Colecovision sound stutters

[herb_fargus]

@EVEGames I'll have to look at the binary we have hosted on our server. I feel like there was a reason we left it... Or maybe just forgot to upgrade. I'll have a chat with @BuZz .

[dman2552]

I recently built a Retropie box from image on a SD card with a Pi 3 B and can confirm the CoolCV sound issue. I've updated to Retropie 4.1.14 and manually updated CoolCV to the latest with no difference. The game slows slightly when there is lot's of sound and although the sound stutters, it doesn't seem to be related to CPU load. I thought I would see the CPU load spiking when there was stuttering sound but the load actually reduces. While playing Ladybug with it's short sfx sounds, CPU was sitting around 25-27%. When it plays it's little tune where the audio is continuous, CPU would drop to 18-20%.

Darren

[raymate]

Any updates on this, its still unplayable, keep updating each week with the hope it's fixed

:( miss the coleco

[mediamogul]

@raymate

The author of CoolCV is aware of the situation and has shown possible recent interest in updating the software with a few new features. If that happens, I'm sure he will address this slow down on the Pi as well. Be sure to watch this space for updates.

[raymate]

@mediamogul Good stuff, thanks for the info and reply

[BuZz]

I have been debugging this, and it is the sdl2.0.5 update that has caused the issue.

Unfortunately as it is closed source, I am unable to debug it further (at least debugging coolcv), and don't know what in SDL2 would have affected it as other SDL2 apps seem ok. (Changed my mind - I can debug SDL of course)

[mediamogul]

@BuZz

Thanks for taking the time to look into this. I've passed the information along to the developer here.

[BuZz]

It's quite likely it's an issue with SDL2.0.5 (SDL 2.0.5 has had heaps of problems on the rpi) - I am going to try and git bisect it, but this will take some time.

If I find the commit in SDL, I will revert it or backport any fix if there is one. If I can't (and the coolcv author cannot work around it), I may be forced to switch back to SDL2.0.4 again...

[BuZz]

I have found the commit that causes the issue (this references our git mirror, not the original repository)

commit f0a9a821497b8e9d3e2496a5c5ab844cdddc5e4c
Author: Sam Lantinga <slouken@libsdl.org>
Date:   Wed Oct 12 22:25:19 2016 -0700

    Work-around for a hang when USB devices are unplugged, contributed by James Zipperer

diff --git a/src/audio/alsa/SDL_alsa_audio.c b/src/audio/alsa/SDL_alsa_audio.c
index 3fdbd82..574d51b 100644
--- a/src/audio/alsa/SDL_alsa_audio.c
+++ b/src/audio/alsa/SDL_alsa_audio.c
@@ -314,9 +314,20 @@ ALSA_PlayDevice(_THIS)
     swizzle_alsa_channels(this, this->hidden->mixbuf, frames_left);
 
     while ( frames_left > 0 && SDL_AtomicGet(&this->enabled) ) {
-        /* !!! FIXME: This works, but needs more testing before going live */
-        /* ALSA_snd_pcm_wait(this->hidden->pcm_handle, -1); */
-        int status = ALSA_snd_pcm_writei(this->hidden->pcm_handle,
+        int status;
+
+        /* This wait is a work-around for a hang when USB devices are
+           unplugged.  Normally it should not result in any waiting,
+           but in the case of a USB unplug, it serves as a way to
+           join the playback thread after the timeout occurs */
+        status = ALSA_snd_pcm_wait(this->hidden->pcm_handle, 1000);
+        if (status == 0) {
+            /*fprintf(stderr, "ALSA timeout waiting for available buffer space\n");*/
+            SDL_OpenedAudioDeviceDisconnected(this);
+            return;
+        }
+
+        status = ALSA_snd_pcm_writei(this->hidden->pcm_handle,
                                          sample_buf, frames_left);
 
         if (status < 0) {

I will see if this has been changed in newer versions and either revert or update.

[BuZz]

Please can you update retropie-setup and update coolcv and let me know if that sorts it (I reverted the problematic commit in sdl2).

[BuZz]

Issue has been reported upstream to sdl here - https://bugzilla.libsdl.org/show_bug.cgi?id=3599

[barbudreadmon]

I'll try to fix fbalpha-libretro's colecovision inputs soon, that way you'll have an alternative to CoolCV.

[BuZz]

@barbudreadmon that would be great :) thanks.

[mediamogul]

@BuZz

Everything is back up to speed and performing beautifully. It really does amaze me that a problem like this can be zeroed in on among an ocean of possible causes and rectified. Also, I know it doesn't "just happen", so again I thank you for taking the time to do this.

@barbudreadmon

I'll try to fix fbalpha-libretro's colecovision inputs soon, that way you'll have an alternative to CoolCV.

That would be fantastic! Thank you.

[EVEGames]

@mediamogul , does that mean there is a new CoolCV binary to be had, with these fixes in place? What would be our best way to get it installed over the top of our existing CoolCV?
Thanks!

[mediamogul]

@EVEGames

There's no new binary, but BuZz fixed the root of the problem and it can be applied by using the 'Update from Binary' option for CoolCV in the RetroPie-Setup.

[dman2552]

Is anyone else here running a USB sound device with CoolCV? It seems as long as my rpi3 is configured for USB sound, my screen goes blank and becomes unresponsive to any connected keyboard/controllers when I try to play any CV game (even launching a game from command line). I have to SSH in to reboot. This happens with a fresh 4.1 install to the latest 4.1.18 update with sound fix. So far everything else I use RetroPie for is fine.

[raymate]

Sounds good, I updated from binary (think I did) and it didnt seem to change, I'm sure Im doing it wrong.

For the newbies out here may just give us a quick guide.

[BuZz]

@raymate you didn't update retropie-setup.

[mediamogul]

My bad. I forgot to reiterate that above.