Well I am stupid. I left my iTunes conversion mode on default which has changed all my tracks that I've imported from CD's to AAC (m4a) rather than mp3. They were all converted at 128kbps. When I then convert them to mp3 with iTunes, I can change them to 160kbps, but the file sizes increase by about 10 - 25%.

Considering they are already 128kbps, should I not bother converting to 160kbps? I guess it doesn't make sense that you can UPscale a sample rate. I'm pretty s***ty with myself that I left it as AAC encoding at 128kbps, but I haven't really noticed a quality difference. Will I notice a quality difference if I convert to mp3 128??

Lots of questions there I know:O Thanks for any help.

Transcoding sucks, re-rip them properly as mp3s.

its completely pointless to convert 128->160 man it will just make the files bigger without increasing the quality. you need to re-rip to 160 from the .wav files or straight from cd

last edited by d[o_0]b at 10:45:19 29/Nov/06

Yes... that'll just mean I need to "re-locate" all the CD's... and there are way too many of them. Will 128 mp3's sound worse than 128 AAC?

not sure on that one, i have no reason to believe otherwise tho... it would probably sound better if your listening to some kind of classical music or something with a lot of instruments otherwise it should just sound the same

If you can't notice the difference between the cds and 128k AAC's, then you're probably not going to notice the difference if you transcode to MP3. But how crappy are the speakers you're using if you can't tell the difference?

The fact is that they are both lossy compression formats and every time you encode them again the quality is going to deteriorate, like taking a digital photo of a photo of a photo etc.

Unless they have Fairplay DRM in them ... Just down load an aac codec to play it in windows, unless its for an mp3 player that's not an iPod!.

Also if you are planning on ripping your cds, use UberStandard from Ubernet. Uses EAC and Lame LAME 3.90.3 (apparently 3.97 does a good job too, most of the ones in between don't). iTunes ripper is ok, but audophiles dislike it alot.

AAC is fine however, and given the brains behind it, in theory it should store better quality in less space.

As for transcoding. dbpoweramp will do it. But its shareware (ie. costs, also don't run multiple sessions of DBpower amp at once or you end up with empty files, select it all right click and covert come back in a day :p)
Otherwise use Foobar or winamp to rip it out to a wav and then use lame to re-encode it (free, painful).

Or You can burn the music out to a cd with iTunes, then use UberStandard to re-rip it (even works with DRM files.. but painful)

(also Audacity can't open m4a/aac :( )

last edited by Obes at 12:04:13 29/Nov/06

if you use the 128kb files to burn to a cd it will convert them to .wave but they will still be the same quality as the 128kb mp3's. Once you convert .wav to .mp3/mpeg4/AAC whatever you decimate the sound quality and it can not be reversed. This is how the compression works it 'deletes unheard parts of the sound frequency' to put it simply.

whatever bit rate you rip the files as is the maximum quality you will get out of that rip. Don't be fooled by the file size changing, its just the same as adding tobacco to your weed - you might get more but you wont get any higher ;)

Yeh I don't get Obes' post:O

I have and use iTunes but was just thinking of different mp3 players. My Nokia mobile plays m4a's.

Unless they have Fairplay DRM in them

Don't they have it by default?

to even pretend to visualise the obes is self-deception and hallucination worthy of shock therapy

Doob, different compression routines have vastly different qualities (because they cut out different things). Compare a 128k CBR mp3 (dome with some early mp3 encoder) to a 128k VBR mp3/wma/aac done with something modern. And file size is important, there are several lossless formats (wav, aac, flac, ape, wma, shn, ofr, tta to name just a few), and they all produce different file sizes and given the are lossless (no loss in quality) I'd say file size is a factor.

So when ripping from an original. Codec does matter! a 192k VBR file is not the same as a 192k CBR file (tho both will be decent at 192k). Transcoding ... yeah that's bad (becuase you can't put back what was lost and infact have added new things that aren't "correct" in the first place)

eg.
http://www.soundexpert.info/coders192.jsp
(Uberstandard is a 192k VBR)
and
http://www.soundexpert.info/coders128.jsp

Anything above 5 is deemed to be imperceptible from the original in a double blind test. Done by normal people on their normal audio environments. The higher above 5 it is, the stronger the reliability of that rating. It also has the minimum rating anyone gave it. Once you hit 224 ... looks like no one was able to even pick it any more.

Other interesting reads
http://www.rjamorim.com/test/
http://ff123.net/abchr/abchr.html
http://www.24-96.net/dither/
http://www.pcabx.com/


Basically...
If you are listening to music in ear buds or a car or crappy little pc speakers. You would be hard pressed to notice the difference between a good 192k VBR mp3/aac (that crappy 92K mp3 rip off a scratched CD that you downloaded off Napster/Kazaa is not a good mp3) and a CD. To say you can is more then likely audio snobbery and if given a double blind test you'd probably prove you can't.

That said transcoding from one lossy codec to another is a bad idea because it creates artifacts on top of artifacts. For the more visually and less drug inclined.
Open a jpg save it a bmp, close it all open the bmp and save it as a jpeg (not a a lossless jpg) the second image will look alot like the first one, but it won't be the same. And if you do it with a poor quality jpg (one with lots of artifacts) it will look even worse.

But saving from an original BMP/tiff whatever with a high quality setting in your jpg editor of choice, you probably won't notice the drop in quality.

Unless they have Fairplay DRM in them

Don't they have it by default?

For iTunes purchases (yeah)
But for the encoder built in to itunes, I don't think so. (But I have never used it, my old man did by accident he used it when he bought his iPod and converted all his cds... so I could just go grab some of his aac's and see)

Anyone heard anything about ipod battery replacement kits? I'm thinking about getting one of these for my 3rd gen 20GB.

http://www.epowermac.com.au/prodtype.asp?PT_ID=152&strPageHistory=cat

The instructions for using them were in a book I bought about iPods... seriously ...

Didn't look too hard, but it did involve pulling it to pieces and they aren't meant to be pulled apart by users (ie. forcing things).
Way I figure it, if you get it, and it works, you just got your ipod working for $30.
If you stuff it ... it was only$30 and an ipod that was already stuffed... and you can atleast use the 2.5"HDD in a a case or something

also ... these guys look cheaper. Jaycar flog em too

Or you can get it all done for you here

worthy of shock therapy

My brother just had shock therapy
true story!

Ta for that. I read some reviews on the apple forums about it and people say that it's very hard to do without at least slightly denting the case. But to be honest I don't really care. My iPod is physically in good condition and I'm not worried about one little dent in it (if I can keep it to just that).

The batteries at global batteries are actually the same as the ones already inside the iPods, 630mAh. The ones I linked to are 850mAh which apparently equates to about 25% increase in charge.

The Jaycar ones look better. Ta.

why not buy a new ipod, they are thiner and sexier now

$30 for new battery vs $300 of nano:O