Tiny Sound Crackling with NTSC games in 60Hz interlaced & progressive modes

[GoogleCodeExporter]

What steps will reproduce the problem?
just try any game. in most of the games i tried there is some tiny 
soundcrackling and popping here & there. tried to turn on/off HQ Sound, Low 
Pass Filter etc. nothing helped. for example phantasy star 2: the intro music 
crackles a bit at the beginning.

What is the expected output? What do you see instead?
clear sound all along

What version of the emulator are you using (official, SVN revision,...)?
1.40 beta

Please provide any additional information below (Video settings, Console
region,...)
PAL Wii, playing on LCD 480p. All my roms are NTSC Games.

Original issue reported on code.google.com by gora.pat...@gmail.com on 28 Jul 2010 at 4:06

[GoogleCodeExporter]

I'm not experimenting any of this and I'm a little surprised since I actually 
did a lot of work around that to make sure sound emulation should be perfect.

what is exactly 1.40 beta ? where and when did you get it ?

Original comment by ekeeke31@gmail.com on 28 Jul 2010 at 5:04

[GoogleCodeExporter]

http://code.google.com/p/genplus-gx/downloads/detail?name=genplus_wii%20%28r471%
29.dol

im talking about this one ;)

Original comment by gora.pat...@gmail.com on 28 Jul 2010 at 5:18

[GoogleCodeExporter]

Can someone else confirm this ? I have the same setup (PAL wii & mostly NTSC 
games) and never noticed any sound crackling or pops...

Can you point some other examples that i could test, with detailled description 
where it happens ?
Also, what video options are you using ?

Original comment by ekeeke31@gmail.com on 28 Jul 2010 at 5:33

[GoogleCodeExporter]

Video Settings
Progressive, 60Hz, Bilinear & VI Trap Filter ON, NTSC Filter Off, no Borders 
and 16:9 AR.

one more example:
Red Zone: while the developer logos etc + intro are shown. (the screen with all 
the gfx features + the introscene where that guy raises his fist).

Original comment by gora.pat...@gmail.com on 28 Jul 2010 at 5:55

[GoogleCodeExporter]

Ok, I can hear it too. The reason I didn't noticed it until know is that it 
only happens in INTERLACED (and apparently PROGRESSIVE but I cannot test it) 
mode, I always use ORIGINAL (non-interlaced) mode and it's crystal clear in 
comparison.

It also only happen with games running at 60hz in NTSC, which means it's 
probably an issue with video synchronization in this mode only, I need to 
investigate.

Original comment by ekeeke31@gmail.com on 28 Jul 2010 at 8:48

• Changed title: Tiny Sound Crackling with NTSC games in 60Hz interlaced & progressive modes
• Changed state: Accepted
• Added labels: Priority-Medium, Type-Defect, VideoEmulation

[GoogleCodeExporter]

yup, just tested ORIGNAL mode and all the crackling and popping is gone. only 
appears in INTERLACED & PROGRESSIVE mode. hope you can fix it, since 
PROGRESSIVE brings a much better & smoother image quality on a LCD.

Original comment by gora.pat...@gmail.com on 28 Jul 2010 at 8:59

[GoogleCodeExporter]

just tried some PAL Games (50hz) with Progressive and they all sound clear.
NTSC only Games running with Interlaced 50Hz sound clear as well. So it seems 
to really only affect NTSC Games running Interlaced 60hz or Progressive.

Original comment by gora.pat...@gmail.com on 28 Jul 2010 at 9:29

[GoogleCodeExporter]

Yes, what I said.
When the wii is using 60hz mode and emulating a NTSC genesis, emulation is 
synchronized with the video interrupt, otherwise it is synchronized with the 
audio interrupt.
Always syncing with audio playback fix the issue (I just checked) but in 60hz 
mode, it gives occasional frameskipping (because of tiny differences between 
audio & video timings in the Wii), hence why emulation needed to be rather 
synced with video hardware, while audio processing was very precisely adjusted 
to ensure audio hardware will always have samples when it needs new ones.

Anyway, it seems like the timings also differ between interlaced/progressive 
and non-interlaced modes, will have to find another solution for this special 
case. Duh.

Original comment by ekeeke31@gmail.com on 29 Jul 2010 at 6:40

[GoogleCodeExporter]

Could you please test this modified version ? It logs the delay between each 
video interrupt and store the result in a file.

Procedure:

(1) pick a display mode in video options (ORIGINAL,INTERLACED, PROGRESSIVE) and 
make sure TV Mode is set to 50/60Hz or 60Hz

(2) load a NTSC game

(3) let the game run a few seconds then return to menu 

(4) go back to the game and repeat (3) several time (~5x) to get enough test 
data

(5) go back to (1) and test the next display mode

Please post the content of the file logtiming.txt that should have been created 
at the root of your sd(or usb device).

