[Flac] 24 bit question

[Nicholas Wilson]

24bits are only 14% more information than 16bits, not as much as it
looks. I presume the downsampling introduces some noise which
compresses poorly (bigger residuals) and pretty much outweighs the
advantage. This does not happen with a lossy codec, if the same error
tolerance is imposed on each stage: a 5% noise introduction (say) at
one stage does not create a problem if a 5% error is allowed to be
introduced later to discard the noisiest 5% of the data. So,
heuristically I would expect most all the gains of reduced detail to
be realised in lossy codecs, and rather little or no space saving with
lossless codecs.

Nicholas

-----
Nicholas Wilson: nicholas at nicholaswilson.me.uk (ncw33)
Site and blog: www.nicholaswilson.me.uk
Peterhouse, CB2 1RD • 86 Heath Road, GU31 4EL



On 2 December 2010 13:15, scott brown <scottcbrown at gmail.com> wrote:
> Someone sent me a question late last night and I briefly looked at his file
> this morning and couldn't figure out the answer, so I'm posting here.
>
> A friend has a a ~275MB 24 bit, 48khz stereo wav file of rock music that
> when compressed using flac level 8 gives a flac file under 110 MB in size.
> When I dithered his file to 16/48 and converted that file to flac, the
> resulting flac file was actually 2 MB *bigger* than the corresponding 24/48
> flac file.  Does this make sense to anyone?
>
> He says that his 24/48 files always compress to around the same size as the
> same files converted to 16/48 or 16/44.1.  I couldn't give him an answer as
> to why.
>
> Does anyone have an answer?
>
> Thanks,
>
> Scott
>
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