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3A Implementation

Of course, a concept is only a concept, so nothing works until you implement the concept. Written down are all specifications for that implementation, as it stands for now (July 2006): everything is moving so we'll try to update this spec sheet whenever something changes.

Design rules

To be able to be as flexible as possible, probably the single most important factor within the 3A concept, we have to set up a number of rules which must be fitted and anchored into the implementation.

  • Make use of open protocols only; de-facto 'industry' standards are not even questioned
  • First choice for software components must be open source; when not available (for a certain platform), at least it should be freeware; we use no shareware or commercial software
  • Expand, extend and combine software (modules) on a need-to-have basis
  • Modular architecture; each module has a base task to accomplish
  • Have only basic specifications for hardware and software components
  • Flexible implementation; choice per component is free as long as it ad hires to general specifications

PC Client

PC is used for ripping, encoding and tagging.

  • Ripping
    • CDex (Windows, open source)
    • Exact Audio Copy (Windows, freeware)
    • Grip (Linux, in combination with CD Paranoia)
    • All rippers make use of FreeDB
  • Encoding
    • FLAC command line encoder (Windows & Linux, open source)
    • Can be used in conjunction with all mentioned rippers
  • Tagging:
    • Foobar2000 (Windows, ?)
    • EasyTag (Linux)

Dedicated audio server

Server is used to store music files, stream music to streaming clients and transcode files from a lossless format (flac) into a lossy (ogg or mp3).

  • Hardware
    • processor: Via Epia M10000
    • internal memory: 512 MB
    • hard disk: 300 GB
    • case: Venus barebone
  • Software (all open source)
    • operating system: Ubuntu Linux 6.06 Server
    • streaming server: Slimserver 6.2.1
    • file sharing: Samba: 3.0.22
    • ogg encoding: OggEnc (Vorbis Tools)
    • mp3 encoding: Lame

Dedicated hardware based streaming client

Dedicated software based streaming client

Codecs

Within 3A, only a few number of audio formats of codes are actively supported:

  • flac for lossless, high quality listening (source for Slimserver and transcoder)
  • ogg (transcoded from flac, can be streamed with Slimserver also)
  • mp3 (transcoded from flac, can be streamed with Slimserver also)

External digital/analog converter

Squeezebox is connected directly to your audio setup. Though Squeezebox has an internal digital audio converter (DAC), to further enhance audio quality, use of an external DAC is highly recommended.

  • Job DA48
  • Entech Number Cruncher 203.2

Network

  • Architecture is based on a (standard) TCP/IP network
    • No explicit demands for Quality of Service (QoS) of the network
    • No explicit demands for scaleability; base point is consumer quality & usage
  • Bandwidth
    • minimum (streaming): 10 Mbit/s
    • recommended for ripping: 100 Mbit/s
    • wireless (802.11b at 11 Mbit/s or 802.11g at 55 Mbit/s) is possible, but not recommended for ripping

Advanced Audio Architecture