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[Saga Musix]

I've already said that OpenMPT plays all those AMS files. OpenMPT is not the same thing as ModPlug Tracker / Player - they haven't been updated in over 10 years, while OpenMPT is still in active development.

I also don't see anything complicated about Charts Overdrive. I've been listening to that tune for many years in various players, and they all play it right (I didn't try Winamp because that is known to be bad anyway) - if any player had major issues with this tune because of its samples, it wouldn't be able to play kind of chiptune correctly.

[eLK]

Okay, it plays - yes it is able to play the AMS files - but did you listen them? It plays totaly wrong! Try e.g. Necrophilia.ams or hullun päiväkirja.ams which are the demo songs of Velvet Studio. They play bad! If you go to menu View and press Find MPT Hacks in Song you will get:

Found invalid pattern commands
Found channel names
Compatible play is deactivated
Found incorrect mix levels (only compatible mix levels allowed)

Yes - the player plays every notes   but thats all..

Try to play it using Velvet Studio - you will hear the difference!  

[eLK]

if any player had major issues with this tune because of its samples, it wouldn't be able to play kind of chiptune correctly.

Not true, if you have a sample only few bytes long or a sample long about 20kB it is a big difference if you take out one byte - it must logicaly affect the sound pitch while for the 20kB sample you should not hear any pitch. Not many chiptunes has as much short samples like Charts Overdrive.

[Saga Musix]

If you go to menu View and press Find MPT Hacks in Song you will get:

And? This is just because OpenMPT must convert any file into one of its four editable formats (MOD, S3M, XM, IT, MPTM) internally, and my AMS loader makes use of as many OpenMPT features as possible to play those files as well as possible - this includes importing channel names, which are not part of the original IT format, but still that's no a valid reason to simply not import them.

Try to play it using Velvet Studio - you will hear the difference!

I never said it would be perfect - but at the same time, I strongly doubt that MilkyTracker would do any better job at it. And unless the author of MPPWC wants to rewrite his engine completely, he will also not managed to do a better job than OpenMPT, as the "best" format supported by both players is IT.

Not true, if you have a sample only few bytes long or a sample long about 20kB it is a big difference if you take out one byte - it must logicaly affect the sound pitch while for the 20kB sample you should not hear any pitch. Not many chiptunes has as much short samples like Charts Overdrive.

Sorry, but you have no idea what you are talking about. 32-byte long samples are very common in chiptunes. Playing a 1kb sample takes as much effort as playing a 32b sample. The pitch of a 32b sample should always be the same, because its loop period is always the same (unless there are off-by-one loop length bugs somewhere, which I've never encountered in regular MOD players)... Maybe you should try implementing your own mod player to understand what this is all about.
There can of course be great differences in interpolation algorithms being used, but using different interpolation algorithms is not a "bug", it's a feature.

[Dege]

I've just looked into AMS features and format.
It seems and extended XM with its shadowed instruments, vibrato (pitch) envelopes, etc.
Altough it has some very unusual features (varying track number for patterns, max 7(! my god..) effects per note, etc.) that seem totally needless for tracking, it does not seem impossible to be supported.

The only worrisome thing is the echo effect. As far as I remember it was mentioned in the tracker user guide but not in the format descripton.

I never said it would be perfect - but at the same time, I strongly doubt that MilkyTracker would do any better job at it. And unless the author of MPPWC wants to rewrite his engine completely, he will also not managed to do a better job than OpenMPT, as the "best" format supported by both players is IT.

