Fixed bug #698 Hans de Goede 2009-02-13 01:10:52 PST Since the new "glitch free" version of pulseaudio (used in Fedora 10 amongst others), the sound of SDL using apps (like a simple playmus call) has been crackling. While looking in to fixing this I noticed that the current pulseaudio code in SDL uses pa_simple. However pa_simple uses a thread to pump pulseaudio events and ipc, given that SDL already has its own thread for audio handling this is clearly suboptimal, leading to unnecessary context switching IPC, etc. Also pa_simple does not allow one to implement the WaitAudio() callback for SDL audiodrivers properly. Given that my work is mostly a rewrite (although some original pieces remain) I'm attaching the new .c and .h file, as that is easier to review then the huge diff. Let me know if you also want the diff. This new version has the following features: -no longer use an additional thread next to the SDL sound thread -do not crackle with glitch free audio -when used with a newer pulse, which does glitch free audio, the total latency is the same as with the alsa driver -proper WaitAudio() implementation, saving another mixlen worth of latency -adds a WaitDone() implementation This patch has been written in consultancy with Lennart Poetering (the pulseaudio author) and has been reviewed by him for correct use of the pa API.

/* Simple test of the SDL threading code and error handling */

#include <stdio.h>
#include <stdlib.h>
#include <signal.h>

#include "SDL.h"
#include "SDL_thread.h"

static int alive = 0;

/* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */
static void quit(int rc)
{
	SDL_Quit();
	exit(rc);
}

int SDLCALL ThreadFunc(void *data)
{
	/* Set the child thread error string */
	SDL_SetError("Thread %s (%d) had a problem: %s",
			(char *)data, SDL_ThreadID(), "nevermind");
	while ( alive ) {
		printf("Thread '%s' is alive!\n", (char *)data);
		SDL_Delay(1*1000);
	}
	printf("Child thread error string: %s\n", SDL_GetError());
	return(0);
}

int main(int argc, char *argv[])
{
	SDL_Thread *thread;

	/* Load the SDL library */
	if ( SDL_Init(0) < 0 ) {
		fprintf(stderr, "Couldn't initialize SDL: %s\n",SDL_GetError());
		return(1);
	}

	/* Set the error value for the main thread */
	SDL_SetError("No worries");

	alive = 1;
	thread = SDL_CreateThread(ThreadFunc, "#1");
	if ( thread == NULL ) {
		fprintf(stderr, "Couldn't create thread: %s\n", SDL_GetError());
		quit(1);
	}
	SDL_Delay(5*1000);
	printf("Waiting for thread #1\n");
	alive = 0;
	SDL_WaitThread(thread, NULL);

	printf("Main thread error string: %s\n", SDL_GetError());

	SDL_Quit();
	return(0);
}