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* Enable setting of global output samplerate on certain targets.Michael Sevakis2013-07-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* Remove explicit config.h and system.h includes from DSP code.Michael Sevakis2013-05-27
| | | | | | | Replace with rbcodecconfig.h and platform.h includes. Remove now- unneeded ones as well. Change-Id: I6111b71e90bf86d9fe272a7916f2d34a5c6dd724
* Introduce new hermite polynomial resampler.Michael Sevakis2013-05-16
| | | | | | | | | | | | | | | 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>
* Rename all the "lin_resample..." stuff to simply "resample_...".Michael Sevakis2013-05-07
| | | | Change-Id: I79f44f0dcc1b23b33a5040795220713660a1d18a
* New crossfeed algorithm for Rockbox: "Meier" crossfeedBertrik Sikken2012-05-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* Fundamentally rewrite much of the audio DSP.Michael Sevakis2012-04-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* Some whitespace correction in dsp_*.SMichael Sevakis2012-04-27
| | | | Change-Id: I6ee14c0adc9dd456c8a2d171952cbaedb3752428
* Build librbcodec with DSP and metadata.Sean Bartell2012-03-18
All associated files are moved to /lib/rbcodec. Change-Id: I572ddd2b8a996aae1e98c081d06b1ed356dce222