While converting an imported format to an own, (and hopefully superior) format is unavoidable in a tracker, it's not necessary in a player at all.
The base problem is that even if a superior format contains all features of another format, it does not mean they are fully compatible. Different trackers may handle (not only) side cases differently. For example, MultiTracker is claimed to be Protracker-compatible, but it's easy to create a sample case where Pro and MultiTracker plays that differently. The same goes to Scream and Impulse Tracker, e.g. defining global volume in IT affects all currently playing channels while only newly started notes in ST3. Even handling the default effect parameter is different between them, etc. There are hundreds of such small fries... (so creating a super container format is impossible.)
In MPPWC, one of the goals was to play each format as if it was played in the corresponding tracker. So it does not convert any supported format to a common internal one. It's core player engine deals only with things that are very basic for each format: BPM, speed, tracks, samples, presence of effects, mixer, and so on. Rest of the playing logic (along with the loader code) is implemented separately for each format. The latter requires reverse engineering trackers. This is what should be done to Velvet Studio as well but it is the most time consuming part.

[eLK]

And? This is just because OpenMPT must convert any file into one of its four editable formats

You talking about nonsense..
You obviously didn´t try Milky Tracker. It plays much better but not everything is good also! OpenMPT plays like it just play notes - it is totally out - and if it is because of that it must convert ?? - how you can convert something what OpenMPT don´t support??? 

And then - it is just a tracker - we are talking about to play the AMS format (of course the right way!) - not to convert to MID then play 

You say - don´t drive formula - take a bus - it is the same 

[eLK]

It seems and extended XM with its shadowed instruments, vibrato (pitch) envelopes, etc.
Altough it has some very unusual features (varying track number for patterns, max 7(! my god..) effects per note, etc.) that seem totally needless for tracking, it does not seem impossible to be supported.

The only worrisome thing is the echo effect. As far as I remember it was mentioned in the tracker user guide but not in the format descripton.

Hi Dege,
yes, it is totaly crazy format Do you think you can make the correct player even that craziness? (and no echo description?) Then there may be the only way to make it correct to play - to compare the outputs from the Velvet Studio by some method.. earmetricaly? 
Thanks.
Lukas

[Dege]

I think Saga Musix speaks about converting imported formats to the native, editable format of trackers. He is right. This conversion process is probably better implemented in one while worse in another. Some of the AMS format features cannot be converted to any other format so they get lost (however I don't know importing capabilites of particular trackers, so I cannot judge if Milky or OpenMPT is better in that). Of course, probably most AMS tunes out there don't utilize those features so they should play fine after importing.

(and no echo description?)

Having another look into the tracker readme, it's the feature of the editor not the format itself, if I got it right. It's good.

Do you think you can make the correct player even that craziness?

to compare the outputs from the Velvet Studio by some method.. earmetricaly?  

Most of the reverse engineering was done earmetricaly, but a strong guess was also needed in most cases.   AMS documentation isn't too verbose, so I don't know... Perhaps.  
A good example: I was fiddling a little with the speed of envelopes to figure out what it means when it's bpm-independent. No success so far, and this one cannot be figured out just by ears. Any "mismeasuring" could mess up a complete song later.  
Implementing 7 effects per note wouldn't be so hard but it implies a lot of questions like how they combines together, what if more than one of the same type are given, etc.
7 effects of more than 16 types are a tremendous number of combinations, even a fraction of them cannot be checked one by one.
(Original source code always helps a lot in such cases.  )

[eLK]

Yes..
I don´t know how can I help you if you will try it.. I only know about that also exists the player of the Velvet Studio AMS files. It is a small DOS 32bit utility. It is a part of the package with it and its name is VPlay.exe.
It is for DOS but it is 32 bit extended DOS. I don´t know how to reverse engineer this even tried it using IDA. But it is somehow packed with D3X DOS Extender by Adam Seychell. I have tried to unpack it using stubx tool, which may have been used to it with no success The only think it gaves me is that the code is starting at 2308h. I don´t think there may be the chance to get source code. Who knows if the developer is reachable yet and still has it.


You can also try to analyze the AMS2WAV converter. It is not packed and should be more readable.. But I am not familiar with this  

[eLK]

Having another look into the tracker readme, it's the feature of the editor not the format itself, if I got it right. It's good.

This I don´t exactly understand.. If the Studio can do it and saves it in AMS, the format must also include it - no?