VRML: Audio

Kenneth C. Jenks (kjenks@sd-www.jsc.nasa.gov)
Thu, 23 Mar 95 08:52:38 -0600

Ed Levinson <elevinso@Accurate.COM> wrote to us all:
>I left out the obvious
> stereo: this is the generic. monaural is subsumed by stereo,
> the unspoken default(?) for audio.

Paraphrasing RFC-1341, the only official audio format so far is
audio/basic, which is sampled audio encoded using 8-bit ISDN u-law
[PCM]. When this subtype is present, a sample rate of 8 kHz and a
single channel (mono) is assumed.

So mono is the default for audio. Ugh. I recommend that you include
an audio/basic version of any sound clips for interoperability between
platforms, but also include an MPEG Audio version of the sound clip for
better sound, more flexible sample rates, stereo, and to support future
standardization on this more mature audio format.

Check out my "Recommended File Formats for WWW Documents,"
These HTML recommendations also apply to external file formats accessed
in VRML scenes.

-- Ken Jenks, NASA/JSC/SD5, Space Biomedical Research Institute
Work: kjenks@gothamcity.jsc.nasa.gov (713) 483-4368
Home: KenJenks@aol.com
Web: http://sd-www.jsc.nasa.gov/folks/kjenks.html

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