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Diffstat (limited to 'plugins/sid/sidplay-libs/resid/NEWS')
-rw-r--r-- | plugins/sid/sidplay-libs/resid/NEWS | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/plugins/sid/sidplay-libs/resid/NEWS b/plugins/sid/sidplay-libs/resid/NEWS new file mode 100644 index 00000000..2f9f3c42 --- /dev/null +++ b/plugins/sid/sidplay-libs/resid/NEWS @@ -0,0 +1,188 @@ +Changes in reSID version 0.13 +----------------------------- + +The internal DC levels of the MOS6581 have been double checked and +corrected. The reason for the asymmetric scaling of the voice output +has been found; there is a DC offset from the waveform D/A converter +in addition to the DC offset from the envelope multiplying D/A +converter. No selected waveform (N=P=S=T=0) yields minimum wave output +level again. + +A bug in the fast version of the envelope clocking has been corrected. +This bug could incorrectly invoke the ADSR delay emulation. + + +Changes in reSID version 0.12 +----------------------------- + +A bug causing incorrect sample spacing in the new SAMPLE_FAST sample +calculation has been corrected. + +Audio clipping has been added to guard against sample overflows. + +To support multi-channel sampling, sample interleaving has been added +to the clock() interface. + +To support synchronization with an external timer, an interface for +sample rate adjustment has been added. + +The internal DC levels have been corrected. No selected waveform +(N=P=S=T=0) yields maximum wave output level. Furthermore, each voice +in the MOS6581 independently contributes to the DC level in the mixer, +and the mixer itself has a small DC offset as well. The MOS8580 has no +DC offsets. + +The spline interpolation routine has been generalized to accept +repeated points to introduce points of non-differentiability and +discontinuity. + +A separate mapping from the FC registers to filter cutoff frequency +has been included for the MOS8580, and the mapping for the MOS6581 has +been refined. + + +Changes in reSID version 0.11 +----------------------------- + +A new clock() interface has been added. This function generates audio +samples into a buffer, greatly simplifying the task of writing driver +code for reSID. It also facilitates more advanced audio sample +generation, as described below. + +Three clocking methods are available: clocking at output sample +frequency, clocking at cycle frequency with linear sample +interpolation, and clocking at cycle frequency with audio resampling. + +Clocking at output sample frequency is fast, and yields acceptable +sound quality, except for the SID combined waveforms, which have a +very high frequency content. + +Clocking at cycle frequency with linear sample interpolation is +approximately five to ten times slower at 44.1kHz sampling frequency, +but the sound quality is improved because of the linear sample +interpolation, and because some sampling noise is removed by the SID +external filter, which attenuates signals above 16kHz. + +Finally, clocking at cycle frequency with audio resampling has a work +rate which is independent of the sampling frequency; it is rather +inversely proportional to the percentage of the bandwidth allocated +to the filter transition band. This implies that e.g. with the +transition band starting at ~ 20kHz, it is faster to generate 48kHz +than 44.1kHz samples. + +Audio resampling is the theoretically correct method for sample +generation, and delivers SID sound quality previously unheard of. This +should make connoisseurs nod in appreciation, and for some time to +come it could possibly also make people tear their hair over having to +buy state of the art hardware to handle the obscene workload in real +time. By trading off passband bandwidth for speed, real time +processing is possible on current hardware. A 60% passband bandwidth +is within the reach of reasonably fast machines, while maximum sound +quality at 90% passband bandwidth, requiring four times the processing +power, is not. Yet. + + +Changes in reSID version 0.10 +----------------------------- + +Libtool is now used to build the library. + +To keep the filters stable it is necessary to clock them at above +sample rate. The chip clocking code has been modified to only +"overclock" the filters, not the whole chip. This yields a +considerable speedup without noticeably lowering sound quality. Note +that this is aimed at slow hardware, if possible the 1 cycle clock +interface should be used to eliminate sampling noise. + + +Changes in reSID version 0.9 +---------------------------- + +The sum of the filter outputs is no longer weighted. + + +Changes in reSID version 0.8 +---------------------------- + +voice3off has no effect if voice 3 is routed through the filter. + + +Changes in reSID version 0.7 +---------------------------- + +The audio output filter in the C64, external to the SID chip, has been +modeled. + +The mapping function between the FC register and filter cutoff frequency can +now be specified with spline interpolation points. This facilitates +interactive modification of the mapping function by graphical presentation of +the interpolation curve. The implementation of this novel spline design is +fast and general purpose, and should be well suited for use in other projects +as well. + +Filtered output has been inverted compared to unfiltered output. + +Aging of the bus value obtained when reading write only registers has been +partly implemented. + +To facilitate offline storage the complete state of SID can be read and +written. + + +Changes in reSID version 0.6 +---------------------------- + +A special case in synchronization has been implemented. + +The Autoconf script is cleaned up to allow compilation in a separate directory. + + +Changes in reSID version 0.5 +---------------------------- + +Emulation of MOS8580 combined waveforms. + +Version string resid_version_string provided for e.g. Autoconf tests. +The string has C linkage. + + +Changes in reSID version 0.4 +---------------------------- + +The implementation of the ADSR delay bug has been refined and should now be +cycle exact. + +The patch for VICE has been removed since VICE 0.15 will include reSID support. + + +Changes in reSID version 0.3 +---------------------------- + +The reSID library has changed name from libmos6581.a to libresid.a + +The pulse+sawtooth combined waveform has been corrected. + +Pulse+test bit samples are implemented. + +The envelope rate periods have finally been exactly determined. + +A new SID bug, the ADSR boundary bug, has been discovered and implemented. +This bug makes it possible to step from envelope level 0x00 to 0xff or from +0xff to 0x00 in one step. + +One-cycle optimized overloads of the clock() functions have been implemented +to facilitate sampling at 1MHz. + +The code has been further optimized for speed. + + +Changes in reSID version 0.2 +---------------------------- + +The implementation of the Envelope Generator has been rewritten to handle +the infamous ADSR delay bug. All known envelope related bugs have been +corrected. + +The maximum filter resonance is lowered to keep the filter stable. + +The reSID API has been simplified. Reading write only registers is allowed. |