Tuesday, October 8 9:00 am 12:00 noon
W13: PERCEPTUAL ISSUES RELATED TO CASCADED AUDIO CODECS
Chair: Thomas Sporer, Fraunhofer AEMT, Ilmenau, Germany
Louis Fielder, Dolby, San Francisco, USA
Jürgen Herre, Fraunhofer IIS, Erlangen, Germany
Andrew Mason, BBC, UK
A representative from, IRT, Munich, Germany
Digital processing seemed to solve the problem of reduced audio quality due to copying forever, but today several stages of the transmission chain include perceptual audio coding schemes like MPEG-2 Layer-2 and Layer-3, MPEG-4 AAC, AC-3 and ATRAC. This mixture of different coding formats leads to significant accumulation of coder distortions in each encoding step (so-called tandem coding) and associated serious loss of subjective audio quality. Additional problems can be caused by processing like equalization and compression.
In this workshop typical usage scenarios are presented and discussed. Results from listening tests conducted by ITU and EBU over the last years are summarized. Different solutions to reduce tandem artifacts and to increase robustness are presented.