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rockbox/lib/rbcodec/dsp/crossfeed.h

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Fundamentally rewrite much of the audio DSP. 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>
2012-03-27 23:52:15 +00:00
/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2006 Thom Johansen
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#ifndef CROSSFEED_H
#define CROSSFEED_H
New crossfeed algorithm for Rockbox: "Meier" crossfeed 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
2012-05-01 07:58:27 +00:00
enum crossfeed_type
{
CROSSFEED_TYPE_NONE,
CROSSFEED_TYPE_MEIER,
CROSSFEED_TYPE_CUSTOM,
};
void dsp_set_crossfeed_type(int type);
Fundamentally rewrite much of the audio DSP. 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>
2012-03-27 23:52:15 +00:00
void dsp_set_crossfeed_direct_gain(int gain);
void dsp_set_crossfeed_cross_params(long lf_gain, long hf_gain, long cutoff);
#endif /* CROSSFEED_H */
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