On 2015-02-06 12:41, David Henningsson wrote:
On 2015-02-04 18:45, Alexander E. Patrakov wrote:
29.01.2015 03:14, David Henningsson wrote:
Hi!
Hui and I have been working on some LFE filter patches lately, and this
is our first draft for review/feedback.
First, I have greedily stolen the math from CRAS, because CRAS is BSD
and
as I understand we don't have a problem with merging more liberal
licenses.
The LFE filter is implemented in the resampler, which means it is done
for
every sink-input rather than every sink - this might mean some
additional
CPU processing if many different streams play back at the same time, but
putting it on the sink side would disable the possibility to mix a 2.0
stream
with a 2.1 stream.
The rewind part is very drafty and untested, and I'm not sure I choose
the
best design here. But at least this is something that could act as
base for
discussion.
Sorry for a possibly-stupid question, but...
Which part of PulseAudio is supposed to disable the effect if the user
plugs headphones in? Or is it yet to be written?
Hrm, that is actually a good question. In theory, I would expect
module-switch-on-port-available to switch profiles between 2.0 and 2.1
as headphones are plugged in and out, but in practice,
- I'm not 100% sure if our "don't switch to HDMI" might prevent
switching from 2.1 to 2.0 when headphones are plugged in, and
- As the 2.0 profile is available on speakers, that will continue to
be selected when headphones are unplugged.
So, while this is not directly related to whether there is an LFE filter
or not - we already have a 2.1, 5.1, etc, profiles - indeed the problem
might become worse with the LFE filter.
Having given this a second thought, I'm thinking maybe an improvement of
the priority-list based routing would be the best option. (Which I'm not
working on as often as I perhaps should...).
I e, the port-based priority list routing should also remember what
profile a particular port was on.
E g, first time boot you will start up on stereo + speaker (because
stereo has higher prio than 2.1).
The user then switches manually to 2.1 which makes the routing module
remember "2.1 profile for speaker port".
Then the user plugs headphones in. That causes a switch to stereo,
because the headphones port is not supported on 2.1.
After unplug again, the routing module will switch port to speaker (the
highest priority port that is available) and profile to 2.1 (because it
remembered that).
--
David Henningsson, Canonical Ltd.
https://launchpad.net/~diwic
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