Introduction to Audiovisual Introduction to Audiovisual - - PowerPoint PPT Presentation
Introduction to Audiovisual Introduction to Audiovisual Introduction to Audiovisual Compression Basics and Compression Basics and Compression Basics and Systems Systems Systems
Audiovisual Compression: from Basics to Systems, Fernando Pereira
Audiovisual Compression: from Basics to Systems, Fernando Pereira
Audiovisual Compression: from Basics to Systems, Fernando Pereira
Audiovisual Compression: from Basics to Systems, Fernando Pereira
Audiovisual Compression: from Basics to Systems, Fernando Pereira
Audiovisual Compression: from Basics to Systems, Fernando Pereira
examples include microphones, loudspeakers, thermometers, position and pressure sensors
Audiovisual Compression: from Basics to Systems, Fernando Pereira
Audiovisual Compression: from Basics to Systems, Fernando Pereira
Audiovisual Compression: from Basics to Systems, Fernando Pereira
Information Entertainment Communication Games Education Shopping …
Audiovisual Compression: from Basics to Systems, Fernando Pereira
Satisfaction of personal needs Added value, new capabilities Interoperability Quality and robustness Content variety (Low) cost of equipment and usage Easy usage
Audiovisual Compression: from Basics to Systems, Fernando Pereira
The minimum required quality of service depends on the service in question:
Facsimile Digital image (bi3level, grey or colour) Analogue TV Videotelephony Videoconference Digital television High definition digital television
Audiovisual Compression: from Basics to Systems, Fernando Pereira
Real3time versus Point3to3point versus point3
multipoint
Unidirectional versus bidirectional
Audiovisual Compression: from Basics to Systems, Fernando Pereira
Audiovisual Compression: from Basics to Systems, Fernando Pereira
Audiovisual Compression: from Basics to Systems, Fernando Pereira
Digital representation bitrate
Claude Elwood Claude Elwood SHA66O6, SHA66O6, 1916 19163 32001 2001 Harry 6YQUIST Harry 6YQUIST, , 1889 18893 3 1976 1976
Channel capacity
Audiovisual Compression: from Basics to Systems, Fernando Pereira
Audiovisual Compression: from Basics to Systems, Fernando Pereira
For example, an image is created and consumed as a set
× × ×6 luminance and chrominance samples with a certain number of bits per sample (L) The total number of bits 3 and thus bandwidth and memory – needed to digitally represent an image is HUGE !!! Without compression ...
Audiovisual Compression: from Basics to Systems, Fernando Pereira
Encoder
Decoder
Audiovisual Compression: from Basics to Systems, Fernando Pereira
Original bitrate (non compressed): 25 images/s with 720 ×
× × ×
576 luminance samples and 360 ×
× × × 576 samples for each
chrominance, at 8 bit/sample
[(720 × × × × 576) + 2 × × × × (360 × × × × 576)] × × × × 8 × × × × 25 = 166 Mbit/s
Practical bitrate (compressed): 2 Mbit/s
=> Required Compression Factor: 166/2 ≈ ≈ ≈ ≈ 80
Audiovisual Compression: from Basics to Systems, Fernando Pereira
REDU6DA6CY – Related to the similarities, correlations and predictability between the samples of images, video or audio.
IRRELEVA6CY – Related to the information inperceptible for the human visual or auditory systems.
Audiovisual Compression: from Basics to Systems, Fernando Pereira
Audiovisual Compression: from Basics to Systems, Fernando Pereira
Audiovisual Compression: from Basics to Systems, Fernando Pereira
Audiovisual Compression: from Basics to Systems, Fernando Pereira
Audiovisual Compression: from Basics to Systems, Fernando Pereira
Audiovisual Compression: from Basics to Systems, Fernando Pereira
A business model is the method of doing business by which a product/service can sustain itself 3 that is, generate revenue.
Some business models are quite simple. Other models can be more complex such as free television. The broadcaster is part of a complex network of distributors, content creators, advertisers, and listeners or viewers. Who makes money and how much is not always clear at the outset.
Digital representations and networks give rise to new kinds of business
models, since acquiring, transmitting, and storing information (now just bits) became much easier.
But it is also likely to reinvent ‘old’ models such as auctions. 6ew and
interesting variations of old models should be expected in the future.
Audiovisual Compression: from Basics to Systems, Fernando Pereira
iPod may play the following audio formats: MP3, WAV, AAC, Protected AAC Protected AAC, AIFF and Apple Lossless.
Audiovisual Compression: from Basics to Systems, Fernando Pereira
Audiovisual Compression: from Basics to Systems, Fernando Pereira
Audiovisual Compression: from Basics to Systems, Fernando Pereira
Audiovisual Compression: from Basics to Systems, Fernando Pereira
Audiovisual Compression: from Basics to Systems, Fernando Pereira
Audiovisual Compression: from Basics to Systems, Fernando Pereira
Audiovisual Compression: from Basics to Systems, Fernando Pereira
Audiovisual Compression: from Basics to Systems, Fernando Pereira
It is today much easier than before to create and sell audiovisual
communication related products (mainly software based).
Internet helps the success of small, innovative companies created
without much investment.
The competition between companies may stimulate also the
Users are increasingly open to new services. International contacts is changing old habits and prejudices …
Moreover, multimedia technology is an interesting field for youn Moreover, multimedia technology is an interesting field for young g engineers with initiative to launch their own companies ! engineers with initiative to launch their own companies !
Audiovisual Compression: from Basics to Systems, Fernando Pereira
This flat TV ad appeared in 1945 in a English newspaper ! Advices about forecasting:
You may try to forecast
‘WHAT’ …
But never try to forecast
‘WHE6’ …