Mixed media .


93 views
Uploaded on:
Description
Utilization Pulse Code Modulation (PCM) to speak to a sound sign by advanced information. ... Figure 4.3 Conversion from Analog to Digital requires an Analog-to-Digital Converter ...
Transcripts
Slide 1

Sight and sound – Digital Audio & Video CSC1720 – Introduction to Internet Essential Materials

Slide 2

Outline Audio/Video on the Web Basic Digital Audio Concepts Streaming Audio Web Audio Formats Basic Digital Video Concepts Video pressure/decompression strategies. Video File Formats Other Multi-media Formats Summary All copyrights saved by C.C. Cheung 2003.

Slide 3

AV on the Web? It is a piece of the Internet. Radio Stations Music, sound clasps Streaming Audio/Video conferencing Digital Cameras Animation on the Web Shockwave, Flash All copyrights saved by C.C. Cheung 2003.

Slide 4

Basic Terms All copyrights saved by C.C. Cheung 2003.

Slide 5

Analog versus Advanced Analog: A sign that has a nonstop nature instead of a beat or discrete nature. Note: Electrical or physical analogies, for example, consistently shifting voltages, frequencies, or stages, might be utilized as simple signs. Advanced: A sign in which discrete steps are utilized to speak to data. All copyrights saved by C.C. Cheung 2003.

Slide 6

Digital Signal Use P ulse C tribute M odulation (PCM) to speak to a sound sign by computerized information. All copyrights saved by C.C. Cheung 2003.

Slide 7

ADC & DAC Figure 4.3 Conversion from Analog to Digital requires an Analog-to-Digital Converter Figure 4.4 Conversion from Digital to Analog requires a Digital-to-Analog Converter All copyrights held by C.C. Cheung 2003.

Slide 8

Basic Digital Audio Concepts Sampling rate Number of test taken of a sign in a given time (normally one second) Bit profundity Describes the exactness of the sound information Channels E.g. Stereo has two diverts Bit rate Measured in kilobits every second (Kbps) is an element of the bit profundity and examining rate All copyrights saved by C.C. Cheung 2003.

Slide 9

Sampling rate The more example taken every second, the higher the exactness. Ordinarily measured in kilohertz (KHz). Cd sound has 44,100 examples for every second (44.1KHz). 8 KHz produces lower quality radio sound. Standard examining rates incorporate " 8KHz " , " 11.025KHz " , … The top of the line 96K is utilized as a part of DVD, yet is not appropriate to the Web. All copyrights held by C.C. Cheung 2003.

Slide 10

Sampling Rate demo All copyrights held by C.C. Cheung 2003.

Slide 11

Bit profundity Also called " examining determination " or " word length " . The more bits, the better is the nature of the sound (and a bigger document obviously). Regular piece profundities are 8-bit ( phone like ), 16-bit ( CD quality ), and 20, 24, 32, 48-bit profundities. What number of sign can a 8-bit and a 16-bit information speak to? 0000  1111 0000  1111 All copyrights saved by C.C. Cheung 2003.

Slide 12

Quantization demo All copyrights held by C.C. Cheung 2003.

Slide 13

Channels Audio document can bolster one to six channels of sound arrangements. Mono – one channel Stereo – two channels Some others – three, four channels. Six channels – 5.1-channel encompass sound. More multi-divert designs report in the coming years. All copyrights held by C.C. Cheung 2003.

Slide 14

Channel Examples All copyrights saved by C.C. Cheung 2003.

Slide 15

Bit rate Audio documents are measured as far as bit rate which is measured in kilobits every second (Kbps). It can be figured by isolating the document size when (in second) to play the sound clasp. E.g. 3Mb document play in 30 seconds 3000k/30 = 100kbps. Quality at various pressure rates All copyrights saved by C.C. Cheung 2003.

Slide 16

Optimizing for the Web Length of the sound clasp Keep the sound clasp as short as could be allowed. E.g. simply keep the most sweetest piece of your welcome. Number of channels A mono sound document is divided the space of a stereo record. Relies on upon your real needs. All copyrights held by C.C. Cheung 2003.

Slide 17

Optimizing for the Web Bit profundity Audio record on the Web are generally 8-bits. A large portion of the span of a 16-bit document. Inspecting rate Half the testing rate will likewise divide the space required. Voice just sound document can be decreased to 8KHz. 22 KHz music clasps are adequate. Assembling all things: Mono, 8-bit, 22KHz, MP3 pressure. All copyrights held by C.C. Cheung 2003.

Slide 18

Calculate sound size 8-bit mono: seconds x KHz 16-bit mono: (seconds x KHz) x 2 8-bit stereo: (seconds x KHz) x 2 16-bit stereo: ([seconds x KHz] x 2)x2 E.g. the record size of 30 seconds of 16-bit, 11KHz mono sound: (30 x 11) x 2 = 660K. All copyrights held by C.C. Cheung 2003.

Slide 19

Streaming Audio What is it? Play very quickly after the solicitation, keeps playing the exchanging information. Preferences: Address the issue of long download time. Control appropriation and secure copyright, in light of the fact that the client can\'t get a duplicate of the document. Impediments: Sound quality might be influenced by low speed or insecure Internet association. Reference All copyrights held by C.C. Cheung 2003.

