From Jason Proctor Sent Sat, Dec 22nd 2018, 00:52
From Jason Proctor Sent Sat, Dec 22nd 2018, 00:52
as Florian and I mentioned earlier in the thread, the current AMT-8 driver works fine with later operating systems. (Sierra, here, at least.) and yes anyone can take advantage of send-ahead timestamping, but whether they do is another matter :-) On Fri, Dec 21, 2018 at 4:49 PM Brian Willoughby <xxxxxx@xxxxxxxxxxxx.xxx> wrote: > > AMT-8 support would require a CoreMIDI driver from Emagic or Apple. Wheth= er CoreMIDI has changed since such a driver was written, and whether it wou= ld still work on a modern OS is the real question. I=E2=80=99m not aware of= any significant changes to CoreMIDI that orphaned any prior drivers, but I= =E2=80=99m also not aware of whether the AMT-8 ever had a CoreMIDI driver. > > At any rate, if there is a CoreMIDI driver then all CoreAudio MIDI softwa= re would be able to take advantage of Advanced MIDI Transmitter features. T= hat=E2=80=99s the beauty of CoreMIDI: They managed to implement send-ahead = timestamping in a way that=E2=80=99s not specific to any particular hardwar= e implementation. Of course, not all apps take advantage of this, but those= that do shouldn=E2=80=99t be tied to any particular hardware. > > If anybody has more information, then please share. I remember strongly c= onsidering the AMT-8 for its features, but settled on the MOTU MTP-AV =E2= =80=9CMIDI timepiece=E2=80=9D with SMPTE. Not that I=E2=80=99ve actually us= ed the thing in decades... > > Brian > > > On Dec 7, 2018, at 9:43 AM, Jason Proctor wrote: > > fwiw, the Emagic AMT-8 and Unitor interfaces implemented send-ahead > > timestamping way back when (hence the name Advanced MIDI Transmitter). > > > > not sure whether any drivers or apps still support it (maybe Logic as > > previously described) > > > > On Fri, Dec 7, 2018 at 9:18 AM Royce Lee wrote: > >> > >> I feel like midi timing on mac went through a U shaped curve, where it= s was okay for a while (for me opcode on a beige power pc),then around the = time of the big blue and white, plastic enclosures (G3,G4) it was horrible,= and now, it is really quite good. > >> > >> During that middle period I always wondered how anybody in the world m= ade records. > >> > >> On Fri, Dec 7, 2018 at 9:41 AM bloke wrote: > >>> > >>> I=E2=80=99m thirding the Mac/MOTU MIDI - just recently I did test sen= ding tight 16ths from logic to MIDI synth (in this case Doepfer MIDI > CV) = recording in the result. > >>> > >>> MIDI timing on the mac has been a bug bear of mine since forever (wel= l actually post RS-232 serial bus days!) and I was impressed - the final ke= y was entering low latency mode in Logic. > >>> > >>> No noticable jitter (I had to offset it a little). This was with a r= eally old MOTU FW 828 MKII on a new MBP and a nightmare USB3 -> lightning -= > FW stack of dongles (=C2=A360!) but worked. Even MIDI clock wasn=E2=80= =99t too bad - there is a calculate plug-in latency mode in Logic which see= ms close to usable. > >>> > >>> If the USB is as good then I wouldn=E2=80=99t have a problem with MOT= U stuff. > >>> > >>> Alex > >>> > >>> From: Bruno Afonso > >>> Date: 7 December 2018 at 13:56:56 > >>> To: Brian Willoughby > >>> Cc: Analog Heaven, Jason Proctor > >>> > >>> Brian is right, what is nice about the motu stuff is their timestampi= ng. Drivers can be finicky at times. I'm curious to know about the timing o= f the newer mio offerings... with a uC or smart oscilloscope one could prop= erly test these. I don't have a mio... > >>> > >>> On Tue, Dec 4, 2018, 22:56 Brian Willoughby, wrote: > >>>> > >>>> Apple has USB-MIDI Class compliant drivers fully sorted. Apple imple= ment every aspect of the specification, where Microsoft Windows versions fa= ll short. I know this because I have designed USB-MIDI hardware and found o= ut the hard way where the OS support for the USB-MIDI specification stops. > >>>> > >>>> For my clients, I deliver firmware that supports Windows, because it= =E2=80=99s a market necessity. Unfortunately, that requires dumbing down th= e feature set to the short list supported by Microsoft. For my personal con= trol surfaces and MIDI interfaces, I use firmware that takes full advantage= of USB-MIDI capabilities, even though these devices only work with Mac OS = X. > >>>> > >>>> > >>>> That said, even the USB-MIDI specification is severely lacking. It p= rovides no timing information, so precise timing of MIDI events is very slo= ppy. This is a shortcoming of the specification itself. > >>>> > >>>> What you=E2=80=99re witnessing is that manufacturers like Roland and= MOTU are trying to improve on USB-MIDI by providing a non-class-compliant = implementation that adds the missing precision. The problem here is that th= ere is no standard for decent MIDI time stamping, so there=E2=80=99s no way= for an OS to ship a class compliant driver. The result is that users must = download drivers from the manufacturer and install them before things will = work well. That=E2=80=99s a difficult task when operating systems are const= antly changing, so I=E2=80=99m not really surprised that hardware vendors s= ometimes fall behind. > >>>> > >>>> > >>>> Note that there is a standard for better-than-USB-MIDI performance o= n macOS. It falls under the umbrella of Apple=E2=80=99s CoreMIDI. Thanks to= CoreMIDI, applications like Logic can access the precise timing of MOTU MT= S (MIDI Time Stamping), and presumably whatever it is that Roland has to ge= t beyond the limitations of USB-MIDI. Applications do not need to be aware = of hardware specifics, or variations in the USB protocol additions. As long= as they support CoreMIDI, and as long as the hardware manufacturers provid= e CoreMIDI drivers in addition to their USB drivers, everything works. > >>>> > >>>> What this means is the Logic can read ahead in your MIDI sequence fi= le, deliver the data to the MIDI interface ahead of time in a way that circ= umvents any bandwidth bottlenecks, and then the shared time reference allow= s the MIDI interface to transmit the MIDI data at the precise time it was a= uthored for. In the other direction, incoming MIDI is marked with a time st= amp that is then delivered to the application via CoreMIDI in a way that pr= eserves sub-millisecond accuracy. The caveat is that you cannot improve rea= l-time passthrough of MIDI data because there=E2=80=99s no looking ahead, a= nd thus any bottlenecks in bandwidth necessarily introduce latency. In this= latter case, you=E2=80=99re better off doing MIDI overdubs, with separate = record and playback passes, rather than attempting to do real-time MIDI man= ipulation. > >>>> > >>>> For the technical reasons described above, I recommend MOTU (Mark of= the Unicorn) MIDI interfaces that feature MTS (MIDI Time Stamping). You ne= ed to make sure that you install the custom drivers, but it=E2=80=99s the o= nly system that doesn=E2=80=99t have serious flaws. (I=E2=80=99ve yet to ev= aluate Roland=E2=80=99s improvements, so perhaps they=E2=80=99re on par) > >>>> > >>>> Brian Willoughby > >>>> > >>>> > >>>> On Dec 4, 2018, at 11:02 AM, Jason Proctor wrote: > >>>>> still a little disappointed that operating systems didn't get MIDI = sorted ages ago and we still have driver compatibility nonsense happening t= his far down the line (and i say this as a developer). > >