This is an improvement to the current compressor which I have added
to my own Sansa Fuze V2 build. I am submitting here in case others
find it interesting.
Features added to the existing compressor:
Attack, Look-ahead, Sidechain Filtering.
Exponential attack and release characteristic response.
Benefits from adding missing features:
Attack:
Preserve perceived "brightness" of tone by letting onset transients
come through at a higher level than the rest of the compressed program
material.
Look-ahead:
With Attack comes clipping on the leading several cycles of a transient
onset. With look-ahead function, this can be pre-emptively mitigated with
a slower gain change (less distortion). Look-ahead limiting is implemented
to prevent clipping while keeping gain change ramp to an interval near 3ms
instead of instant attack.
The existing compressor implementation distorts the leading edge of a
transient by causing instant gain change, resulting in log() distortion.
This sounds "woofy" to me.
Exponential Attack/Release:
eMore natural sounding. On attack, this is a true straight line of 10dB per
attack interval. Release is a little different, however, sounds natural as
an analog compressor.
Sidechain Filtering:
Mild high-pass filter reduces response to low frequency onsets. For example,
a hard kick drum is less likely to make the whole of the program material
appear to fade in and out. Combined with a moderate attack time, such a
transient will ride through with minimal audible artifact.
Overall these changes make dynamic music sound more "open", more natural. The
goal of a compressor is to make dyanamic music sound louder without necessarily
sounding as though it has been compressed. I believe these changes come closer to this goal.
Enjoy. If not, I am enjoying it
Change-Id: I664eace546c364b815b4dc9ed4a72849231a0eb2
Reviewed-on: http://gerrit.rockbox.org/626
Tested: Purling Nayuki <cyq.yzfl@gmail.com>
Reviewed-by: Michael Giacomelli <giac2000@hotmail.com>
The quickscreen calls settings_apply() and the crossfeed code wasn't
checking that the right crossfeed was set before updating the filter
for the custom setting, which was overwriting the Meier crossfeed
data (custom and Meier share the same data space).
Change-Id: Ifaa2f46fe062d4497681a2dd0d5068ec906c96a3
Replaces the NATIVE_FREQUENCY constant with a configurable frequency.
The user may select 48000Hz if the hardware supports it. The default is
still 44100Hz and the minimum is 44100Hz. The setting is located in the
playback settings, under "Frequency".
"Frequency" was duplicated in english.lang for now to avoid having to
fix every .lang file for the moment and throwing everything out of sync
because of the new play_frequency feature in features.txt. The next
cleanup should combine it with the one included for recording and
generalize the ID label.
If the hardware doesn't support 48000Hz, no setting will be available.
On particular hardware where very high rates are practical and desireable,
the upper bound can be extended by patching.
The PCM mixer can be configured to play at the full hardware frequency
range. The DSP core can configure to the hardware minimum up to the
maximum playback setting (some buffers must be reserved according to
the maximum rate).
If only 44100Hz is supported or possible on a given target for playback,
using the DSP and mixer at other samperates is possible if the hardware
offers them.
Change-Id: I6023cf0c0baa8bc6292b6919b4dd3618a6a25622
Reviewed-on: http://gerrit.rockbox.org/479
Reviewed-by: Michael Sevakis <jethead71@rockbox.org>
Tested-by: Michael Sevakis <jethead71@rockbox.org>
The old presets never made sense for Rockbox's EQ. They were apparently
copied from some other software. We have a parametric EQ, that means that
EQ bands can be made wider or narrower. Putting two identical bands side
by side just wastes battery life and adds rounding error. Replacement
presets are on gerrit but they need more work. In the mean time, users
should probably not be using these.
Change-Id: I85213100129fafd3ac0fa1a9438cb4d651bb94cb
Uses the Catmull-Rom case of Hermite cubic splines.
Vastly improves the quality and accuracy of audio resampling with a
rather minor additional overhead compared to the previous linear
implementation.
ARM and Coldfire assembly implementations included.
Change-Id: Ic45d84bc66c5b312ef373198297a952167a4be26
Reviewed-on: http://gerrit.rockbox.org/304
Reviewed-by: Michael Sevakis <jethead71@rockbox.org>
Tested-by: Michael Sevakis <jethead71@rockbox.org>
DSP_SWITCH_FREQUENCY has been deprecated and the same enumerated value
as DSP_SET_FREQUENCY since major DSP revisions were committed. This
task should have been performed much earlier but, oh well, do it now.
