Humm... I have the same problem now, but as I switched from kernel 2.4 to kernel 2.6 and from a 1 month old dosbox to 0.61 at the same time, I can't tell which one is responsible for this sound problem.

I used to run OMF 2097 without any problems before, but now (as in many other games), sound is stuttering. At loudest sound level, one can hear clicks when sound is stuttering.

As for the source of the problem: dosbox itself, threads, SDL? Who knows (other linux applications don't have any sound problem on my box though).

I run dosbox (home compiled) at around 5000 cycles, frameskip 1, on my athlon-4 900Mhz

I'll try on my old 2.4.20 kernel, see if it changes something.

I ran into the same problem, using Gentoo with kernel 2.4.24-ow1. I managed to fix it by removing some lines from MIXER_Mix() in src/hardware/mixer.cpp. I tried to understand how this mixer thing works and create a decent fix but it would take too much time as the source is lacking comments or it's just me being too little of a coder, never mind. Removing these lines alone makes it work fine for me and that's all that matters ;-)
If you decide to do the same, the lines are 215-217:

1        Bitu size=MIXER_BUFSIZE+mixer.out.write-mixer.out.read;
2        if (size>=MIXER_BUFSIZE) size-=MIXER_BUFSIZE;
3        if (size>mixer.blocksize*2) return;

I have also produced another hack, a FPS limiter which does just that - limit FPS to 30. That's a much better way to improve performance than just skip n frames before rendering one. If anyone's interested, I'll be glad to post it.[/code]

I ran into the same problem, using Gentoo with kernel 2.4.24-ow1. I managed to fix it by removing some lines from MIXER_Mix() in src/hardware/mixer.cpp. I tried to understand how this mixer thing works and create a decent fix but it would take too much time as the source is lacking comments or it's just me being too little of a coder, never mind. Removing these lines alone makes it work fine for me and that's all that matters ;-)
If you decide to do the same, the lines are 215-217:

1        Bitu size=MIXER_BUFSIZE+mixer.out.write-mixer.out.read;
2        if (size>=MIXER_BUFSIZE) size-=MIXER_BUFSIZE;
3        if (size>mixer.blocksize*2) return;

I have also produced another hack, a FPS limiter which does just that - limit FPS to 30. That's a much better way to improve performance than just skip n frames before rendering one. If anyone's interested, I'll be glad to post it.

Oh, sorry for the double post ;-/

Unavowed wrote:

Removing these lines alone makes it work fine for me and that's all that matters ;-) If you decide to do the same, the lines are […]
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Removing these lines alone makes it work fine for me and that's all that matters 😉
If you decide to do the same, the lines are 215-217:

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1        Bitu size=MIXER_BUFSIZE+mixer.out.write-mixer.out.read;
2        if (size>=MIXER_BUFSIZE) size-=MIXER_BUFSIZE;
3        if (size>mixer.blocksize*2) return;

Well... That works. Yep, works. But why?..

Unavowed wrote:

I have also produced another hack, a FPS limiter which does just that - limit FPS to 30. That's a much better way to improve performance than just skip n frames before rendering one. If anyone's interested, I'll be glad to post it.

Sure, post it! 😀

OK, then.
In src/gui/render.cpp, add

1#include "timer.h"

after the initial includes, then add this to the very beginning of RENDER_StartUpdate():

1        const static Bit32u interval = 1000/30;
2        static Bit32u next_frame = 0;
3        Bit32u now;
4                                                                                
5        now = GetTicks();
6                                                                                
7        if (now >= next_frame)
8          next_frame = now + interval;
9        else
10          return false;

I think it would be a good thing to add this kind of code to dosbox itself, making the number of FPS configurable. I could create such a patch if it were desired by the author. (So that this is not a feature request, just an offer to help ;-))

I've made the changes, very cool (hovewer I've increased fps to 35, 30 seems a little bit slow for Pinball Fantasies).

I've used "SDL_timer.h" instead of "timer.h" and "SDL_GetTicks" instead of "GetTicks".

Could also try enabling ASYNC_BLITS in sdlmain.cpp i think, should help it on some systems that spend too much time blitting the graphics to the screen. Although still have to finish the new vga screen updating to go in the smaller blocks, that's the main cause for stuttering now anyway, especially since we removed the multithreaded display updates.

Thanks Harekiet, I'll try to.

But could you please clarify, how and why the above patch to the mixer code improves sound performance? I mean, if it's not needed, why is it here, and if it's needed, why does DOSBox works without? I couldn't actually understand that from the code.

Ah the sound sound great now! (including midi players with news GUS patches 😁 ).

But I'm curious too, what do these code lines do? Prevent an empty mixer buffer? a full mixer buffer?

Oups sorry I forgot to log on before expressing my joy at hearing fluid sound 😊

Harekiet wrote:

Could also try enabling ASYNC_BLITS in sdlmain.cpp

Can't find it. BTW, does it use blitting in fullscreen too? Isn't it possible to do page flipping?

Is it SDL_ASYNCBLIT, like mentioned in SDL/SDL_video.h ?

Well, I applied the fps patch, but that didnt help. Then I also applied the mixer patch, but that doenst help either.
I also tried frameskip at 1 and 4, cycles at 2500 and 3500 and as soundcard SB (mono, 16 stereo) and GUS. And also the mixer setting 2048 and 4096.

But nothing helped.

I'm using alsa and kernel 2.6.4 on a suse 9.0 box

felix

btw: I'm trying to run the 2nd Reality demo

Everything works fine for me on my 2.6.4 kernel by commenting out the 3 mentioned lines in src/hardware/mixer.cpp. I didn't tried the fps patch though.

Btw, I have a mixer setting of 2048, frameskip at 1 (sometimes 0), cycles between 5000 and 6500 (depends on the game).

I don't know what is 2nd reality, is it a recent game?

Hmm. same thing with 5000 cycles.
2ndReality is a quite old graphic demo. You can get it here:
ftp://ftp.demon.co.uk/pub/ibmpc/dos/apps/demo … ew/2ndreal1.zip

I heard some people reporting it works fine under windows.

felix

Hum... it is quite fluid here(almost no sound stutter with firefox,sylpheed & others in the background), both with SB pro and with GUS (nice demo by the way!).

I also use Alsa for my sound driver (basic via82xx for my laptop), and I often have esd lying around, but no sound problems in dosbox since I commented out the lines in mixer.cpp!

Have you checked the compilations options after you rebuilt dosbox? Without -O option, dosbox can be way slower and if you don't have the latest Opteron...

Damn I was sure I had logged in before replying... Anyway last post is from me 😁

I had to set SDL_AUDIODRIVER=dma to get continuous sound. Kernel 2.6, snd_intel8x0 (alsa) driver.