DILATATION ET TRANSPOSITION SOUS CONTRAINTES PERCEPTIVES DES SIGNAUX AUDIO : APPLICATION AU TRANSFERT CINEMA-VIDEO

Abstract : Coexistence of different formats for cinema (24 frames/s) and
video (25 frames/s) involves speeding up or slowing down the
soundtrack when converting from one format to another. This causes
a temporal modification of the sound signal, and therefore a
spectral modification with a change in timbre. Audiovisual
post-production studios have to compensate this effect by an
appropriate sound transformation.

The aim of this work is to propose to the audiovisual industry a
system which allows the counteraction of timbre modification
caused by a change in the playback rate. This system consists of a
processing algorithm and a machine on which it is implemented. The
algorithm is designed to respect sound quality and multichannel
compatibility constraints. The machine, named HARMO, is designed
for this purpose by the company GENESIS. It is based on digital
signal processors and has to respect real-time constraints. The
commercial aspect of the project is linked to economic and timing
constraints.

A state of the art based on a quasi-exhaustive bibliography leads
to an original classification of existing time-stretching and
pitch-shifting methods. Well-known time-domain and
frequency-domain methods are studied, and time-frequency methods
are introduced. This classification allows the creation of several
innovative methods:

. two time-frequency methods using an analysis technique adapted to the human ear,

. two coupled methods using advantages of both time-
and frequency-domain methods,

. a method which proposes an improvement of time-domain methods.

Algorithms are evaluated using a bank of test sounds specially
designed to highlight characteristic artifacts. The time-domain
approach is selected and optimized thanks to criteria based on
normalized autocorrelation and detection of transients. This
algorithm is integrated into a software designed for multichannel
real-time running, and implemented on the HARMO hardware.
Complete list of metadatas

https://tel.archives-ouvertes.fr/tel-00003363
Contributor : Grégory Pallone <>
Submitted on : Saturday, February 17, 2007 - 12:11:32 AM
Last modification on : Monday, March 4, 2019 - 2:04:03 PM
Long-term archiving on : Thursday, September 23, 2010 - 3:40:13 PM

Files


Identifiers

  • HAL Id : tel-00003363, version 3

Citation

Grégory Pallone. DILATATION ET TRANSPOSITION SOUS CONTRAINTES PERCEPTIVES DES SIGNAUX AUDIO : APPLICATION AU TRANSFERT CINEMA-VIDEO. Modélisation et simulation. Université de la Méditerranée - Aix-Marseille II, 2003. Français. ⟨tel-00003363v3⟩

Share

Metrics

Record views

9

Files downloads

513