[earplay]

Aleg (or anyone that knows),

You seem to know more about computer audio than I, so I'll ask a question that has been with me a long time. Why convert cd .aiff format to other formats?

I understand that one would want to save space, but since there is so much emphasis on reducing processing for optimal sound quality, I think that audiophiles would want to go for the best possible sound. Since .aiff files are what is found on cd's, why convert them?   

Best wishes, earplay

[srb]

Why convert cd .aiff format to other formats?  Since .aiff files are what is found on cd's, why convert them?

The actual files on a redbook CD are CD-DA (Compact Disc-Digital Audio) files.  When they are viewed on a Windows computer, they are listed as .CDA files.  When that CD is viewed on a Mac OSX computer, they are listed as .AIFF files.
 
The Mac listing of .AIFF files on a CD is an operating system convenience feature.  Windows has no such feature, and the files have to be "ripped" with software to get either .WAV or .AIFF.
 
When you copy or drag files from a CD on the Mac to a hard drive, there is a small on-the-fly conversion performed.  Because both .AIFF and .WAV files are lossless uncompressed PCM files, the difference lies in the file header containing metadata "tags", or in the case of .WAV, there are no metadata tags.
 
If you don't use software to rip the CD to .AIFF files, but merely copy or drag them on the Mac, they don't contain metadata tags, and will haved to be tagged in a separate operation with either stand-alone file tagging software or file tagging software function that may be integrated into a music file player.
 
Steve

[Aleg]

Aleg (or anyone that knows),

You seem to know more about computer audio than I, so I'll ask a question that has been with me a long time. Why convert cd .aiff format to other formats?

I understand that one would want to save space, but since there is so much emphasis on reducing processing for optimal sound quality, I think that audiophiles would want to go for the best possible sound. Since .aiff files are what is found on cd's, why convert them?   

Best wishes, earplay

Hi Earplay

What is found on CD is in fact a PCM signal (a stream of bits representing an anlogue signal in a digital way). The way bits are stored on CD (which is just a stream of bits with not much structure at all) cannot be handled in the same way by a(ny) computer. On a computer these bits have to be stored in files to allow them be handled by the computer. THe files come in different varieties or file formats.

These files in their different formats are actually what we call containers. It is a file with a header and a data section. The header has information about what kind of data and how the data is actually stored in the data section.

Uncompressed file formats like wav and aiff store these PCM-bits from the CD in the data section and the header section describes what is stored (e.g. sample rate, bit depth, meta information about album, artist and loads of other possible stuff).
The way these header files are structured are different in .wav and in .aiff, but both can contain the same information (yes wav can also contain tags of meta data although it is not used very widely). The actual data in the data section is the same for both formats because they just store the plain PCM as read from the CD.

FLAC is also a type of container which is widely used because it is open standard and offers a lot of options for metadata and many programs support it.
The flac standard also offers a compression algorithm to use less storage space for storing the PCM data. The compression algorithm is completely reversable, i.e. it is lossless and enables you to recreate the original data without losing any bits at all. When compressing with flac you can give a compression level of 0 - 12 to indicate how much compression you would like to achieve. Level 0 is the lowest but is still compressed. The higher compression levels also require more processing for de-/compressing.
However flac also offers the possibility to store data as uncompressed PCM, just like in wav and aiff. This is called by dBPoweramp converter "lossless uncompressed flac" and in flac technical speak it is called "verbatim" or "no-prediction", and again this is different from level 0 compression which is still compression.

Apple being and wanting to be different that Microsoft, has decided to use a different file format than Windows PC's for storing audio files. Apple has gone for .aiff and Windows has chosen .wav. In essence they contain the same data, but headers are (incompatibly) different.

So why convert files?
1. because the original file format is not supported by your computer or your program;
2. because you want to use less space for storing your audio files. You might choose a compressing format like flac level 0 -12 or .ape or one of several other possibilities;
3. because you want a container format that is widely supported and can handle tags for storing metadata, so you would choose flac or ape on PC or some other on Apple;
4. because you want to avoid any possible compromise to sound quality and choose an uncompressed file format like .wav, .aiff, flac uncompressed, or some other less obvious ones.

