Joint source/channel decoding of scalefactors in MPEG-AAC encoded bitstreams

Olivier Derrien (1, 2) , Michel Kieffer (3) , Pierre Duhamel (3)

1 UTLN - Université de Toulon
2 LMA - Laboratoire de Mécanique et d'Acoustique [Marseille]
3 L2S - Laboratoire des signaux et systèmes

This paper describes a bandwidth-efficient method for improved decoding of MPEG-AAC bitstreams when the encoded data are transmitted over a noisy channel. Assuming that the critical part (headers) of each frame has been correctly received, we apply a soft-decoding method to reconstruct the scalefactors, which represent a highly noise-sensitive part of the bitstream. The damaged spectral data are reconstructed using an intra-frame error concealment method. Two methods for soft decoding of scalefactors are described: blind mode and informed mode. In the latter, a very small amount of additional data is included in the bitstream. At medium SNR, this method provides a significant improvement in perceptual signal quality compared to the classical hard-decoding method.

Mots clés: décodage source-canal; codage audio; MPEG-AAC

Domaines: Traitement du signal et de l'image [eess.SP]; Traitement du signal et de l'image [eess.SP]

Olivier Derrien, Michel Kieffer, Pierre Duhamel. Joint source/channel decoding of scalefactors in MPEG-AAC encoded bitstreams. EUSIPCO 2008, Aug 2008, Lausanne, Switzerland. CD-ROM (5 p.). ⟨hal-00467527⟩