Originally posted by RD Thanks Dibrom, its always a pleasure to read your responses...
I guess your new compile of lame is mostly aimed at fixing transients/pre-echo then or will it have any benefits for rock and metal music too?
Oh btw, how is the tweaking coming along? (Sorry--dying to know when the new compile might be ready...)
Finally, what is this "better tonality estimation" thing about? What is tonality? Does it play a part in determining whether or not the encoder uses short or long blocks? I know at least a little something about most aspects of lossy compression, but I know nothing about this tonality thingy....
Originally posted by Dibrom The idea is that if a signal is more tonal it probably requires more masking but if it is less tonal and more noiselike, you can be more aggressive with the quantization.
- Mp3 lacks a scalefactor for the last scalefactor band. This means that you can never get nearly 100% dropout free encoding over 16khz. For many people this may not be much of a problem really, but besides the fact that it is a possible quality concern (even at 320kbps).
It also causes very large bitrate increases as you attempt to approach the point of increasingly diminishing returns of getting that extra little bit above 16khz encoded.
very large bitrate increases as you attempt to ... [get] that extra little bit above 16khz encoded.
Originally posted by RD Hmm... so I guess that means that above 16Khz Lame's noise shaping is either technically non-existent, or is at least considerably impaired (i.e. we still can use a noise measuring criterion, e.g., -X3, but it is really inefficient without a scalefactor for the last band....)
Do other mp3 encoders have a scalefactor for the last band?
A whopping 44% increase for frequencies above 16Hz!
If we had a scalefactor band for the last band, would this increase be a lot less, or only a little less?
I end with a technical question about high frequencies... My understanding is that the wavelength (distance between the crests/peaks shortens as you go from 20 Hertz to 20 Kilohertz...Thus it would seem that there is a lot more information to store in the higher frequencies than the lower ones...is this ALSO one of the reasons for the:Or is this not one the reasons at all...?
I end with a technical question about high frequencies... My understanding is that the wavelength (distance between the crests/peaks shortens as you go from 20 Hertz to 20 Kilohertz... Thus it would seem that there is a lot more information to store in the higher frequencies than the lower ones...is this ALSO one of the reasonsNo, this doesn't really have anything to do with the scalefactor issue.
Originally posted by RD Thanks so much to everybody esp. Dibrom, Tangent, John V, and Garf, for their great comments.How could we create a scalefactor for the last band--through listenting tests? Is it feasible? or should we just forget about it...?Dibrom said its not in the specification, but will adding oneaffect decoding? Obviously we want mp3 files that work with all decoders....Because if we can "fix" this problem.... lame will greatly benefit...RD