Change-Id: I3f30d651b894136a07c7e17f78fc16a7d98631ff
Input type can only change once per call because the DSP parameters
are only copied at the start and input is always taken from the src
buffer which means sample input format switching can be once per call
instead of once per loop.
Change-Id: Ifa3521753428fb0e6997e4934f24a3b915628cc7
Some things can just be a bit simpler in handling the list of stages
and some things, especially format change handling, can be simplified
for each stage implementation. Format changes are sent through the
configure() callback.
Hide some internal details and variables from processing stages and
let the core deal with it.
Do some miscellaneous cleanup and keep things a bit better factored.
Change-Id: I19dd8ce1d0b792ba914d426013088a49a52ecb7e
This is going right in since it's long overdue. If anything is goofed,
drop me a line or just tweak it yourself if you know what's wrong. :-)
Make HW/SW codec interface more uniform when emulating HW functionality
on SWCODEC for functions such as "audiohw_set_pitch". The firmware-to-
DSP plumbing is in firmware/drivers/audiohw-swcodec.c. "sound_XXX"
APIs are all in sound.c with none in DSP code any longer.
Reduce number of settings definitions needed by each codec by providing
defaults for common ones like balance, channels and SW tone controls.
Remove need for separate SIM code and tables and add virtual codec header
for hosted targets.
Change-Id: I3f23702bca054fc9bda40f49824ce681bb7f777b
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>
Instead of 3 cfg lines per eq band there is now a single line
for each:
<config name>: <cutoff/center freq>, <q>, <gain>
In addition, the config value names make a bit more sense.
The old settings are still readable but config.cfg and any new
settings files will be written with the new config values. (The
old settings will be removed completly sometime after the next
stable release).
Also a slight rework of the advanced EQ menu UI
Change-Id: I9008658d36ded442a5f2f825916df42a3934cbef
Reviewed-on: http://gerrit.rockbox.org/394
Reviewed-by: Jonathan Gordon <rockbox@jdgordon.info>
- A 10 Band EQ for Rockbox w/ presets adapted
from VLC
- frequency stepping at 32, 64, 125, 250, 500
1K, 2K, 4K, 8K, 16K
Change-Id: I85ad84d70a534edfc66c6ad9af8a76f022a02ec7
Reviewed-on: http://gerrit.rockbox.org/386
Reviewed-by: Jonathan Gordon <rockbox@jdgordon.info>
The old GCC version currently required (sbox-arm-linux-gcc 3.4.4
release) apparently has trouble with function pointers used as
static array initializers when using indexed initializers + ranges
(ie. [A ... B] = fn).
Change-Id: I494c2b607e4d93a9893264749d0ac257fb54ce3b
Emulates the basic "Meier" crossfeed (2 capacitors, 3 resistors)
as discussed in
http://www.meier-audio.homepage.t-online.de/passivefilter.htm
This crossfeed blends a bit of low-pass filtered L signal into
the R signal (and vice versa) while adding about 300 us delay
to the crossfed-signal. A difference with the crossfeed already
present in rockbox, is that this algorithm keeps the total
spectrum flat (the one currently in rockbox accentuates
low-frequency signals, making it sound a bit muffled).
This implementation is quite lightweight, just 3 multiplies per
left-right pair of samples. Has a default C implementation and
optimized assembly versions for ARM and Coldfire.
The crossfeed effect is quite subtle and is noticeable mostly
one albums that have very strong left-right separation (e.g.
one instrument only on the left, another only on the right).
In the user interface, the new crossfeed option appears as
"Meier" and is not configureable. The existing crossfeed is
renamed to "Custom" as it allows itself to be customised.
There is no entry for the user manual yet.
Change-Id: Iaa100616fe0fcd7e16f08cdb9a7f41501973eee1
When it was inactive but enabled, the format change hook was dropping
through to code that it shouldn't execute without it also being active
in processing samples.
Change-Id: Ie7899df0395d3f0d10f2bf2b55ea549dd06749a7
This is needed on app targets as e.g. ".section .icode" leads to the
code getting linked to incorrect locations (0x0 in this case).
Change-Id: Ic28c5ae6d4f8001d211d685b5ca92d5ffff0c7b2
Use memmove instead of memcpy for overlapping copy, fixes
crackling in sims and warble on my system. Native targets
seem to have been unaffected.
Change-Id: I265d4ce373e224581bd2f5ba15c75b473ec231f2
If the settings, like samplerate, were to go out of range where
timestretch drops out of processing and then go back to the same as
when they were valid, it would fail to switch back on by itelf.
