I'm thinking of transcoding some audiobooks, and wondering what's the lowest bitrate recommended to use VBR? Or put another way is 80 kbps (LAME) too low and it should just be CBR? I know I should test for myself, but since it would require several books to test significant fluctuations in voices, reading patterns, etc., I was curious if anyone has any experience they want to share?

Thanks.

If we limit ourselves to the recommended version, i.e 3.90.3. The lowest recommended VBR preset is --preset standard -Y, which I have heard is roughly 170 kbps. Below that ABR (--preset <bitrate>) is recommmended over CBR (--preset cbr <bitrate>), at least down to 80 kbps. 80 kbps is the lowest bitrate that the presets were designed for. However, using the modified compile, you can go below that, and ABR should still be better than CBR.

I don't think CBR is ever recommended qualitywise with Lame.

Right now im ripping cd´s into 96-128kbit vbr with Lame 3.97(-V5--atha sensitive 1). (Just for portable use). Are you saying that its better to use abr at such low rates? why?
Thx

For the "presets" there's also --preset medium which is pretty close to 160kbps on average. The VBR setting used for the 128k test recently (-V5 --athaa-sensitivity 1) did very well, so I suspect VBR is "vindicated" at that bitrate, probably lower. I don't know what setting you'd want for your purposes - perhaps -V6 or -V7 would be in the range you're looking for...

No I am not saying that.

But lets start with pointing out that 3.97 is alpha (last time I looked) and should not be used for regular encoding. You should at least step back to 3.96.

What I said that was that with the recommended Lame version (3.90.3) and using the recommended settings, ABR is preferred at those bitrates.

Problem here is that we now have 3.96, which seems to perform very well. But it is still regarded not to have been tested sufficiently to replace 3.90.3 as the recommended version. For 3.96 the settings recommended in the recommended settings thread is probably not valid any more. With 3.96 VBR (-V5 --athaa-sensitivity 1) seems to perform better than ABR at lower bitrates as well.

So on one hand we have the recommended compile & settings thread (which have been pretty much a bible so far) and on the other hand we have the recent tests that so far indicate that 3.96 could be the new version and -V5 --athaa-sensitivity 1 the new setting recommended at these bitrates.

A bit difficult to say something really conclusive I think.

IMHO, at 96kbit you should NOT use the (current) recommended version, but instead LAME 3.96 in VBR or ABR mode.

The 3.90.3 vs. 3.96 listening test has shown that LAME 3.96 has made good improvements especially at medium-low bitrates. So, the probability that LAME 3.96 is at least better than 3.90.3 at near 128kbit is very high.

- Lyx

P.S.: i really think the recommended version should finally be changed to 3.96. Currently, we have a very vague situations, since the tests have shown that 3.96 is probably at least the same quality as 3.90.3 at high bitrates, and with a high certainity better at lower bitrates than 3.90.3. So, there currently is a gap between "official" and "unofficial" recommendations on HA. Most people have already switched to 3.96, and if the recommended version isn't changed based on the listening-tests done, then we may get into a situation were "the ha-recommended version" is only theoretical.

Specifically for audiobooks I use -mm --preset 56, and it works very well.

I'm not so enthousiastic. The -V 5 preset performed very well on most samples used in the last test, but these samples are “difficult” to encode. They are maybe common, but they're still difficult.
I've recently encoded some albums in -V 5. Classical music, with wide dynamic, near-silent part, very quiet moments, etc... Bitrate sometimes drop to worrying level (70-80 kbps). Quality is in consequence: bad. Sometimes awful after MP3gain adjustment (I've encoded these albums for my portable).

Audiobooks, with speech, are not comparable to the samples tested recently. I suppose that ABR is the best solution, or at least the safest.



EDIT: the Debussy sample is close to be a speech sample. Lame VBR was unimpressive, clearly worse than ATRAC3 and probably worse than WMA:

Hi iam a newbie to this forum, but i have used lame in the past with total recorder at 96 kbps, recording to total recorder from the sound board with no artifacts at all, but now that i am encoding with total recorder using software mode and lame 3.96 for a lower bitrate (48kbps, which other audiobook sharers seem to prefer - some even 32!) i get metallic artifacts, something which never happens if i record forst to 128 and use cdex to convert down with the same lame .dll. I use highest quality lame setting too.

But yes i was using constant bitrate. So is there anysetting you can recommend to keep file size small (i am often encoding 20-30 hour audiobooks)

Thanks!