Wave or Flac

A couple of questions:

How do I transcode upstream?
Also, can my HDX be set to transcode from FLAC to WAV on the fly?

I originally ripped all my CD as WAVs on the HDX. I then transcoded the whole library to FLAC but now realise I prefer the sound of the WAVs.

I do have a back-up of the original Wavs but think transcoding on the fly or upstream might be a better option for me.

Martin.

Having read through the thread, it seems the comparison is between uncompressed Wav vs compressed FLAC. But what about uncompressed FLAC and Wav? There should be no difference there, while the superior tagging characteristics of FLAC can be utilised. Or am I missing something?

Agreed. In the case of compressed FLAC, there is a difference in processing vs Wav. But when both are uncompressed, there is no difference in how the music gets decoded.

Are you sure? Remember my description of information encoding. FLAC uses a different encoding method to WAV irresepectoive of compression, and so the algorithm and therefore the work to unpack the PCM samples will be different between FLAC and WAV.

Simon

Yes. Uncompressed FLAC (not compressed at level 0, that is not the same) works the same as WAV in so far that the music bit is effectively PCM. The difference between uncompressed FLAC and WAV is only the expanded metadata capabilities of FLAC. You'll find that an uncompressed FLAC is slightly larger than the WAV of the same file or the uncompressed AIF. The larger size is caused by the more elaborate support for metadata (artist, album, cover art, etc)

Here is an interesting test to read.

http://www.computeraudiophile....2-final-results-155/

What it boils down to: you can show there are differences between compressed and not compressed, but they are *very* subtle and should be inaudible in practise. For FLAC vs WAV, there is no difference when FLAC is uncompressed. Both are straight PCM.

Having a FLAC with compression level 0 is not the same as an uncompressed FLAC. Although the file sizes of the two are identical, the first file is not straight PCM, while the second file is. The first file will therefore go through an extra conversion step to get to PCM before it can go to the DAC, while the latter can go straight to DAC.

Can you work with an uncompressed FLAC and compare against a WAV? Would be interesting if that yields any finds.

PepsiCan, unfortunately you miss my point entirely. I suspect the algorithm to encode PCM from the FLAC encoding is pretty similar no matter what the encoding compression factor is. The WAV and AIF algorithms for extracting PCM from the WAV/AIF file is very straightforward.

I don't know for sure, but I am fairly certain that FLAC compression level 0 doesn't simply replace the FLAC data segment with a PCM data chunk. Perhaps you can point me to the specification that says that, because I have looked and got find it anywhere.

Simon

No, you missed my point. PCM is PCM. And as I said, compression zero is not the same as uncompressed. For uncompressed FLAC, we use PCM. There is no decompression, just like with WAV and AIFF.

See the release notes of dbpoweramp for the details. When uncompressed FLAC was introduced with R14 the note said it was for those who want WAV with the enhanced metadata, or something to that extend. There are some other sources that are more technical. The most elaborate of course being the FLAC specification website itself. Google for things like "uncompressed FLAC vs FLAC" or "uncompressed FLAC vs WAV". Uncompressed FLAC is a relatively new standard that has only been around for a few years.

Also, the people at computer audiophile did some elaborate test comparing the output sound waves as well as hearing tests. They presented some pretty compelling evidence that uncompressed FLAC and WAV sound identical, while compression does sound different from uncompressed. Albeit that the differences on the latter are probably beyond what many can hear.

I also refer you to my response to Graham. He says he uses compressed 0 as opposed to uncompressed FLAC (or at least that was my understanding). And that means your hypothesis as to why he hears a difference with WAV still stands. He needs to convert from FLAC 0 to uncompressed FLAC and then there is no difference with WAV anymore as both containers will store pure PCM.

The simplest way is to compare file sizes. But you could also check the metadata in the file or check with the seller. 

Note that as per Simon's explanation the sound difference occurs due to the need for the decompression steps. But FLAC is still losless. So after you download the file you can just convert to another format.

PepsiCan, your statement 'PCM is PCM' is meaningless in this context. The sample values for FLAC/WAV/ALAC/AIFF are PCM, it is how they are stored and conveyed in the respective file formats that we are talking about. FLAC conveys a wide set of (with varying degrees of encoding compression) PCM sample stream types according to its standard.

In reading the FLAC technical standard I can not see how you can substitute the RICE encoding for a string of stereo sample words.

There are some third party extensions that are registered, but they look to be metadata and application chunk related data. Is it one of these that is structured a sample word string? If so can you point me to the specification, I would like to learn more, and perhaps so would other amateur software developers.

