Sequence problems

Started by swirlythingy, November 01, 2009, 12:55:10

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swirlythingy

Take the following Cutcreator tune:

http://www.amp.dascene.net/analyzer2.php?idx=12277

This exhibits a problem I've seen on a few other tunes too, such as some of Nuke's 'Universe' compilations.  The length-of-sequence byte appears to be too large.  This results in the zero padding beyond the end of the sequence being counted as part of it, and interpreted by the player as an order to play pattern 0 nine times over.  Any idea what causes this problem?  I assume it's the result of a faulty ripping program somewhere along the line...

Another, unrelated, quick question: What was the original Ghosts and Goblins tune?  Searching for 'ghost' turns up two pages of remixes!

Asle

Hi,

I'm not sure I understand your problem with this song. What do you call "length-of-sequence", and what means " too large" ?. I've loaded up the song in Milkytracker and there's no "empty" space in any sample.
And what player are you using to replay this ? (DP is fine for this).

Regarding Ghost and Goblin's, well, you can get it here : http://www.exotica.org.uk/wiki/Ghosts_%27n_Goblins
It's no tracker music (as far as we know) and, as such, not on AMP.

Cya
Sylvain

swirlythingy

Quote from: Asle on November 01, 2009, 13:54:40
I'm not sure I understand your problem with this song. What do you call "length-of-sequence", and what means " too large" ?. I've loaded up the song in Milkytracker and there's no "empty" space in any sample.
And what player are you using to replay this ? (DP is fine for this).

ModInfo says:

Pattern order: 1 ,9 ,2 ,3 ,5 ,4 ,6 ,7 ,8 ,0, 10 ,11 ,7 ,8 ,12 ,4 ,6 ,3 ,5 ,13, 14 ,15 ,16 ,17 ,18 ,0 ,0 ,0 ,0 ,0, 0 ,0 ,0 ,0

I'm pretty sure those nine zeroes at the end aren't meant to be there.  (It's more obvious if you listen to the tune.)

There are two possible reasons:

One, the author put them there as padding when composing the tune and forgot to remove them afterwards (I'm not familiar with ProTracker, so I don't know how easy it is to do this), or:

Two, the tune was ripped from something and the ripper misinterpreted the byte giving the length of the song (or the byte was corrupted at some stage), resulting in it thinking the sequence data (or 'pattern order', above) was longer than it actually was.  This is far easier to do in ProTracker than in other formats, because the length of sequence data is constant - 128 bytes.

Quote from: Asle on November 01, 2009, 13:54:40
Regarding Ghost and Goblin's, well, you can get it here : http://www.exotica.org.uk/wiki/Ghosts_%27n_Goblins
It's no tracker music (as far as we know) and, as such, not on AMP.
Oops - sorry, betraying my ignorance of Amiga music history there! :(

Asle

Right, well, the "number of position" in Protracker is a box in itself. The composer chose to set it to 34 and decided to set the last 9 positions with pattern 0 to be played.
So, "One", it's very likely the composer set it that way in purpose
"Two" is unlikely as I don't see where ripping process could mess with this byte. Also, I couldn't find any Amiga prod with this music. Usually, the header is either completely empty or as if. Since all sample names are here, I guess that if it was ripped, it was that way for this byte (i.e. with value 34) in the prod it comes from.
If you want, just hex-edit the file and overwrite the byte at position 950 with 0x19 (Presently it's 0x22).

Sylvain