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Old 11th November 2015, 16:26   #13601  |  Link
madshi
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Thanks!
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Old 11th November 2015, 16:29   #13602  |  Link
nevcairiel
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Quote:
Originally Posted by Zenitram View Post
And as I also said, I understand the reason it is made, but this is not a reason for changing reality of mathematics, and relying on only this check is not perfect. If you can rely on something else (e.g. metadata) please priotize this method over zeroes checking (zeroes checking should be only a fallback in the case there is not such metadata)
Well it really comes down to one simple argument:

Zeroes in the LSBs are useless ("empty" information), and therefor if metadata says 24-bit, but the signal consistently has 8 bits of zero at the end, can encode as 16-bit, save space, lose no signal information at all.
That seems really the information that madshi/eac3to is after.
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Old 11th November 2015, 16:34   #13603  |  Link
Zenitram
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Quote:
Originally Posted by nevcairiel View Post
Zeroes in the LSBs are useless
They are not. as 0 does not say the same thing as 0.0000 (and yes, quantization bits are similar to float).
I understand this is same for your ears, but it may be different for some compression algorithm and/or for people looking for the count of bits used for quantization (again, zeroes with 16-bit is not same as zeroes with 24-bit, zeroes with 24-bit quantization say that this is more sure that it is silence for real)

It is all about precision information, I understand that you don't care, but that does not mean it is useless for everybody. It is very important for a couple of people I work for.
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Last edited by Zenitram; 11th November 2015 at 16:37.
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Old 11th November 2015, 21:16   #13604  |  Link
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I'm glad to see MediaInfo will recognize HDCD; now I can script a test for it and mark such albums in my collection. Thanks.

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Old 12th November 2015, 03:19   #13605  |  Link
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Originally Posted by 73ChargerFan View Post
I'm glad to see MediaInfo will recognize HDCD; now I can script a test for it and mark such albums in my collection. Thanks.

It doesn't literally "detect" HDCD, it just reads a tag EAC3To has been adding to the FLAC files it produces.

If you have a HDCD FLAC/ALAC/WAVPACK file that DOESN'T have the tag MediaInfo will not detect it.

In that case, you could run your files through EAC3To or Foobar and get the tags added/add them yourself.

(MediaInfo has always displayed the HDCP tag, it just attached it to the file rather than the stream which means the tag was discarded if it was muxed into a Matroska file.)
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Old 12th November 2015, 10:38   #13606  |  Link
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You don't seem to be interested by the information I mentioned yesterday, your HDCD files are maybe not really HDCD, look at the link I gave in this post ;
http://forum.doom9.org/showthread.ph...26#post1746126
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Old 12th November 2015, 10:50   #13607  |  Link
Zenitram
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Quote:
Originally Posted by Music Fan View Post
You don't seem to be interested by the information I mentioned yesterday, your HDCD files are maybe not really HDCD, look at the link I gave in this post ;
http://forum.doom9.org/showthread.ph...26#post1746126
And there is a link to a post saying that this is not correct.
And now?
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Old 12th November 2015, 11:16   #13608  |  Link
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Interesting, this guy is not 100 % certain about it but he has good arguments.
If he is right, I wonder why MvB heard differences between the 2 ripping methods (with and without subchannels), admitting he was honest and not trying to discourage people to copy HDCDs.
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Old 12th November 2015, 11:23   #13609  |  Link
madshi
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FWIW, eac3to contains a user written HDCD decoder which seems to work just fine on WAV source files. I've no idea how the HDCD decoder works internally, though, nor can I guarantee whether it's 100% complete and accurate.
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Old 12th November 2015, 11:33   #13610  |  Link
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Ok, I never tried to decode HDCD files with eac3to, I guess the goal is to produce 24bit wav to keep HDCD quality without needing HDCD player ; in this case, one shouldn't specify the command -down16, right ?
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Old 12th November 2015, 11:39   #13611  |  Link
madshi
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If your target is lossless, eac3to by default doesn't decode HDCD, but leaves it untouched, so input and output bitdepth stays at 16bit. You can force HDCD decoding by using the "-decodeHdcd" switch. Or if you transcode to a lossy format, eac3to automatically decodes HDCD, so that the input to the lossy decoder has the highest possible quality. If you want to decode HDCD, and preserve its full quality, "-down16" is obviously not a good idea.
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Old 12th November 2015, 11:51   #13612  |  Link
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Quote:
Originally Posted by madshi View Post
If your target is lossless, eac3to by default doesn't decode HDCD, but leaves it untouched, so input and output bitdepth stays at 16bit.
In this case, why to use eac3to with HDCD wavs ?
If one needs Flac, I guess the HDCD information will be lost (except if -decodeHdcd is used and -down16 is not, therefore you get 24 bit Flac with HDCD quality).

