Sample Rate and H/W Buffer negotiation woes.

[mesaone]

1. Can you change H/W Buffer Size from within PT without the need to quit PT?
   No.
2. Can you switch between sessions with varying odd sample rates from within PT without PT either locking up, refusing to play, or the need to quit PT? I am specifically talking about switching between 44K1<>96K, 44.1K<>48K and 48K<>88K sample rates.
   Yes. Commonly switching between 88.2 kHz and 48 kHz, depending on which projects I'm working on.
3. Which audio interface did you use for these questions?
   RME UCX (Pro Tools HD 11.2.1 on Windows 7 Professional SP1), RME Babyface (Pro Tools HD 11.2.1 on Windows 8.1).

[Sheldon Cooper]

Can Focusrite call RME and ask them how do they do it?

[hjorte]

Originally Posted by Sheldon Cooper

Can Focusrite call RME and ask them how do they do it?

It's not a clear cut, is it? We have answers from two RME users. Regarding question no. 2 (sample rate change), one say no, the other say yes.

Originally Posted by Joe.LoDuca

1. Can you change H/W Buffer Size from within PT without the need to quit PT?
   No.
2. Can you switch between sessions with varying odd sample rates from within PT without PT either locking up, refusing to play, or the need to quit PT? I am specifically talking about switching between 44K1<>96K, 44.1K<>48K and 48K<>88K sample rates.
   Absolutely not, PT will not tolerate that for a microsecond!!
   
3. Which audio interface did you use for these questions?
   RME to MULTIFACE which is 16 i/o.

Originally Posted by mesaone

1. Can you change H/W Buffer Size from within PT without the need to quit PT?
   No.
2. Can you switch between sessions with varying odd sample rates from within PT without PT either locking up, refusing to play, or the need to quit PT? I am specifically talking about switching between 44K1<>96K, 44.1K<>48K and 48K<>88K sample rates.
   Yes. Commonly switching between 88.2 kHz and 48 kHz, depending on which projects I'm working on.
3. Which audio interface did you use for these questions?
   RME UCX (Pro Tools HD 11.2.1 on Windows 7 Professional SP1), RME Babyface (Pro Tools HD 11.2.1 on Windows 8.1).

Thanks for the report mesaone, that's very interesting. Is there any chance that you are good at making screencast videos - showing your success in jumping between Pro Tools sessions with odd different sample rates, preferably using USB?

I know this is a huge request, but it would be invaluable as documentation for people with issues to bring to their respective manufacturers and developers. I fully understand if you can't be bothered.

[mesaone]

Originally Posted by hjorte

Thanks for the report mesaone, that's very interesting. Is there any chance that you are good at making screencast videos - showing your success in jumping between Pro Tools sessions with odd different sample rates, preferably using USB?

I can do that. Probably not until this weekend.

There's also an important factor that this poll doesn't take into account. Windows sound settings. When a device is set as default in the Sound control panel, it hampers sample rate switching.

[hjorte]

Originally Posted by mesaone

I can do that. Probably not until this weekend.

Looking forward to that!

There's also an important factor that this poll doesn't take into account. Windows sound settings. When a device is set as default in the Sound control panel, it hampers sample rate switching.

Unfortunately, that has no influence here whatsoever. My Audient iD22 audio interface can be set as default windows sound card, it can be deselected as default, or even be disabled alltogether - none of it makes any difference.

Change of sample rate can't happen without the below error, followed by PT hanging for a while and finally followed by a PT restart.



Interesting note:
When I try switching betwen sessions with different sample rates, like 44.1 > 48, Pro Tools actually manages to communicate a change of sample rate to the iD22 mixer application. And I also hear a destinct "click" in the monitors indicating that something has been switched / reconfigured. And when checking the iD22 mixer app, I can see the sample rate has been changed. But when I press Play in Pro Tools, the above error pops up and PT needs to quit.
-

[hjorte]

A video of me trying to switch between 44k1 and 48k sessions, in case anyone finds this misery amusing:

https://www.youtube.com/watch?v=Ylnz...ature=youtu.be

[YYR123]

Originally Posted by Sheldon Cooper

Can Focusrite call RME and ask them how do they do it?

Haha call focusrite and get them to hire the rme guys

[mesaone]

RME is good about this kind of stuff. They even add functionality to discontinued products. Earlier this year they released updated drivers and extended TotalMix FX support for interfaces they debuted as far back as 2001. They even released updated product manuals for these products, documenting the added functionality.

I don't know of any other company that does stuff like this for 13-year-old products, resurrecting them years after EOL.

Edit: Actually, I thought of another company that does. Metric Halo is the same way.

[mesaone]

Okay, I had time to film it tonight. Had to spend a bit of time working with the trial version of Expression Encoder, because FRAPS is apparently unable to film outside of DirectX applications in Windows 8.
I'm all ears if anyone knows of a better screen capture software.

Anyway, here's the video. I open a 44.1 kHz project, then open a 48 kHz project. My interface is also set as the default Windows playback device, and I demonstrate how it passes audio from both Pro Tools and the OS just fine, even after switching sample rates. The mouse is a bit jerky, I had to use this awful touchpad because my wireless mouse was charging.

I forgot to demonstrate the lack of buffer switching. Here's a pic. The buffer size is controlled by the driver control panel, and Pro Tools can't switch it because only the current size is selectible.

I hope this helps.

[hjorte]

Originally Posted by mesaone

I'm all ears if anyone knows of a better screen capture software.

I am not familiar with Expression Encoder so I can't promise that Open Broadcaster Software is better, but it's what I use. It's free and pretty powerful when you give it time and learn it. It can do streaming very well too. Recording virtual audio (Windows Stereo Mix) alongside video is tricky here, but maybe not so on your setup.

Originally Posted by mesaone

Anyway, here's the video.

Thanks a lot, I really appreciate it! Your RME works just like I would like my interface to work. Very interesting!

Originally Posted by mesaone

My interface is also set as the default Windows playback device, and I demonstrate how it passes audio from both Pro Tools and the OS just fine

That part works fine here too. I guess it's called a multiclient capable ASIO driver.

Originally Posted by mesaone

I forgot to demonstrate the lack of buffer switching. Here's a pic. The buffer size is controlled by the driver control panel, and Pro Tools can't switch it because only the current size is selectible.

Yes, it's the same here and the reason for it is described in kdarbyshirebryant's quote elsewhere in this thread. Both RME and TC detects if the DAW is Pro Tools and if so, they do not allow Pro Tools to change it (quote TC: -We only lock the buffer size for Pro Tools so that other better behaving ASIO hosts will retain the ability.)