# hootvopm

This script converts a [Hoot](http://snesmusic.org/hoot/v2/) memory dump into an .opm instrument pack, suitable for the VOPM VST plugin. It's an extremely rudimentary way of extracting FM instruments from games, but it works.

## Usage

`./hootvopm.py [-b] -t chip_type input_file`

Input file can also be `-` to read from stdin.

Output is dumped straight to stdout; redirect it to a file if you want to save it.

Pass -b to instead read straight binary data instead of comma-separated values.

### Currently-supported chip types

* OPM
* OPN
* OPNA (equivalent to OPN)
* Raw data in 32-byte groups (see below)

#### Raw data format
| Offset | Value       |
|--------|-------------|
| 0x00   | DT/MUL*     |
| 0x04   | TL*         |
| 0x08   | KS/AR*      |
| 0x0C   | AMS-EN/D1R* |
| 0x10   | DT2/D2R*    |
| 0x14   | D1L/RR*     |
| 0x18   | FL/CON      |
| 0x19   | AMS/PMS     |

Rows marked with * are groups of 4 bytes, one per operator.

## Capturing memory in hoot

* Left- and right-clicking the "driver work" area flips between available memory pages. Scrolling the wheel in this area scrolls through the current page; you can also use Ctrl-(Up/Down/PgUp/PgDn) for this purpose.
* When you see the area you need to capture, use Ctrl-C to copy it to the clipboard. This copies the entire page to the clipboard in a human-readable format, with 16 comma-separated hex bytes per line (plus a comma at the end for whatever reason, but this is ignored).
* Paste this into a file, trimming it down to get the register area of the FM sound chip. Save it as whatever.

### Tips
* Most chips (read: all of the ones currently supported by this script) have a 256-byte register area, meaning you'll need to trim it down to 16 lines.
* From what I've seen, the chip's register area almost always resides on the first page, starting either at 0x0000 or 0x0100.

## Known issues
* Since the script looks at a simple static memory dump, it has no way of capturing certain data, instead replacing it with placeholders. These include:
    * LFO data
    * Operator on/off state; all operators are considered to be in use (this *could* potentially be inferred, though)
    * Panning, though VOPM doesn't seem to use this