COM 597 Streaming Media Lecture 3 June 27, 2006. Streaming v. Streaming As we discussed last week, the term “Streaming Media” has become somewhat of a.
<ul><li><p>COM 597Streaming MediaLecture 3</p><p>June 27, 2006</p></li><li><p>Streaming v. StreamingAs we discussed last week, the term Streaming Media has become somewhat of a catch-all phrase for digital media distributed over an IP network</p><p>This is technically inaccurate</p></li><li><p>Streaming v. StreamingIBMs definition to delineate the different types of digital media works wellDigital media is unstructured content audio, video, and images that cannot be stored in a traditional database.</p><p>The two major segments of digital media are:Media that has intrinsic value or in other words value that is inherent to the media itself (e.g. movies, documentaries, and music videos)Media that has business process value where the media becomes valuable due to the context in which it is used (e.g. training and corporate communications.)</p></li><li><p>So for the purpose of this class we will be exploring Digital Media over the course of the term. </p><p>Tonight we will be studying Streaming Media.</p></li><li><p>What is a webcast?Webcasts can include audio, video and other data like PowerPoint, animation, and even whiteboard applications</p><p>Many webcasts also include some form of communication between the audience and the talent or host.</p></li><li><p>Some advantages of webcasting over traditional broadcastingLower cost of entryUnlimited spectrum dont need a license from the FCCNot limited by geographyCan be targeted to a specific audience</p></li><li><p>Some of the disadvantages of webcastingSmaller audience</p><p>Incremental cost per viewer</p><p>Quality</p></li><li><p>Many business and education enterprises are deploying webcasting as a cost-cutting enterprise for both internal and external communication</p></li><li><p>What is streaming media and how does it workWebcasting is a specialized application of streaming media technologyStreaming enables real-time (or close to it) delivery of media across a network</p><p>This technology is similar to how the web delivers web pages, with one big difference:Web servers download files, streaming media servers stream files.Downloaded files are displayed after the entire file has been delivered </p></li><li><p>Streaming files play as they are delivered (this is not progressive download)</p></li><li><p>For large files the advantage of streaming are:Real timeControl/interactivity (real-time presentations)Security (not stored on the hard drive)Live broadcasting</p></li><li><p>Bandwidth CapacityYMMV</p><p>Connection TypeBandwidth / BitrateDial-up (56K modem)34-37 KbpsBroadband (Cable / DSL)200-1000 KbpsFrame Relay, Fractional T1128Kbps 1.5 MbpsT11.5 MbpsEthernet10 MbpsT345 Mbps</p></li><li><p>Bandwidth of individual audience members determines how the webcast should be encodedThe bandwidth at the site determines how much data can be sent to the distribution serversThe aggregated bandwidth used determines the bandwidth charge</p></li><li><p>Load balancingStreaming media servers receive the incoming stream from an encoder (or encoders) and then may distribute the media to the audience. A server may also send the stream to other servers for load balancing and redundancyLoad balancing is where a number of servers are used to distribute a webcast to improve performance and reliability</p></li><li><p>ProtocolsTo facilitate communication there are standardized protocols used so the servers, players and encoders work properlyFor example http stands for hypertext transfer protocol. ftp stands for file transfer protocolrtsp stands for real time streaming protocol This is the most common protocol used, but not the only one.</p></li><li><p>Expected streaming media quality at different bit rates</p><p>Bit rateAudio QualityVideo Quality32 Kbps (56K modem)FM Radio QualityVery small screen (160x120) Acceptable for talking heads64 Kbps (ISDN)Very good quality. CD Quality at approximately 96 Kbps, depending on codec usedSmall screen (196x144, 248x180) Acceptable for talking head content, dreadful for high-motion contnent256 Kbps (typical low end broadband sustainable speed)ExcellentQuarter Screen (320x240) Good quality for talking heads, acceptable quality for most content except very high motion content like sporting events and music videos700 KbpsExcellentExcellent quality for all content at quarter screen size (320x240); good quality for full screen size (640x480)1.5 Mbps (Ethernet and High Speed Internet)ExcellentExcellent full screen quality for almost all content</p></li><li><p>Business ConsiderationsWho is the intended audience for this webcast?What is the purpose of the webcast? What is the need? Is a webcast the most efficient way to distribute the message?Where is the webcast taking place?When is the event?Why? Is there really a need to do this or is it just cool? Will the webcast pay for itself with new revenue or through cost savings?</p></li><li><p>If you have good answers to the previous questions then ask these:Does it have to be live?What are the cost considerations?What is the ROI?Are there legal considerations?</p><p>Live is always more expensive than recording and archiving it for later use.