Hello, can I get a recommendation about good, widely accepted and in long time period proofed output quality I could rely, in another words bitrate small enough to utilize at portable storage and high enough to make no or seamless difference against lossles at portable equipment (assume standard HF headset), good compromise. For now I think a setting at ~0.25 is the one but wouldn't like to find in future not as good and re-rip my collection. NeroAAC is assumed. I know I could find such a setting self but, such way is quite time expensive for me.

Can I find public listening tests at portable devices somewhere?

Thank for all relevant information.

For my own personal use, I found a good compromise between file size and quality was simply using LAME -V 5, or iTunes at 128kbps. So, I would recommend either of those.

As what some people will suggest, try an ABX test out and hear it for yourself.

If your hardware is supporting HE-AAC v1 you can try go down to q=0.16, but if not you shouldn't go below q=0.31 (lower limit for LC-AAC).

Yeah my phone supports he aac, I've heard that aac is surprisingly good at ~48kbps but I m not sure if it will sound always same good. Is it good idea to transcode mp3 above 192 kbps mostly by lame to aac at 0.25 ?

My Nokia N70 can play 48kbps HE-AAC/M4A, but with I settled with 64kbps, since i found that setting not annoying compared to 48kbps.

Did you find noticeable artifacts @48 kbps? People say 48 is sufficient for phone but I don't believe that much

very much noticeable on earphones, somewhat grainy and swooshy sound on high frequencies. try to listen two tracks, 48 and 64 kbps, on your portable and play on random without looking at the screen. on first try you'll already notice which is inferior. if not, you're lucky you cannot distinguish the difference, and you get to save 16kbps.

That may completely depend on codec used. I suppose you talk about nero's which should process best at low bitrates. I'm afraid I might even hear no artifacts on early listenings so I'm better to ask and rely to opinions of others having read their chosen bitrate thoroughly.

Sorry i forgot to mention that i used the nokia pc suite to rip and encode some tracks way back then. not nero. it was an unfair case of comparison.

Since you might have not heard of artifacts, i guess it's good anyway.

It really depends on your equipment and your ears.


Personally I use -q0.27
But it really is a personal thing. I decided on 0.27 by doing the following:

Encode a piece of music at a bitrate you consider transparent. Then encode that same piece at 0.15, 0.18, 0.21, 0.24, 0.27, 0.30 etc.
Listen to them, alternating between the compressed versions and the wav, starting with the highest bitrate. Stop when you start to notice artifacts you find unacceptable. Then do it again at finer resolution around that range eg. if you stopped at 0.21, then do 0.24, 0.23, 0.22 etc.

Then try a few different types of music at your chosen quality setting, and adjust it as nessecary.
Finally, inrease it by a couple of points if you want to be on the safe side.

IIRC, nokia pc suite encoded to LC-AAC, not to HE-AAC, but I also tried it a couple of years ago so I could be wrong. I just briefly remember that for 64kbps and for listening on-the-go (with the supplied earphones) it was good enough. (read: artifacts were relatively unimportant)

Then my assumption .25 was almost exact. I'd like to know the portable device used. I use sony ericsson with standard shipped headset. So if someone encountered artifacts at bitrates around this on comparable equipment I'd be thankful to hear.

Yet I'm curious about good target quality when transcoding from mp3@192kbps - is the quality decrease too perceptual?

No offence intended, but haven't you had the time in the two weeks since starting this thread to find that answer for yourself? It wouldn't take more than an hour or so to find out what suits you. Bear in mind that although others may have the same equipment as you, nobody else has your ears or knows how tolerant you are to artifacts. Only you hold the answer to your own question ultimately.

Cheers, Slipstreem.

Hi,

You can convert those mp3 files to wav first, then you convert the wav files to aac.....
That may minimize quality loss....

BTW, are you encoding a lot of songs to be moved into your phone?
if you have a big storage capacity, then i suggest that you use q 0.45.
then you don't have to worry about artifacts or else and enjoy your music to the fullest.
(i didn't say there's no artifact, but it's hard to hear one....)
I'm using q 0.5 for my nokia and it's impossible for me to distinguish the audio from the original wav file.

anyway, if you saving some space then q 0.25 HE-AAC should be good (sounds like mp3 vbr -V5 to me....)
and you might want to consider this:


I read it at the wiki.

well, it all depends on your hearing....

In my opinion the intermediate wav already inherits all the maladies of former mp3 so it's exactly same as transcoding via foobar (in another words loosy compression is applied twice on original)



I'm afraid big storage capacity is out of question on portable devices unless they have hard drive

No opinions needed here - transcoding from lossy to lossy will lose quality. An intermediate step going to a WAV file (or any other lossless file) will provide no benefit.

If you're concerned about quality, avoid transcoding from lossy to lossy.
http://wiki.hydrogenaudio.org/index.php?title=Transcoding