AUDIOVIDEOFLASH
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
0
5
10
15
20
25
30
35
40
45
50
1 2 3 4 5 6 7 8 9 100
5
10
15
20
25
30
35
40
45
50
1 2 3 4 5 6 7 8 9 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 rateVoice: ~ 4000 Hz -> 8000 HzMusic: ~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:Link to fileStreaming
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:RealAudioQuickTimeWindows MediaFlash
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: 320x240Download: 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.htmlFlash: 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?