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Originally Posted by madshi View Post
If you want to decode HDCD, and preserve its full quality, "-down16" is obviously not a good idea.
Ok, does its full quality correspond to 20 or 24 bit ?
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Old 12th November 2015, 12:02   #13613  |  Link
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Why would HDCD get lost when using FLAC? It doesn't. FLAC is lossless.
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Old 12th November 2015, 12:09   #13614  |  Link
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Do you mean that if -decodeHdcd is NOT used, and if the target format is Flac 16 bit, the Flac will still include the HDCD information that can be decoded as HDCD Flac ?
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Old 12th November 2015, 12:16   #13615  |  Link
madshi
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That's what I just said.
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Old 12th November 2015, 12:25   #13616  |  Link
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I'm surprised because I wonder how the HDCD information -which is done for LPCM- can be kept in Flac.
IIRC, HDCD encoding use random bits and I don't see how a FLac encoder can recognize this kind of pattern and keep it. It is lossless, ok, but its structure is different than LPCM.
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Old 12th November 2015, 12:38   #13617  |  Link
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What part of "lossless" do you not understand? FLAC is like a zipped WAV/LPCM file.
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Old 12th November 2015, 12:39   #13618  |  Link
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http://www.audiomisc.co.uk/HFN/HDCD/Enigma.html
https://en.wikipedia.org/wiki/Compac..._Digital_Audio

It's possible he's right. CD's aren't strictly LPCM, they have a variable gain control.

Quote:
Some CDs are mastered with pre-emphasis, an artificial boost of high audio frequencies. The pre-emphasis improves the apparent signal-to-noise ratio by making better use of the channel's dynamic range. On playback, the player applies a de-emphasis filter to restore the frequency response curve to an overall flat one. Pre-emphasis time constants are 50Ás and 15Ás (9.49 dB boost at 20kHz), and a binary flag in the disc subcode instructs the player to apply de-emphasis filtering if appropriate. Playback of such discs in a computer or 'ripping' to wave files typically does not take into account the pre-emphasis, so such files play back with a distorted frequency response.[
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Old 12th November 2015, 14:48   #13619  |  Link
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Interesting. But I believe HDCD and CD with De-emphasis are 2 different things and thus need different ripping method.
Anyway, I kept searching informations and it seems that when ripping HDCDs in a simple way (copying waves instead of making ISO keeping cd's sub channels), a part of the needed information to decode properly HDCD is not retained.
I found a post that summarizes clearly everything I read on this subject ;
http://forums.stevehoffman.tv/thread.../#post-5695519
Quote:
Originally Posted by GreenDrazi
Foobar2000 and dBpoweramp HDCD detection & decoding are based on HDCD.exe, which was created by emulating Windows Media Player. What WMP does not do (and consequently, neither does HDCD.exe) is decode the transient filter function. Although, it can detect it.
And the transient filter information is apparently in the sub channels I evoked earlier.

It means that the HDCD conversion is done but not exactly how it should be.

Last edited by Music Fan; 12th November 2015 at 14:52.
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Old 12th November 2015, 15:01   #13620  |  Link
madshi
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Regardless of whether that's true or not, none of this has anything to do with eac3to, because eac3to does not rip CDs or ISOs. eac3to does the best it can with the data it gets. If something is lost when ripping a CD to WAV then this loss has happened before eac3to was involved. There is no (further?) loss when using eac3to, as long as the audio data is kept lossless. So this is my last post about this topic.
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