audio_driver = "alsathread" seems to create random audio drop

yewox50273

As described here by @dankcushions

Re: Pi4 - 4.7.1x after recent update audio little glitch/struttering or miss some frame on some libretro core... it's fixable ?

I noticed this symptom since around fall 2021 on a Pi 3B (not plus) after an update. Basically all emulators would get a random 0.5sec-ish audio drop (I use HDMI out to TV, nothing fancy), not limited to SNES. The same symptom persisted to Pi 4 (100% setup from scratch from official image).

I have tried a whole bunch of audio related settings (config_hdmi_boost, hdmi_drive, hdmi_group, etc. etc.) and none helped until I came across that thread.

I'm not noticing any performance drop so far setting it to "alsa". Disclaimer: the most "demanding" emulators I use are likely redream and lr-pcsx_rearmed on 2x resolution.

nesfredo

@yewox50273 Hello. I installed the new version Retropie 4.8 pre-made image on my Raspberry Pi3 and in all games there are random sound dropouts.

nesfredo

@yewox50273 I will try the solution you propose and let you know.

dankcushions

yes, the issue is as described. interesting that it also affects rpi3. i wonder if it's possible to bisect the issue to a specific version of retroarch?

@yewox50273 said in audio_driver = "alsathread" seems to create random audio drop:

I'm not noticing any performance drop so far setting it to "alsa". Disclaimer: the most "demanding" emulators I use are likely redream and lr-pcsx_rearmed on 2x resolution.

there's definitely a performance drop if you benchmark it. note that redream is not a libretro emulator (so won't use the setting). something like lr-duckstation will be affected, for example.

nesfredo

@dankcushions Retroarch version 1.10.0

dankcushions

@nesfredo it's before then as the original issue was logged a year ago when retropie was on 1.9.x

bisecting means getting to the exact commit that the issue appeared.

nesfredo

@dankcushions Before testing Retropie 4.8 (Retroarch 1.10.0) I was using version 4.7.1 (Retroarch 1.8.8) updating only the script without any sound problem.

yewox50273

@dankcushions said in audio_driver = "alsathread" seems to create random audio drop:

i wonder if it's possible to bisect the issue to a specific version of retroarch?

@nesfredo said in audio_driver = "alsathread" seems to create random audio drop:

@dankcushions Before testing Retropie 4.8 (Retroarch 1.10.0) I was using version 4.7.1 (Retroarch 1.8.8) updating only the script without any sound problem.

maybe the answer to @dankcushions' question is 1.9.5?

https://www.libretro.com/index.php/retroarch-1-9-5-released/

so everything was fine pre-1.9.5, because it wasn't even using alsathread (meaning, alsathread has been doing this audio drop thing since inception, just no one knew).

dankcushions

@yewox50273 no, alsathread has always (at least, for longer than this issue) been used for pi3, which is why i was clarifying what @nesfredo was using. the change you refer to only made it the default on pi4.

it didn’t cause the skipping issue on pi3 in years past, so clearly alsathread/RA has had some kind of change causing the issue. we should bisect this to a specific retroarch commit (version is not specific enough) to find the culprit, but it would be tricky to do so since the issue seems to occur after a game has been running a while and is sometimes hard to spot.