</p></li><li><p>What are possible events with time sensitive content?Breaking NewsDistance LearningStock Market activitiesMusic EventsSporting EventsCommunity Event</p></li><li><p>Where are you going to spend your money?Budget will determine both the quality and reliability of a webcastSingle or three camera shoot? Your most exorbitant line item will be your production costs.Bandwidth costs</p></li><li><p>Where are you going to spend your money?Unlike radio or broadcast television, you must pay for the additional bandwidth required each time someone tunes into your webcast. The prices are astoundingly random based upon what carrier you use. Figure somewhere between $75 and $35 per megabit from network carriers. Shop around before you buy.</p></li><li><p>How do you know your bandwidth needs?Measured in bits per second (bps) of the information sent concurrentlyBecause these numbers get big fast we use Kbps and Mbps</p><p>A kilobit is 1024 bits Megabit is 1024 Kilobits (1024x1024) or 1,048,576 bits</p></li><li><p>How do you know your bandwidth needs?Here is the rub</p><p>Data is measured in bytes, not bits.There are 8 bits to a byteA gigabit is 1024 Megabits</p><p>So</p></li><li><p>Lets say you have a show</p><p>There are 100 viewers for your webcastThey will all watch a 300Kbps stream300Kbps x 100 = 30000KbpsThis number is too unwieldy, so lets figure out how many Megabits per second</p></li><li><p>30000 / 1024 = 29.3 MbpsAdd about 20% for overhead and you land at:35Mbps sustained bandwidth</p></li><li><p>But how long is your show?Lets say it is 1 hour35Mbps x 60 seconds per minute x 60 minutes per hour35x60x60 = 126000 Megabits</p></li><li><p>But wait, we need bytes, not bits.126000 / 8 = 15750 MegabytesThe number is still too unwieldy so divide by 1024 to get Gigabytes15750 / 1024 = 15.38 gigabytes</p></li><li><p>How do you know your bandwidth needs?So when you talk with a content delivery network about prices you can confidently state that you need approximately 35 megabits of concurrent capacity, and you expect to transfer about 16 gigabytes of data.</p></li><li><p>Usage Logs and MetricsThey will vary based on the CDN you choseHow many watchedHow long they watchedWhere they were from</p></li><li><p>RightsDo you have rights to the images and music used in the webcast?Do you have rights to the graphics and video used?How likely are you going to be sued?Do you have releases from all people and locations used in the webcast?Do you have a labor union to deal with either on site or licensed material?</p></li><li><p>So how are webcasts produced?The process is essentially the same as producing a program for broadcast, except the signal is sent to a streaming encoding solution instead of a broadcast tower or cable system. The same approach of good audio and video engineering applies to both. Crap in equals crap out.</p></li><li><p>The difference between an on demand streaming file and a webcast is there is no room for error. It is live so you need to have it tested and working prior to the event. Because it is a real-time event, it will affect every phase of production.</p></li><li><p>This includes:Planning justifying costs, location, tools, crewProductionEncodingAuthoring connecting the audience to the webcast via a link on a web pageDistribution securing an infrastructure that is robust for your needsRemember: If you have not planned it right your webcast can grind to a halt. This can be a career-ending move. Be certain you have not only created a plan, but you have redundancy in place in case of failure</p></li><li><p>Where do we start?Step one: Plan 95% of the work happens before the eventStep two: Plan some moreStep three: Check out your location do you have power? How do you connect to the web? What are the acoustics like? Who are your points of contact?Step four: Change your plans</p></li><li><p>Where do we start?Spend a significant amount of time planningDo a site checkAcquire and test all the equipment necessary for the webcastAcquire and test all the encoding hardware necessary, bring extraExamine and test your streaming server architecture any license issues with the number of streams you expect to distribute simultaneously?Do a body count do you have enough of the right people in the right jobs?Test connectivity on site BEFORE the webcast This includes testing the broadcast equipment, load-testing the server, test the links on the website</p></li><li><p>Where do we start?Bottom line:Take the time to planKeep it simpleBring two of everythingBe kindStart early</p></li><li><p>Business considerationsAs discussed earlier:</p><p>Who is your audience?Do you really NEED to do a webcast? Is there a better solution?How much might it cost?What is the return?</p></li><li><p>Production ConsiderationsDo it yourself or outsourcing</p><p>Which parts?How do you find a partner?Production PartnerDistribution partnerMarketing partnerAsk to see examples of their work</p></li><li><p>Some nasty questions to ask a potential encoding partnerDo they know how to set up redundant encoders?Have they had experience bonding ISDN lines and knowing how to force them to dial long distance?Do they know how to remix the audio and switch between multiple video inputs?Do they know how to work with the camera technicians to have the video shot in a way that works best for a webcast?Will they advise you on what backgrounds and colors work best for streaming media?