NvAUDIO

Digital multi-track audio recording system with special interface for the blind.

Project done in 2001 for the Cooperativa senza Barrriere (Cooperative without Barriers) in the municipality of Borgo Valsugana in Trento.

OPERATION

The system was made from a server that records audio tracks in real time or in CD-Audio format recorded straight to the HardDisk.. The system was subsequently expanded to integrate non-linear editing features as well as the use of non-commercial vocal synthesis (MBROLA).

FEATURES

Developed on Linux using the Perl and "C", languages, and the PostgreSQL database. MP3 audio compression. Slow-motion features (forward, reverse, fast forward e reverse, stop) that simulate a traditional recording, and also usable by blind users. Recording from FM radio signal (with appropriate tuner card).

WORKING ENVIRONMENT

The original system was based on Linux hardware and the DOS Client station with the support of vocal synthesizing in Italian for business; tested for Sound Blaster 128 or Live. Subsequently, with use of non commercial synthesis (MBROLA), it was possible to remove the DOS client.

System features:

  • Device prepared for recording, digital archiving of sound sources with interface specifically designed for the blind
  • System composed of digital signal processor with standard, easily replaced components on the market: CPU Pentium II or K6, RAM memory
  • 64Mbyte, 6 Gbyte SCSII disk (Ultra Wide SCSII)
  • CD-Audio and CD-ROM reading and burning unit, 4x recording speed
  • High-speed interface (10baseT) for PC
  • Console with vocal synthesis (Audiologic)
  • Interface with audio format conversion management for "Duetto" card in order to allow import and export of recorded tracks with your current digital recording system
  • Capable of recording in mpeg, wav, raw, and aiff format
  • Seach tracks by category, title, author, publisher, year, and length (see attached client specifications)
  • Memory card dimension totaling 120 hours of mp3 audio at 32Khz sampling
  • Full duplex audio input and output
  • Audio in: stereo 16 bit, 48Khz max sampling
  • Audio out: stereo 16 bit, 48Khz max sampling
  • Use of public domain software and algorithms for the recording section in order to ensure maximum compatibility of audio formats
  • Specific management for storage and burning CD-AUDIO or CD-ROM in mpeg format.
  • Transfer files from CD-ROM or DAT to audiobook

Subsequent features integrated by other subjects (with release of code always under GPL licence

  • non-commercial speech integration (MBROLA)
  • vocalisation of track numbers on the index
  • non-linear audio mixer: audio track manipulation commands: cut, merge, delete, move tracks into list, insert blank spaces
  • track search
  • manual or automatic audio level management
  • master total time management
  • burning without blank spaces between one track and another
  • regularisation of mp3 compression quality with disk capacity
  • manage backup files on digital audio tape (DAT)

Software Licence

GPL Licence http://www.gnu.org/copyleft/gpl.html

Download source code

Topic revision: r13 - 17 Jun 2016, PaoloRomero
 
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