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Originally Posted by Rockaria
I appreciate the hydrocents! Grains of salt.. I will drop by more often to read the news, even if I am not planning on posting on the forum yet.
Btw, a recent CT based-Winamp5.1 encoder DLL frontend CLI (enc_aacPlus.exe) now seems to support the bitrate-based(better result size estimation than quality based one) vbr(or abr) encoding.
I am not sure if Nero's encoder is also providing the bitrate-based VBR and still being puzzled by the quality factor mentioned in the original quote.
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Yes, new upcoming Nero encoder will have CBR, ABR, quality based VBR and 2-Pass VBR which gives specified bitrate/size.
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If it is related to naac.exe's quality grades(3~10) and actually having the varying bitrate to keep the given even quality grade,
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New VBR won't be similar in any way to old one used in current N7 encoders.
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I believe the algorithm would be very different than CT's one.
And of course, it is very hard to get the similar overall bit rate(yeah, it didn't mentioned the result bit rates for the vbr keys), which makes the comparison vary rough on the very bitrate-sensitive low-bitrate area. The ABR with entire segment would be similar to CT's one, if I am correct.
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VBR can be quite different yes, but for SBR 48 kbps bit rate deviation is much smaller than people would expect - and hence the small quality difference as noted in last Nero-internal test.
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Another thing to mention is the algorithm optimization for the target bitrate zone : I guess the AAC HE is optimized for the bit rate around 64k(ST) , overlapped then sundued by PS(optimized @ around 32k?) below 48k.
If the VBR(or ABR) does not yield the noticeably(far more than 2.2% I guess) better quality than CBR, I believe it's the algorithm optimization problem on the zone.
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Indeed, each codec/profile has a "sweet spot" - problem of quality expectations is quite complex, as there is not too much to "tweak/optimize" in SBR (leave alone PS) , as more than 50% of the spectrum is the parametric reconstruction of the low part coded with LC-AAC. You have not too much choices what to improve in SBR (maybe filtering / noise floor estimation and up to some point pre-echo detection) - and LC-part of the SBR has not so much impact to total quality.
With that in mind - I think even 2.2% quality improvement is a success
But I do expect 2-pass to yield even better results, so there is definitely more space for improving.