Addressing RAM - CDDA Challenges in DC Games

[CrisMod]

Welcome to the new topic dedicated to exploring and addressing the challenges related to RAM and CDDA management in some 3D heavy DC games.

List of Games with CDDA / RAM Issues:

1. Dave Mirra Freestyle BMX.
2. Pen Pen.
3. Quake 3 Arena.
4. Railroad Tycoon II - Gold Edition.
5. Racing Simulation 2.
6. Re-Volt.
7. Sega Extreme Sport.
8. Sega GT.
9. Sega Rally 2.
10. Toy Commander.
11. Toy Racer.
12. Vanishing Point.

Throughout this discussion, we will delve into the issues encountered in these games, where CDDA audio may lead to crackling and malfunctions. Additionally, we will discuss potential solutions and advice provided by @SWAT.

Response from CrisMod:
In my response to Freudi93 (if you are interested check it out here: http://www.dc-swat.ru/forum/thread-4041.html ), I shared the results of my tests on specific games. I highlighted how enabling CDDA can cause audio crackling in the games, while disabling CDDA allows the user to hear sound effects but not the background music. I theorized that this is due to the management of background music in games that require more RAM, with the audio (a part of it usually music) constantly loaded (from IDE interface) and unloaded (from RAM) in small blocks due to limited space in RAM.

Response from @SWAT:
@SWAT has provided valuable insights on how to address the issue. In response to my theory, which aligns with my observations of how the Dreamcast operates and interacts with Dreamshell/Isoloader code, he explained that for the PCM track (game audio), the available RAM might not be sufficient, leading to playback in small segments. He suggested exploring the possibility of changing the location of the HEAP (memory allocation) as a solution to resolve this issue.

Conclusions:
This topic has been created to discuss, share information, and seek solutions regarding RAM and CDDA-related issues in some Dreamcast games (as we know are 11 for now, if you have others please share and will be added to the list). We hope to find ways to optimize the gaming experience and resolve any audio issues. We invite you to actively participate in the discussion and share your experiences and solutions.

[Freudi93]

I think all games from the list of dragooncity with cdda on has the same issue (there are more than 60 Games)
https://docs.google.com/spreadsheets/d/1...1719450497

These are other games I tested with same result:
Vanishing Point
Pen Pen
Racing Simulation 2
Sega Extreme Sport
Railroad Tycoon

[CrisMod]

(07.11.2023 02:24)Freudi93 писал(а):  I think all games from the list of dragooncity with cdda on has the same issue (there are more than 60 Games)
https://docs.google.com/spreadsheets/d/1...1719450497

These are other games I tested with same result:
Vanishing Point
Pen Pen
Racing Simulation 2
Sega Extreme Sport
Railroad Tycoon

Thank you for sharing this list of games to add to our ongoing investigation. I have also conducted tests using headphones, and I can confirm that these titles exhibit the same issue.

While we currently suspect that there are around 60 games affected by this CDDA problem, I would like to propose that we collectively test all 60 games. This way, we can avoid the situation where everyone provides their own insights, potentially leading to confusion. It's crucial that we approach this systematically and meticulously to provide accurate data. I hope you all agree with this approach and are willing to contribute in this way the shared effort.

[SWAT]

SQ mode in last versions can save at least 8 KB memory with IRQ, and 16 KB without IRQ.
But I'm not sure that memory is a issue for all these games. Most issues gives channel usage conflict between ISO loader and the game.

[CrisMod]

(07.11.2023 12:11)SWAT писал(а):  SQ mode in last versions can save at least 8 KB memory with IRQ, and 16 KB without IRQ.
But I'm not sure that memory is a issue for all these games. Most issues gives channel usage conflict between ISO loader and the game.

Hey @SWAT, it's great that you occasionally provide more insights into the functions, giving us a chance to have better control over the settings we adjust rather than going blindly. So, thanks for the tips.

For those who may not be familiar with these terms, I'll try to explain in simple terms (SWAT, feel free to correct me if I'm wrong):

1. Sound Queue (SQ): The Sound Queue is a mechanism that manages the order in which sounds are played or processed by an audio system. It functions like a queue where incoming sounds are organized and played one by one in the order they were added. This is useful to prevent audio overlaps or conflicts when multiple sounds need to be played simultaneously. These are essentially the audio packets that are queued in the limited RAM before being reintegrated into the same available RAM blocks once they're processed. These are the audio glitches that we hear and SQ could help on it because will keep ready the next package of datas.

