Presentation on theme: "Digital Media Technology : Real World Applications June Bicknese."— Presentation transcript:
Digital Media Technology : Real World Applications June Bicknese
Table of contents 1. Digital media technology in media production 2. Overview of digital technology and a media server 3. A case study on a production company - digital technologies applied to kiosk system architecture
Digital Technology + Media Production 1. Traditional media production and its shortcomings - Inconvenience of an analog and linear videotape - Continuous demand for expanding video tape storage space - Retrieval of a videotape from a tape library 2. Advantage of using digital techniques - Digital tapes are non-linear. - For storing a digital video, various compression algorithms are used. - Retrieval is easy, if used with a server. 3. Current status of migrating from analog to digital - Commercial playback loops - Analog/digital editing system such as Avid
Video Server Technology Processing Editing Compressing & Encoding Storage Archive Retrieval Output Media ServerInput Network Analog Digital Analog Digital
Getting an input Analog input 1) Analog structure: Luminance(Brightness) + Chrominance(Color) => Frame like a picture => Series frames as moving images => A VHS tape 2) Digitizing a VHS video => Import the analog tape into a digitizing software => Digitizing software makes the analog input into the digital format => Transfer the digitized data into an editor Digital input : directly transferred into an editor Frame => Frame …… : instructions to recreate an analog video
Video Processing Editing - Software-specific - Popular software: Avid Xpress, Avid Composer, Windows Media Encoder, Quicktime Pro Compressing - The method that makes the digital media small enough to fit through the network
Video Compression Why do we need compression? Successive video images have redundant and repeated images. So, compression makes the repeated images be encapsulated in such a way that nearly every piece of redundant content should be expressed once. Since there are some limitations that human can perceive in visual and auditory systems, digital compression can take advantage of this fact.
Two types of compression method (1) Lossless compression: Data can be compressed and decompressed without losing any of the original data so that the decompressed data matches the original data exactly. (2) Lossy compression: Data is lost during the compression process and cannot be recovered during the decompression. The amount of how much data is lost is depending on what kind of compression scheme is applied to the data. Ex) streaming media
Processing- Encoding Encoding - The way to put the digital media in the correct format so that the media can be downloaded or streamed via network
Storage What is the ideal disk storage? Reliable Available Scalable Fault tolerant
RAID Popularity Disk storage: capacity, cost Fault tolerance: multiple disk drives appear as a single storage system. If one of them fails, other remaining drives can continue to operate without compromise. Easy replacement: The failed drive can be replaced without seriously degrading ongoing operations.
Common Levels of RAID RAID 1: Data mirroring Disk Mirroring Disk 0 Disk 1
Common Levels of RAID RAID 3: Striped array + Parity Byte Striping + Parity Drive Disk 0 Disk 1 Disk 3 Disk 2 Parity P3P2 P1
Common Levels of RAID RAID 5: Striped array + Distributed parity Block Striping + Rotating Parity Disk 0 Disk 1 Disk 3 Disk 2 Disk P P P4 P P
Digital Archiving Problem of current analog tape library : continuous tape expansion -> more space needed : constant management by tracking all the videos : time-wasting retrieval of a video clip Digital media archive : effective compression -> store videos in smaller storage space : frequently used data can be stored at fast-accessible storage seldom-used data can be at less expensive storage : disk storage and backup -> multiple copies available : proper network setup -> retrieve data fast
Playing a video over Internet Web server vs. Video server Retrieving a video with a metafile Streaming vs. Downloading Playing a video on a client browser
Web server vs. Video server Using a web server only : If you need small amount of video or audio clips to be played over the network, your web server doesn’t need to have a separate video server. Your web server can accommodate the basic functions of a video server. Combining a web server and a video server : If we are considering media production and distribution of the output over the network, we definitely need a video server that has higher quality digital services than the web server.
Retrieving a video with a metafile Windows Media Metafile (1) contains the location of the media file (2) references the media file for playing its video over the network Why do we need a metafile? (1) Guide a browser what to do with the requested video link : metafile will properly link to the media file and the video will be played accordingly. (2) Instructs Windows Media Player to go the location and play the media file accordingly. (3) Great way to combine a web server and a video server
Retrieving a video with a metafile Creating a Windows Media Metafile (a) ASX defines the enclosed script as being part of a Windows media metafile. (b) ENTRY specifies the digital media (c) Ref href specifies the URL of the media. (d) MMS is the Windows Media Streaming protocol.
