I think by full 'Quality' on the graph they mean that it will never be bit exact quality from the source file. You never will be guaranteed that it will be lossless even if you pump up the bitrate to 320Kbit/s.Transparent might be the wrong word. Transparent means that is 'sounds' transparent to the user.Even though 192Kbit/s or even 320Kbit/s Vorbis sounds 'transparent' to me doesn't mean that is is full 'Quality'.
What is the definition of "transparent"?
Quote from: Notat on 29 August, 2011, 12:17:20 AMWhat is the definition of "transparent"?Assuming you do not intend this question to be rhetorical, I would suggest a definition of "demonstrable over the course of multiple double-blind listening tests to be indistinguishable from the uncompressed (or losslessly-compressed) source with a statistical signifcance of p<0.05".
I have read the HA wiki and Wikipedia. Neither your [Zarggg] proposed definition nor either of these articles tells me precisely what listener we're talking about.
[. . .] Apparently he thinks the graph shows mp3s can never be transparent. You see the artificial gulf there? [. . .] [This] hinges on the strictest definition of 'transparent', and puts a burden on that graph that it wasn't meant to bear. Misses the forest for the trees.
Transparency, like sound quality, is subjective.
I think far longer has now been spent discussing that graph than went into making it. It would probably have been better if the quality scale had no units. I'm not aware of any reliable units of subjective audio quality which have a globally understood and repeatable quantity in the same way as the units on a ruler.
The HA article, for instance, describes how to demonstrate non-transparency then lists some transparent audio formats that I'm pretty sure have been shown to be non-transparent by these guidelines at least with specific program material and ears.
"Is 320 kb LAME transparent?" So long as we can agree on a technical definition of "transparent" it seems like a simple experiment to conduct.
What about a perceived quality vs size graph?Arbitrarily, I'd give the following quality levels:--abr 56: 3--abr 90: 5-V5: 7-V4: 8-V3:8.5-V2: 8.7-V0: 9.1-b 320: 9.2This is purely informal, but if you trace a graph of perceived quality vs average size, you will probably obtain a nice curve with valuable indication regarding efficiency of the settings.
I added -V1 in there, to get the unsightly kink out of the first graph (qualily value is simply the average between -V2 and -V0).
And yet we have many audio lovers (including HA members) who insist on using lossless formats. And why is that? Because lossless gives them peace of mind? Because they think lossless sounds better? Or is it because perceptual coding, no matter the sophistication or bitrate, potentially introduces significant and audible degradation?
I think the main reason that many of us here at HA use lossless encoding is to avoid generational degradation.
I think there might a benefit to defining terms for "transparency" in regards to the degree of "lossy quality."
I have gone ahead and updated the caption for the graph in the wiki, and linked to the relevant discussions.
I take it that, in a technically defined sense, "transparent" means that in a particular (series of) test(s), particular listener(s) were unable to tell the difference between specific lossily-coded sample(s) and their original(s). Even in this defined sense, transparency can't be proved, since individual listeners can have good days and bad days.
I don't ever recall there being a problem with the meaning of the word as it relates to how it is used on this forum.transparent = perceptually indistinguishable