CLAM (C++  Library  for  Audio  and  Music)  is  a  framework  for  audio  and  music  programming.  It  may  be  used  for  developing  any type of audio or music application as well as for doing more complex   research   related   with   the   field.   In   this   paper   we   introduce  the  practicalities  of  CLAM’s  first  release  as  well  as  some of the sample application that have been developed within the  framework.See for a  more  conceptual  approach  to  the  description of the CLAM framework.  

HOW IT WAS MADE?

CLAM is programmed in C++. Code is regularly compiled with gcc  in  Linux,  Microsoft  and  Intel  compilers  in  Windows  and  Code Warrior in Windows and MacOS. We have had the chance to test  how  differently  compilers  behave  and  how  bad  most  of  them adjust to the ANSI ISO standard. Altl  this  is  specially  true  when  it  comes  to  the  use  of  the  most  recent  C++  features,  such  as  templates,  and  related  techniques,  such   as   template   metaprogramming.   This   techniques   where   initially    considered    as    potentially    useful    in    the    CLAM    framework, but this lack of language support in most compilers, together with the need of optimizing the compiling speed of the library, has led to a rather scarce use of them. On  the  other  hand,  a  technique  considered  obsolete  as  it  is  the  use   of   C   macros,   has   proven   very   useful   to   minimize   programmer's  effort  and  enable  the  implementation  of  rather  complex behaviors (one of the good things of developing with a multi-paradigm language like C++ is that you can always find a more  or  less  immediate  workaround).    Also,  C  macros  are  a  simple   compiler   feature   which   is   available   in   all   C++   development platforms. 

CLAM CAN BE USED FOR 

CLAM  responded  to  an  urgent  internal  need  for  having    a  structured repository of signal processing tools focused on audio and  music.  For  that  reason,  it  has  been  used  as  an  internal  development framework since its very beginning. Of course, our patient  users  have  had  to  cope  with  multiple  refactoring  periods that have led to the implementation of a rather complex branching  scheme  on  our  CVS  repository.  But  on  the  other  hand,  we  have  been  able  to  implement  an  spiral  iteration  process,  redefining  requirements  and  redesigning  our  model  at  each turn. Thus,  CLAM  applications  have  been  developed  and  have  been  used  as  benchmarks  to  test  the  feasibility  of  the  library.  In  the  following lines, the main characteristics of these applications are outlined.  All  of  them  share  the  same  underlying  structure  and  have  at  least  a  Windows  and  Linux  version  that  highlights  the  portability spirit of the framework. SALTO is  a  software  based  synthesizer.It is  based  on  a  spectral  modeling  technique  named  SMS.  It  implements  a  general architecture for these synthesizers but it is currently only prepared to produce high quality sax and trumpet synthesis. Pre-analyzed  data  are  loaded  upon  initialization.  The  synthesizer  responds to incoming MIDI data or to musical data stored in an XML file. Output sound can be either stored to disk or streamed to  the  sound  card  on  real-time.  Its  GUI  allows  to  modify  synthesis parameters on real-time. Time  Machine is  a  high  quality  time  stretching  algorithm  that  is  already  being  used  in  some  commercial  products.  It  is  a  clear example of how the core of CLAM processing can be used in isolation as it lacks of any GUI, audio input/output.SMS  Analysis/Synthesis  illustrates  the  core  of  the  research  being  carried  out  at  the  MTG.  It  is  a  complete  rework  of  the  already  public  SMSTools  application  that  has  become  flagship  of  the  group.  Configurations  are  loaded  from  XML  files.  Using  these  parameters  the  input  sound  can  be  analyzed,  looked  at  using  the  GUI,  transformed  and  synthesized  back.  The  result  of  the analysis can be stored in MPEG-7 like XML format. RAPIDD has been designed for performing real-time audio processing/transformation.  It  has  proven  to  be  a  robust,  reliable  and efficient sound processor in a live performance. A prototype was used for accomplishing real-time morphing of a harp and a viola  in  a  composition  by  Gabriel  Brnic  that  was  performed  in  the  Multiphonies  2002  concert  cycle  at  the  GRM  in  Paris.  The  GUI for that particular application was developed using QT and it  used  a  CLAM-based  signal  processing  library  as  its  sound  engine.

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