Retrieving a video with a metafile The name convention: The name of a metafile corresponds to its media file. Ex) Media file: MyVideo.wmv, Metafile: MyVideo.wvx Adding the metafile on a web page Easiest way to play a media on a web My video
Streaming vs. Downloading Downloading: copying a file over a network. (1) Time wait for an entire file to be transmitted (2) Memory space to store the downloaded file. Media file => The media file is divided into multiple packets to be delivered over network ServerClient Packets of the media file are delivered to its destination Original media file
Streaming vs. Downloading Streaming: delivering a file over a network and playing the file instantly. (1) As soon as enough data are buffered, the video starts to play. (2) After playing, the file is not stored in memory. So, no extra memory space is necessary Media file = ServerClient Original media file Upon the request of the media file, the file is streamed by sending data bit rate-by-bit rate. The media file is compressed and encoded into a certain bit rate. It is stored at a server. =>
Streaming vs. Downloading Intelligent streaming : It dynamically adjusts the bit rate of streaming video as the network bandwidth changes. It is beneficial for a video to be streamed via networks with different bandwidth over the Internet. However, the quality of the video may be downgraded. Media file Original media file ServerClient ServerClient ServerClient Encode the media file with different bit rates Send the encoded file based on the network bandwidth
Streaming vs. Downloading Advantage of streaming over downloading Real-time playback Significantly reduced waiting time Only small portion of memory space for buffering Cancellation of playback at any time Same control options such as play, stop, pause, fast-forward, and rewind. Disadvantage of streaming over downloading Limitation of continuous playback for higher bandwidth than the bit rate Possibility of unpredictable long buffering time -> discontinuous playback In case of intelligent streaming, the video quality is not as good as its original file.
Playing a video on a client browser A media player on a client side decompresses the transmitted data and converts the digital instructions into analog video or audio form. Different ways to use a media player A link from a web page to a Media Player outside the browser - Audio or video will be played outside the browser. - This scheme enables the end user to continue to surf with the browser while listening/watching the streaming clip. => Frame …… ……
Playing a video on a client browser Different ways to use a media player (continued) embedding a media player in a web page using OBJECT tags - This method enables you to integrate the design of the player with that of your page. - You can also customize the playback control buttons. In order to embed the player, add an OBJECT element for the Windows Media ActiveX control like the following example:
Playing a video on a client browser Widows Media PlayerEmbedded Media Player Media Player’s original functionsEmbedded and controlled functions
Network architecture for digital media Network requirements for media delivery The network should be able to deliver multi-media in a time-sensitive manner. Packet switching vs. Circuit switching In packet switching, although data can tolerate delays in delivery, audio and video cannot tolerate time delays. => fast packet switching allows control parameters that specify the importance of in- time delivery in a network header. => Multimedia protocols such as RTP or RTSP In circuit switching, once virtual circuit is set up, it is remained until the end of usage and the virtual circuit guarantees fast delivery. Ethernet and ATM are a good match Ethernet is used inside the building for data traffic among personal workstation or desktop ATM is used for backbone network. Most of all, Ethernet and ATM are good setup for both of the Internet and multimedia that have to share the links.
Case study of a media production company Current status of digital media usage In production area, digital media technology has been used mostly for video editing and commercial playback. A video server is not used for the production. The closest of using digital technology is the kiosk systems. Kiosk systems are using essential digital media technology. So, kiosk system can be a good example of the current applications for digital technology.
Overview of Kiosk systems Kiosks are located at the First Union Center. They are used to help the sports fans and audiences get information about the facilities and events. Kiosk touch screens are especially popular during a sports game intermission. During the intermission, people can see the major highlights that just happened during the game. Main ConcourseLuxury SuitesLexus Club
The major applications of a kiosk Adobe Photoshop Adobe Illustrator MS SQL The overall interface design is done in Macromedia Flash movie
The major applications of a kiosk SMS (Systems Management Server) – check the status of all the kiosk systems and allows us to remotely trouble-shoot all the kiosk systems. Advantage: Rebooting each kiosk can be done remotely at one workstation rather than doing each computer at its location. Disadvantage: For remote trouble-shooting, the only function is to turn on and off a kiosk. Luxury Suites Main Concourse Lexus Club SMSSMS
The major applications of a kiosk symantec pcAnywhere – remotely access the server and update the contents of the server, and to transfer files to the server. Advantage: we can remotely access the server machines rather than we have to physically go to each server and update contents. Disadvantage: Once a user accesses the server with the authorized user name and password, it lets a user allow any changes the user can make in the server. Video Server pc Anywhere Web Server First Union SpectrumFirst Union Center
Video Server- Video Server Architecture Main functions of the media server: storage of videos and streaming Compressed digital video input Stores the input in order in primary disk array. Retrieve the requested video file in real time. Stream the video Transmit the video file Windows Media Player requests for the media file with the metafile. Streaming Downloading
Video Server- Getting a new input Video inputs: game highlights or concert footage 30 seconds to 1 minute 30 seconds long Process of getting a new video file Shoot videos with the analog camera Transfer the videos as composite or component inputs into Avid Xpress A component input separates analog video signal into three different elements of red, green, and blue(RGB) and uses three different cables, so that they produce better image quality. A composite input combines all of three elements and use one cable so that it is easier to import the input but has less image quality.
