alt-preset standard problem samples, with Lame 3.93.1 and before. Options

[JohnV]

There are lots of cases when alt-presets or any mp3 are not transparent, but I gather few "easy" but distorted cases which should be used to further tweak and check alt-preset standard quality.

I'll put more samples here in the future so that those are easier to find and can be found from the same place.
My intention is not to list clips with very hard attacks, other known extreme clips or clips which cause great trouble for every codec.
More like "easier" cases which in my opinion should be handled better by alt-preset standard.

http://static.hydrogenaudio.org/extra/samp...es/sophia2.flac
Clip found by Wombat. Introduces added noise from 1.2-2sec and 4-6sec.

http://static.hydrogenaudio.org/extra/samp.../vangelis1.flac
Although soft attacks, still introduces pre-echo hiss (most noticeable in the beginning).

http://static.hydrogenaudio.org/extra/samp...dogwhistle.flac
Dogwhistle is chirping.

http://static.hydrogenaudio.org/extra/samp.../liebestod.flac
Audible distortion in the background.

http://static.hydrogenaudio.org/extra/samp...ples/birds.flac
In all 4 vbr presets distortion is added, mostly with the "e" when she sings "become".

http://static.hydrogenaudio.org/extra/samp...mples/erhu.flac
Very bad distortion at about 3.5 sec.

This post has been edited by JohnV: Dec 5 2002, 09:22

[Dibrom]

Originally posted by Wombat
Damn! The solution was that easy, i had to play around with that
Liebestod sample to try a switch we all know for ages.

--ns-bass -8 DOES the trick!! The distortions are nearly gone!

Not only with that, sophia and Birds are cured also.

Does ns-bass affect anything else with alt standard deep inside the code?

Wombat

Hrmm, interesting. --ns-bass -8 shouldn't really cause any problems though, other than causing the bitrate to increase. I'll try to take a look at this sometime this week, maybe it would be possible to implement a fix without having to resort to using --ns-bass all the time on these samples..