Slide 20

What is Streaming? All copyrights saved by C.C. Cheung 2003.

Slide 21

Packet are sent to a cradle on the getting Computer, the RealPlayer will play the sound File when support full Web program Web program ask for a RealAudio from the web server RealAudio Server Web server How can it work? Spilling sound All copyrights saved by C.C. Cheung 2003.

Slide 22

Quality Comparison http://www.cit.cornell.edu/atc/itsupport/streamcompare.shtml All copyrights held by C.C. Cheung 2003.

Slide 23

Web Audio Formats WAV/AIFF (.wav/.aif/.aiff) The Wav eform Audio File group (.wav) was created by Microsoft, underpins subjective examining rates and bit profundities. The A udio I nterchange F ile design (.aif, .aiff) was created for Macintosh stage. They are more outlandish utilized on the Web, since individuals use " mp3 " or " spilling " . All copyrights saved by C.C. Cheung 2003.

Slide 24

http://www.nuance.com/prodserv/demo_vocalizer.html WAV/AIFF Try the Bell-lab blend join. http://www.bell-labs.com/venture/tts/voices.html Select the Audio design All copyrights saved by C.C. Cheung 2003.

Slide 25

(.mp3) Able to keep up great sound quality at little record sizes. The pressure diminishes a sound record to one-tenth of its unique size. E.g. 40MB record  3.5MB MP3 is really MPEG-1 Layer-III Good for dispersion of HQ sound. Demo: www.mp3.com All copyrights saved by C.C. Cheung 2003.

Slide 26

What is MP3 advanced encoding? MP3 is really the record expansion for MPEG, sound layer 3. Layer 3 is one of three coding plans (layer 1, layer 2, and layer 3) for the pressure of sound signs. Layer 3 utilizes perceptual sound coding and psychoacoustic pressure to evacuate all pointless data. (All the more particularly, it evacuates the excess and superfluous parts of a sound sign - the stuff the human ear doesn\'t hear at any rate). It additionally includes a MDCT (Modified Discrete Cosine Transform) that executes a channel bank, expanding the recurrence determination 18 times higher than that of layer 2. All copyrights held by C.C. Cheung 2003.

Slide 27

MP3 Players All copyrights held by C.C. Cheung 2003.

Slide 28

Apple QuickTime Audio (.mov) QuickTime is an understood video design, yet it can make sound just motion pictures. QuickTime is a holder configuration, which can store still pictures, film designs, … Excellent pressure, genuine spilling Netscape and IE have Plug-in now. Quicktime : demo All copyrights saved by C.C. Cheung 2003.

Slide 29

MIDI (.mid/.midi) MIDI stands for " M usical I nstrument D igital I nterface " which is created for electronic musical instruments. MIDI records are extremely minimal and useful for low-data transmission conveyance. Instruments are " piano, drums, bass, symphonic strings, … " It is extremely alluring for adding MIDI document to your site with next to no download time. Demo: www.findmidis.com All copyrights held by C.C. Cheung 2003.

Slide 30

MIDI http://www.findmidis.com/All copyrights held by C.C. Cheung 2003.

Slide 31

RealMedia/RealAudio (.rm/.ra) RealAudio is a server-based spilling sound organization. The RealServer reactions to the solicitations and conveys the gushing parcels, including the data transmission arrangement. A vigorous RealServer can bolster a huge number of concurrent audience members. Useful for ceaseless playing sound and live telecasts to an expansive gathering of individuals. Case: RTHK Radio All copyrights held by C.C. Cheung 2003.

Slide 32

RealMedia/RealAudio All copyrights held by C.C. Cheung 2003.

Slide 33

Windows Media (.wma/.asf) Windows Media is a gushing framework. It wraps all media components into an Active Streaming File (.asf). Sound might be spared as non-spilling Windows Media Audio group (.wma). Useful for consistent play sound. The encoder and player is Free, sent with Windows OS. All copyrights saved by C.C. Cheung 2003.

Slide 34

Windows Media All copyrights held by C.C. Cheung 2003.

Slide 35

Choosing a sound organization All copyrights held by C.C. Cheung 2003.

Slide 36

Add Audio to your Web Page A straightforward connection <A HREF= " sound/song.wav " >Play the melody </A> <A HREF= " music.mp3 " ><IMG SRC= " catches/play.gif " ></A> Background Sound <BGSOUND SRC= " sound/song.mid " LOOP=3> Link to RealMedia <A HREF= " song.ram " >Link to the song</A> pnm://domainname.com/song.rm All copyrights saved by C.C. Cheung 2003.

Slide 37

Break Time – 15 minutes All copyrights saved by C.C. Cheung 2003.

Slide 38

Basic Digital Video Concepts Movie length Frame size Frame rate Quality Color piece profundity Data rate (bit rate) All copyrights saved by C.C. Cheung 2003.

Slide 39

Movie length File size is relative to the film length. Recordings longer than 1 or 2 minutes cause long download times. On the off chance that it is a long video, consider to utilize stre

Recommended
View more...