❞ مذكّرة فصل الصوت عن الموسيقى ❝

كتاب صغير يناقش فصل الصوت عن الموسيقى في اي مقطع فيديو

IC
Bhiksha Raj, Paris Smaragdis, Madhusudhana Shashanka
Mitsubishi Electric Research Labs
Cambridge MA 02139
Rita Singh
Carnegie Mellon University
Pittsburgh PA 15213
ABSTRACT
IC
Bhiksha Raj, Paris Smaragdis, Madhusudhana Shashanka
Mitsubishi Electric Research Labs
Cambridge MA 02139
Rita Singh
Carnegie Mellon University
Pittsburgh PA 15213
ABSTRACT
In this paper we present a algorithm for separating singing voices
from background music in popular songs. The algorithm is derived
by modelling the magnitude spectrogram of audio signals as the outcome
of draws from a discrete bi-variate random process that generates
time-frequency pairs. The spectrogram of a song is assumed
to have been obtained through draws from the distributions underlying
the music and the vocals, respectively. The parameters of the
underlying distribuiton are learnt from the observed spectrogram of
the song. The spectrogram of the separated vocals is then derived by
estimating the fraction of draws that were obtained from its distribution.
In the paper we present the algorithm within a framework that
allows personalization of popular songs, by separating out the vocals,
processing them appropriately to one’s own tastes, and remixing
them. Our experiments reveal that we are effectively able to
separate out the vocals in a song and personalize them to our tastes.
Index Terms— Probabilistic Latent Component Decomposition,
Signal Separation
1. INTRODUCTION
We introduce a framework for personalizing music by changing its
inherent characteristics through signal processing. In this framework,
pre-recorded music, as exemplified by popular movie songs
and independent albums by singers in popular genres worldwide,
is first separated into its components, modified automatically and
remixed to sound personally pleasing to an individual listener.
Our motivation for this was initially to make some extremely
high-pitched female vocals produced in Indian movies sound more
pleasing by bringing down the pitch of the singer to a softer, more
natural level without affecting the overall quality of the song and
background music. Note that in making this statement we neither intend
to criticize Indian female singers, nor Indian listeners who find
high pitched voices pleasing to the ear. We merely bring to attention
the well-known fact that music is an acquired taste in human beings,
and what may sound pleasing to a group of people may not sound
equally pleasing to another group who may have been exposed to
different strains of music altogether. We realize that in most cases,
these songs are beautiful creations otherwise, and our attempt was
initially to merely create the technology that would present this facet
of Indian popular music to the world. In retrospect, we found that the
uses of such a framework can be numerous, as we will later explain
in this paper.
To understand how our framework functions, we need to first
understand how the majority of studio-recorded studio music is currently
produced throughout the world. A good piece of popular music,
such as an Indian movie song, is usually a pleasing combination
of some background music and one or more foreground singing
voices. In a typical production, multiple channels of music and the
singer are separately recorded. Individual channels are edited and/or
corrected, their relative levels are adjusted, and the signals are mixed
down to a small number of channels, typically two. The final sounds
we hear are the outcome of this process.
The development of our framework begins with addressing the
problem of reversal of this process. Given a segment of a song inclusive
of vocals and background music, is it possible to separate
these components out to extract, say, the singer in isolation? This is
the topic we address in this paper. We do not attempt to completely
invert the process of mixing to separate the song out into all of the
component channels (although such separation is certainly not beyond
the scope of the technique presented here); we are content to
separate the foreground singer from the background music.
The separation of foreground vocals from background musical
accompaniment is a non-trivial task that has so far not attracted much
attention in the scientific community, although several parallel topics
such as automatic transcription of music, separation of musical
constituents from an ensemble, and separation of mixed speech signals
have all garnered significant attention in recent times. Literature
on the topic of separating vocals from background music is relatively
sparse. Li and Wang [1] attempt to perform the separation using principles
of Computational Auditory Scene Analysis (CASA). In this
approach, the pitch of the foreground voice is detected, and spectrotemporal
components that are presumed to belong to the voice are
identified from the pitch and other auditory principles and grouped
together to extract the spectrum (from which, in turn, the signal is
extracted) for the voice. Similar CASA-based techniques have also
been attempted by Wang [2]. Meron and Hirose [3] attempt to solve
the simpler problem of separating background piano sounds from a
singing voice. Sinusoidal components are learned for both the piano
and the voice from training examples and are used to perform separation
using a least-square approach. Alternately, the musical score
for the background is used as prior information to enable the separation.
Other proposals for separation of music from singing voices
have also followed similar approaches, namely those of utilizing either
explicitly stated harmonic relationships between spectral peaks,
or through prior knowledge obtained from a musical score.
The framework described in this paper, on the other hand, does
not take any of the approaches mentioned above. Instead, it is built
upon a purely statistically driven method, where the song is hypothesized
as the combined output of two generative models, one that generates
the singing voice and the other the background music. What
distinguishes our approach from other statistical methods for signal
separation (e.g. [4], [5]) is the nature of the statistical model used.
We model individual frequencies as the outcomes of draws from a
discrete random process, and magnitude spectra of the signal as the
outcome of several draws from this process. The model is perfectly
additive in which the spectrogram of a mixed signal is simply modeled
as the cumulative histogram of the outcome of draws from the
processes underlying each of its constituent signals. The problem of
-
من كتب شروحات البرامج العامة والخدمية - مكتبة الكتب والموسوعات العامة.