Current File : //usr/share/doc/libasound2-plugins/upmix.txt
UPMIX PLUGIN
============
The upmix plugin is an easy-to-use plugin for upmixing to 4 or
6-channel stream. The number of channels to be expanded is determined
by the slave PCM or explicitly via channel option. For example, the
following PCM defines upmixing to 5.1 from 1-6 channels input:
pcm.upmix51 {
type upmix
slave.pcm "surround51"
}
You can use this PCM as a default one by defining below:
pcm.!default "plug:upmix51"
The upmix plugin copies left and right channels to rear left and right
with a certain delay. The delay size can be specified by "delay" PCM
option in msec. For example, to set 10ms delay in the above case:
pcm.upmix51 {
type upmix
slave.pcm "surround51"
delay 10
}
As default, 15ms delay is used.
The channel option specifies the number of channels of output. Either
4 or 6 channels are supported. When 0 is passed, the plugin tries 4
or 6 channels appropriately suitable for the slave pcm. The channel
option is useful if the slave PCM has no strict input condition (like
plug or route plugin).
pcm.myupmix {
type upmix
slave.pcm "something"
channels 6
}
The center and LFE channels are the average of sum of left and right
signals.
The accepted format is currently only S16.
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