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Scientific Discussion / Major update to the DolbyA compatible decoder.
Last post by jsdyson -
This is now pro-quality but needs a little work to be complete (e.g. missing several 100 samples of audio, phase inversion, a few freq response anomalys (even though it appears that it spectrally matches a DolbyA within very few tenths of a dB. )) The distorion reduction is incredible -- anyone who has listened to ABBA on headphonrs might remember the rough sound.  That rough sound is due to DolbyA distribution onto CD and vinyl -- but vinyl releases are usually properly decoded.  The CDs (listen to SuperTrouper) are really oddly distorted -- I have heard very few American releases that aren't distorted.  Some of the Polar/Polydor releases aren't too bad.

There is distortion cancellation code in the decoder -- some I cannot describe due to intellectual property reasons.  However, there is a mode which removes more noise than a DolbyA (it takes advantage of decoding differently -- and uses some techniques at decoding time to benefit.)

The examples before weren't too bad -- mostly better that a Dolbya because of intermod.  These examples are essentially as good as theoretically possible (I might be able to eeek out a little more quality, but already the examples sound nearly perfect.)

An example is the "supertrouper" item -- there is a chorus burst which is normally mired in deep intermod -- but even though there is a bit of a distorted sound in my result, the intermod is well under control.  I use ABBA as my basket case test -- because of the voices and recording technique it drives DolbyA crazy.
I intend someday soon to distribute a consumer version of the decoder -- it will still sound really good, but might not be quite as good as the pro version, be limited to 48k, and might be limited in decoding length.  (albums tend to be longer than perhaps the 10minute timeout that I might plan -- that will probably thwart commercial use.)

Listen to the examples, and compare with your CDs...  I have to say 'wow' and I was almost crying with relief early today.

I uploaded mp3 versions of the ABBA decoding -- doesn't sound perfect and significant mp3 loss but at the beginning of snippet 1, the beginning has no intermod.  The second snippet near the end is a little rough -- but NOWHERE near the intermod of almost any release.  (It might sound slightly different than commercial releases because some aren't decoded.)  This is from ABBA Gold, 1992 which the copy that I have is undecoded (believe it or not.)  The repo has more complete examples.

https://spaces.hightail.com/space/xghqJodgrj

John
5
AAC / Re: TVBR vs CVBR
Last post by ThaCrip -
TVBR is typically the better of the two given both are pretty much the same sound quality wise (some claim CVBR 'might' have a tiny advantage) but TVBR generally gives smaller files so it's more efficient which makes it the overall better of the two.

I think where CVBR can come in handy at times is at lower bit rates like 96kbps as it seems to limit the encoder from having the bit rate drop too low as looking through my collection, which is 96kbps TVBR (Apple AAC encoded with Foobar2000 QAAC), 53kbps is the lowest and 121kbps was the highest although the average bit rate over all of the files is 93kbps.

but like you said in your post above... you can't really tell the difference so you might as well go with TVBR since it generally uses less bit rate.

there was one song I encoded not long ago that there was one part in a song (when the singer said a certain word at one part in the song) that I could tell the difference between TVBR and CVBR (with CVBR being better but the bit rate was noticeably higher than the TVBR file) but that was at the 96kbps setting and the bit rate between the two tracks was about 20-30kbps between TVBR and CVBR if I recall correctly which probably explained it. but at your super high bit rates I doubt that would occur because at 224kbps is already a bit overkill as it seems, given tests around here, 192kbps is about the max dang near everyone would need.

if you don't mind me asking...

what headphones are you using and how old are you? ; I say that because it seems only those quite young can hear the super fine detail or maybe it partially comes back to fancy headphones etc.

also, when you ABX the music @ 128kbps and 160kbps etc is it something you can detect fairly quickly or does it take a good amount of effort to notice differences between say 128kbps to 160kbps? ; I am sort of wondering what you personally would consider the 'sweet spot' of bit rate? ; it almost seems 160kbps might be your sweet spot given what you said.
6
Site Related Discussion / Re: Why am I banned?
Last post by TheEmpathicEar -
HA = HydrogenAudio.
Is there a way to delete/remove just the HA history and not everything else in Google Chrome?

Copy and paste "chrome://settings/siteData" (without quotes) into the address bar in Chrome, then search for "hydrogenaud.io" and delete the cookies it finds.
I did that on both PCs [after closing tabs with HA open]. Opened browser on desktop to HA, still banned. Obviously, Ok here on laptop.
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