Lists

Open Menu Close Menu

Terms and Conditions
Lists hosted on this site
Email the Postmaster
Tips for posting to public mailing lists

Re: core midi time stamping

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: core midi time stamping

Subject: Re: core midi time stamping
From: Herbie Robinson <email@hidden>
Date: Sat, 16 Jul 2005 14:06:30 -0400

At 4:40 AM -0700 7/15/05, Brian Willoughby wrote:

A custom driver is required to get better MIDI latency performance than this over USB.

Careful with terminology there. Depending on who you are talking to (as in most Musicians who use computers), latency means the time it takes to echo back an input event for monitoring purposes. No fancy driver stuff can improve that over USB. Ideally for USB, it would be 1 msec average (1/2 msec for input and 1/2 msec for output). In practice, it seems to be more like 2-3 msec.

Time-stamping will improve the timing accuracy of both recording and playback, but not monitoring during recording. One the hardware I've tested, time-stamping didn't help very much (pulled of maybe 1 msec). I suspect that the device firmware also introduces a lot of delays, but don't have the means to really tell for sure.

I have no experience with the limitations of FireWire for MIDI time stamping.

The isochronous heartbeat it 1/8 msec. If MIDI is done isochronously, then it would insert 1/16msec average latency. If it's not isochronous (MIDI really shouldn't be, because we don't want MIDI packets dropped), then it could be faster, but 1/16th msec is probably faster than the OS can schedule; so, I suspect the hardware isn't going to be the limiting factor. -- -***************************************** ** http://www.curbside-recording.com/ ** ****************************************** _______________________________________________ Do not post admin requests to the list. They will be ignored. Coreaudio-api mailing list (email@hidden) Help/Unsubscribe/Update your Subscription: This email sent to email@hidden Follow-Ups: Re: core midi time stamping From: Brian Willoughby <email@hidden> Re: core midi time stamping From: Bob Lang <email@hidden> Re: core midi time stamping From: Yoshiharu Honjo <email@hidden> References: >core midi time stamping (From: david tay <email@hidden>) >Re: core midi time stamping (From: Brian Willoughby <email@hidden>) Prev by Date: Lowest latency I/O Next by Date: Re: core midi time stamping Previous by thread: Re: core midi time stamping Next by thread: Re: core midi time stamping Index(es): Date Thread