Talk:Manual: Song Properties

From OpenMPT Wiki
Jump to: navigation, search

Alternative Tempo Mode - Row Duration (ms)[edit]

(Moved here from User talk:Saga Musix)

I'm learning about the various tempo modes. In this edit to Manual: Song Properties, you added that in the Alternative Tempo Mode, the Row Duration in milliseconds is "60,000 / (1.65625 × Speed × Tempo)". But the other information in that section suggests the Row Duration in milliseconds is 1000 × (Speed / Tempo). Is there more information about how your formula is derived somewhere? I want to make sure I understand the tempo mode correctly. --Bavi H 06:26, 15 February 2012 (UTC)

You're totally right, the formula is incorrect. It was derived from some code in OpenMPT which obviously does not compute what it claims to compute. I'll have to revise that formula, both in the wiki and in the actual program. --Saga Musix 18:12, 15 February 2012 (UTC)

Tempo Modes[edit]

I found the decription of the tempo modes very confusing. I'm drafing a possible revision to that section that addresses the problems below. I'm new to OpenMPT, so I hope I haven't misunderstood anything. Anyone have any comments? --Bavi H 23:41, 4 March 2012 (UTC)

1. Here are some cluttered and confusing parts in the introduction that currently begins with "To understand tempo modes":
> The duration of a tick and the number of ticks per row are therefore factors that affect playback speed.
In the Modern tempo mode, neither of these affect the playback speed.
> In total, four parameters can affect playback speed, which are explained in detail below.
The four parameters listed in the table for each tempo mode are Tempo, Speed, Rows per Beat, and Rows per Measure. But in all three tables, the Rows per Measure item says "This tempo mode is not affected by the Rows per Measure, though the value is used to calculate the time signature of a module that is sent to some plugins." So in fact there are only three parameters that may affect playback speed: Tempo, Speed, and Rows per Beat. And in each tempo mode only two of those parameters actually affect playback speed. In Classic and Alternative tempo modes: Tempo and Speed. In Modern tempo mode: Tempo and Rows per Beat. It might be clearer to:
  • Remove the statements about ticks per row and "four parameters" affecting playback speed from this introductory section.
  • Remove the Rows per Measure from the tempo mode comparison tables, since it has no effect on the playback speed.
  • Revise the explainations of the tempo modes to show what values can affect the playback speed.
2. In every tempo mode description, Speed is described as "Sets the number of ticks per row." It might be helpful to define Speed up front, then just mention in the tempo mode comparisons if changing the Speed affects the playback speed or not.
3. The tables comparing the tempo modes contain the following descriptions
Classic Tempo Mode: Tempo "Sets the duration of a tick."
Modern Tempo Mode: Tempo "Fixes the exact beats per minute of your song."
Alternative Tempo Mode: Tempo "Fixes the ticks per second."
These explanations make it confusing to tell what the Tempo value represents. It might be clearer to state what the Tempo value represents in similar units for each mode, like this
Classic Tempo Mode: the Tempo value is in units of 24 ticks per minute.
Alternative Tempo Mode: the Tempo value is in units of 60 ticks per minute (ticks per second).
Modern Tempo Mode: the Tempo value is beats per minute.
4. Alternative tempo mode is described with "This is a slightly more complex tempo mode devised by Ericus for the mathematically minded. It allows for very fine tuning." This description still leaves me wondering why the Alternative tempo mode was devised and why you would want to use it. I think the Alternative tempo mode has something to do with letting you use higher Speed or Rows per Beat, but I'm new to OpenMPT and not sure. In any case, I think the description could be revised to better explain this mode.
I think the alternative tempo mode doesn't work as intended, but after so many years that can't really be changed anymore. I am very sure it was supposed to work differently, so "really fine tuning" should have been possible, but right now it's just an adjusted "classic tempo mode". But I really like your changes so far. Just pay attention with the formatting so that the tables still look nice when being printed to PDF (you can preview what it would look like in the manual by choosing "Download as PDF" from the navigation). --Saga Musix 23:30, 10 March 2012 (UTC)
I made a few changes so the table in the PDF looks the same as the online version. The PDF creator doesn't use the specified column widths, so I had to put in a few non-breaking spaces to make the columns appear the same way. It also ignored the highlights in the formulas, so I changed them to bold. --Bavi H 04:14, 24 March 2012 (UTC)

I've put my revisions in the document. I don't like that the table is so large, but I like the way you can compare everything at once. --Bavi H 04:14, 24 March 2012 (UTC)

Looks good. Thanks for the work you've put into this!