About the Sample Rate of Audio CD

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dengsirtc
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About the Sample Rate of Audio CD

Unread post by dengsirtc »

I like to play Audio CD with MEGA-CD core or PCE-CD core, but I find that optical output can only output 48Khz or 96KHz (MiSTer.ini)
Is this the Spec of MiSTer (Linux)? Is there any way to break through and output a true 44.1KHz?

I am not a developer, can anyone give a simple technical explanation?
dshadoff
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Re: About the Sample Rate of Audio CD

Unread post by dshadoff »

Each of these consoles has various sound sources, all with different timebases. For any digital output frequency, there is necessarily going to be one or more sources not outputting at its ‘natural’ sample rate. On original consoles, this mixing - and subsequent filtering - was done in the analog domain.
I can say specifically about the PCE core, all audio is upsampled to an integer multiple of all sources (if I recall, it was something like 7MHz), then digitally filtered, then mixed, and finally downsampled to the appropriate output, which is the best possible approach.
The team has meticulously performed refinements through MDFourier to be as closed as possible to an original console’s output, so this is better than those official ‘mini’ consoles released over the past few years.
dengsirtc
Posts: 7
Joined: Tue Mar 02, 2021 9:04 pm

Re: About the Sample Rate of Audio CD

Unread post by dengsirtc »

I understand. Thank you for your detailed explanation.
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