View Issue Details

IDProjectCategoryView StatusLast Update
0001276OpenMPT[All Projects] Playback Compatibilitypublic2019-11-10 20:02
ReporterSaga Musix Assigned ToSaga Musix  
PrioritynormalSeverityfeatureReproducibilityN/A
Status assignedResolutionopen 
Product Version 
Target VersionOpenMPT 1.29 / libopenmpt 0.5 (goals)Fixed in Version 
Summary0001276: Implement A1200 filter for Amiga resampler
Description

Add an option to switch from A500 to A1200 filter coefficients for clearer playback.

TagsNo tags attached.
Has the bug occurred in previous versions?
Tested code revision (in case you know it)

Activities

Saga Musix

Saga Musix

2019-10-27 18:39

administrator  

paula-v1.7z (24,571 bytes)
Saga Musix

Saga Musix

2019-11-10 19:35

administrator  

Paula-v2.7z (25,001 bytes)
Saga Musix

Saga Musix

2019-11-10 19:35

administrator   ~0004151

2nd version of the patch with reduced aliasing at the cost of slightly increased CPU usage. Implementation is finished, which mostly leaves the libopenmpt up for discussion.

The options are:

  1. Leave render.resampler.emulate_amiga as a boolean setting, and add render.resampler.emulate_amiga_type as a new string setting with values "a500", "a1200", "unfiltered", "auto" (default). Making A500 the default for "auto" would be compatible with the current implementation, however A1200 definitely has the better sound so it would be a better default value. Plus, A1200 will be the default in OpenMPT 1.29. This has the advantage that the setting can simply be toggled on and off, but for anyone caring about choosing the filter, two library calls are involved. This the variant currently implemented in the patch.
  2. Turn render.resampler.emulate_amiga into a string setting with values "0", "1", "a500", "a1200", "unfiltered". This has the advantage that it's easier to write code that is backwards-compatible with libopenmpt 0.4 (no #ifdefs necessary). People who don't care about the exact filter being emulated can keep using "0" and "1" (equal to "auto" in variant 1) as they have in previous versions of the library. The library user only has to remember a single setting. This is what OpenMPT also does internally.
Saga Musix

Saga Musix

2019-11-10 19:38

administrator   ~0004152

v2 was incomplete.



Paula-v3.7z (26,067 bytes)
Saga Musix

Saga Musix

2019-11-10 20:02

administrator  

Paula-v4.7z (35,026 bytes)

Issue History

Date Modified Username Field Change
2019-10-27 18:39 Saga Musix New Issue
2019-10-27 18:39 Saga Musix File Added: paula-v1.7z
2019-10-27 18:39 Saga Musix Assigned To => Saga Musix
2019-10-27 18:39 Saga Musix Status new => assigned
2019-11-10 19:35 Saga Musix File Added: Paula-v2.7z
2019-11-10 19:35 Saga Musix Note Added: 0004151
2019-11-10 19:38 Saga Musix File Added: Paula-v3.7z
2019-11-10 19:38 Saga Musix Note Added: 0004152
2019-11-10 20:02 Saga Musix File Added: Paula-v4.7z