I was just curious... Among all the popular lossy codecs and formats, what bitrates or settings are generally considered transparent?

For example, with LAME 3.98, there seems to be a consensus that by using VBR, transparency can be achieved by using the setting -V3 (appx 175kbps) or higher. Obviously that won't be transparent for everyone, but it seems to be a general guideline.

Have there been any tests with LAME to determine a guideline for the CBR or ABR algorithms?

How about the other formats? OGG? QT AAC? Nero AAC?

You really need to ABX to dertermine at what level you can achieve "transparency" at. I can't really speak for Nero AAC or QT AAC, but when encoding them with them I am personally inclined to use a -q 0.65. It's a good tradoff between size and quality. I just recently transcoded a CD of mine from FLAC -> Nero AAC for use on my PS3. I found that to be a good level. Vorbis I can speak for though. In the wiki and in the community the general consensus is that -q 5 is more then adequate enough on most material. You really should start at a -q 4 and ABX your way up. Some people prefer to use -q 6 and above though as they have the space and need for it. I personally would use somewhere between -q 6.5 - 8. This is what I use, but again might be considered "overkill". You need to experiment ultimately.

I realize total transparency at 192 kbps (VBR) on iTunes for most music, but find that I need to go to 256 kbps for live rock albums, especially those containing a lot of crowd noise.

This question is asked about once a week. Or is it just me?

This question does get asked ad nauseum.

I myself find the Nero AAC encoder to be transparent at -q0.45 to -q0.50 and the iTunes AAC encoder to be transparent at 192kbps VBR. I think a good rule of thumb is to start at 128kbps VBR and then work your way up.

Listening tests show that many people think that 128kbps VBR (with Lame mp3, Nero AAC, and iTunes AAC) is a setting that is able to achieve transparent results for many samples.

You can find more direct answers by searching the forums (there will be all sorts of results since this question gets asked a lot) or by looking at the results from past listening tests.

Let's face it though. Nothing out does the ad nauseum EAC questions on this forum that have been answered in about 600 different ways in the wiki. Yet people still find the need to write more guides or ask the same questions over and over again. I think -q 0.50 seems to be transparent for the most part with Nero AAC. I was using it yesterday. I find that is a good tradeoff between quality and space (something which I have a lot of).

Sorry if the question is constantly asked. I know there are a lot of related threads out there. I was just trying to get a quick comparison in the sense that you can get transparency (for most people) with LAME somewhere around ~155-175kbps using VBR, approximately xxx kbps using Nero AAC, approximately yyy kbps using OGG, etc.

For myself, I've done the ABX testing and have found that LAME -V4 ~155kbps is transparent to my ears on my simple setup, and the LAME wiki seems to suggest that this is about right for a lot of people. I was just trying to get a feel as to what was "about right for a lot of people" with the other formats out there, or even LAME using different CBR or ABR.

I could throw in ballpark figures for CBR and ABR of 192Kbps and 160Kbps respectively from a personal perspective, but anyone who wants LAME to work at the highest efficiency possible for general audio CD conversion is more likely to be using VBR anyway as the quality to file size ratio can't be beaten by LAME in either CBR or ABR when you sit just above the typical required level for perceptual transparency.

As a very general rule of thumb, -V3 (~175Kbps in VBR) seems adequate for most semi-fussy listeners with LAME 3.98.2 and is considered by some to match the perceived quality of earlier implementations of LAME at -V2. It's all guesswork though when you consider that some listeners really do need -V0 (~245Kbps), at least some of the time, and some others can never ABX -V5 (~130Kbps).

There is no global answer, and the same follows for any lossy encoders. Ultimately, there really is no option but to test them for yourself.

Cheers, Slipstreem.

I generally agree with that.

Lame -v2
ogg vorbis -q6