| الوصف: |
Osnovni cilj magistarskog rada je programska izvedba MPEG-4 audio kodera. Osim same izvedbe kodera, rad nastoji dati i zaokruženi uvod u cjelokupno podruje percepcijskog audio kodiranja, sa naglaskom na MPEG-4 standardu. Magistarski rad se sastoji od deset poglavlja, a ugrubo se može podijeliti na tri cjeline. Prva cjelina daje openiti uvod u audio kodiranje, druga cjelina opisuje MPEG-4 audio standard, dok trea cjelina opisuje konkretnu izvedbu audio kodera. Prvo poglavlje daje uvod u stanje multimedijalnih tehnologija danas, sa naglaskom na audio kodiranju. Drugo poglavlje ukratko opisuje ljudski slušni sistem i služi kao uvod u tree poglavlje koje opisuje psihoakustike principe na kojima audio kodiranje poiva. Nakon upoznavanja sa glavnim principima psihoakustike, u etvrtom poglavlju je opisana tipina arhitektura audio kodera koju slijede gotovo svi audio koderi danas. U istom poglavlju je dan i sažetak povijesnog razvoja audio kodera. Peto poglavlje daje openiti opis danas najsofisticiranijeg multimedijalnog standarda ISO 14496 (MPEG-4). U šestom poglavlju poinje opis konkretne programske izvedbe audio kodera prema dijelu MPEG-4 standarda koji se odnosi na kodiranje širokopojasnog, složenog audio signala (MPEG-4 General Audio). Audio koder je nazvan RAAC prema RASIP Advanced Audio Coding. Sedmo poglavlje opisuje psihoakustiki model izveden u RAAC koderu, dok osmo poglavlje opisuje posebne blokove za obradu spektra izvedene u RAAC koderu koji su presudni za kvalitetu kodera. Deveto poglavlje je posveeno subjektivnoj i objektivnoj analizi i evaluaciji izvedenog kodera, dok je u zadnjem desetom poglavlju dan zakljuak. Master's thesis main goal is MPEG-4 audio encoder software implementation. However, the thesis also aims to give an overall introduction to perceptual audio encoding, with an emphasis on MPEG-4 standard. The thesis consists of ten chapters, generally divided into three groups. First group gives overall introduction to audio coding, second group describes MPEG-4 audio standard, and the third group describes actual audio encoder implementation. Chapter 1 gives a short introduction to multimedia technologies, with an emphasis on audio coding. Chapter 2 briefly describes human auditory system and serves as an introduction to Chapter 3, which describes psychoacoustic principles that, in fact, represent fundamentals of audio coding itself. After explaining the basic psychoacoustic principles, Chapter 4 describes a typical audio encoder architecture that is followed by nearly all audio encoders now days. Same chapter gives a concise description of historical audio encoder development. Chapter 5 gives overall introduction to the most sophisticated multimedia standard today – ISO 14496 (MPEG-4). Chapter 6 starts the description of the concrete software implementation of the audio encoder according to MPEG-4 General Audio – a part of MPEG-4 standard that relates to high bandwidth, complex audio signal encoding. Audio encoder is called RAAC according to RASIP Advanced Audio Coding. Chapter 7 describes psychoacoustic model implemented in RAAC encoder, while Chapter 8 describes main MPEG-4 audio blocks also implemented in RAAC encoder. Chapter 9 is devoted to subjective and objective analysis and evaluation of RAAC implementation, while Chapter 10 gives the overall conclusion. |
