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Why does a Music Server require high processing CPU power?

I noticed that some music servers use, for example, a dual multicore CPU’s running under a custom assembled operating system.  In addition, the server is powered by a linear power supply with choke regulation and a large capacitor bank utilizing the highest audiophile grade capacitors.  Various other music servers have similar high CPU processing capabilities.  

I know that music is played in real-time so there is not much time to do any large amounts of processing.  I also know that the data stream needs to free of jitter and all other forms of extra noise and distortion.   I believe that inputs and outputs are happening at the same time (I think).

I also know that Music Servers needs to support File Formats of FLAC, ALAC, WAV, AIFF, MP3, AAC, OGG, WMA, WMA-L, DSF, DFF, Native Sampling Rates of 44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz, 192kHz, 352.8kHz, 384kHz, 705.6kHz, and 768kHz and DSD formats of DSD64, DSD128, DSD256 and DSD512 including Bit Depths of 16 and 24.  

Why does a music server require high processing power?   Does the list above of supported formats etc. require high processing power?  Assuming the Music Server is not a DAC, or a pre-amp, what is going on that requires this much processing power?   

What processing is going on in a music server?  How much processing power does a music server require?  

Am I missing something?   Thanks.   


hgeifman
erik_squires
16,138 posts
 
Roon may over-estimate it’s CPU requirements, mostly because they want to specify a CPU that is capable of doing all the upsampling you might ask it to do.

I’m running an 8 y.o. AMD A10 with no issues, but if I attempt high level DSD sampling I won’t be able to. It also sounds bad IMHO, so I lose nothing.

Also, Roon does all the EQ and upsampling in the server, so for every DAC end point you need to account for that.
But overall, I think it’s pretty light. I’ve also seen Logitech Media Server run on routers. That’s extremely lightweight.
djones51
4,947 posts
 
Let us assume an AIFF Coded album.   What exactly is involved in preparing the AIFF Album file (or any of the other formats) for inputting to the DAC and does this require large amounts of processing power (probably yes)

Think of audio compression like a zip file, it's already been compressed the codec uncompresses then software and other firmware in the device send it on to the DAC. Unless some sort of manipulation of the file is being done like upsampling or EQ it's not a very CPU intense operation. 
erik_squires
16,138 posts
 
Here, take a look at the GNU gzip code:
https://savannah.gnu.org/projects/gzip/
That may help you understand. Every instruction takes CPU time.  The faster the CPU, the less time that instruction takes.

Best,
E
djones51
4,947 posts
 
I believe Compression was an answer in the 1980's when CPU power and storage space was at a premium. I think the bottle neck now is bandwidth. I could just as easily store and stream uncompressed wav on a home network but compression is still advantageous over the internet. CPU'S have been fast enough to deal with audio compression for a long time now. 
djones51
4,947 posts
 
.
Or, are there other processes going on in the streamer that requires high processing power? If yes, what are they? Thank you very much
There’s nothing going on that requires what we would consider in today’s times as high processing power. I use a raspberry pi4 as a roon bridge from an NUC Roon server none of this uses high processing power. Nothing in a basic home server client relationship requires the kind of processing you’ve been talking about, Dual Xeons and megagigs of memory.
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