4 Serving SMIL Methods for Serving SMIL Presentations

4.1 Serving Up SMIL SMIL files are text files they contain no binary data No more than few 10’s of KB Many are < 10KB in size SMIL clients differ in the file formats that can be handled Media clips used in the presentation that are the issue Text files are small and lightweight HTML for XHTML+TIME RealText for RealONE In-line text within SMIL or plain text file Images will vary in size Edit to reduce size Audio files do not need to be large 20 to 30 Kbps is OK for voice 64Kbps is OK for music 32Kbps is approx. 240KB per minute Video files are the largest Use an encode limit that produces acceptable results Approx. 350Kbps for 256x192 or 320x240 Good quality from professional formats Work with your AVS and media production professionals DIY may not be the most practical solution Do this regardless of how content is to be served IT infrastructure and SMIL clients need to be available as standard

SMIL files are text files they contain no binary data

No more than few 10’s of KB

Many are < 10KB in size

SMIL clients differ in the file formats that can be handled

Media clips used in the presentation that are the issue

Text files are small and lightweight

HTML for XHTML+TIME

RealText for RealONE

In-line text within SMIL or plain text file

Images will vary in size

Edit to reduce size

Audio files do not need to be large

20 to 30 Kbps is OK for voice

64Kbps is OK for music

32Kbps is approx. 240KB per minute

Video files are the largest

Use an encode limit that produces acceptable results

Approx. 350Kbps for 256x192 or 320x240

Good quality from professional formats

Work with your AVS and media production professionals

DIY may not be the most practical solution

Do this regardless of how content is to be served

IT infrastructure and SMIL clients need to be available as standard

4.2 Delivery Options Use fixed write once media such as CD-R/DVD Low media costs but administration overheads Serve from fileserver Works OK but no streaming protocol support May have to replicate content across servers Serve from HTTP server Add required MIME types to HTTP server No support for time based media delivery in HTTP Multiple encodes in single media file not supported Serve using dedicated Media Server Ensures reliable delivery of time based Allows bandwidth management

Use fixed write once media such as CD-R/DVD

Low media costs but administration overheads

Serve from fileserver

Works OK but no streaming protocol support

May have to replicate content across servers

Serve from HTTP server

Add required MIME types to HTTP server

No support for time based media delivery in HTTP

Multiple encodes in single media file not supported

Serve using dedicated Media Server

Ensures reliable delivery of time based

Allows bandwidth management

4.3 Delivering a SMIL Presentation Use a media server supporting both RTSP and HTTP Helix Universal Server from RealNetworks Expensive but very reliable and robust Runs on Linux, Solaris and Windows 2K Streams QuickTime and Windows Media Use an HTTP server such as Apache or IIS Apache runs on many OS including Win 2K Add the necessary MIME types and serve Use .htaccess file in Apache MIME types in IIS Authentication to manage access to content Place content on a file server Manage access For example use Active Directory users and groups

Use a media server supporting both RTSP and HTTP

Helix Universal Server from RealNetworks

Expensive but very reliable and robust

Runs on Linux, Solaris and Windows 2K

Streams QuickTime and Windows Media

Use an HTTP server such as Apache or IIS

Apache runs on many OS including Win 2K

Add the necessary MIME types and serve

Use .htaccess file in Apache

MIME types in IIS

Authentication to manage access to content

Place content on a file server

Manage access

For example use Active Directory users and groups

4.4 Using a Hybrid Approach Source media clips from the most appropriate location Allows scalability for serving time-based media Enables cross-institutional collaboration and assistance JISC initiatives Streaming server Video, audio files HTTP server SMIL file, text, images and animations Use file system and/or HTTP approach Small audiences, short clips and short duration Reliable high-bandwidth network and servers Use Helix Server and RealONE client Afford the capital and ongoing support costs Want “state-of-the-art” SMIL 2.0 infrastructure Trial accounts on a Helix Server for evaluation Contact: [email_address]

Source media clips from the most appropriate location

Allows scalability for serving time-based media

Enables cross-institutional collaboration and assistance

JISC initiatives

Streaming server

Video, audio files

HTTP server

SMIL file, text, images and animations

Use file system and/or HTTP approach

Small audiences, short clips and short duration

Reliable high-bandwidth network and servers

Use Helix Server and RealONE client

Afford the capital and ongoing support costs

Want “state-of-the-art” SMIL 2.0 infrastructure

Trial accounts on a Helix Server for evaluation

Contact: [email_address]

4.5 Pre-fetching content <prefetch> manages client/server transfers of media Prevents buffering delays for streamed media Defined in the SMIL 2.0 Content Control Module Not yet supported in RealONE player and Helix Server Use for presentation with video and audio content Requires preceding low-bandwidth content Don’t use for content served via HTTP or files system Manages pre-fetching using three attributes bandwidth – how much of client bandwidth to use mediaSize – amount of the clips total data to pre-fetch mediaTIme – amount of a clips total duration to pre-fetch <par> <!– Preceding low bandwidth seciton --> … <prefetch src=“rtso://boombox.ucs.ed.ac.uk/video1.rm” mediaTime=“15” bandwidth=“100000”/> <!--video plays later --> <video id=“video1” src=“rtsp://boombox.ucs.ed.ac.uk/video1.rm” …/> </par>

<prefetch> manages client/server transfers of media

Prevents buffering delays for streamed media

Defined in the SMIL 2.0 Content Control Module

Not yet supported in RealONE player and Helix Server

Use for presentation with video and audio content

Requires preceding low-bandwidth content

Don’t use for content served via HTTP or files system

Manages pre-fetching using three attributes

bandwidth – how much of client bandwidth to use

mediaSize – amount of the clips total data to pre-fetch

mediaTIme – amount of a clips total duration to pre-fetch

4.6 Review SMIL and XHTML+TIME files are small Media clips that are large  Optimise video, image and audio Select a delivery method that matches your budget and intended use Use existing HTTP and File server systems Using Helix Server and RealONE Experiment with pre-fetching data

SMIL and XHTML+TIME files are small

Media clips that are large 

Optimise video, image and audio

Select a delivery method that matches your budget and intended use

Use existing HTTP and File server systems

Using Helix Server and RealONE

Experiment with pre-fetching data