Multi-Threaded Video Rendering

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Multi-Threaded Video Rendering

• COMP400 Project 2006
• Yohan Launay

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Agenda

• Basic System Description Demo
• Quick Multi-threaded Programming Guide
• Video Channel Description
• Graphical Engine Description
• Results

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Basic System Description

• Client system connected to a video server
• MPEG4 Streaming
• Multivision System (1 screen X cameras)
• Client OpenGL graphical engine GTK GUI
• Existing system audited, re-designed
  optimized
• Optimization for multi-core systems
• 100 Thread safe design ? MT Programming Guide
• Performances Gain
• Live Demo !

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MT Programming Guide (1)

• Modular System Mandatory
• 1 thread 1 module (Core)
• Set of rules for safe MT programming (see report)
• 1 mutex per core handled by the core itself not
  externally
• Consequence Extensive use of Controller Façade
  Pattern

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Graphical Engine Architecture Overview
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MT Programming Guide (2)

• Mutex Class Lock/Unlock (Existing)
• Guarantee exclusive access to resources
• Synchronize Class (Optimization)
• Lock/Unlock ExclusiveLock/ExclusiveUnlock
• Read/Write Access
• AutoMutex Class (Ease of coding)
• Uses variable scope to lock/unlock Mutex

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Video Channel Description

• Connect to the video stream
• Fetch picture
• Ask for display
• Use of flags and IDs Avoid memory copy
• Try to save space (pictures are big gt 1MB)

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Graphical Engine Description (1)

• OpenGL GTK need specific design
• Widget System
• Widget (Abstract)
• WidgetContainer
• WidgetTexture
• Chain of command horizontal vertical hierarchy
• OpenGL 1 Thread 1 Rendering Context
• Use of message pump / Command pattern

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Widgets Architecture
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Graphical Engine Description (2)

• Texture Register
• Avoid textures duplication in Graphical Card
• Manage texture loading and release
• Manage texture update
• Extensive use of display lists
• Use of glTexSubImage partial update
• On-demand display of channels

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Video Rendering Process
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Results
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Results

• Optimized for dual-core systems
• Unlimited number of cameras on the screen,
  performances limited by the hardware.
• 400 FPS multivisions ! (hardware related)
• Future Plans
• OpenGL Game Mode (no more window GTK)

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Contact InformationYohan Launay

• Mail yohan.launay_at_gmail.com
• McGill yohan.launay_at_mail.mcgill.ca
• MSDL http//msdl.cs.mcgill.ca/people/yohan
• Past Work http//hellaynnea.free.fr
• Thank You For Your Attention!