High bitrate MP3 vs. Lossless ABX Tests?, Are there any studies...? Options

[Street Samurai]

Hi All,

I've been corrected before on this site for making the statement: "I can tell the difference between an MP3 and lossless". I've never ABX'ed myself but I was wondering if there has been a statistically significant (with regard to population) ABX study done with (say) Lame insane vs. Lossless?

Clearly for myself it makes more sense to do a personal ABX but I was wondering in general about the population.

I searched manually through the posts in this forum (since search seems useless for the term 'mp3') and didn't see anything.

Thanks for help,

ss.

This post has been edited by Street Samurai: Jun 2 2005, 01:02

[2Bdecided]

Woodinville,

I'm not quite sure what you're trying to say about the official tests.

It's true that mp2 and mp3 "failed" at the target bitrates.

However, AAC Main Profile at 128kbps did rather well (if not a 100% perfect pass) here:

http://www.mp3-tech.org/programmer/docs/w2006.zip

I haven't seen any such test for "high bitrate" mp3, though we know some specific samples where Lame mp3 has difficulty, while commonly high bitrate Lame passes ABX tests for most samples - though some listeners find problems on certain types of sound.

Cheers,
David.

[Woodinville]

However, AAC Main Profile at 128kbps did rather well (if not a 100% perfect pass) here

The AAC Main Profile, with what the developers of the codec believed was the best available encoder, still provided a non-random (to many orders of magnitude, I've forgotten how many) ID rate in reference identification in the final AAC verification test, which I suspect is the best test run with AAC.

The impairments that were listed were quite small, but many (not all) listeners were easily able to ID the reference signal, which shows that there is "indistinguishable" according to MPEG (all items over 4.0), and "transparent" according to ABX id rate, and that while MPEG's definition is very good, it's not perfect.

In that test, some listeners were excluded for having negative impairment scores, this was used as a screening method. None the less, there were far, far too many people who ID'ed beyond the significance required by the number of trials and subjects, especially on the most difficult tracks.

I think this says it all, quoting the report:

The AAC Main 128 codec is indistinguishable from the original for 8 of 10 items, the AAC Main 96 for 3 items, the AAC LC 128 for 8 of the 10 items,

Note that this is a weaker test than asking what the ID rate for the reference is, as well.

This post has been edited by Woodinville: Jun 6 2005, 18:47