"Saracon is not only the world's best audio sample rate converter (cross
platform!). It's also a great batch renamer, format converter, interleaver, de-interleaver, word length reducer and all-round utility tool!" Bob Katz, Digital Domain, USA

Saracon - a versatile multichannel file format and sampling rate conversion tool of utmost sonic quality and unprecedented conversion speed. All standard sampling rates between 44.1kHz and 384kHz are supported, including DXD and DSD. DSD in both 2.8224 MHz and 5.6448 MHz variants. POW-R dithering is also standard procedure of course.

Saracon runs on Windows or OSX platforms and comes in two variants: SARACON and SARACON-DSD. The latter also supports DSD conversion.

The Super Audio Center recommends Saracon-DSD for DSD conversion.

SARACON is a batch processor working on source and destination files. It does not support streaming modes.

Saracon users group: http://groups.google.com/group/saracon-users

Features:

• Sampling Rates (input/output): 44.1k, 48k, 88.2k, 96k, 176.4k, 192k, 352.8k, 384k, DXD, DSD
  
• Wordlengths (input/output): 16/20/24/32 bit fixed point, 32/64 IEEE float, DSD
• File Formats (input/output): wav, aiff, au, bwf, sd2, caf, paf, mat, raw, dsdiff, FLAC, Ogg/Vorbis
• Wordlength Reduction Methods: Flat TPDF dither, POW-r 1, POW-r 2,
  POW-r 3
• THD+N PCM to PCM: better than –180dB for 32 Bit fixed point I/O, unweighted
• THD+N PCM to DSD: better than –147dB for 32 Bit fixed point Input, unweighted
• Number of channels: PCM to PCM: unlimited, DSD to PCM: unlimited, PCM to DSD: up to six
  
• Weiss quality conversion algorithms
• Ergonomic user interface
• Built in sine-generator for testing purposes

Specific for DSD:

• Extensive DSD Conversion analysis
• Log files
• Selectable interpolation / decimation filter sets for DSD conversion
• Flexible input to output channel routing
• Different modulators selectable, each with its own options like gain, dithering etc.
• Upsampler characteristics selectable (different interpolators)
• Log window shows time tagged events (e.g. overs)
• Non-volatile level / peak meter / history with full featured viewer.

System Requirements:

• Intel Pentium 4 Processor
• Windows 2000 or XP
• 256MB RAM (recommended)
• Screen Resolution of 1024x768 (recommended)
• One USB port for Dongle

or

• PowerPC architecture (G4/G5) or Intel i386
  
• OSX 10.5 or higher
  
• 256MB RAM (recommended)
  
• Screen Resolution of 1024x768 (recommended)
  
• One USB port for Dongle

I like hardware better:

If you prefer a hardware based sampling rate converter then check out our SFC2 unit.