XXHighEnd

Ultimate Audio Playback => XXHighEnd Support => Topic started by: jhmvl on August 11, 2015, 07:03:58 pm



Title: delay before playback starts - WAV vs FLAC
Post by: jhmvl on August 11, 2015, 07:03:58 pm
Ok, so I bought the xxHE PC from Peter and I have to say that it is a vast improvement.

I am left with one smaller issue though and that is the following: some songs still take a longer time (up to 10 seconds) to start playback. My collection of music is split in wav files that are all (no exceptions) 44.1kHz files ripped from the cd's I have. These files contain no tags. The other part of the collection consists of FLAC files that are all highres, i.e. 44.1 kHz and up and 24bit. These files do (still) contain tags.

The longer time to playback never occurs in the wav files. These start playback almost instantaneously. The longer start time is usually with the flac's, where bigger flacs take longer it seems.

Is this behaviour that others see or have encountered as well? If so, what could you do (if anything) to reduce the start time? Could the longer start time have to do with the fact that the flacs still contain tags?

Look forward to hearing about this.

Hans


Title: Re: delay before playback starts - WAV vs FLAC
Post by: PeterSt on August 12, 2015, 10:29:57 am
Hi Hans,

I'm inclined to think that you have a small apples and oranges problem. :yes:

First off, I feel that you compare this in Attended Mode (user interface stays). But, not 100% sure. Anyway, when apples and oranges are left out of the equation and Unattended (interface disappears) is in order, a WAV album may start in 6-8 seconds and a FLAC in 2 or so.
How ?
Because the FLAC conversion is performed in parallel for each track (for 12 tracks at the time for your 12 core PC), while WAV "copying" happens per track subsequently.
This latter is the case when any "copying" as such is implied, which may not be your case (with your settings).

Already confused ?

Not necessary - and not even necessary to really understand. The point is : you compare en e.g. 50MB of WAV track with a 30MB of FLAC which needs to expand to 150-300MB. Look :

Your FLAC is say 30MB.
Uncompressed this would be 50MB again *if* it would be 16/44.1 like your WAV. But it isn't 16/44.1, and thus is the 30MB already wrong (it is larger). But never mind, because the math goes like this :
50MB for 16/44.1
This is 100MB for 16/88.2
This is 150MB for 24/88.2
which is 300MB for 24/176.4.

This 150 or 300MB needs to be "written". So apart from the time it takes to do the processing (of uncompressing) it is a sheer 150 or 300MB which needs to be written to disk (the FLAC becomes a WAV).
And your WAV ? 50MB to write only, *if* at all, depending on your settings. So maybe no need to write (= copy) anything (which would be the default for settings).

Summarized :
Your FLAC files are Hires while your WAV's are not.
(this one liner could have been the short answer)

In addition (but already implied) :
If you'd use the on-board RAMDisk and set the Playback Drive to B:\, all will be copied to B: (which would be the RAMDisk) before playback commences. Also WAV. And I assume the "normal" Unattended Playback.
If the FLAC now is 16/44.1, you will see that this copying of all the tracks of a FLAC album takes as long as its longest track (so say 2 seconds) while the copying of the WAV album takes the required time per track subsequently (think 10x 1 second for your comfort).

And so ...
So it is all the other way around as your thought / seem to notice. :swoon:

Peter



Title: Re: delay before playback starts - WAV vs FLAC
Post by: jhmvl on August 12, 2015, 09:40:55 pm
Hi Peter,

Thanks for the answer. I think I understand how it works now. Consequence of what you are saying is that it is better to keep your files in flac because of the parallel processing that you do not get with wav's (assuming unattended playback). Correct?

Second, I think my observation on flac vs wav is correct but would be due to the fact that the wav files I referred to are on average around 30-60MB but the flac files I was referring to are between 150 and 300MB so they would become really big once transformed and uncompressed explaining the time consumption (ie apples and oranges indeed).

Regards

Hans


Title: Re: delay before playback starts - WAV vs FLAC
Post by: PeterSt on August 13, 2015, 08:26:56 am
Hey Hans,

Whether FLAC is faster than WAV net, depends. Best is to simply say Yes.

But I have some HDD's which are so super fast that WAV can win it after all. Notice that now I am talking about READING. Think like reading a complete album within 2 seconds or so.
Sadly I don't even know why these HDD's are so fast. But I think it is the new low level (WD) formatting. Something with 4K blocks or whatever (for the 2TB+ HDDs) ...

In the end I really don't care. I have WAV and leave it like that and I also have FLAC and leave that be as well.

Quote
but the flac files I was referring to are between 150 and 300MB

I know. This is where I said that my math would be correct anyway. So I first normalized the numbers to 16/44.1.
In the end, if your FLAC is 300MB, that will turn out to be 700MB or so in WAV. Of course it also depends on the length (running time) of the track.
Anyway, you got the idea already ...

Regards,
Peter