Step 4 Functionality of XG Checker
	XG Checker has the following functions. ** Checking functions 1. Maximum simultaneous notes Locations where more than the specified number of notes (normally 32 notes) are sounding will be checked 2. Multiple notes Locations where identical notes overlap in the same channel will be checked 3. XG initialization The data will be checked to see whether the XG tone generator initialization message "F0 43 10 4C 00 00 7E 00 F7" is being used correctly 4. Note-on and Note-off ranges Note events will be checked to see whether they are within the normally used range of note numbers (21-108). 5. Timbres Bank Select MSB, Bank Select LSB, and Program Change messages will be checked to see whether the sounds are specified by XG 6. Parameter changes Parameter changes (various types of SysEx) will be checked to see whether they are being used correctly. 7. Data traffic The spacing of MIDI events will be checked to see whether they are more densely packed than a specified value 8. Control changes The use of control changes will be checked for appropriateness 9. XF messages The use of XF-related events will be checked for appropriateness 10. Low velocity Notes with a velocity below a specified value will be detected 11. Pitch bend The use of pitch bend will be checked for appropriateness 12. Pressure data Poly/mono aftertouch data (the use of which the XG format prohibits) will be detected 13. Multiple control events Errors in which multiple values of the identical control change exist at the same timing in the same channel will be detected 14. Short durations Notes with durations (gate times) shorter than a specified value will be detected 15. Other The use of meta events such as time signature, tempo, key signature, text etc. will be checked for correct usage

	**Correction functions 1. Multiple Notes If multiple note messages of the identical note number exist at the identical timing, the last one will be preserved, and the others will be deleted. * Multiple events located at the same timing are not internally sorted in the file, so the last-occurring one will kept. * This correction is carried out mechanically, so in some cases the results may not be what you expect. 2. Control On Same Tick If multiple control changes of the identical number exist at the identical timing, the last one will be preserved, and the others will be deleted (figure 5). Figure 5 * Multiple events located at the same timing are not internally sorted in the file, so the last-occurring one will kept. * This correction is carried out mechanically, so in some cases the results may not be what you expect. 3. Control + Note On If note-on and control change events exist at the identical timing, the control change will be moved one tick toward the beginning of the song (figure 6). control change and notes are in the same timing Figure 6 * This correction is carried out mechanically, so in some cases the results may not be what you expect. * This measure prevents the disordering of internal event processing order which can occur on many sequencers when reading or writing SMF data. 4. SysEx. Device Number For any SysEx data with a device number other than 1 (i.e., cases of F0 43 1n 4C... where "n" is not 0), the device number will be forcibly set to 1. 5. MIDI Master Volume If the master volume messages used to fade in or fade out are XG messages (F0 43 10 4C 00 00 04 mm F7), they will be replaced with the universal realtime message Master Volume. * This measure is taken in consideration of playback on GM sound modules etc. If redundant End Of Exclusive (F7) bytes are found, the extra F7 bytes will be deleted. 6. End Of Exclusive If redundant End Of Exclusive (F7) bytes are found, the extra F7 bytes will be deleted.
	The file which has been corrected in this way will automatically be written as a separate file, without changing the original MIDI file in any way.