HydrogenAudio

Hydrogenaudio Forum => General Audio => Topic started by: alienlogic on 2013-03-25 20:23:24

Title: Opinions on CoreAudio downsampling
Post by: alienlogic on 2013-03-25 20:23:24
Greetings,

I've spent a couple of hours searching the forums and haven't seen this discussed, so opening a new topic to ask the question...

Does Apple's CoreAudio produce quality downsampling results? Since it's already built-in to OS X, I'd just as soon use that than grab other tools. I'm aware of the testing page here (http://src.infinitewave.ca), but I fully admit to being a novice when it comes to reading these graphs. I think it shows well (Leopard more than Lion), but I don't have the training or experience to determine authoritatively. I'm also hoping that the quality hasn't dropped between the Leopard and Mountain Lion releases...

So does anyone have any experience with this? And related- does the XLD tool leverage CoreAudio properly and use good settings for SRC?

(I would be downsampling from 48khz and 96khz to 44.1)

Thanks all
Title: Opinions on CoreAudio downsampling
Post by: saratoga on 2013-03-25 21:49:02
Looking at your link, its as good as anything else on that page.
Title: Opinions on CoreAudio downsampling
Post by: DVDdoug on 2013-03-25 22:22:42
I've never heard any aliasing or artifacts from resampling.  As far as I know, the "worst" downsampler is better than human hearing.  ...Well, I'm sure there are some poorly written re-sampling algorithms around, but I'm confident that Apple knows what they are doing and it's not something that I'd loose sleep over.

On the other hand, it you hear a defect (noise, distortion, compression artifacts, or frequency response deviations), it's probably worth tracking down the source of the defect.
Title: Opinions on CoreAudio downsampling
Post by: Arnold B. Krueger on 2013-03-26 11:11:54
Looking at your link, its as good as anything else on that page.


I agree. I see no artifacts that could be even remotely thought to be audible.

The basic technology of resampling has been settled for more than a decade. I suspect that people can open textbooks and/or download files and obtain good source code in a variety of languages for this sort of thing.
Title: Opinions on CoreAudio downsampling
Post by: alienlogic on 2013-03-26 18:01:31
Thanks all. I'd seen reference in other discussions to the quality of some free ones, and how not-good even some professional SRCs could be, so wanted to be sure. Appreciate the feedback.