rockbox/firmware/export/pcm-internal.h, branch working

Greatly reduce volume-change zipper artifacts with SW volume.

2014-03-08T07:04:41+00:00

Uses a cosine factor to smoothly shift the PCM level from the old level
to the new one over the length of a frame.

Implements indirect calls to PCM scaling function instead of testing
conditions on every callback, cleanly assigning a different call to
do the volume transition. The volume change call then assigns the final
scaling function.

Change-Id: If1004b92a91c5ca766dd0e4014ec274636e8ed26
Reviewed-on: http://gerrit.rockbox.org/763
Reviewed-by: Michael Sevakis 
Tested: Michael Sevakis

Provide high resolution volume and prescaler to hosted targets.

2013-04-27T04:59:27+00:00

HAVE_SW_VOLUME_CONTROL is required and at this time only affects the
SDL targets using pcm-sdl.c.

Enables balance control in SDL targets, unless mono volume is in use.

Compiles software volume control as unbuffered when
PCM_SW_VOLUME_UNBUFFERED is defined. This avoids the overhead and
extra latency introduced by the double buffer when it is not needed.
Use this config when the target's PCM driver is buffered and sufficient
latency exists to perform safely the volume scaling.

Simulated targets that are double-buffered when made as native targets
remain so in the sim in order to run the same code.

Change-Id: Ifa77d2d3ae7376c65afecdfc785a084478cb5ffb
Reviewed-on: http://gerrit.rockbox.org/457
Reviewed-by: Michael Sevakis 
Tested-by: Michael Sevakis

Implement universal in-PCM-driver software volume control.

2013-04-11T20:55:16+00:00

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 
Tested-by: Michael Sevakis

Clean up peak calculating code.

2012-05-03T00:53:07+00:00

Mixer needn't keep peak data around that will never be used. Just
pass pcm_peaks structure to it instead of allocating for every
channel. Plugin API becomes incompatible.

vu_meter digital mode was still using global peak calculation;
switch it to playback channel like the rest.

Remove some accumulated soil peaks inside pcm.c and make it more
generic.

Change-Id: Ib4d268d80b6a9d09915eea1c91eab483c1a2c009

Revise the PCM callback system after adding multichannel audio.

2012-03-03T06:23:38+00:00

Additional status callback is added to pcm_play/rec_data instead of
using a special function to set it. Status includes DMA error
reporting to the status callback. Playback and recording callback
become more alike except playback uses "const void **addr" (because
the data should not be altered) and recording  uses "void **addr".
"const" is put in place throughout where appropriate.

Most changes are fairly trivial. One that should be checked in
particular because it isn't so much is telechips, if anyone cares to
bother. PP5002 is not so trivial either but that tested as working.

Change-Id: I4928d69b3b3be7fb93e259f81635232df9bd1df2
Reviewed-on: http://gerrit.rockbox.org/166
Reviewed-by: Michael Sevakis 
Tested-by: Michael Sevakis

Add more INIT_ATTR and add config.h includes to header files with INIT_ATTR.

2011-12-19T20:12:52+00:00

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@31370 a1c6a512-1295-4272-9138-f99709370657

Use a macro for aligning PCM chunks instead of explictly coding it each time.

2011-12-05T13:58:35+00:00

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@31152 a1c6a512-1295-4272-9138-f99709370657

Shuffle some functions around so that interfacing with playback.c in particular isn't required. Though playback does finish the audio init, pcm doesn't care who does it.

2011-09-01T12:15:43+00:00

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@30403 a1c6a512-1295-4272-9138-f99709370657

Use playback channel directly for peakmeters and plugins using peak calculation. Also, for now, don't allow mixer playback to overlap recording, even if full duplex works.

2011-07-02T11:55:38+00:00

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@30119 a1c6a512-1295-4272-9138-f99709370657

Commit FS#12150 - Fully-functional audio mixer - and finally whip old limitations about playback of voice and other sounds when paused. Channels are independent in state and amplitude. Fade on stop/pause is handled by the channel's volume control rather than global volume which means it now works from anywhere. Opens up the possibility of plugin sounds during music playback by merely adding an additional channel enum. If any PCM drivers were not properly modified, see one of the last comments in the task for a description of the simple change that is expected. Some params are tunable in firmware/export/pcm-mixer.h as well.

2011-06-29T06:37:04+00:00

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@30097 a1c6a512-1295-4272-9138-f99709370657