Naoki not implementing PNS for LAME. :)

2001-11-12 12:17:33

To help low bitrate encoding, Naoki is coding PNS (Perceptual Noise Substitution) for Lame along with new tonality estimation. If lowbitrate improvements are made it only makes sense to include intensity stereo, so I believe also it will eventually be done.

This is quote from www.audiocoding.com site about PNS for MPEG4-GA, I'm not sure exactly about Naoki's implementation...
The technique of Perceptual Noise Substitution is based on the observation that one noise sounds like the other. This means that the actual fine structure of a noise signal is of minor importance for the subjective perception of such a signal. Consequently, instead of transmitting the actual spectral components of a noisy signal, the bitstream would just signal that this frequency region is a noise-like one and give some additional information on the total power in that band. PNS can be switched on a scalefactor band basis so even if there just are some spectral regions with a noisy structure PNS can be used to save bits. In the decoder, a randomly generated noise will be inserted into the appropriate spectral region according to the power level signaled within the bitstream.
From the above description it is obvious that the most challenging task in the context of PNS is not to enter the appropriate information into the bitstream but reliably determining which spectral regions may be treated as noiselike and thus may be coded using PNS without creating severe coding artifacts.

Naoki not implementing PNS for LAME. :)

Reply #1 – 2001-11-12 13:43:34

Are you sure about it? PNS is an AAC tool, not an mp3 tool. (although mp3pro and mp3+v could use it in the extension part)

Naoki not implementing PNS for LAME. :)

Reply #2 – 2001-11-12 18:57:43

Yep - that way it would ruin ISO compatibility

maybe perceptually controlled Intensity Stereo would help?

Naoki not implementing PNS for LAME. :)

Reply #3 – 2001-11-12 19:39:12

I came into this thread wondering why Naoki wanted to implement Post Menstrual Syndrome into LAME. It's not like as if LAME itself doesn't suffer from PMS...

Naoki not implementing PNS for LAME. :)

Reply #4 – 2001-11-12 19:46:01

hehe

Naoki not implementing PNS for LAME. :)

Reply #5 – 2001-11-12 23:49:28

Yeah, I think the issue here is his new tonality estimation, which principles he will use for both PNS and secret project.

PNS would certainly seem to need support in decoder level, unless it's something totally different than MPEG4 PNS and he just calls it PNS...

Naoki not implementing PNS for LAME. :)

Reply #6 – 2001-11-13 09:15:27

It's misunderstanding that I will implement PNS for lame.
I said that I'll have some experiments using PNS, but  that's not for lame.
I'm a member of lame project, but it doesn't mean that I'm only interested in MP3 format.
(and, this comment doesn't mean that I'll move to another project.  )

Naoki not implementing PNS for LAME. :)

Reply #7 – 2001-11-13 09:30:43

Ok, so it seems to be misunderstanding. But I definitely got the impression from our discussion that it would be for low bitrate Lame when we talked about it and new Lame tonality estimations.
I mentioned also other formats when asking about your secret project but you didn't imply you're working with other existing audio formats...

Sorry about that.