How do you convert file formats?
Best option on PC's is IMHO  dBPoweramp,  on Apple I believe consensus is on XLD.
Being a PC user myself and not a great Apple fan, above is mostly spoken from a PC point of view.

A bit clearer?

-
aleg

[earplay]

srb and Aleg,

Thank you for your informative answers. Now I have a much better understanding of what is happening with these files.

Because I use iTunes for importing files from disc, whether on my Mac's or Windows machines, I thought .aif was the standard file format for cd's. Now I understand that .aiff is not a type of encoding and that the music files can be stored in a variety of file types and be converted without affecting the fundamental music data.

Aleg, on the basis of your information, I'll have to consider my various computer audio playback options and decide whether or not to convert my main music library. Pros and cons... pros and cons.

I spend time on this forum because of the wonderful help I get. It's the people in these forums and their willingness to share their effort an knowledge that allows the hobby (obsession?) to be enjoyable.   

Best wishes, earplay

[kyrill]

no further reactions?

I am curious, did you try it out?
If yes would you share your experiences here?
It does not matter how good yr USB dac is, when it gets a cleaner signal it will sound better

[earplay]

Well, I haven't converted files to try Pure Player. The reason is that if I decide to go that route, I'll have to convert my entire music library. I don't know if I want to go thru that.

As for my opinion of JPlay, I said this a few posts ago:
After I posted my comments here yesterday, I decided that the trial version of JPlay is now my main music player, even though it lacks the convenience of a gui interface and even though it stops playback regularly. JPlay is so natural sounding that I won't go back to iTunes, despite iTunes convenience. (And you can quote me on that.)

I plan to convert some of my favorite .aiff files to .wav format and try Pure Player in my main system. Then I'll have an opinion about how Pure Player works in my system, my room, etc.

[kyrill]

Hi Earplay

I have seen yr posts
I did mean more the others, as far as I can see, all PC USB listeners would benefit especially if they could use KS. And less than 2-3 reactions based on actual listening would suggest no interest?

[kyrill]

There is now an even better Jplay version 3.3. If you cant afford it sell an IC or powerchord as Jplay will sound much better than what you just sold 

[kyrill]

I skip my preamp analogue part with its analogue volume control as a direct link between my dac and poweramp sounds more pristine and transparent and saves in many cases an xtra IC.

That leaves only a digital volume control of the player on my PC or digital DEQX. But digital volume control sounds beneath -20, -30 db less dynamic and with less transparency than full analogue controls. The development of Jplay added now a digital master volume control and the ability to make the original music file  16 bit or 24 bit file into  32 bit.
The dac will bring 32 down to 24 bit, but the digital volume being in the 32 bit domain has NO disadvantages  for original 16 or 24 bit files to an analogue volume control

With this addition in Jplay PC owners do not need a preamp between dac and poweramp for the volume.
In short it sound much better

[Vincent Kars]

The development of Jplay added now a digital master volume control and the ability to make the original music file  16 bit or 24 bit file into  32 bit.
The dac will bring 32 down to 24 bit, but the digital volume being in the 32 bit domain has NO disadvantages to an analogue volume control for orginal 16 or 24 bit files.

I’m afraid this is not really very spectacular.
The Win 7 mixer converts everything to 32 float to do the processing.
JRiver does all its processing in 64 bits.
If you do many calculations a higher precision is beneficial.
If you do a simple calculation e.g. a onetime multiply by .5 to reduce volume by half; one might wonder if 32 or 64 really makes a difference.
However no matter what precision is used, in de end you do have to convert to 16/24 integer and are inevitably confronted with a quantization error.

