Vgm ptch
General VGM patching utility; allows editing the VGM header (chip clocks/chip settings), checking/fixing VGMs and stripping chips/channels.
Please note: vgm_ptch always edits the original file(s). It doesn't create new files, so you probably want to create your own backups first.
Help
Usage:
vgm_ptch [-command1] [-command2] file1.vgm file2.vgz
Command names are case insensitive.
General Commands
| -Help | Show this help |
|---|---|
| -ChipCmdList | List all supported chips with SetHzxx command |
| -StripList | List all supported chips and channels for the Strip command |
Patching Commands
| -SetVer | Set Header-Version (e.g. 1.51, don't use with v1.00-1.10) |
|---|---|
| -UpdateVer | Update Header-Version (additional changes if neccessary) |
| -MinHeader | Minimize Header Size (v1.50+, useful after stripping chips) |
| -MinVer | Minimize VGM Version (v1.50+, useful after stripping chips) |
| -SetRate | Sets the Playback rate (v1.01+) |
| -SetHzxxx | Sets the xxx's chip clock (see -ChipCmdList for details) |
| -SetLoopMod | Set the Loop Modifier (Format: *2, /2.0, 0x20) |
| -SetLoopBase | Set the Loop Base (-128 to 127) |
| -SetVolMod | Set the Volume Modifier (Format: 1.0, 0x00) |
Commands to check the lengths (total, loop) and offsets (EOF, loop, GD3)
| -Check | asks for correction |
|---|---|
| -CheckR | read only mode |
| -CheckL | autofix mode, recalculates lengths |
| -CheckO | like above, but tries to relocate loop offset |
| -Strip | Strip the data of a chip and/or channel (see below). Does not yet work with all chips. |
Tip: Stripping without commands optimizes the delays.
Stripping Format
-Strip:Chip[-Num][:Ch,Ch,...];Chip
e.g.:
-Strip:PSG:0,1,2,Noise,Stereo; YM2151 -Strip:YM2612-0; OKIM6295-1
Stripping unused chips from a VGM
First use vgm_cnt on it to see if there really are any unused chips. Unused chips will usually have 0 for both Commands and Notes. The SEGA VDP PSG is probably unused if it has no Notes.
If you do find an unused chip, you can strip it with the Strip option, specifying the chip (and channel, if necessary), such as like the following examples.
vgm_ptch -Strip:AY8910-0 file.vgm; strip first AY chip vgm_ptch -Strip:AY8910-1 file.vgm; strip second AY chip vgm_ptch -strip:ym2151 "04 Credit SFX.vgm"; strip YM2151