Only the console version of SID2MIDI comes with more documentation. Please consult that package for additional notes. Since quite some of the features are experimental and/or suggested by users, it doesn't make much sense to provide more documentation than a few notes.
The main window also accepts sidtunes via drag'n'drop. The scroll-bar in the middle is the sub-song selector. The field labelled "Seconds" is the period SID2MIDI will process the sidtune and collect data. If you want a longer period, you can configure it via the "General options" dialog. You may need to disable the songlengths database. The average sidtune is no longer than 4-5 minutes, so default of 300 seconds would be reasonable.
1 - The higher the noise level the more noisy SID sounds (e.g. effects or percussions) get mapped to MIDI channels. The more of these sounds, the less usable the MIDI file sounds. Level 1 is likely to give more pleasing results for the average sidtune. Try increasing the level if you think some voices are missing.
2 - Pitch to note conversion: Convert any sufficient change of a SID voice's frequency into a new note instead of a pitch wheel controller command. Depending on the pitch to note threshold, convert any smaller changes of frequency into pitch wheel controller commands as usual unless the pitch to wheel option is disabled. By default, pitch to note conversion is off. Important note: This option is required by Paul Norman's and some of Fred Gray's sidtunes, for instance. It can also be used as an alternative to capture arpeggio. If you get too many notes on a voice which makes heavy use of arpeggio, portamento, or strong vibrato, set a low value to limit the number of individual notes being created, e.g. '4' will create at most four notes.
3 - Pitch to wheel conversion: This controls how many pitch-wheel controller events are created for sustaining frequency changes. By default, as many events as necessary are created in order to convert effects like vibrato, arpeggio or portamento. Important note: Some sids apply heavy Vibrato and/or Portamento and trigger new notes with a large frequency offset. If that is the case, disabling pitch to wheel conversion completely would cause SID2MIDI to catch wrong notes due to lack of subsequent changes in frequency.
4 - Tempo: Override the default tempo in beats per minute if automatic tempo-detection is disabled.
Timebase: Override the used timebase in pulses per quarter note.
Pitchbend sensitivity: Specify the range of your MIDI pitch-wheel in number of semitones. The SID chip can do portamento over its full-range of 8 octaves (96 semitones). Important note: If your MIDI hardware or software can only do two or three octaves, SID2MIDI may not be able to convert long-range portamento slides correctly.
Scale speed: Fine-tune the speed of the sidtune above or below 1.0 (normal).
Pitch to note threshold: When pitch to note conversion is enabled, this value specifies in which range changes in pitch are allowed without triggering pitch to note conversion. It defaults to 1 semitone. For instance, if you want heavy vibrato to be converted into pitch-wheel controller events, but much longer portamento slides converted into new notes, you can increase this value until vibrato doesn't trigger pitch to note conversion anymore.
5 - Check envelope: Optimize note lengths by means of envelope emulation. Uses the ADSR volume envelope emulation to determine the duration of each note. Not using this may result in sounds "hanging" eventually.
Auto-detect tempo: Disables the "Tempo" field and makes SID2MIDI determine a suitable BPM value for the MIDI file.
Extra events: Write a SID voice's pulse-width and volume level to unused controllers 110 and 111. Note that the Text Output mode is better for analyzing what the sidtune does with the SID chip.
Use this options dialog to point SID2MIDI to where you keep the songlengths database file (usually called Songlengths.txt). The "Autosave" feature constructs an output file name for the MIDI (or text) file based on where you told SID2MIDI to save the last output file the last time.
These are explained on the SIDPLAY Home Page in the documentation section. With modern sidtune collections like the HVSC, it should not be necessary to enable the PlaySID memory model. That's why this feature is disabled. It is recommended that you don't enforce NTSC song speed.