[linux-audio-user] Latency

From: David Baron <d_baron@email-addr-hidden>
Date: Sat Feb 25 2006 - 22:43:12 EET

There are several latency problems, especially on older hardware but still
around on that 64-bit dual core screamer:

1. Sync of MIDI (~0 latency) and audio (> 0 latency). On Windows, N-track
could not do it, Jazz did not work. Only Cakewalk--I mean, solid. I can
record vocals over MIDI, digitize the MIDI, record more vocals, etc., without
any ado. The clips start precisely where needed. Nothing else worked.

I have not gotten to trying this on Rosegarden yet (because my better sound
card has no alsa driver) and the MIDIs are produced on Windows programs so I
just work with Cakewalk going to audio. I could load the MIDI into Rosegarden
or Muse and try recording with what I have, I suppose. Have any list members
been successful with this?

2. Sync of VST or DX plugins with their input audio data. This is handled in
correctly programmed plugins by look-ahead. Sometimes, on must set up the
host for enough latency to "cover" the plugin's internal latency. Most of
this stuff simply plays without intervention but I have had plugins with the
wet result delayed if the host latency is set too low. In one case, the other
track needed to be delayed appropriately to use the pluging (very rare).

3. Sync of direct playing of a file and live play and synthesis. Try this one:
Fire up "horgand", a cute little software organ with accompaniment. Turn on
the accompaniment and try to play along. On older hardware, this is
impossible, on newer stuff, near-impossible. Key-press to sound is delayed
while the accompaniment plays on.

Even if I had a tap-tempo thingie (as proposed here), this timing problem
would remain.

So some kind of triggering is needed. After all, in live performance, the
accompaniment follows the lead, not visa-versa :-)
Received on Sun Feb 26 20:21:31 2006

This archive was generated by hypermail 2.1.8 : Sun Feb 26 2006 - 20:21:31 EET