Media Streaming By Derek Aten – Digital T.V. and HDTV Maria Preciado – Audio Streaming Genevieve Taduran – Data Streaming
Media Streaming Streaming MediaStreaming media is audio and video that is transmitted over the Internet in a streaming or continuous fashion, using data packets. The most effective reception of streaming media requires some form of broadband technology such as cable modem or DSL.
Introduction • Intro • Dividing a Station's Signal into Several "Channels" • Why Digital Pictures Are So Good • Interacting with TV Programs
Digital Television • The idea of sending multiple programs within the 19.39 Mbps is unique to digital TV and is made possible by a digital compression system. • The transmission is pure digital , along with reception and display of those signals on the digital TV set. • Digital signals are transmitted through air, cable, and satellite system. • Home use a decoder receives the signal and uses it, in digital form, to directly drive your digital TV set.
High Definition TV • High-resolution digital television combined with Dolby Digital surround sound. • New production and transmission equipment at the HDTV stations, as well as new equipment for reception by the consumer. • Imagine 720 or 1080 lines of resolution compared to 525 lines used in US • There are 18 DTV formats and 6 are HDTV formats, 5 are based on progressive scanning and 1 on interlaced scanning. Remaning formats 8 are SDTV with 4 of them for wide screen 16:9 ratios, the other 4 are 4:3 for normal viewing. The other 4 remaining are video graphics VGA formats.
High Definition TV • Formats used in HDTV • 720p – 1280*720 pixels progressive • 1080i – 1920*1080 pixels interlaced • 1080p – 1920*1080 pixels progressive • Sanning system Interlaced | Progressive • Interlaced format - the screen shows every odd line at the screen, and follows that up with the even lines in a second scan • Progressive format – scanning shows the whole picture, every line in one showing. Better quality but more bandwidth.
MPEG – 2 • Digital TV is compressed and encoded using MPEG-2 • Each image the MPEG-2 software records just enough of the picture without making it look like something is missing. • Reduces the amount of data by about 55 to 1. • Standard for DVD video and some satellite TV broadcast systems. • Compression reduces image quality from what is seen by the digital camera at the studio. • The quality of the image is still better then analog TV. • HDTV receiver to interact with computer multimedia applications directly
Audio Streaming • Audio streaming is a technique used for transferring audio data • Streaming technologies are becoming increasingly important with the growth of the Internet • With streaming, the client browser or plug-in can start displaying the data before the entire file has been transmitted. • For streaming to work, the client side receiving the data must be able to collect the data and send it as a steady stream to the application that is processing the data and converting it to sound or pictures.
Type of Audio Streaming Applications • Real Player • Windows Media Player • MusicMatch Jukebox • Quicktime
Audio Streaming File Formats • The RealAudio Format • This format allows streaming of audio with low bandwidths. • Sounds stored in the RealAudio format have the extension .rm or .ram. • The AU Format • The AU format is supported by many different software systems over a • large range of platforms. • Sounds stored in the AU format have the extension .au. • The AIFF Format • The AIFF (Audio Interchange File Format) was developed by Apple. • Sounds stored in the AIFF format have the extension .aif or .aiff.
Audio Streaming File Formats • The WAVE Format • The WAVE (waveform) format is developed by IBM and Microsoft. • Sounds stored in the WAVE format have the extension .wav. • The MP3 Format (MPEG) • MP3 files are MPEG files. • MP3 is one of the most popular sound formats for music recording. • Sounds stored in the MP3 format have the extension .mp3, or .mpga (for MPG Audio).
Examples of Audio Streaming The Killer Oldies Website has a live streaming radio. www.killeroldies.com
Streaming vs. Downloading -Pros/Cons
Audio File Downloading Pros • Provides more accurate data streaming • Less errors in transmission Cons • Takes up disk space
Audio Streaming Pros • streaming server opens a conversation with the media player Cons • Data accuracy is not great • Allows for data distortion
OVERVIEW • Process • Protocols • Applications
DEFINITION • continuous transmission of data • Unicast • Multicast .
PROCESS • Record media • Digitize and create files – editing softwares • Place and provide access to files for streaming
FILES • Different speeds - surestream (real media) - intelligent streaming (windows media)
MEDIA PLAYERS • Real Player - Real Networks • Windows Media Player - Microsoft • Quicktime Player - Apple • Mpeg TV Player - Linux/Unix • Pocket TV – Windows CE devices
SERVERS - Real Producer Basic • Windows Media Services • Windows Media Encoding Tools • QuickTime Streaming Server • QuickTime Pro
PROTOCOLS - RTP (RFC 1889) - RSTP (RFC 2326) - Shoutcast Streaming Protocol (MP3 streaming, HTTP streaming, Icecast) • Microsoft MMS MMSU – UDP MMST – TCP • MSBD • HTTP (RFC 2616) – port 80
APPLICATIONS • Entertainment • Trading • Military • Schools • Business .