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MPEG-4 Structured Audio. Mihir Anandpara EE 382C – Embedded Software Systems. Overview. Structured Audio Systems Audio Synthesis and Effects processing in MPEG-4 AudioBIFS layer in MPEG-4 Software Implementation and Results Conclusions and Future Work. Structured Audio.
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MPEG-4 Structured Audio Mihir Anandpara EE 382C – Embedded Software Systems
Overview • Structured Audio Systems • Audio Synthesis and Effects processing in MPEG-4 • AudioBIFS layer in MPEG-4 • Software Implementation and Results • Conclusions and Future Work
Structured Audio • Structured Coding v/s Traditional Coding • Audio Synthesis through programs
Structured Audio in MPEG-4 • Structured Audio Orchestra Language – SAOL • Run-time control of sound through score • Audio rate and Control rate separation • Custom effects processing on sound signal
AudioBIFS • Audio Binary Information For Scene Description • Audio Composition, Effects Processing and Virtual Reality Modeling • Scene Graph setup
AudioFX node • Download of custom effects post-processing on the composited/decoded sound signal • Examples: • Simple echo • Reverberation • Chorus
Complexity of Effects processing algorithms • Critical issue in studying implementation of an execution engine for effects processing • Complexity Vector • Core Opcode calls • Floating point divides, multiplies • Memory accesses
Software Implementation • Scene Graph setup • AudioMix, AudioSwitch, AudioDelay nodes for sound composition • Flexible and scalable signal processing engine for AudioFX node to implement several effects
Results • Implementation of a subset of the AudioBIFS system • SAOL execution engine for AudioFX • Complexity analysis of typical effects processing algorithms • Investigation of parallel execution of effects processing algorithms
Future Work • Implementation of block-based signal processing at control rate