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 ??