I'm especially interested in getting the result for PROGRESSIVE video mode, as 
well as the results on a NTSC Wii in all modes to see if there are any 
differences with PAL Wii running at 60Hz.

Original comment by ekeeke31@gmail.com on 29 Jul 2010 at 12:38

[GoogleCodeExporter]

here's my file. tested Red Zone and Phantasy Star 2 in all 3 modes.

Original comment by gora.pat...@gmail.com on 29 Jul 2010 at 2:25

Attachments:

• logtiming.txt

[GoogleCodeExporter]

Thank you, it matches with my own result the game you use to test does not 
really matter).

So basically, the interval between video frame interrupts in 480i/480p modes is 
~16683 usec which makes ~59.94 frames per seconds.

However, in non-interlaced mode (240p), it seems that the average framerate is 
slower, with an interval value of 16715 usec (this is the value I actually 
measured and which I'm using to synchronize audio/video). The fact the minimal 
value is still approx. 16683 msec could be explained by the fact that the video 
hardware need to resynchronize fields when switching from 
interlaced/progressive (which the menu is using) to non-interlaced, so it's 
very likely the first frame is running at the previous rate.

Sadly, using the first value when using interlaced or progressive mode does not 
seem to fix the issue :-(

Original comment by ekeeke31@gmail.com on 29 Jul 2010 at 2:48

[GoogleCodeExporter]

ok. so i guess i'll have to play in original mode for now. hope you find a fix 
for it soon. :)

Original comment by gora.pat...@gmail.com on 29 Jul 2010 at 3:18

[GoogleCodeExporter]

For the record, the difference is due to the fact that there are always 263 
lines per field in non-interlaced mode, while in interlaced mode, there are 
alternatively 262 and 263 lines per fields (one NTSC frame is 525 lines).

In progressive mode, the clock runs 2x faster and process all 525 lines in one 
field so the average framerate is the same as in interlaced mode.

Original comment by ekeeke31@gmail.com on 29 Jul 2010 at 3:55

[GoogleCodeExporter]

same thing happens in original video mode with like say sonic 2 but im on a 
ntsc-u tv and 480i /=

Original comment by Darkone...@gmail.com on 31 Jul 2010 at 2:37

[GoogleCodeExporter]

In sonic 2 vs mode ? Would he the same problem 

Original comment by ekeeke31@gmail.com on 31 Jul 2010 at 8:47

[GoogleCodeExporter]

 I mean, sonic 2 vs mode switches into interlaced mode, even when using original display setting (its 240i actually) so it can actually have the same issue (occasional sound buffer desync)

Since you have a ntsc wii, please try a game (not sonic 2 vs mode though) with 
the special version i posted above, just make sure to follow the test procedure 
i described and test all 3 display mode if you can, its interesting data for me.

Original comment by ekeeke31@gmail.com on 31 Jul 2010 at 1:35

[GoogleCodeExporter]

oh ok for me its only during the intro of "sonic 2(ntsc-u)" and "aero the 
acrobat 2" rare but randomly,in original mode the sound issue seems to be 
corrected in sonic 2,interlaced it'll do like very soft pop sound then stop for 
abit,same thing happens in aero 2,except not in the intro more so in the middle 
of the game/=

Original comment by Darkone...@gmail.com on 31 Jul 2010 at 6:10

[GoogleCodeExporter]

as mentioned above, just do a test with any ntsc game with the test version in 
comment 9, to get the timings from a ntsc wii.

Original comment by gora.pat...@gmail.com on 31 Jul 2010 at 6:49

[GoogleCodeExporter]

where exactly in the middle of the game ? if you aren't precise, it doesn't 
help at all fixing issues, especially when I can't reproduce them. At least, 
please do the test as I've asked, it can help clearing some things up.

now, I've played these 2 games quite extensively in original mode and didn't 
notice any unusual pops or hicups with sound. In sonic 2, it happens in vs mode 
but it's barely noticeable. Sound is perfect on title screen (btw, "sega" 
scream is supposed to be a little scratchy sometime if that's what you are 
referring to). Aero 2 does not switch to interlaced mode and had perfect sound 
during the whole first level.

Original comment by ekeeke31@gmail.com on 1 Aug 2010 at 8:31

[GoogleCodeExporter]

right by the ramp type thing in aero 2 fist lvl it'll happen there sometimes 
with the interlaced mode turned on,it also happens when you jump on one of the 
bed springs with interlaced turned on i think in lvl's 1 and 2?

Original comment by Darkone...@gmail.com on 1 Aug 2010 at 1:51

[GoogleCodeExporter]

I am aware of issues with sound in interlaced mode, it's what this talk is all 
about. And that's why i need timing data in all modes, are you going to try the 
test .dol i posted in comment #9 or not ?

