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    Audio. Video Audio. Video Presentation Transcript

    • AUDIO VIDEO FLASH DIGITAL MEDIA: COMMUNICATION AND DESIGN 24.04.2007
    • Digital Media: Communication and Design F2007 Comments  Web 2.0 guest lecture  Evaluation  Intro to scripting (PHP)  Intro to Flash  Mandatory assignment due to 01.05 at 9.59
    • Digital Media: Communication and Design F2007 50 45 40 35 30 25 20 15 10 5 0 1 2 3 4 5 6 6 7 8 8 9 9 10 10 11 12
    • Digital Media: Communication and Design F2007 Index  Audio  Video  Flash
    • Digital Media: Communication and Design F2007 Audio  What can audio do for us?
    • Digital Media: Communication and Design F2007 Audio  Audio is analogue  Encoding: we sample the wave and round the value to an allowed value
    • Digital Media: Communication and Design F2007 Sampling rate (Hz)  How many times per second we have a sample  Max frequency and recommended sampling rate  Voice: ~ 4000 Hz -> 8000 Hz  Music: ~20000 Hz -> 44100 Hz
    • Digital Media: Communication and Design F2007 Bit rate (bits)  How many bits we use to describe the values  8 bits: 256 values  16 bits: 65536 values (CD quality)
    • Digital Media: Communication and Design F2007 Ripping a CD to MP3  Bitrate: how many bits per second  Radio: 64 kbps  CD: 128 kbps (192)  Sampling rate:  CD: 44.1 KHz  Radio: 8 KHz  Channels:  Mono / stereo / joint stereo
    • Digital Media: Communication and Design F2007 File formats  WAV: Wave file  Not compressed  NOT for the web  MP3: MPEG 1 Layer 3  Lossy compression (1/10 of WAV)  OGG (Vorbis):  Lossy compression  Free format  MIDI:  Contains information about notes and instruments to play
    • Digital Media: Communication and Design F2007 File formats II  QuickTime:  Container for audio, video, images...  RealAudio  Pioneer on streaming audio  PC World: #2 worst tech products of all time  Windows Media Audio  Popular for streaming (.asf files)  AAC (Advanced Audio Coding)  Substitute of MP3 (?)  Flash
    • Digital Media: Communication and Design F2007 This is Sparta 44 KHz, 228 KB 22 KHz, 114 KB 11 KHz, 57 KB 8 KHz, 42 KB
    • Digital Media: Communication and Design F2007 Audio  2 methods:  Linkto file  Streaming
    • Digital Media: Communication and Design F2007 Link to a file <a href=“audio/sparta.mp3”>Download song (1.5 Mb)</a> <embed src=“starwars.mid” autostart=“true” hidden=“true”></embed>
    • Digital Media: Communication and Design F2007 Streaming  The file starts playing right away  The file is not downloaded: protect copyright  The server must have a special configuration  Good for broadband connections
    • Digital Media: Communication and Design F2007 Streaming  Typical formats:  RealAudio  QuickTime  Windows Media  Flash
    • Digital Media: Communication and Design F2007 Audio editing  Audacity (open source, free)  Sound Forge  Audition (old Cool Edit)  Garage Band (Mac)
    • Digital Media: Communication and Design F2007 Index  Audio  Video  Flash
    • Digital Media: Communication and Design F2007 Video  What can video do for us?
    • Digital Media: Communication and Design F2007 Properties of video  Movie length  Frame size  Streaming:320x240  Download: 640x480 (HD: up to 1920x1080)  Frame rate (fps)  TV: 25 fps (interlaced, 50Hz)  Streaming: 10 fps
    • Digital Media: Communication and Design F2007 Properties of video II  Quality:  Degree of compression  Bit depth:  Number of colours (usually 24 bits)  Bit rate:  Number of bits per second (kbps)  Audio + video
    • Digital Media: Communication and Design F2007 Compression  Lossless: no information is lost  Lossy: throw away information we cannot see  Spatial:  Every frame, similar to JPEG  Temporal:  Areas that don’t change over time
    • Digital Media: Communication and Design F2007 Popular codecs  MPEG-1: VHS, VCD  MPEG-2: DVD, Digital TV  MPEG-4 Part 10: HD-DVD, Blu-ray, iPod, PSP  MPEG-4 Part 2: DivX, Xvid  Sorenson 3: QuickTime  Theora: OGG video  WMV: Similar to MPEG-4
    • Digital Media: Communication and Design F2007 Popular formats  QuickTime (.mov)  Can contain audio, video, images...  Good for streaming  AVI (Audio Video Interleave)  MP4 (.mp4, .m4a, .m4p)  ASF (Advanced Systems Format)  Windows Media  Real Media (.rm)  Broadcasting  Flash
    • Digital Media: Communication and Design F2007 Video
    • Digital Media: Communication and Design F2007 Streaming
    • Digital Media: Communication and Design F2007 Video in an HTML document <a href=“video/holidays.avi”>See the video of my holidays (90 Mb)</a> <object classid=“clsid:02BF25D5-8C17-4B23-BC80-D3488ABDDC6B” codebase=“http://www.apple.com/qtactivex/qtplugin.cab” width=“480” height=“276”> <param name=“type” value=“video/quicktime” /> <param name=“src” value=“poster.png” /> <param name=“href” value=“sample.mov” /> <param name=“controller” value=“false” /> <param name=“autoplay” value=“true” /> <param name=“target” value=“myself” /> <object type=“video/quicktime” data=“poster.png” width=“480” height=“276” class=“hide”> <param name=“href” value=“sample.mov” /> <param name=“controller” value=“false” /> <param name=“autoplay” value=“true” /> <param name=“target” value=“myself” /> </object> </object> QuickTime: http://www.ceprix.net/examples/qt/example4-1.html Flash: http://www.ceprix.net/examples/qt/example4-2.html
    • Digital Media: Communication and Design F2007 Index  Audio  Video  Flash
    • Digital Media: Communication and Design F2007 Flash  What can Flash do for us?
    • Digital Media: Communication and Design F2007 Questions?