Simon

 http://xiph.org/flac/format.html

Very interesting read. Im sure a lot of posts are to follow.

This is my fault, i actually convert all my flac files to "uncompressed" in dbpoweramp and not "level 0" as i have made it sound above. I am adamant i can hear a difference between this and wav through my NDX, although i have not tested this blind. Maybe this is something to try.

while i would say the difference is subtle, once you know what the effect sounds like it seems quite easy to pin point it. Can of worms spring to mind. Are our ears fooling us.

Graeme

Ok, I have looked through the the FLAC API libraries and there is no such thing as a 'no compression' mode. However you can over ride and disable the routines called and referenced by the 0 to 8 encoding compression library call.

Therefore all I can conclude, unless someone can give me a concrete coding reference,  that so called 'No compression' FLAC is an encoding with perhaps the LPC completely disabled and perhaps block specifically set or other disablements..... as this is a bespoke use of the FLAC APIs only the code developer who called the APIs in their app can say for sure.

however the transport and conveying of the PCM samples are in the standard  native FLAC container. Therefore the decode process is a regular native FLAC container decode.

Sure the algorithmic decode flow may well be slightly different (so might 'sound' different) from the standard FLAC compression 0 as a consequence of the encoding parameters set,  but this is still quite different from reading a string of PCM sample words as in AIFF and WAV.

Simon (all in my opinion of course)

Agreed. And the can of worms is overflowing Maybe it isn't the ears, but our brains?

Just for the record, I am not in any way saying you're (not) hearing things. I'm as intrigued as you are and I'm just trying to find an explanation. And I would be interested to see what would happen in a blind test.

But to summarise:

1. You compared uFLAC with WAV.
2. I content there should be no (audible) difference because both containers are PCM.
3. Simon says there is still a difference in how uFLAC and WAV are decoded.

Fare summary?

p.s.: one would think this is a hot topic at the Naim R&D department (and Linn and others....)? If only they would give us a bone here?

I would think that they have better things to do ...

1. Whilst slightly off the subject - I have all my music currently ripped as ALAC. Whats the best way to store (structure) another library in additional formats e.g I also want to store FLAC, so that the UnitiQute doesn't pick up multiple copies of the same albums/tracks
2. Also, am I better off
3. • Doing a conversion of all my ALAC to FLAC for the new library
   • Re ripping all to FLAC
   • Is db power amp the best tool to do this?

Thanks

All of the formats are losless. The hypothesis here is that any heard differences are due to the decompression and subsequent conversion to PCM to get it to the DAC. But in principle the same music quality is embedded in the various losless files. So you can therefore convert at your own leisure from ALAC to whatever format you want.

DBPoweramp is a very popular tool for this, mainly due to AccurateRip and Ultrasecure ripping. A freeware alternative is EAC. It has similar abilities but some say the interface is more clonky and not as straight forward. I guess it is a personal choice more than anything else.

I can't help you about the UnitiQute set up as I don't own that machine. No idea how that works.

I need to go back to the drawing board. Up to a few hours ago, I thought that Graeme was comparing FLAC compressed 0 to WAV. It turns out I misunderstood and he is comparing uFLAC to WAV. My hypothesis was that the decompression steps were the bits that were getting in the way and causing the difference.

Of course that goes out of the window now.

Perhaps. But at the same time companies like Naim, Linn and Focal have a vested interest in getting this debate sorted, both from the hardware perspective as well as the software perspective.

Poggy, you don't say how you're playing your files i.e. from a PC/Mac or via from a NAS drive also you haven't mentioned what media server software you are using or why you would want the same files in different formats.

If you just want to backup your files in flac and don't need to stream/play them on your UQ you could just keep them in a separate "unshared" folder so they wouldn't be seen on your network. Otherwise if you have JRiver or similar media server software you could set up separate libraries or separate DLNA servers for the different formats again keeping the files in different parent folders.

The UQ would then see the different servers at root level and you could then choose which server/file format you wish to listen to.

It is sorted and has been for quite some time. Only a minority of esoterics still THINKS that they can hear a difference. The debate is being held purely for the sake of itself.

I believe the uncompressed flac is using the Verbatim Prediction method, causing no compression.

besides that in the rice partition one could specify Escape code causing storage of unencoded binary (I don't know if that is actually being done though):

• <tt>0000-1110</tt> : Rice parameter.

• <tt>1111</tt> : Escape code, meaning the partition is in unencoded binary form using n bits per sample; n follows as a 5-bit number.

Source: 

https://xiph.org/flac/format.html

So I would say it could be possible to store uncompressed PCM

cheers

Only the bits-are-bits ignorants would say such a thing.