move target-specific pcm operations into builtin_pcm_sink.
in subsequent commits, another pcm_sink is added, and it becomes
possible to switch between them.
Change-Id: I8f8b9661e01d6e6472f34224ddc3760856778457
Replace the factor calculation from pcm-alsa.c, which
is based on signal *power* ratios, with the fp_factor()
calculation that is based on amplitude ratios. Because
power changes with the square of amplitude, this means
1 dB of power equals 2 dB of amplitude.
Rockbox's volume controls are amplitude-based, so the
smallest step size for pcm-alsa was effectively 2 dB.
The fp_factor() method supports 0.1 dB steps and is a
bit more accurate besides, so it's simply superior in
all respects (aside from taking a few more CPU cycles
to calculate the factor).
Change-Id: I34d143c225d8b5e085cde299fc405f83c13314bf
A small negative offset seems to silence all
play/pause clicking on the PCM5102A.
Also adding PCM soft muting, and muting the headphone amp
when the headphones are detected as removed. This has been
tested to not cause any unintended side effects on the
line out.
Also confirmed the numerical dB values are (approx.) correct.
Change-Id: I689d68887c86add9cc5e0ccb0c7de01aaa69b4d9
Nothing in the core has used it for some time. It's exported to the
plugin API but the last plugins to use it were switched to the mixer API
back in 2011.
This allows us to get rid of pcm_play_dma_pause() from all audio drivers
Change-Id: Ic3fa02592316f84963e41d792d1cabb436d1ff6b
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 <jethead71@rockbox.org>
Tested: Michael Sevakis <jethead71@rockbox.org>
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 <jethead71@rockbox.org>
Tested-by: Michael Sevakis <jethead71@rockbox.org>
pcm_set_master_volume had two implementations, one for a prescaler
and one without one but the differences can be made minimal enough
to combine them.
Change-Id: I889e60b50b9f046c093853cb1685058796fe9067
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>
