Reicast questions - RPi3 build, audio and resolution?

pjft

Hi all,

Apologies for the trouble here. I've recently tried to set up dreamcast emulation, and for the most part it's been successful, which was a nice surprise.

I've read several things on audio problems, input lag and such, and wanted to run a couple of questions by you as you will have had more experience with the emulator so far and may help me better set expectations.

Audio and RPi 3 build: On the wiki, it says that there's audio but I have no audio coming out of my HDMI port. I read on a post here (https://retropie.org.uk/forum/topic/3456/reicast-lost-sound-after-update/18) that I may need to go to the runcommand menu and choose oss-audio, which I'll try later today. I have, however, also read something around there being an old Pi2 fork of Reicast without audio (see welshy's post on https://www.raspberrypi.org/forums/viewtopic.php?f=78&t=155168, or https://www.raspberrypi.org/forums/viewtopic.php?f=78&t=100076, https://www.raspberrypi.org/forums/viewtopic.php?f=78&t=54357), so I was wondering how I'd be able to check whether my version was the right one. I have updated my set up with all the apt-get update XXX, from the source retropie 3.8 SD image for RPi3 to 4.0.x now. Would reicast have been updated as well, and would it be the proper RPi3 build (if this makes sense)?
Resolution: it states that performance should be good at lower resolutions, not HD. I believe by default it's 640x480, and it's still very choppy, with loads of frameskip. If I reduce it to 320x240 it plays perfectly. So I'm just wondering, once again, if I am on the right build, or if 320x240 is what's recommended for performance on a RPi3.

The game I'm playing is Virtua Striker 2, which shows as playing well on a RPi2 (80%-90% speed), hence my questions.

Apologies for the trouble, and do let me know what else may I provide to help with this.

Thanks!

dankcushions

@pjft said in Reicast questions - RPi3 build, audio and resolution?:

I have updated my set up with all the apt-get update XXX, from the source retropie 3.8 SD image for RPi3 to 4.0.x now. Would reicast have been updated as well, and would it be the proper RPi3 build (if this makes sense)?

apt-get update doesn't update anything specifically retropie related. to update retropie (or individual emulators) you follow this https://github.com/retropie/retropie-setup/wiki/updating-retropie

Resolution: it states that performance should be good at lower resolutions, not HD. I believe by default it's 640x480, and it's still very choppy, with loads of frameskip. If I reduce it to 320x240 it plays perfectly. So I'm just wondering, once again, if I am on the right build, or if 320x240 is what's recommended for performance on a RPi3.

where does it state that? 640x480 is the native dreamcast resolution, so you go lower than that and you're not really emulating a dreamcast anymore :) but sure, lower resolutions will always perform better than higher ones, at the cost of fidelity.

dreamcast emulation is pretty ropey on the pi. i'm not aware of any games that look perfect and play full-speed at 640x480 resolution on a pi3. hope someone can prove me wrong here.

pjft

Hi @dankcushions !

Sorry, you're absolutely right - I updated the apt-get things, and also performed the update from the retropie menu. My bad. I might try to go there again today and make sure everything is up to date. Thanks for the clarification, though, as I'm still trying to become fully acquainted with all the nuances here :) I'll explicitly update reicast via that menu later, though.

As for the resolution, in https://github.com/retropie/retropie-setup/wiki/Dreamcast it states "Low screen resolution are recommended to get best performance. Performance suffers if HD resolutions are used." That's what I meant by the resolution statement. I know that 640x480 is the actual dreamcast resolution, though it does work at 320x240 as well - obviously there the graphics are not as sharp, and some smaller text is no longer readable so to some extent you are right that we are not really emulating a dreamcast anymore :)

I'm reasonably happy with playing this at 320x240 if it needs to be (I'll actually try 480x360 later today, just for kicks though I fear it might be less than ideal), but wanted to check as the statement on the wiki wasn't clear in terms of what resolutions are recommended, and if there are any that would have worked well for others. I have not overclocked my RPi3, nor am I considering doing so.

Thanks for your prompt answers as usual!

pjft

So, a couple of updates:

The audio problem was indeed fixed with the OSS version. That being said, it is choppy, which was unexpected. I ended up going back to the no-audio version.
I updated Reicast from source. On compilation, it does state that platform is RPi2, but I checked the compilation script and it seems it's just a common flag for the RPi build. I wonder if there'd be any particular compilation flags that would help on the Pi3, but I am certainly not an expert on those nuances.
Resolution-wise, I tried 480x360, but it became slightly more laggy, which turned out to be a worse experience, so I reverted back to 320x240. Performance is perhaps 90% I suppose, which is a positive.
Next steps: I may try to set the CPU governor to performance on the runcommand menu. Can I set it only for a specific emulator/rom, or is it set globally? I read some scary things about temperatures, and as I have seen the yellow square at one point, I want to make sure that setting the governor to "performance" will NOT override the thermal throttling if/when it's necessary. Any thoughts?

Thanks all.

pjft

Ok, so just finally updating in hopes that it benefits others.
I tried to overclock my RPi3 with common settings shown in several other tests - even though I know that there's not a one size fits all solution for overclocking - and even though the performance was slightly better, I wasn't thrilled with it.
I tried to monitor the temperature of the CPU playing another game that had caused my PI to overheat when not overclocked (Euro Champs 92 on lr-MAME2003/lr-fba-next) and the temperature went over 80ºC after 5 mins or so, so I decided to revert the overclock changes back to the default values.
So that's my adventure with it. Summarizing:

320x240 resolution on dreamcast emulator, no audio for now as it's choppy.

Cheers.

bfenty

What kind of controller did you use? I'm trying to set up mine with keyboard controls (mapped from GPIO inputs) but not having any luck.

pjft

@bfenty
I used a PS3 SIXAXIS original bluetooth controller, as it's automatically mapped, it seems.
I don't have any experience with other types of controllers, but the reicast page on the wiki seems to have a dedicated section on controllers, even non-standard ones.
Maybe the "For mapping non-standard controller" section at the end can help?
Best.

bfenty

ah yes, I did that, and the script ran and recognized my input, but in the emulator I just get the 'enter date' screen and I can't interact with it.

Just hoped since you spent so much time setting this up, you might have some ideas. Thanks!

pjft

Hmm... Sorry, alas I don't :(
I assume you used the inputs then to edit the right file.
I'm assuming @Folly would know more - or searching for his posts might be able to help. After all, it seems he was the one who suggested that tip there.
Hope you can sort things out!
Best of luck.