A bit more on digital volume control: http://www.resonessencelabs.com/invicta/invicta_analog_vs_digital_volume.pdf

[kyrill]

hi Vincent

this is what I know from the author of Jplay

"yes, of course: IF you want to manipulate source bitstream the higher precision is beneficial - but we DON"T

We want to keep source bitstream as 'virgin' as possible...
even if you use 64bit precision to e.g. change volume you'd end up with bitstream looking quite different from source signal - If, however, you simply 'shift' the bits around you leave the original bitstream intact...
the price to pay is that you can change volume only in 6dB steps which may not be convenient for everyone - but jplay was never about convenience anyway...

does it matter in the end?
i think so but i can't prove it - in fact, nobody can prove it as it depends on listening...
i guess it's just the belief that things should be kept 'as simple as possible'....
"

[Vincent Kars]

By shifting one chops of the LSB hence the 6 dB reduction.
We might call it a special case as reducing the gain by a power of 2 would yield the same result.
When playing 16 bit sources on a 24 bit DAC you can chop off 8 bits=6*8=-48 dB reduction without resolution loss.
If one applies the same trick on a 16 bit DAC without applying dither the results are probably disastrous..

[kyrill]

yes you are right

I found Jplay will refuse to implement this volume control to dacs or in between USB converters who cannot handle 24 bit (or -I am not a full 100% sure about this- downsample it to 16 bit by just removing these last "0000..")

BTW the build in volume level variant of Jplay is still in beta level, but I asked for one as I need it to weaken the signals to my digital preamp, who has only a digital volume control. So I force this digital volume, to "act'  between 0db (full volume) and -20db. I understood at those "high" levels, the difference between digital and analogue volume controls does not exist yet or can safely be ignored as undetectable.

[Vincent Kars]

Much to my surprise, a digital volume control degrades very rapidly.
20 is at the verge
http://www.resonessencelabs.com/invicta/invicta_analog_vs_digital_volume.pdf

An alternative would be to leave everything at 100% and use a passive attenuator in the analogue chain e.g. between pre- and power amp

[kyrill]

By now there is for those who still hesitate to buy a new version 4.1 which sounds twice as good as my original enthusiasm 7 months ago.

I cannot tell you enough that there  is NO alternative to Jplay's purity of sound for your high end set up regardless of price. It is matter of short time and all high end reviewers of 6moons, TAS, Enjoy the music, Postive FB and many others, will all use it too as default when not using Linux
With some other tweaks, galvanic isolated hdd outside the PC and clean power it will equal or supersede a 5000$ MC in a high end turntable.
It will not add much for your NAD receiver though and JPlay hates MP3, just like all high end music lovers. Still I listen to Mp3 in the kitchen when preparing meals

[doctorcilantro]

I'm curious to try JPlay against JRMC's WASAPI [Event] mode.

Did yo try Pureplayer with wasapi mode?
http://www.purediy.gr/downloads/pureplayer.zip

[JEaton]

I cannot tell you enough that there  is NO alternative to Jplay's <etc.> <etc.> <etc.>

You bring up an important point: ARE there any alternatives?

Or is this the only tweaky addon like this for Windows based audio? I know there are several for Mac based audio, but I'm unaware of anyone else doing this on Windows.

[wushuliu]

I'm curious to try JPlay against JRMC's WASAPI [Event] mode.

No comparison. Seriously. There is a reason Jplay is now usable as a plug-in to JRMC.

You bring up an important point: ARE there any alternatives?

Or is this the only tweaky addon like this for Windows based audio? I know there are several for Mac based audio, but I'm unaware of anyone else doing this on Windows.

Out of the box? I am going to say No. Can you come close or equal otherwise? Well the CMP/Cplay crowd are pretty confident theirs is better - after you modify the living hell out of your OS and hardware. Linux crowd also seem pretty confident - provided you want to put up with, well, Linux. I have also had good luck with Stealthplayer via ASIO as well as JRMC via ASIO w/ upsampling. Very good results. But not quite as good as Jplay. The price is tough to swallow I know. That's the real sticking point. You can get 90% of Jplay performance for free but it will take a lot of work and experimentation.

[JEaton]

No comparison. Seriously. There is a reason Jplay is now usable as a plug-in to JRMC.

Out of the box? I am going to say No.

I'm not talking about how effective jplay may or may not be. Simply: Is there even a competing product for Windows audio? cplay is a player (and a hardware 'recipe' and even a philosophy to some), not an enhancement for other Windows audio players.

When someone states that there "is no alternative" I'm not sure it means a whole lot when indeed there actually is no alternative.

[wushuliu]

?

It's music playback software, just like the others previously mentioned.