#531 Very choppy animation when enabling sound

audio (2)

I'm using version 2.1.5, and also tried current SVN, but both have the same problem: when I enable sound support, every game gets very choppy. What was running with 60FPS before looks like 15FPS after enabling sound. Which sound settings I use doesn't matter (like frequency, quality, etc.)

CPU load on my machine is low and doesn't spike. It's an i5 2500K system running at 3.3GHz. Software or OpenGL doesn't make a difference.

I'm using Gentoo Linux 64-bit, kernel 3.4.7 with ALSA (no PulseAudio) and SDL 1.2.15.


  • Lukas Sabota

    Lukas Sabota - 2012-08-10
    • labels: --> audio
  • Lukas Sabota

    Lukas Sabota - 2012-08-10

    Thanks for bringing this to our attention. I'm unable to reproduce on a (somewhat) similar system (Arch Linux 64, kernel 3.4.7 w/ ALSA (no pulse), SDL 1.2.15

    I've committed a change in the most recent SVN where you can see the literal FPS when enabling the SHOWFPS build option in the "SConstruct". Would you be able to compile with the SHOWFPS option to see how many literal frames per second you are losing when enabling sound?

    Also -- what soundcard / drivers are you using/ Could you provide the output of the following commands on your system?

    lspci | grep -i audio
    lsmod | grep snd


    • Nikos Chantziaras

      OK, I've pulled from current SVN and did a clean build. The FPS display works fine. I enable sound and the game gets very choppy, but the FPS display displays a constant 60 (jittering a lot between 59.9 and 60 of course.)

      So the framerate doesn't dip at all. The choppy display comes from elsewhere. I should note that Nestopia has the same problem when using SDL. When setting it to use ALSA directly without SDL, then Nestopia works fine though.

      Another issue I have with FCEUX is that it always segfaults when loading a ROM (any ROM.) When running it in gdb though, then there's no crash (so it's impossible to get a backtrace.) Same with Valgrind, btw; doesn't crash in it. This pretty much means I always have to run it in gdb to be able to use it.

      Edit: I was able to get a backtrace of the crach. I opened a new bug about it.

      Last edit: Nikos Chantziaras 2012-08-10
    • Nikos Chantziaras

      Oops, I forgot the info you requested. I'm using an Asus Xonar D1 sound card. It has a dedicated driver in ALSA and I'm using it, built-in into the kernel, I don't use kernel modules (meaning that "lsmod" only shows the nvidia module from their driver, nothing else.)

      $ sudo lspci | grep -i audio
      01:00.1 Audio device: NVIDIA Corporation GF110 High Definition Audio Controller (rev a1)
      04:01.0 Multimedia audio controller: C-Media Electronics Inc CMI8788 [Oxygen HD Audio]

  • Lukas Sabota

    Lukas Sabota - 2012-08-10

    FWIW; my fps dips from 60 to about 57 when enabling sound on my thinkpad x220 (i7 @ 2.8GHz)

  • Anonymous - 2012-08-14

    Is there anything else I can do to track this down? Trying out any patches or anything?


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