len0rd/rockbox
1
0
Fork 1
mirror of https://github.com/Rockbox/rockbox.git synced 2025-10-13 18:17:39 -04:00
Code Issues Projects Releases Packages Wiki Activity Actions

Implement universal in-PCM-driver software volume control.

Browse source 
Implements double-buffered volume, balance and prescaling control in
the main PCM driver when HAVE_SW_VOLUME_CONTROL is defined ensuring
that all PCM is volume controlled and level changes are low in latency.

Supports -73 to +6 dB using a 15-bit factor so that no large-integer
math is needed.

Low-level hardware drivers do not have to implement it themselves but
parameters can be changed (currently defined in pcm-internal.h) to work
best with a particular SoC or to provide different volume ranges.

Volume and prescale calls should be made in the codec driver. It should
appear as a normal hardware interface. PCM volume calls expect .1 dB
units.

Change-Id: Idf6316a64ef4fb8abcede10707e1e6c6d01d57db
Reviewed-on: http://gerrit.rockbox.org/423
Reviewed-by: Michael Sevakis <jethead71@rockbox.org>
Tested-by: Michael Sevakis <jethead71@rockbox.org>
This commit is contained in:
Michael Sevakis 2013-04-05 04:36:05 -04:00
parent a9049a79d7
commit f5a5b94686
13 changed files with 478 additions and 156 deletions
Download patch file Download diff file Expand all files Collapse all files

3
firmware/SOURCES
View file

@ -355,6 +355,9 @@ sound.c
pcm_sampr.c
pcm.c
pcm_mixer.c
#ifdef HAVE_SW_VOLUME_CONTROL
pcm_sw_volume.c
#endif /* HAVE_SW_VOLUME_CONTROL */
#ifdef HAVE_RECORDING
enc_base.c
#endif /* HAVE_RECORDING */