2. Interrupt Request (IRQ): Interrupt Requests are signals sent by the Dreamcast's hardware to the IDE interface where you've installed your mods. If you have the MOD LED, you'll notice it behaves differently when these parameters are enabled (or disabled). The LED is an excellent MOD signal to give you an idea of the data bus frequency between the DC hardware and the IDE MOD, and also what's happening in the background. In simplified terms, it briefly interrupts the continuous requests you see when the CDDA is turned on. So, what SWAT means is that if you activate it, you allocate 8KB of RAM to add this feature, and if you deactivate it, you free up more RAM, making an additional 8KB (16KB) available for the presumed audio needed by the CDDA mechanism.

@SWAT, the issue I've noticed (with some quick testing) is that when you enable those 2 functions, for example "Racing Simulation 2," which has the least audio stutter compared to others – in other words, it's the game that might come closer to somewhat bearable audio when CDDA is enabled – the problem is that when you activate SQ or IRQ, these functions not only affect the audio part but also influence all the game's data buses that need to be reloaded into RAM on the next reload cycle. So, whatever settings are applied for Sound Queue and Interrupt Request, they also apply to the entire graphical aspect and create stutters throughout the game, with some risk of minor graphical artifacts in-game.

[Freudi93]

The sound crashes sounds like the music File ist loading to slow. Is there maybe a way to compress the audio? If you Change to Mono sound in game the crashes become fewer.

[CrisMod]

(07.11.2023 13:27)Freudi93 писал(а):  The sound crashes sounds like the music File ist loading to slow. Is there maybe a way to compress the audio? If you Change to Mono sound in game the crashes become fewer.

Exactly it's what I was thinking as well, maybe could be nice to have one test to unpack and repack the GDI with the Sound a bit more degradated like different kbps that can keep the sound in something "hearable" but more smooth.....

[fafadou]

(07.11.2023 12:11)SWAT писал(а):  SQ mode in last versions can save at least 8 KB memory with IRQ, and 16 KB without IRQ.
But I'm not sure that memory is a issue for all these games. Most issues gives channel usage conflict between ISO loader and the game.

I think you right, you talk about the loader or the iso loader software ?
I didn't know iso loader can generate channel usage conflict.

Anyway we still can list the cdda games with issue, and trying them, when I want to tests games, sometimes I don't know what game is relevant

[Freudi93]

Sega Rally 2: the music is also broken nur mit cracking. I think it is playing really slow there. So my idea is to shrink music. How can i do that best?

[CrisMod]

(09.11.2023 00:26)Freudi93 писал(а):  Sega Rally 2: the music is also broken nur mit cracking. I think it is playing really slow there. So my idea is to shrink music. How can i do that best?

Yes just tested with CDDA and another Loader, I confirm the music in-game...... Added.

[fafadou]

I rewire my sh4 overclocking and it looks it works now, I have to check it again but in my memories :
Sega rally 2 with dreamshell RC4, the cdda music plays still at the same speed and now it's faster with RC5...
Same thing with homebrews and TMU1.

I believed at the beginning of dreamcast era at least, cdda were used to by pass the sh4 and relieved him.
with dreamshell RC4 there are no mit cracking with TMU2 for cdda, hope the next release will patch this... I know it's not easy, and you changed this for good reasons.

Excuse me if I'm saying something stupid.

[CrisMod]

(09.11.2023 00:26)Freudi93 писал(а):  Sega Rally 2: the music is also broken nur mit cracking. I think it is playing really slow there. So my idea is to shrink music. How can i do that best?

I'm currently exploring the complete image of Sega Rally 2 for testing and rebuilding with new audio. However, the intriguing aspect is that the in-game audio that is experiencing cracking is not part of the group of ".wav" audio. While all the menu audio, which does not exhibit cracking, is in ".wav" format, the background music audio that cracks during gameplay appears to be in a different format. This could be the reason for the audio issues, as it seems to be an audio file outside the group of certain sounds.

Perhaps for some, what I'm stating now is nothing new, but bear with me as I immerse myself back into the Dreamcast world, not so long ago...

[Freudi93]

Is there a way to Change audio Format of Game?

[CrisMod]

(10.11.2023 12:44)Freudi93 писал(а):  Is there a way to Change audio Format of Game?

I need to find the Audio file, I tried to looking for it in almost all the Game files Audio supported, but I still looking for it, i don't know where they put......

[Freudi93]

Also in Re-Volt No Wav Files for ingame audio or menu

[MilkeyWilkey]

I wonder if the tracks you are searching for are in ADX format. It's compressed ADPCM

[CrisMod]

(11.11.2023 10:53)MilkeyWilkey писал(а):  I wonder if the tracks you are searching for are in ADX format. It's compressed ADPCM

Hi @MilkeyWilkey, thank you for the tips.
Yes, i did, I read some where a small list of 3 files that should be find into the GDi images, and no one of the 3 files extension was ther included ADX (except wav.

Where I can find a complete list of audio supported by Dreamcast and inserted into the GDI images files to looking for?

At least I will check some other specific file, if they used another format files audio for that game/in-game song.