Original comment by ekeeke31@gmail.com on 1 Aug 2010 at 3:40

[GoogleCodeExporter]

no,i am using a compiled one i got from gbatemp,i asked you in the post about 
the tmss bios not working if you wanted me to send you the dol,well anyways 

Original comment by Darkone...@gmail.com on 2 Aug 2010 at 6:37

[GoogleCodeExporter]

For the last time, I don't care about your dol

.read comment #9 on this page and download the attached boot.dol
.follow the steps and test a NTSC game in all 3 modes 
(ORIGINAL,INTERLACED,PROGRESSIVE)
.upload the file logtiming.txt that has been created on your SD

I know my english is not perfect but is that so hard to understand ???

Original comment by ekeeke31@gmail.com on 2 Aug 2010 at 8:46

[GoogleCodeExporter]

Here is my logtiming file ekeeke31. Tested with Michael Jackson's Moon Walker

Original comment by geno11...@yahoo.com on 3 Aug 2010 at 11:06

Attachments:

• logtiming.txt

[GoogleCodeExporter]

I could not get progressive scan. Sorry :<

Original comment by geno11...@yahoo.com on 3 Aug 2010 at 11:07

[GoogleCodeExporter]

Sorry for the 3rd post. My HDTV always have crackling sounds though if the 
sound is loud. Vizio 26inch Tv

Original comment by geno11...@yahoo.com on 3 Aug 2010 at 11:13

[GoogleCodeExporter]

Thanks for the input, is it from a NTSC Wii ?

Original comment by ekeeke31@gmail.com on 4 Aug 2010 at 9:16

[GoogleCodeExporter]

Yes, it is from a NTSC-U Wii.

Original comment by geno11...@yahoo.com on 4 Aug 2010 at 2:51

[GoogleCodeExporter]

ok, this confirms NTSC and PAL Wii have the same timings when using 60 hz 
interlaced modes (and most probably 480p as well). I know have to figure why 
using this timing for audio/video sync (48000 samples per second / 59.94 frames 
per second = 800.8 samples per frame) does not work as expected.

Original comment by ekeeke31@gmail.com on 4 Aug 2010 at 4:44

[GoogleCodeExporter]

I think I fixed it, please give a try to the attached .dol

The solution was indeed to run sound emulation exactly at 59.94 frames per 
seconds in interlaced (or progressive) modes, but I also had to fix how I was 
syncing sound chips when FM resampling was used (High Quality FM mode).

Since I'm not sure if the changes I made could not break in very specific 
conditions and since I cannot test every sensitive game again, please report 
any sound issues or crash when running games with High-Quality FM enable (in 
original mode as well).

Original comment by ekeeke31@gmail.com on 7 Aug 2010 at 5:50

[GoogleCodeExporter]

tried a couple of ntsc games in progressive mode + HQ FM and no sound crackling 
or any other bugs far and wide anymore. :)
one question: is this fixed version based on r471 or newer, in other words does 
it include all other improvements, so that i can now use this dol here as the 
most accurate?

Original comment by gora.pat...@gmail.com on 7 Aug 2010 at 6:45

[GoogleCodeExporter]

ahh just found a bug in this version, but it has nothing to do with sound. in 
Gynoug Level 1 when the screens is shaking, there are graphical glitches on the 
left side.

Original comment by gora.pat...@gmail.com on 7 Aug 2010 at 7:01

[GoogleCodeExporter]

This is actually not a bug, happens on real hardware as well (i verified it).

This version is based on my latest build yes (and also includes some stuff that 
are not commited yet, i.e a new -but not working atm- cheat menu), 

Original comment by ekeeke31@gmail.com on 7 Aug 2010 at 7:15

[GoogleCodeExporter]

Original comment by ekeeke31@gmail.com on 7 Aug 2010 at 7:16

• Changed state: Verified

[GoogleCodeExporter]

True. Just hooked up my Megadrive. Wow, i never noticed it.

Original comment by gora.pat...@gmail.com on 7 Aug 2010 at 7:26

[GoogleCodeExporter]

Yes, genplus gx is actually the only emulator which emulates this accurately ;-)

Other games making use of this behavior: Kawasaki Superbike and F1 from Domark 
(left-most column is fine on genplus-gx and real hardware but glitchy on Kega, 
Gens, etc)

Original comment by ekeeke31@gmail.com on 7 Aug 2010 at 7:38

[GoogleCodeExporter]

now if only there would be sega cd emulation for Snatcher & Co i could finally 
say byebye to my old xbox. ;)

Original comment by gora.pat...@gmail.com on 7 Aug 2010 at 7:42