Phantom Resampling

[alexeismith]

EDIT: Please ignore this post, the problem was caused by a library dependency for my plugin, and not Reaper doing anything weird.

Hi, first post here so sorry if I miss anything...

I'm developing a VST plugin which wraps an audio processing library, and I'm trying to validate its output against some reference output files for the library. This involves comparing the individual samples of each output. My problem is that Reaper appears to be resampling the audio, which is jeopardising my comparison efforts. I would expect no resampling: the input audio file, project settings and render settings are all at 48kHz & 16bit (WAV). But when I change the 'Resample mode (if needed)' before rendering, the output is quite different, suggesting that some resampling is happening.

Can anyone suggest why this might happen? Is there another sample rate setting somewhere I've missed? Might Reaper be resampling going in and out of my plugin? (which it shouldn't because the plugin is supposed to use 48k)

FYI the input audio, plugin and mixing is all 8-channel, if that makes a difference...

Thanks

Alexei

[nofish]

Hi and welcome to the forums,

you can set a project sample rate which can be independent from the soundcard's sample rate in File -> Project settings -> Project settings tab -> Project sample rate.
Maybe you have this enabled by chance?

[cyrano]

Windows, Mac, Linux?

[alexeismith]

Originally Posted by nofish

Hi and welcome to the forums,

you can set a project sample rate which can be independent from the soundcard's sample rate in File -> Project settings -> Project settings tab -> Project sample rate.
Maybe you have this enabled by chance?

Thanks for the suggestion, but that is indeed enabled and set to 48k! The same as the soundcard

[alexeismith]

Originally Posted by cyrano

Windows, Mac, Linux?

Windows 64bit

[Justin]

What audio device mode are you using? If you look in the upper-right of the menu bar, does it show 48k too?

Post a simple .RPP project that is not behaving as you expect and we can take a look.

[alexeismith]

Originally Posted by Justin

What audio device mode are you using? If you look in the upper-right of the menu bar, does it show 48k too?

Post a simple .RPP project that is not behaving as you expect and we can take a look.

Yes that shows 48k as well. Unfortunately the plugin is commercially confidential so I can't post a project file - I could remove the plugin but there would be nothing left apart from one track with a wav on it.

I modified the plugin to write a wav itself to compare against the Reaper output. There are artefacts from the plugin's limiter present in my output (desired for testing purposes) but not in the Reaper output. Does Reaper auto-detect true peaks / oversample / have some kind of clipping protection that you know of?

[Justin]

Originally Posted by alexeismith

Yes that shows 48k as well. Unfortunately the plugin is commercially confidential so I can't post a project file - I could remove the plugin but there would be nothing left apart from one track with a wav on it.

I modified the plugin to write a wav itself to compare against the Reaper output. There are artefacts from the plugin's limiter present in my output (desired for testing purposes) but not in the Reaper output. Does Reaper auto-detect true peaks / oversample / have some kind of clipping protection that you know of?

You don't need to include the plug-in itself, just post the .RPP file and the .WAV file. REAPER does not do anything fancy, other than some very very quiet denormal noise, unless your render settings are configured for things special (which is why I suggested you post the .RPP).