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Topic: Best LAME setting for low bitrate mono/stereo... (Read 16936 times) previous topic - next topic
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Best LAME setting for low bitrate mono/stereo...

After a few trys with a few encoders (and looking at space concerns) I think ~64 kbps mono and ~80 kbps stereo will work for encoding audioplays or audiobooks (which sometimes have a little music in dramatic points or between chapters). The source files are sometimes in mono and sometimes stereo and recorded at various levels of quality. I am sometimes because of format, needing to transcode (another reason the bitrates are kinda high for speech).

Question is what is the best LAME setting (-h -b 64 -m m, --alt-preset cbr 64 -m m, etc.) for these low bitrates? Should stay away from ABR and VBR when going this low? Can I use additonal settings like -m safely with presets?

Any help would be greatly appreciated.

Best LAME setting for low bitrate mono/stereo...

Reply #1
What's your playback scenario? Are formats other than mp3 an option? Ogg Vorbis and AAC would be viable options at such low bitrates as well.
A riddle is a short sword attached to the next 2000 years.

Best LAME setting for low bitrate mono/stereo...

Reply #2
Quote
What's your playback scenario? Are formats other than mp3 an option? Ogg Vorbis and AAC would be viable options at such low bitrates as well.
[a href="index.php?act=findpost&pid=224791"][{POST_SNAPBACK}][/a]


MP3 is my lossy archive preference for audiobooks (for compatibility), so I'd rather stick to that.

Best LAME setting for low bitrate mono/stereo...

Reply #3
...lame (mp3 in general) will sound like crap @ 64kbps

vorbis/aotuv is your best free bet @ q0/q1 (or megamix, or 1.1rc1, etc...)


later

Best LAME setting for low bitrate mono/stereo...

Reply #4
Me too I'm interested in the best mp3 at low bitrate (around 64 in mono).
I need to play it in a flash component, so I'm stuck with mp3...
What are the best encoder/options?

Best LAME setting for low bitrate mono/stereo...

Reply #5
Regarding audiobooks, I'm very satisfied with LAME 3.96 and the "128 kbps-Setting"  -V5 --athaa-sensitivity 1, which results in bitrates around 85 kbps. Mono sources shoudn't be a problem.

Best LAME setting for low bitrate mono/stereo...

Reply #6
LAME is fine for this task if you want to stick with MP3. Try "--preset 64 -mm --lowpass 11000". Change the 64 to whatever bitrate you want and play around with the lowpass depending on the source material.

Best LAME setting for low bitrate mono/stereo...

Reply #7
I'm pretty happy with lame -q0 -V 9 --vbr-new. The input wav is already mono and lowpassed. I got around 60 kbs with a good quality for prelistening. Lame version 3.90.2.
Any suggestion?

Best LAME setting for low bitrate mono/stereo...

Reply #8
Quote
I'm pretty happy with lame -q0 -V 9 --vbr-new. The input wav is already mono and lowpassed. I got around 60 kbs with a good quality for prelistening. Lame version 3.90.2.
Any suggestion?
[a href="index.php?act=findpost&pid=224907"][{POST_SNAPBACK}][/a]


In the more recent Lame versions there is a  setting for --preset voice.  That has worked well enough for me.  The --preset help command says that it is a 56kbps mono setting.

Best LAME setting for low bitrate mono/stereo...

Reply #9
Quote
In the more recent Lame versions there is a  setting for --preset voice.  That has worked well enough for me.  The --preset help command says that it is a 56kbps mono setting.
[a href="index.php?act=findpost&pid=225021"][{POST_SNAPBACK}][/a]

Thx Danimal, I tried it in lame 3.90.2, works fine too. The quality is slightly better with my settting (-q0 -V 9 --vbr-new) for only 4 kbs less.
Also the voice preset resample to 24khz, it should take more cpu during the playback and we are using it in a flash interface already greedy in cpu.

Best LAME setting for low bitrate mono/stereo...

Reply #10
Quote
xmixahlx Posted Jul 10 2004, 09:20 PM
  ...lame (mp3 in general) will sound like crap @ 64kbps

vorbis/aotuv is your best free bet @ q0/q1 (or megamix, or 1.1rc1, etc...)


later


Have you actually listened to Lame VBR Mp3 at 64kbps.

My experience is that it will sound pretty good for audio books.

Best LAME setting for low bitrate mono/stereo...

Reply #11
Have you actually tried Vorbis at this bitrate / for this application? It's not just being recommended for fun..
A riddle is a short sword attached to the next 2000 years.

Best LAME setting for low bitrate mono/stereo...

Reply #12
Quote
Quote
xmixahlx Posted Jul 10 2004, 09:20 PM
  ...lame (mp3 in general) will sound like crap @ 64kbps

vorbis/aotuv is your best free bet @ q0/q1 (or megamix, or 1.1rc1, etc...)


later


Have you actually listened to Lame VBR Mp3 at 64kbps.

