Galron
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Joined: 18 Dec 2019, 01:12

Loadstar: The Legend of Tully Bodine (sound issues)

14 Jan 2020, 11:40

As I test through various Sega CD games, I noticed a problem with this one... The sound in the introduction video starts to 'skip' about mid-way through or rather it seems to play, but there seems to be overlapping voices playing as well, as if the next line starts is being played too early, and it gets out of sync. Another timing issue?

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neodev
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Re: Loadstar: The Legend of Tully Bodine (sound issues)

14 Jan 2020, 17:16

Are you using a megasg? Ensure you test with fully buffered mode. Using zero delay buffering affects framerate and might cause desyncs.

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neodev
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Re: Loadstar: The Legend of Tully Bodine (sound issues)

16 Jan 2020, 08:51

I've just tried with megasg and yes, zero delay buffer mode causes that issues, as it speeds up the refresh rate by a very small percentage, and ir affects audio/video sync. Just set it to fully buffered and it will work fine.

Steven
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Re: Loadstar: The Legend of Tully Bodine (sound issues)

16 Jan 2020, 09:33

Yay, broken stuff thanks to the extra blast processing of zero delay. Does single buffer fix this or stuff in general? I'm not very familiar with exactly how the buffer modes work and I can't test since I'm not home right now.

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neodev
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Re: Loadstar: The Legend of Tully Bodine (sound issues)

16 Jan 2020, 11:33

As the megadrive real speed is out of the range of hdmi frame rate specifications (It's 59.something, but outside of the allowed range), some tvs might have issues, so buffering modes make the frame rate fall into the spec in 3 ways:

Zero delay. It sopeeds the framerate up a bit to spec (i think 59.97Hz), that means the console clock is running slightly faster, fast enough for the a/v sync to fail in long cutscenes in some cd games, as it's slowly accumulating error, as video frames are played faster that what they should, while audio is played at the normal cd hardware speed.

Fully buffered. The console (i suppose) has a triple buffer, so when a new console frame has finished rendering, it's added to the queue, and the current one is marked as free. There is an extra buffer frame to avoid tearing, so it always swaps completed frames in the vblank (3 buffers: display buffer, anti tearing buffer, render buffer) so there is extra input lag.

The other mode name I can't remember: instead of 3 buffers, this mode only has 2 (display buffer, render buffer), so it has less lag. As soon as a buffer completes rendering, it's swapped with the display buffer, sometimes mid-frame, so tearing can appear.

Steven
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Location: Tokyo

Re: Loadstar: The Legend of Tully Bodine (sound issues)

16 Jan 2020, 11:42

Yeah, I think the original refresh rate is 59.54Hz or something like that (probably not 59.54, but I always forget) instead of actual NTSC spec. I don't remember, but it's a slight bit slower than NTSC while the SFC/SNES runs at 60.08Hz, which is easy to remember for some reason.

The other one you forgot the name of is single buffer. I meant if changing the buffer mode to single buffer fixes broken CD games like fully buffered does; I worded it quite badly. It is interesting to look more into exactly what the buffer modes do, though, so thanks for that. I always forget they are there in the options menu.

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neodev
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Re: Loadstar: The Legend of Tully Bodine (sound issues)

16 Jan 2020, 11:46

Yes, single buffer should fix it too, although it might cause tearing

Steven
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Joined: 24 Oct 2019, 18:04
Location: Tokyo

Re: Loadstar: The Legend of Tully Bodine (sound issues)

16 Jan 2020, 11:49

Tearing is better than lag, I think, so that's an acceptable sacrifice. It looks like the NTSC Mega Drive/Genesis run at 59.92Hz. Not sure why I thought it was 59.54Hz or where I got that number from.

Edit: But you know, I had always been wondering about the audio desync thing you mentioned. I guess it might actually be noticeable in Road Blaster FX/Road Avenger in some of the longer levels, but I didn't notice anything when I played it.

Galron
Posts: 84
Joined: 18 Dec 2019, 01:12

Re: Loadstar: The Legend of Tully Bodine (sound issues)

22 Jan 2020, 05:28

Well thanks for the help. It's good to know. Not the best game, but good to check those different settings depending on the issues in the games, if this problem occurs for other games.

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