[linux-audio-dev] libsndfile and WAVEX

[Alfons Adriaensen]

On Fri, Apr 14, 2006 at 07:46:38PM +1000, Erik de Castro Lopo wrote:
> Alfons Adriaensen wrote:
> 
> > I've gone through the docs a number of times, but can't find
> > a way to read / write the channelmask and guid in a WAVEFORMAT
> > extensible file.
> 
> I thought the guid was determined by the data encoding ie once
> you decide to write PCM data, you have to use a specific guid.

You obviously need access to the channelmask when reading or creating
multichannel files.

As to the GUID, there are e.g. special GUIDs for Ambisonics files,
see  <http://dream.cs.bath.ac.uk/researchdev/wave-ex/bformat.html>.

BTW I don't understand the relation between the definition of
the GUIDs on that page

  SUBTYPE_AMBISONIC_B_FORMAT_PCM  {00000001-0721-11d3-8644-C8C1CA000000} 
  SUBTYPE_AMBISONIC_B_FORMAT_IEEE_FLOAT {00000003-0721-11d3-8644-C8C1CA000000}

and the example representation of the first one further down:

  {0x00000001,0x0000,0x0010,  {0x80,0x00, 0x00,0xaa,0x00,0x38, 0x9b, 0x71}}

Does it make sense to you ?


-- 
FA

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