Amiberry / Pimiga 3

[vatovey]

Hi all,


Am running Pimiga 3 updated to use the latest Amiberry (v5.6.1), mostly running really well, except for one issue which I'm hoping to get some advice on.


When setting my workbench resolution to be 1920x1080p and quite a few other resolutions I get considerable audio choppyness, some resolutions work fine - I am using 1440x900 atm with no issues whatsoever. I set the Debian screen resolution the same as what the Amiga resolution is.



I have changed hdmi cables, even tested another monitor (currently using an AOC 2k monitor, tested a new-ish Dell 1080p monitor to).


I have played about with most of the audio settings, along with the refresh rate settings on the Debian side of things.


I used to run Amibian and used to experience the same issue on that to.


Any suggestions ?

[vulture]

Had similar issues at first and solved them by using a better psu (3mA) and a good usb type-c cable (65W). Maybe it's the same for you.

[vatovey]

Cheers for the suggestion Vulture.

I have just checked and I am using an official Raspberry Pi psu, 5v @ 3.0a

[giantclam]

The CEA MODE 31 1920×1080@50hz can be selected if you are in a PAL region and it wont support @60hz, however this “may” cause audio to skip sometimes. Should there be issues, reset to CEA MODE 16 .

https://cubiclenate.com/pimiga/


Tried that?

[vatovey]

Cheers Giantclam.

Have tested modes 16 and 31, unfortunately - same audio issues in both.

Any other suggestions gratefully received.

[vulture]

is this a pi3 or 4 you're using?

[vatovey]

Pi 4

[vulture]

Last thing I can think of is trying a different microsd with better throughput, maybe U3 class?

Also, maybe check your cpu speed, what frequencies are reported?

[stainy]

Set the RPi config.txt file to force 1080p or lower at 60Hz, or else the EDID profile of the monitor/TV will auto set it to 4K/30 or 4K/60

[vatovey]

@Vulture - thanks for suggestion, have tested various microsd cards - same result on all, if it was a SD card issue, surely the issue would be seen in all resolutions ?, as opposed to certain resolutions only. Pi 4 is slightly overclocked - CPU = 1.7GHz, GPU = 700MHz, over-voltage = 6, I have a ice tower cooling solution.

@Stainy - I have set hdmi_group=1 and hdmi_mode=16 (and tested 31) in config.txt, doesn't this force 1080p @ 60Hz ?

[vulture]

@vatovey

Everything seems proper, I'm scratching my head....

As for the SD, some cards eat up more cpu than others during transfers and as 1080p also requires more cpu time, that could also be a factor.

Have you tried to oc it just a little bit more, like 1.8GHz and see what happens out of curiosity? If choppiness goes away, we'd then know there's something about it and investigate further.

[giantclam]

Originally Posted by vatovey

Pi 4

...well, seeing as I've been bug hunting amiberry for months now (x86-64 build), I'll actually find it interesting to install pimiga on my rpi4 and see if I can recreate this ~ might take me a few days to find the time, but I will and report back... =)

[stainy]

Originally Posted by vatovey

@Vulture - thanks for suggestion, have tested various microsd cards - same result on all, if it was a SD card issue, surely the issue would be seen in all resolutions ?, as opposed to certain resolutions only. Pi 4 is slightly overclocked - CPU = 1.7GHz, GPU = 700MHz, over-voltage = 6, I have a ice tower cooling solution.

@Stainy - I have set hdmi_group=1 and hdmi_mode=16 (and tested 31) in config.txt, doesn't this force 1080p @ 60Hz ?

config.txt link

You`ll have to tweak it to force the JDMI group and mode that works for your display.

Also OC'ing might have a detrimental effect.

[vatovey]

@vulture - have just clocked it to 1.8GHz, unfortunately no change at 1080p, audio still extremely choppy, everything working ok at 1440x900 though (which is the next biggest screen resolution offered to me Amiga side).

@giantclam - I have been trying to get to bottom of this issue for a while, and have been chatting with Lifeblower on the Pimiga discord server, he mentioned that he's heard of this problem previously, but didn't know what the resolution was, or even if there is one at the point.

@stainy - Tested at stock CPU/GPU frequency, I only tried overclocking because 1080p wasn't working as I would expect it to.

The monitor I am using Pimiga on is an AOC Q2778VQE, I have also tested it on a Dell 1080p monitor, model P2219H - same problem on both monitors.