Change-Id: Ic5bcb268540b0db8e0483117b8a5a0ce5c5a9db0
Makes quite a huge difference to get rid of 64-bit math in a hot
area. Cuts about 12 MHz. Generic routine generates good code on
ARM and asm cuts no instructions there.
Change-Id: I4ac647406006c42004f9f5ab396cbf4e85688854
Wrap up the the stereo case into loops and remove unused calculations
hanging out in tdspeed_update().
A wee little bit of code style and column policing.
Change-Id: I8dd3ab4b3e7e56b55dc00c00f3e32996228cc457
Also move the definition to config.h
Change-Id: I36bb5020c5e06b2344292bc05e8c13ccc7a6a1ff
Reviewed-on: http://gerrit.rockbox.org/234
Reviewed-by: Nils Wallménius <nils@rockbox.org>
Input functions have common setup sequences that can be placed
into an inline function instead of repeating it all repeatedly.
Change-Id: I9e62904ff0948651c64ddf160ed4400ed6dc81ff
Move code dealing with rockbox specific buflib allocations into a
rockbox specific file and implement buffer allocation with
malloc/free for warble/stand alone lib.
Based on patch by Sean Bartell.
Change-Id: I8cb85dad5890fbd34c1bb26abbb89c0b0f6b55cf
Reviewed-on: http://gerrit.rockbox.org/144
Tested-by: Nils Wallménius <nils@rockbox.org>
Reviewed-by: Michael Sevakis <jethead71@rockbox.org>
Reviewed-by: Nils Wallménius <nils@rockbox.org>
It's always used in MONO mode and doesn't need the IRAM sample/
resample buffers and 1280 bytes can be freed.
M5 can now have its PCM mixer downmix buffer in IRAM.
Change-Id: I0af08be5b212b7dfe382bba588a6585eb328a038
Use them to move tick counting, yielding and coldfire macsr handling
code to a rockbox specific file.
Change-Id: Id7417dc98c08a342eba45ba56b044a276e50564b
Reviewed-on: http://gerrit.rockbox.org/229
Tested-by: Nils Wallménius <nils@rockbox.org>
Reviewed-by: Nils Wallménius <nils@rockbox.org>
Moves replaygain definitions to lib/rbcodec/dsp/dsp_misc.h.
Intermediate functions in misc.c handle any adjustment and calling
the rbcodec APIs.
Change-Id: I9f03561bca9aedd13760cf19c4e19aa3c68e7024
Reviewed-on: http://gerrit.rockbox.org/140
Reviewed-by: Michael Sevakis <jethead71@rockbox.org>
Move a few functions to .text that probably don't see a huge benefit
from being .icode. Will scrutinize later.
Change-Id: I7bdffc326076c5cd7e6a1c57d25d31e653920327
Creates a standard buffer passing, local data passing and messaging
system for processing stages. Stages can be moved to their own source
files to reduce clutter and ease assimilation of new ones. dsp.c
becomes dsp_core.c which supports an engine and framework for effects.
Formats and change notifications are passed along with the buffer so
that they arrive at the correct time at each stage in the chain
regardless of the internal delays of a particular one.
Removes restrictions on the number of samples that can be processed at
a time and it pays attention to destination buffer size restrictions
without having to limit input count, which also allows pcmbuf to
remain fuller and safely set its own buffer limits as it sees fit.
There is no longer a need to query input/output counts given a certain
number of input samples; just give it the sizes of the source and
destination buffers.
Works in harmony with stages that are not deterministic in terms of
sample input/output ratio (like both resamplers but most notably
the timestretch). As a result it fixes quirks with timestretch hanging
up with certain settings and it now operates properly throughout its
full settings range.
Change-Id: Ib206ec78f6f6c79259c5af9009fe021d68be9734
Reviewed-on: http://gerrit.rockbox.org/200
Reviewed-by: Michael Sevakis <jethead71@rockbox.org>
Tested-by: Michael Sevakis <jethead71@rockbox.org>
dsp_set_eq_coefs now has parameters for the band settings, so it doesn't
need to access global_settings.
Change-Id: I29ac19fc353b15a79cb25f0e45132aef0881e4c9
Reviewed-on: http://gerrit.rockbox.org/138
Reviewed-by: Nils Wallménius <nils@rockbox.org>
Differences between signed samples cover the entire unsigned 32-bit
range. "abs" will think any difference exceeding INT32_MAX is negative
which is not corrent. Test which argument is greater and subtract the
lesser from it, outputting unsigned difference.
Change-Id: I73a8e5e418d49ff73d1a7c98eeb4731946dcfe84
