AAC for ipods ? anyone ?
in [UK Mac]
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From: James Jolley on 14 Jan 2010 17:51 On 2010-01-14 22:35:31 +0000, Paul Grayson <1810paulg(a)googlemail.com> said: > On Jan 14, 9:29�pm, use...(a)alienrat.co.uk (Woody) wrote: > >> Turns out that AIFF just has lossy compression under OSX. I have a >> losless encoder that I used under OS7/8, but I haven't used it since OSX >> (no need to compress). > > The compressed AIFF format is known as AIFF-C, and supports multiple > codecs. The codec is stored in the header of the file. > > Even uncompressed AIFF files can be marked as being compressed. The > original AIFF format was big-endian, naturally, as the then processors > were big-endian. Which the switch to little-endian Intel processors it > required a change of the AIFF format, but of course there's no endian > support in the standard AIFF headers. To get around this little-endian > issue, Apple introduced a fake AIFF-C codec called AIFF-C/sowt, which > is nothing more than a little-endian standard AIFF. The term 'sowt' is > just twos backwards, you see! Great info. Appreciate little titbits like this. Thanks. Best -JAmes-
From: Jack Campin - bogus address on 14 Jan 2010 18:26 > So there's lossy compression available on AIFF. > Lossless compression's what's required. AIFC is lossless, according to this: http://dotwhat.net/aifc/111/ But this suggests it's actually a container format supporting a variety of compression schemes, which may include ulaw and alaw which are lossy: ftp://ftp.sgi.com/sgi/aiff-c.9.26.91.ps.Z So are those used in practice? The official spec should be at http://www.cnpbagwell.com/aiff-c.txt but that site doesn't exist any more and I can't find any copy of it. ----------------------------------------------------------------------------- e m a i l : j a c k @ c a m p i n . m e . u k Jack Campin, 11 Third Street, Newtongrange, Midlothian EH22 4PU, Scotland mobile 07800 739 557 <http://www.campin.me.uk> Twitter: JackCampin
From: Rowland McDonnell on 14 Jan 2010 18:41 Jim <jim(a)magrathea.plus.com> wrote: > Rowland McDonnell <real-address-in-sig(a)flur.bltigibbet.invalid> wrote: > > > > It's a standard part of 10.6, or so I think. Why not try it for the 10 > > > seconds it will take to prove/disprove? > > > > So there's lossy compression available on AIFF. > > > > Lossless compression's what's required. > > Actually I've just checked and I'm wrong about Pro being a standard part > of 10.6 - it will install QT7 Player and accept Pro codes but it's not a > standard bit of 10.6. > > However, the original post of yours that I was replying to merely > mentioned compressed AIFFs - lossy or lossless wasn't mentioned. You > appeared, to me, to think there was no such thing as a compressed AIFF. > That's what I was replying to. <sigh> If you'd actually read the discussion, you'd've known that it was all about picking a *lossless* format. Rowland. -- Remove the animal for email address: rowland.mcdonnell(a)dog.physics.org Sorry - the spam got to me http://www.mag-uk.org http://www.bmf.co.uk UK biker? Join MAG and the BMF and stop the Eurocrats banning biking
From: Rowland McDonnell on 14 Jan 2010 18:43 Jack Campin - bogus address <bogus(a)purr.demon.co.uk> wrote: > > So there's lossy compression available on AIFF. > > Lossless compression's what's required. > > AIFC is lossless, according to this: > > http://dotwhat.net/aifc/111/ > > But this suggests it's actually a container format supporting > a variety of compression schemes, which may include ulaw and > alaw which are lossy: > > ftp://ftp.sgi.com/sgi/aiff-c.9.26.91.ps.Z > > So are those used in practice? > > The official spec should be at > > http://www.cnpbagwell.com/aiff-c.txt > > but that site doesn't exist any more and I can't find any copy of it. The AIFC standard is indeed lossless; but there seems no obvious way of getting to use it on MacOS X unless you buy an pro audio app. Rowland. -- Remove the animal for email address: rowland.mcdonnell(a)dog.physics.org Sorry - the spam got to me http://www.mag-uk.org http://www.bmf.co.uk UK biker? Join MAG and the BMF and stop the Eurocrats banning biking
From: Jim on 15 Jan 2010 01:23
Rowland McDonnell <real-address-in-sig(a)flur.bltigibbet.invalid> wrote: > > There is - there is a screenshot of the export aiff box with a clearly > > visible compression dialog. > > `Compressor: None' is what is says. It's a dropdown, however. That implies that 'None' is just the first option. Otherwise why have a dropdown? Jim -- "Microsoft admitted its Vista operating system was a 'less good product' in what IT experts have described as the most ambitious understatement since the captain of the Titanic reported some slightly damp tablecloths." http://www.thedailymash.co.uk/ |