Re: Idea: audio_cd_fs .

H. Peter Anvin (hpa@transmeta.com)
2 Aug 1998 03:47:22 GMT

Followup to: <199808011446.QAA00715@cave.BitWizard.nl>
By author: R.E.Wolff@BitWizard.nl (Rogier Wolff)
In newsgroup: linux.dev.kernel
>
> A friend just told me:
>
> Irix automatically mounts audio CDs using some audio filesystem.
>
> It makes the TOC into an index file, and shows the rest of the CD
> as large files.
>
> Wouldn't be too hard to make. I would personally like to have
> every file in there as raw CDDA data, but als as a complete
> WAV file, with the header prepended....
>

Not too hard in theory, but it involves a layering violation due to
the structure of audio CDs (I believe DVDs don't share this
misfeature, by the way.) Furthermore, the sector size of audio CDs is
not a power of two (2352 bytes), which complicates things. Also,
prepending a header that is not an integral number of blocks isn't
trivial.

The lack of adequate framing data and adequate ECC is yet an additional
problem for random access to CDDA data. Check out the hoops that
cdda2wav jumps through to detect framing errors, dropouts and
scratches and remove them.

Doable, yes, but not as easy at it looks.

-hpa

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