I have just enabled the status line to check what the refresh rates are, at 1080p running Eagleplayer or A-Player I am averaging 30-38 FPS, at 1440x900 I am getting a reasonably solid 60FPS, occasionally dropping down to 59FPS - as would be expected the fraction of a second it drops to 59FPS I also get a small audio glitch.

[giantclam]

Are you using HDMI audio out or 3.5mm jack?

[vatovey]

3.5mm jack - which is being fed into a small soundbar.

[giantclam]

...I should've said a few weeks.... being a grandpa is hard work during school holidays =)

So this evening I get to this.... I just tried things in default (as the pimiga images comes, HDMI audio out).... just note, I never, ever, run amiga emulation in widescreen...it's not 'period correct' (I have several 19"/21" 5:4 monitors for this)...a pointer to the fact I never come across such issues, I think primarily due to the fact that I only ever use 1280x1024 resolution =)

Very first thing...I picked a demo (scoopex) and the video ran like crap, stuttering like crazy... seen this before...HDMI audio was fine, but this is JIT ...F12, CPU and FPU tab, disable JIT ~ video now working properly....

...have you tried that? (disabling JIT)

Next....I'll flip it to 3.5mm audio out, and update amiberry.... is there any (perhaps demo as part of the pimiga image) that's best to example the audio issue?

...more later...

[giantclam]

....just a perspective, m'kay?...



Pironman case with installed RPI4 B 8gb ...behind it, Lenovo ThinkCenter M93p. Anyone can figure out the cost of the first setup (has a 128gb M.2 in slot as well)... off ebay, the M93p cost me AU$85 (with 500gb ssd). As far as cost versus features, performance and speed, the M93p humiliates the RPI4 by some considerable measure, caveat the additional wattage (which isn't as much as you think ~ running amiberry on a x86-64 4core only consumes around 1.3 CPU core time..so it's around 60% idle time =)

...but I digress.... I happened to note this in the pimiga install docs ... something to the effect that pimiga is using pulse-audio or such and similar. I'm just about to attack this, and if I have any audio problems this'll be the first thing I remove from the underpinning debian bookworm system ~ you don't need it, amiberry doesn't need it, and as long as you can live with only one program being able to access sound devices at any given time, it removes the possibility that PA has something to do with it.

[giantclam]

...right ... I was able to recreate it to some degree (as in, unreliably) but enough to hear the noise --- there's 2 issues at play here -- the JIT code (or some other code using it)... there's already a ticket on that bug in github, I'll chime in confirming it later ... and something else I can't quite put my finger on yet (sound familiar? =)...but I've a hunch it's related to another bug already on the todo list...

....I'll have to do some more testing ~ with the x86-64 build target (where I spend all my time wrt amiberry), JIT is unavailable and thus doing this on the rpi4 platform is as much 'first exposure' to the JIT code myself ~ NOW I understand what the other user was detailing. The only up side is the pimiga image dist. is an easy route to recreate the problem =) So.. turn JIT off for sure...

..next bit.. turn off pulse-audio for the pi user -- F12 -> quit the amiga emulation/amiberry
and back to the debian desktop, open a xterm, issue the following commands (as the user pi, no sudo required);

systemctl --user stop pulseaudio.service pulseaudio.socket
systemctl --user disable pulseaudio.service pulseaudio.socket
systemctl --user mask pulseaudio.service

Now start amiberry itself from cmdline..ie; ~/amiberry/amiberry

Configurations tab, load the pimiga config entry
CPU and FPU tab, turn off JIT
Sound tab, select desired output device (you'll now see the chip-id)..I use Push mode, value of 2
Configurations tab, save config -> quit
Doubleclick on Pimiga desktop icon, and see how it goes.

[vatovey]

Hey Giantclam,

Oh my goodness, I can't thank you enough for spending so much time trying to get to the bottom of this.

Tested at 1080p with JIT off - same issue, FPS averaging 30-35, very choppy audio.

Tested at 1440x900 with JIT off - FPS pretty much locked in at 50, perfect audio.

Tested at 640x480, 640x512, 720x400, 720x576, 800x600, 1024x600, 1024x768, 1280x720, 1280x1024, 1440x900 - audio working perfectly, FPS locked at 50FPS for these resolutions.

Tested at 1920x1080 - audio choppy, FPS 32-42fps

Tested at 2560x1440 - audio choppy, FPS 32-42fps

Removed Pulse audio as suggested, didn't resolve audio choppyness at 1080p

Is this a monitor issue possibly.