My experience is that it will sound pretty good for audio books.
[a href="index.php?act=findpost&pid=225406"][{POST_SNAPBACK}][/a]

I can confirm, in mono, it makes the job.

Best LAME setting for low bitrate mono/stereo...

Reply #13
Quote
Have you actually tried Vorbis at this bitrate / for this application? It's not just being recommended for fun..
[a href="index.php?act=findpost&pid=225415"][{POST_SNAPBACK}][/a]

I have to use it in flash. I can only play mp3.

Best LAME setting for low bitrate mono/stereo...

Reply #14
I recently ripped a long, 22 CD audio book, with the aim of fitting it on one CD. Vorbis AoTuv at Q3 mono produced an average 70 kbps and sounded very nice. Much better than Speex, even at Q10. For some reason, Speex in ultra-wideband mode produces a very annoying artifact, and I don't like the loss of high end going down to 16 khz.

Vorbis also had the advantage that I could make my own very customized tags. I used Title for chapter name, Chapter for chapter number, Index to count how the chapters are split into multiple tracks, and Disc to show what CD the track originally came from.

Best LAME setting for low bitrate mono/stereo...

Reply #15
I appreciate all the responses. Let me be clear though. I need MP3 for compatibility. I personally can play MP3 or AAC on my iPod, but I can't count on AAC, Ogg, etc. for others. Plus at least a couple of these files will have to be transcoded. I'd really hate to have to transcode a third time in the future. I think for this use MP3 (even if at a necessary higher bitrate) would be better. I actually thought 64 kbps mono and 80 kbps stereo was being pretty safe with speech, but I could be wrong. Just wanted the best quality for the space I was going to give. I'm open to other bitrates though.

Let me ask again though, is VBR an issue at this low bitrates? Don't want major fluctuations in the sound if possible.

Thanks again.

Best LAME setting for low bitrate mono/stereo...

Reply #16
1) I don't expect VBR will be an issue at low bitrates, unless your player has trouble seeking in VBR (a few do, but this isn't too much of a problem anymore, in my understanding). VBR will get you some quality over CBR, although the encoder is tuned to choose the optimum bitrate for music, not speech specifically. Nevertheless, VBR will still give you better quality/size than CBR.
2) forced mono should be fine, although it won't actually gain you much over joint stereo in the lower bitrate department (or higher quality at a given bitrate)
3) if you don't plan to transcode again (hopefully you don't, and won't have to if you're using mp3, which is why you're using it), you might downsample to 22,050 Hz. This cuts your high-end frequencies off at 11khz, but for books it might not be an issue. Try a couple of encodes and see if you find it problematic. If you don't, this will really allow you to drop bitrate without getting artifacts.

I recently encoded some voice stuff using Lame 3.96 --preset medium, but downsampled to 22,050 Hz and forced mono. --preset medium did an admirable job here, giving me files around 55 kbps, with no discernable quality diff (to my ear) compared to the original, except for the slight loss of high end. If you downsample the wav file to 22050 first, and just run --preset medium, there isn't any audible quality difference that I can hear.
God kills a kitten every time you encode with CBR 320

Best LAME setting for low bitrate mono/stereo...

Reply #17
Just recently I was looking for the same thing (archiving audio books at the lowest possible bitrate that still sounds good in mp3 format).  Also sometimes the source will already be encoded, so I'd be transcoding down to the mp3.

  After scouring these boards for suggestions (there are various related threads on the topic), and trying out a bunch of options, here's what I''ve decided to use

lame3.96
alt-preset medium -a --lowpass 10 -b 32

What this has been resulting is : 64kbit VBR, mono, 24khz files.

64kbps is good for me (lower is always nice, but  I am happy with the relatively small file sizes), and more importantly, to my (by no means audiophile ears) it sounds "transparent" to my sources.

  I tried various other options to try and shave the bitrate further, but anything below this rate would produce increasingly more obvious artifacts (the "under water"/gargling noise that you see in alot of low audiobook encodes.

I believe the interesting parts of these settings are (i'm no lame expert)
-a (switching to mono. No real need for stereo for spoken word)

- preset medium (Vbr is a plus, standard is too high, medium is next lowest)

- lowpass 10  Filtering out frequencies above 10khz.  The idea being that there aren't many high frequencies in spoken word audio, so they will not be missed too much. (And it also helps to remove high frequency artifacts that come up in such a low bitrate?)

  This is the best I've been able to come up with, as I am no lame expert, there might be an easier/more preferable way to get this result.  I did try alot of recommendations from the forums, and this seemed to work the best for me.

Hope this helps

Aggies

Best LAME setting for low bitrate mono/stereo...

Reply #18
Quote
lame3.96
alt-preset medium -a --lowpass 10 -b 32

To me this seems to be a good command line for your purpose. (but -b32 is probably useless)

You also have to know that with 3.96, medium is the same as -V4, and standard is the same as -V2. It means that between both you could also try -V3.

 
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