Video Server- Getting a new input Digitize the analog inputs Compress the video with 2-to-1 compression algorithm and save it as motion-JPEG => Frame …… Higher compression : Less space More artifacts Lower compression : More space Better looking 2 to 1 3 to 1 …….. 20 to 1
Video Server- Getting a new input Motion JPEG ‣ JPEG is a standard for compressing and storing digital images. Motion-JPEG extends this standard by supporting videos. ‣ In motion-JPEG, each frame in the video is stored with the JPEG format, and compresses each video field separately, returning the resulting JPEG bit streams consecutively in a single frame. Frame Frame 2 Frame 3 JPEG 1 JPEG 2 JPEG 3 Frame 3 Frame 2 Frame
Video Server- Getting a new input Avid Xpress for digitizing and compressing Frame Frame 2 Frame 3 JPEG 1 JPEG 2 JPEG 3 Frame 3 Frame 2 Frame (1) Digitizing (2) Compression into a series of JPEGs with 2-to-1 compression Transfer into Avid Xpress
Video Server- Getting a new input The motion-JPEC file is changed into.omfi file. The file is exported from Avid Xpress and imported into Windows Media Cleaner. OMFI file as a universal compressed file format ‣ Motion-JPEG has no universal decoding algorithm standard. This means that a motion-JPEG file may produce different results on different applications. In video imaging, transporting a compressed video in its native compression format between different applications may require common denominator. ‣ For this reason, omfi is used as the interchange of digital media data between different platforms or applications. OMFI means Open Media Framework Interchange, a registered trademark of Avid Technology, Inc. It is a standard format of the interchange of digital media data among heterogeneous platforms.
Video Server- Getting a new input In the Windows Media Cleaner, encode it as a Windows Media file Windows Media Cleaner for encoding Encoding for media streaming
Video Server- Getting a new input Save the digital video clip as a media file(.wmv) and create its metafile(.wvx) in a notepad. Transfer the metafile(.wvx) into the web server and media file(.wmv) into the media server Video Editing Station Web Server Video Server Metafile Media file
Video Server- uploading video during game During the game, if there is a memorable moments, the highlight is uploaded into the video server so that audience can see it again during the intermission. This uploading is almost like real-time updating, but it takes about 5 minutes after the actual event. All games are recorded into Avid Xpress. Once there is a good highlight, it is edited and exported into the Windows Media Cleaner. In the Cleaner, encode it as a Windows Media file Save it as a Windows Media file and Windows object file. Transfer the wvx and wmv files into the two different server machines.
Video Server- Storage RAID level 5 – RAID 5 allows three or more drives to stripe the data across drives. Even two drives can function well. Video Naming in the Web and Video Servers Video name: team name / show name + purpose + number in order For example, the first Flyers history video is named as flyhis01.wvx in database and flyhis01.wmv in the video server. There are subvideos. These are smaller video files than video files. It is used when somebody comments on a particular game or play that happened. It is played with the main video clip. The processes of uploading and retrieving a subvideo file are same as the video ones.
Video Server- Storage VideoID (PK) Date Description Team EventID History Highlights Profile Community Filename PlayerID Video SubVideoID (PK) VideoID (FK) Description Filename Subvideo
Video Server- Storage VideoIDDateDescriptionTeam……Filename 10055/19/19741 st Stanley CupFlyers……flyhis05 …… SubVideoIDVideoIDDescriptionFilename Clarkeflyper MacLeishflyper Parentflyper06
Video Server- Digital Archive Tape backup is done every night At the end of the season, most of the used videos are removed
Video Retrieval Process of retrieving a video clip from the Windows Media Server A user clicks on the video icon A video is selected by a user.
Video Retrieval Action script Flash at kiosk ASP as Middleware Video (Subvideo) table in the Web Server Video Server Get the requested metafile Reference the video using its metafile Play the video by streaming Request the metafile with video id Embedded Media Player
Video Retrieval Metafile: Windows Media Protocol + Windows Media Server + video folder + media file. A single file retrieval mms://ctc_wms/video/sixgre03.wmv / Multiple file retrieval mms://ctc_wms/video/flyhis05.wmv mms://ctc_wms/video/flyper04.wmv mms://ctc_wms/video/flyper05.wmv mms://ctc_wms/video/flyper06.wmv
Video Retrieval The metafile has been sent to Windows Media Server. It opens and references the actual media file in the video server. As soon as the enough data is arriving, the embedded Windows Media Player decompresses the digital file, transforms it into analog format, and plays it by streaming.
Video Retrieval If there are multiple requests from multiple clients, the server do multi- streaming The server usually can multi-stream videos more than 200 streams, considering the total of around 150 kiosks. No Intelligent streaming a. It provides a poor quality video b. Streaming uses the dedicated network between two buildings. So, the bandwidth can be considered as a constant. kiosk Multiple Streaming kiosk flyper04.wmv flyhis05.wmv flyper05.wmv flyper06.wmv sixgre03.wmv
How-to: streaming video Recommended web site: For doing simple media streaming over the Internet, check out the web site, There are specific instructions depending on which application you are using. RealMedia, QuickTime, and Media Cleaner Pro. For Windows Media Encoder, check out msdn library.
Network Architecture for video
RTSP (Real Time Streaming Protocol) : RTSP is an application-level protocol for control over the real-time data delivery. It is associated with the port 554. Sources of data can be audio, video, or live data feeds. This protocol is designed to cope with bandwidth- demanding and real-time streams. Video Server Media file + RTSP TCP IP Ethernet Kiosk Client Windows Media Player TCP IP Ethernet Frame Relay Gateway IP Physical
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