Subject: RE: [linux-audio-dev] Random thought on HDR latency compensation
From: Tom Pincince (stillone_AT_snowcrest.net)
Date: Mon Apr 24 2000 - 10:39:07 EEST
Based on Richard's definitions, I am contemplating both process and
systematic latency. I am trying to understand how Paul's statement,
that plugins don't contribute to latency, is true. For example, let's
imagine 2 soundfiles with the same start time, each playing back through
a separate channel. Channel 1 has no plugins and channel 2 contains 2
plugins connected in series. As I try to imagine the first sample in
soundfiles 1 and 2 reaching their respective d/a's simultaneously, some
simple questions come to mind. I realize that the nature of these
questions reveals my relative level of ignorance, but my interest in
this topic is so strong that I must dare myself to ask them. I feel
confident that after I gain just a little more knowledge I will be able
to make meaningful contributions to this cause, since I have actually
been contemplating these issues deeply for 15 years but have not felt
inclined to interact with developers working on proprietary platforms
and have only recently become aware of the Linux way.
1) Does plugin 1 process an entire frame before outputting to plugin 2,
with the output taking the form of a single, completely processed frame,
or are individual samples sent from plugin 1 to plugin 2 as they are
processed? For this process to produce no latency I imagine that the
former must be true.
2) Does the audio in channel 1 travel from the hd to the d/a in frames
equal in size to the frames being processed by plugin 1?
3) Is the total amount of time available for a frame to be processed by
both plugins equal to the time between hd reads?
4) If 3 is true, is a partially processed frame simply sent on its way
and a new frame loaded into plugin 1 at each hd read?
Tom
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