video and audio
• Encoding
• Simple Video Editing
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Cropping
Resizing
Cutting & Joining videos
Add Audio Tracks
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Produce - Record Mockup
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Produce - Editing Mockup
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Teleconference - Overview
• Audio and video Teleconferencing using Helix
• Senior Capstone Project
• Year long project required for graduation
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Teleconference - Overview
• Will use both HxRecord & HxPlay
• 1:1 Video and or Audio at usable rates
• CPU power bigger issue than bandwidth
• M:N Conferencing may not be possible with CPU
limitations
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Teleconference - 1:1 Workflow
Child 1
Child 2
Producer (out)
Player (in)
Player (in)
Producer (out)
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Teleconference - M:N Challenges
• Every Participant adds 2 streams
• Videos must be decoded and drawn to screen
• Audio must be multiplexed
Child 1
Child2
Producer (out)
Combined
Stream
Producer (in)
Audio
Child3
Player (in)
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Teleconference – Special
Requirements
• All communication between laptops must use
Python dbus
• XO has special libraries for locating and
communicating with peers on the mesh
• Plugins will be required for both Producer and
Player
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Webcaster – Overview
• PowerPoint + Recorded Audio
• Proposed project
• Will probably be done in pieces as class projects
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Recap
• Python API – A lot of momentum
• Helix On the OLPC:
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Watch & Listen
Produce
Teleconference
Audio Presentations Via Producer
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Questions?
• Peter Krenesky
• Email: [email protected]
• Web: http://osuosl.org
• Ribosome Targets:
• Player_kit_python
• Player_kit_python_hxrecord
• http://laptop.org
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