I can fit up to 100 albums on my Rio Nitrus if I encode them at CBR32. I'm using Smpman's stable LAME compile with the following switches:

-b 32 -m j

The results are plenty good enough for subway listening and then some. Much better than same bitrate WMA or MusicMatch 8 MP3 (Fraunhofer codec). Good frequency range and very little flanging.

Question:

> Are there any other switches I should add to the LAME command line to make these low-bit files sound even better?

Thanks if you respond.

wow 32kbit/s is really low for mp3, that must sound awful ... try something like

-b 64 -h --resample 32

(-h for slower HQ mode, resample for, well resample to 32KHz)

Try using just --preset 32 with either lame 3.93.1 or the modified 3.90.3.

Maybe add -a to force mono?

32 kbps ... good enough for subway listening ... fair enough.

Anyway, I would use the following option (with LAME 3.90.3):



However, MUSICMATCH Jukebox should produce better quality as it uses the Fraunhofer encoding engine (which is better at bitrates under 128 kbps).

I had read that about MM8/Fraunhofer, but found that some of the MP3s I created that way had "skipping" problems on my Nitrus. The same files created with LAME don't have that problem.

Thanks for the responses...

Might be caused by Intensity Stereo.

Not sure what you mean by "Intensity Stereo".

I do get some stereo effect from LAME even at this low bitrate. I prefer that to MM8 in mono.

Thanks.

There are 4 types of Joint Stereo frames:

Simple Stereo
Mid/Side Stereo
Intensity Stereo
Mid/Side Stereo & Intensity Stereo (Mixed)

LAME can only use Simple Stereo and Mid/Side Stereo, while Fraunhofer encoders also support Intensity Stereo and Mixed Stereo.

Edit:

Simple Stereo: The encoder will produce a left and a right channel, while assigning more bits to the channel which has a higher dynamic and less bits to the channel with less dynamic. It will NOT divide the bitrate 50/50, as that method is called Dual Mono!

Mid/Side Stereo: The encoder will produce a middle and a side channel. The middle channel receives more bits than the side channel. The encoder uses this formula for dividing / assembling the channels (99.9% losslessly):

M = (R + L) / 2
S = (R - L) / 2

R = M - S
L = M + S

Intensity Stereo: The encoder will encode portions where the left and right channels are almost the same as mono, while still providing a limited stereo effect when the two channels are differen (lossy)

Mixed Stereo: The encoder mixes the Mid/Side Stereo method with the Intensity Stereo Method.

Cool...

I have a thread open over on the Rio forum to troubleshoot this problem with the Nitrus. Do you mind if I share your thoughts there?

http://www.riovolution.com/forums/viewtopi...0d377a7575dbcb5

No, not at all. Anyway, I am not sure if the skipping problem is really caused by the Intensity Stereo frames

OK, I have found another possible source for your problem: MPEG 2.5. Players are not required to support MPEG 2.5 as it isn't part of the ISO standard, but was added by the Fraunhofer Institute in order to support low sampling rates.

You could try to encode a file with LAME using the additional option "--resample 8" and check if the file skips. If it does, the problem is with MPEG 2.5.

what are you listening with? melbourne subway is pretty loud, and even with the windows down i could still hear grossness at 32kbps. mp3 as a whole simply breaks down at that level unless you're doing 22050 mono, or 11025 forced joint stereo with no short blocks.

LAME is damn good, but not THAT good

[edit]
personally i'd settle for fitting 33.3333 albums on a player at 96kbps (the absolute lowest i'm able to get lame sounding nice). maybe even settle for 25 albums at 128kbps. don't know what train you take, but it's not going to take 25 albums to get you home...

Just as an educational aside.. the (b) option is the same method used to encode stereo FM broadcast signals.

Is "intensity" similar to the noise reduction used for weak signals in FM where you low-pass (and maybe attenuate) the difference signal ?

Doesn't the Nitrus support ogg?