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DV over IP. Björn Thorsén Hallberg Eva Codina Sanuy Fredrik Blomqvist Johan Fredriksson Tobias Karlsson. Team 18. May 2000. Agenda. Overview Technologies used Business ideas Video Questions. DV over IP. Main goal: develop a Remote Lecture System using DV on Linux Platforms. - PowerPoint PPT Presentation
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DV over IP
Björn Thorsén Hallberg
Eva Codina Sanuy
Fredrik Blomqvist
Johan Fredriksson
Tobias Karlsson
Team 18
May 2000
Agenda
• Overview
• Technologies used
• Business ideas
• Video
• Questions
DV over IP
Main goal: develop a
Remote Lecture System using DV
on Linux Platforms
DIF
RTP
IP network
FireWireDV Server
DV Client
UDP socket
DIF
RTP
DIF DIF DIF
CIP
DIF DIF
DIF
DIF
DIF DIF DIF
DIF DIF DIF DIF
DIF
RTP
IP network
FireWireDV Server
DV Client
UDP socket
DIF
RTP
DIF DIF DIF
CIP
DIF DIF
DIF
DIF
DIF DIF DIF
DIF DIF DIF DIF
Digital Video (DV)
• provides high-quality video data
• individual frame compression
• supports NTSC and PAL video formats
Digital Interface Format (DIF)
DV Frame
DIF sequence 0 DIF sequence n-1DIF sequence 1
HeaderSection
SubcodeSection
VAUXSection
Audio & Video Section
DIF block 0 DIF block 1 DIF block 2 DIF block 149
(120.000 bytes)
(12.000 bytes)
NTSC: n=10PAL : n=12
FireWire (IEEE 1394)
• High Perfomance Serial Bus
• Characteristics:– Low cost– High-bandwidth
• Topology:– Peer-to-peer protocol– Automatic bus configuration
FireWire (IEEE 1394) cont.
• Benefits:– Guaranteed bandwidth– Hot plugging– Scalability– Flexibility– Universal interconnection– Cable power
Common Isochronous Packet (CIP)
• FireWire supports isochronous transfer
• isochronous data transfer– ensures constant data rate– time-dependent
• 6 DIF blocks in each CIP packet
isochronous = equal time
GNU/Linux IEEE1394 Subsystem
The driver hierarchy:
• provides end-to-end delivery services for data with real-time characteristics
• services: – timestamping– sequence numbering – payload type identification
• “sublayer” of the transport layer
Real-time Transport Protocol (RTP)
Server application – DV Server
Main program:There are two processes working with shared memory:
– Read CIP packets from the FireWire
– Send the DIF blocks encapsulated in RTP packets through the UDP socket to the IP network.
• Functionality: decode and display DV data• Input: series of frames
frame = full video image + 1/30 sec. sound + aux. data
• Algorithm (3 steps)1. Decode DIF blocks
2. Run iDCT (inverse-Discrete-Cosine-
Transformation) luminance & chrominance
3. Convert YCrCb to RGB and draw the data on
the screen
Client application – DView
Client application – DView
Options to improve the perfomance:1. Downscaling: reduces the displayed size of the
video
2. Reduced rendering precision
3. Grayscaling: removes the need of:- decode and render the chrominance
- convert from YCrCb to RGB
KnowDV
• The objective of the company:– provide real-time video transfers
• How will we succeed? – unique and useful products– user-friendly interface– consultant services – multi-platform solutions
DV Lecturing System
• The product: DV Lecturing System– Cheap– High quality video – Multi-platform
• Target groups:– Companies– Universities– Private users
• Competitors:– No similar product for Linux platforms yet– Applications with less bandwidth
requirement– Conferencing systems
DV Lecturing System
• Market segmentation:
DV Lecturing System
Questions ??
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