</p><p>From Hands-On Guide to Webcasting</p></li><li><p>Pricing and ProvidersEntering into an agreement with a CDN (Content Deleivery Network) is not unlike buying a carThere is lots of smoke and mirrors and no one can agree on what to call the same service from provider to provider</p></li><li><p>Two primary charge models for webcasting distribution:RSVP Model charged based on the number of simultaneous streams used at any one given time. Usually a reserved number of streams</p><p>Throughput model charged based on the total amount of data delivered over the network during the course of the event.</p></li><li><p>The factors common to any charging model would be:Length of the eventTime of the eventNumber of formatsNumber and size of bit ratesGeographic distribution</p></li><li><p>Additional fees may include:Some sort of registration to authenticate a userPay Per ViewLate notice or last minute event</p></li><li><p>Who to talk to about a CDN SolutionLimelight Networks (www.limelightnetworks.com)Akamai (www.akamai.com)Mirror Image (www.mirror-image.com)SAVVIS (www.savvis.com)VitalStream (www.vitalstream.com)</p><p>For Small BusinessPlayStream (www.playstream.com)</p><p>For Financial BusinessThompson (www.thompson.com)ON24 (www.on24.com)</p></li><li><p>OK, you are on your own</p></li><li><p>Equipment and crewWhat is your video source (type and fps of video feed)?What is your audio source?Are you renting the gear? Purchasing it?Are you hiring a 3rd party company to produce the video feed?</p></li><li><p>Some of the gear you will need:Microphones (Lav, handheld, shotgun, spares)Cables of many typesCameraAudio mixerVideo switcher if multi-cameraDistribution Amps (so you can split your feeds)Isolating transformers and humbuckersBatteriesEncoding computersMonitorsCommunication system (for crew and back to broadcast operations center)</p></li><li><p>What Crew might you need?Camera OperatorsAudio EngineersVideo Engineer / Technical DirectorEncoding TechnicianProduction AssistantsDirectorProducer</p></li><li><p>Computer hardwareHow much horsepower will you need?Do you need a capture card?Do you need an external capture unit?</p><p>What software do you need?If you are encoding via software do you have the proper encoder?Will you be generating multiple platforms? (Real & Windows Media for example)</p></li><li><p>What do you need to deliver?What is your desired bit rate?What is your desired canvas size?Do you need to deliver multiple bit rates?</p><p>When you stream you also archive</p><p>Oddly, most viewers will see the webcast as archived mediaYou will need to archive the webcast somewhereIf not on tape or from the distribution point then you will archive locally</p></li><li><p>Make sure you have room on your hard driveThese files are not that huge so space should not be that much of a problem unless you are archiving uncompressed media</p><p>Bit RateOne Hour FileHours of storage per Gigabyte37 kbps16 megabytes64128 kbps56 Megabytes18300 kbps132 Megabytes7 700 kbps308 Megabytes3 </p></li><li><p>Suggested minimum Audio bitrates for streaming</p><p>Bit RateMinimum Audio Bit RateQualityDial-up (34-37 kbps)8 kbpsAM RadioLow Broadband (64-128 kbps)16 kbpsNearly FM RadioStandard Broadband (200-300 kbps)32 kbpsFM Radio</p></li><li><p>Suggested Screen resolutionsFor the most part, these sizes are glorified postage stamps</p><p>Bit RateLow Motion ProgrammingHigh Motion ProgrammingDial-up (34-37 kbps)176x132160x120Low Broadband (64-128 kbps)240x180192x144Standard Broadband (200-300 kbps)320x240240x180</p></li><li><p>Some Hardware solutions for streaming mediaCommunitek (www.communitekvideo.com)Digital Rapids (www.digital-rapids.com)Sunnyside Software (www.sunnysidesoft.com)Viewcast (www.viewcast.com)Winnov (www.xstreamengine.com)</p></li><li><p>Distribution PlanningAudience size will directly impact the amount of distribution you require</p><p>Small may only need a single local server, large may require geographically distributed server farms. Discuss your needs with your network administrator</p></li><li><p>How will you author the web site?Will the stream be incorporated into a dynamic site?</p><p>Have you already built and tested the shell?</p><p>Will this be a pop-up player or embedded into a web page.</p></li><li><p>Authoring considerations:How is the website going to be featured on the website?Link on the homepage?Will that link go to an intermediate page or directly to the stream?Will a user have to fill out forms or enter passwords?Will the media be embedded, use a pop-up window or a stand-alone application?</p></li><li><p>Authoring considerations:Always put a link to your webcast on your home page. There is no reason someone should have to search for the feed.A complex home page combined with a streaming media event can overload your server and bring the whole thing down. Think about perhaps simplifying your home page on the day of a big event</p></li><li><p>Emedded or stand-aloneNo clear answer.Some embedded players are seen as a security risk by the browser or operating system on a users computer. While it only requires enabling something as simple as a java script to run, some users may be scared off by the warning.On the other hand, a player like Flash is installed on over 98% of the web browsers world-wide.Consider offering the option of a link to an embedded player and one to a stand-alone player</p></li><li><p>Linking to a stand-alone playerYou cant link directly to the streaming media. Browsers use HTML an...</p></li></ul>