Re: Motu 896Mk3Hybrid dump

[Takashi Sakamoto <o-takashi@sakamocchi.jp>]

Hi,

On Wed, Feb 08, 2023 at 05:00:31PM +0100, M. Armsby wrote:
> > I made a short video demonstrating this.
> >
> > https://www.transfernow.net/dl/20230206jG0fet84/OFRBRajr
> Thanks for your taking and uploading the video.
> The below figure illustrates your cases:
>
> ++======================++    +-------+    ++===============++
> ||       Traveler       ||    | frame |    ||  Application  ||
> ||                      ||    |       |    ||               ||
> || headphone output 1/2 || <- |  0/1  | <- ||  Output 1/2   ||
> || analog output 1/2    || <- |  2/3  | <- ||  Output 3/4   ||
> || analog output 3/4    || <- |  4/5  | <- ||  Output 5/6   ||
> || analog output 5/6    || <- |  6/7  | <- ||  Output 7/8   ||
> || analog output 7/8    || <- |  8/9  | <- ||  Output 9/10  ||
> || AES/EBU (XLR) 1/2    || <- | 10/11 | <- ||  Output 11/12 ||
> || S/PDIF (opt) 1/2     || <- | 12/13 | <- ||  Output 13/14 ||
> ++======================++    +-------+    ++===============++
>
> I note that the effective source of headphone output is selectable
> between the above 7 pairs. Additionally, when enabling ADAT optical
> output, 8 channels are newly added to the frame thus 22 channels are
> available in a view of application.
> Well, inconveniently to you, the above mapping is expected. ALSA
> firewire-motu driver passes no information to the application about
> what the channel of frame is assigned to, due to technical reason of
> ALSA interface to user space application. As a result, the
> application just enumerates audio sample in its order.
>
> ________
>
> I can understand your description but disagree that just because
> it's Linux, all Motu users must deal with false output allocation.
> The first pair should be 1+2 not headphones.
>
> Is it not possible to find a remedy instead.
>
> The Windows driver shows headphones much later in the output
> numbering.

Indeed, it is inconvenient in the view of user. But let us focus on how
to support MOTU 896 mk3 hybrid at present, since the issue includes many
technical topics; each application, drivers in kernel, libraries, and
interface between them.

> See Pictures taken from Reaper in Windows 10

Would I ask you to avoid attaching pictures to open mailing list? The
message with many files is easily judged as spam message.


Regards

Takashi Sakamoto