A method for evaluation of parasitic frequency modulation (wow) in archival audio is presented in this paper, published in the PrestoSPACE project. The proposed approach utilizes sinusoidal components as their variations are highly correlated with the distortion variations. The sinusoidal components are extracted from audio signal by means of sinusoidal modeling procedures being often severely distorted and in case of …
Evaluation of the maximal modulation frequency for wow and flutter detection
Author of this paper participated in the development of several algorithms for wow and flutter characteristic determination. The algorithms were found useful in some real-life restoration procedures, however, there was no study of their capabilities in terms of the maximal determined modulation frequency. This paper presents such a study for three algorithms, i.e. the power-line hum tracker, high frequency bias …
Determining techniques for “wow”distortion
Algorithms for determining the wow distortion characteristic are proposed. These are the power-line-hum tracking algorithm, the high-frequency-bias tracking algorithm, and the algorithm based on an adaptive analysis of the center of gravity of the spectrum of the distorted signal. All of the algorithms presented allow a hardware- or software-based implementation.
MTS Pilot tracking algorithm for “wow”distortion
New algorithm for detection of the wow distortion characteristic basing on the MTS pilot tracking is introduced. By observing a variation of the pilot frequency, the depth of the parasitic modulation can be estimated. MTS is an audio coding system used in an NTSC television standard, thus the algorithm is applicable only in that type of recordings. It is based …
EBU recommendation: Digitisation of programme material in audio archives
This EBU recommendation specifies technical requirements for the transition of analogue audio material in archives to a digital form.
National Film Preservation Board
This website of the National Film Preservation Board, founded by the American Library of Congress, contains a list of research resources publicly available.