Search found 299 matches

by tryphon
Wed Jul 17, 2019 3:06 pm
Forum: SGDK
Topic: 4 PCM example
Replies: 3
Views: 76

Re: 4 PCM example

ok, I'm going a similar way (except that, since I didn't know MML, I used a custom format).
by tryphon
Wed Jul 17, 2019 7:25 am
Forum: SGDK
Topic: 4 PCM example
Replies: 3
Views: 76

4 PCM example

Is there somewhere a VGM (or at least an XGM one) file that uses all 4 PCM channels (or at least more than 1) ?

All the samples from xgmplayer example use only one PCM channel.

Or do I have to mix my channels "by hand" ?
by tryphon
Fri Jul 12, 2019 9:31 am
Forum: SGDK
Topic: Internal XGM specs ?
Replies: 5
Views: 191

Re: Internal XGM specs ?

Do you think it'd be feasible to add a kind of JSR feature (jump to another part of the xgc code, and a return code) ?

It'd allow to store separately instruments settings, or isolate repeating patterns of music ?

I guess it's not so easy, because you must have thought about it.
by tryphon
Fri Jul 12, 2019 6:24 am
Forum: SGDK
Topic: Internal XGM specs ?
Replies: 5
Views: 191

Re: Internal XGM specs ?

Salut Stef, j'espère que tout va bien, je te croise plus trop sur le forum des malades (qui porte de "mieux en mieux" ce titre). The first reason is that I don't want to rely on any external tool (besides the ones I wrote myself). The second reason is that, at some point, I may want to modify the XG...
by tryphon
Wed Jul 10, 2019 12:58 pm
Forum: SGDK
Topic: Internal XGM specs ?
Replies: 5
Views: 191

Internal XGM specs ?

Bilingual post :P Je veux générer moi-même mon code XGM. Je me suis donc orienté vers la spécification du format qu'on trouve ici : https://github.com/Stephane-D/SGDK/blob/master/bin/xgm.txt Et j'ai voulu m'assurer de deux-trois trucs en regardant un XGM directement dans la ROM de sample/xgmplayer. ...
by tryphon
Wed Jul 03, 2019 9:04 am
Forum: Sound
Topic: Is there a way to fake the YM2151 2nd detune ?
Replies: 0
Views: 176

Is there a way to fake the YM2151 2nd detune ?

The YM2151 has a second Detune parameter which affects noticeably the generated sound. Is there a way to reproduce it ? I can't change the channel frequency because it affects only one operator...

Is the only way to turn it into a sample ?
by tryphon
Sat Jun 15, 2019 7:15 pm
Forum: Sound
Topic: How DAC works ?
Replies: 8
Views: 352

Re: How DAC works ?

Thank you !
by tryphon
Sat Jun 15, 2019 9:22 am
Forum: Sound
Topic: How DAC works ?
Replies: 8
Views: 352

How DAC works ?

I have some questions about channel 6 DAC mode : 1) do you confirm there's a 9th bit of value at bit 3 of register 2C ? I don't see this register mentioned in most documentations, nor in VGM specs, in particular data blocks are byte based, does it mean that all YM2612 vgm dumps are wrong ? 2) if I w...
by tryphon
Sat Jun 15, 2019 9:14 am
Forum: Sound
Topic: Why change TL before key on ?
Replies: 2
Views: 221

Re: Why change TL before key on ?

Thanks, that confirms what I thought!
by tryphon
Sun Jun 09, 2019 7:05 pm
Forum: Sound
Topic: Why change TL before key on ?
Replies: 2
Views: 221

Why change TL before key on ?

I'm "disassembling" some VGM from MD games, and notice many weird stuffs. For example, I have something like that : 000000: [channel 1] [operator 3] TL = 16 000000: [channel 1] key off 000000: [channel 1] [operator 3] TL = 8 000000: [channel 1] [operator 3] TL = 29 000000(1FD6): [channel 1] key off ...
by tryphon
Thu May 02, 2019 8:31 pm
Forum: Sound
Topic: Some beginner questions concerning YM2612
Replies: 24
Views: 2505

Re: Some beginner questions concerning YM2612

So, according to this page, it seems that in audio we use the dB for tensions (why ?), which is different (why ?).

So it's indeed 10^(dB/20), which indeed equals roughly 2^(dB/6).

Thanks :)
by tryphon
Thu May 02, 2019 4:40 pm
Forum: Sound
Topic: Some beginner questions concerning YM2612
Replies: 24
Views: 2505

Re: Some beginner questions concerning YM2612

Your formula is an approximation of mine (with a division by 3 rather than 6, unless I missed something, like efficace value or something like that, which is quite possible).

10^(db/10) = (2^1/log(2))^(db/10) = 2^(db/(10log(2))

and 10log(2) = 3.0103...

Unless the true formula is 10^(db/20) ?
by tryphon
Thu May 02, 2019 4:03 pm
Forum: Sound
Topic: Some beginner questions concerning YM2612
Replies: 24
Views: 2505

Re: Some beginner questions concerning YM2612

Another question : when I translate decibel coordinates to linear ones (whatever they are), I did : attenuation_in_dB = 10*log(I_max/I) where I is my linear amplitude and I_max the maximum amplitude (since I use 16 bits integer, I_max = 32767), which led to : I = I_max*10^(-attenuation_in_dB/10) = I...
by tryphon
Wed May 01, 2019 9:50 am
Forum: Sound
Topic: Some beginner questions concerning YM2612
Replies: 24
Views: 2505

Re: Some beginner questions concerning YM2612

Stupid me. Of course it makes sense ! Thanks :)
by tryphon
Wed May 01, 2019 8:35 am
Forum: Sound
Topic: Some beginner questions concerning YM2612
Replies: 24
Views: 2505

Re: Some beginner questions concerning YM2612

Something I can't find in the above thread (but it may have overlooked it) : In the Envelop Generator, how is the attenuation initialized in the attack phase ? is it 1023 ? if so it means that if TL isn't 0 dB (maximal volume), then operator will remain silent for some time ? or is it initialized at...