Fixed bug #698 SDL-1.2
authorSam Lantinga <slouken@libsdl.org>
Mon, 21 Sep 2009 09:27:08 +0000
branchSDL-1.2
changeset 42165b99971a27b4
parent 4215 d83830711a5b
child 4217 4c4113c2162c
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.
src/audio/pulse/SDL_pulseaudio.c
src/audio/pulse/SDL_pulseaudio.h
     1.1 --- a/src/audio/pulse/SDL_pulseaudio.c	Mon Sep 21 09:18:42 2009 +0000
     1.2 +++ b/src/audio/pulse/SDL_pulseaudio.c	Mon Sep 21 09:27:08 2009 +0000
     1.3 @@ -1,4 +1,3 @@
     1.4 -/* -*- Mode: C; c-basic-offset: 8; indent-tabs-mode: t -*- */
     1.5  /*
     1.6      SDL - Simple DirectMedia Layer
     1.7      Copyright (C) 1997-2009 Sam Lantinga
     1.8 @@ -30,6 +29,7 @@
     1.9  #include <unistd.h>
    1.10  #include <signal.h>
    1.11  #include <errno.h>
    1.12 +#include <pulse/pulseaudio.h>
    1.13  #include <pulse/simple.h>
    1.14  
    1.15  #include "SDL_timer.h"
    1.16 @@ -55,6 +55,7 @@
    1.17  static void PULSE_PlayAudio(_THIS);
    1.18  static Uint8 *PULSE_GetAudioBuf(_THIS);
    1.19  static void PULSE_CloseAudio(_THIS);
    1.20 +static void PULSE_WaitDone(_THIS);
    1.21  
    1.22  #ifdef SDL_AUDIO_DRIVER_PULSE_DYNAMIC
    1.23  
    1.24 @@ -74,19 +75,44 @@
    1.25  	int *error
    1.26  );
    1.27  static void (*SDL_NAME(pa_simple_free))(pa_simple *s);
    1.28 -static int (*SDL_NAME(pa_simple_drain))(pa_simple *s, int *error);
    1.29 -static int (*SDL_NAME(pa_simple_write))(
    1.30 -	pa_simple *s,
    1.31 -	const void *data,
    1.32 -	size_t length,
    1.33 -	int *error
    1.34 -);
    1.35 +
    1.36  static pa_channel_map* (*SDL_NAME(pa_channel_map_init_auto))(
    1.37  	pa_channel_map *m,
    1.38  	unsigned channels,
    1.39  	pa_channel_map_def_t def
    1.40  );
    1.41  
    1.42 +pa_mainloop * (*SDL_NAME(pa_mainloop_new))(void);
    1.43 +pa_mainloop_api * (*SDL_NAME(pa_mainloop_get_api))(pa_mainloop *m);
    1.44 +int (*SDL_NAME(pa_mainloop_iterate))(pa_mainloop *m, int block, int *retval);
    1.45 +void (*SDL_NAME(pa_mainloop_free))(pa_mainloop *m);
    1.46 +
    1.47 +pa_operation_state_t (*SDL_NAME(pa_operation_get_state))(pa_operation *o);
    1.48 +void (*SDL_NAME(pa_operation_cancel))(pa_operation *o);
    1.49 +void (*SDL_NAME(pa_operation_unref))(pa_operation *o);
    1.50 +
    1.51 +pa_context * (*SDL_NAME(pa_context_new))(
    1.52 +	pa_mainloop_api *m, const char *name);
    1.53 +int (*SDL_NAME(pa_context_connect))(
    1.54 +	pa_context *c, const char *server,
    1.55 +	pa_context_flags_t flags, const pa_spawn_api *api);
    1.56 +pa_context_state_t (*SDL_NAME(pa_context_get_state))(pa_context *c);
    1.57 +void (*SDL_NAME(pa_context_disconnect))(pa_context *c);
    1.58 +void (*SDL_NAME(pa_context_unref))(pa_context *c);
    1.59 +
    1.60 +pa_stream * (*SDL_NAME(pa_stream_new))(pa_context *c,
    1.61 +	const char *name, const pa_sample_spec *ss, const pa_channel_map *map);
    1.62 +int (*SDL_NAME(pa_stream_connect_playback))(pa_stream *s, const char *dev,
    1.63 +	const pa_buffer_attr *attr, pa_stream_flags_t flags,
    1.64 +	pa_cvolume *volume, pa_stream *sync_stream);
    1.65 +pa_stream_state_t (*SDL_NAME(pa_stream_get_state))(pa_stream *s);
    1.66 +size_t (*SDL_NAME(pa_stream_writable_size))(pa_stream *s);
    1.67 +int (*SDL_NAME(pa_stream_write))(pa_stream *s, const void *data, size_t nbytes,
    1.68 +	pa_free_cb_t free_cb, int64_t offset, pa_seek_mode_t seek);
    1.69 +pa_operation * (*SDL_NAME(pa_stream_drain))(pa_stream *s,
    1.70 +	pa_stream_success_cb_t cb, void *userdata);
    1.71 +int (*SDL_NAME(pa_stream_disconnect))(pa_stream *s);
    1.72 +void (*SDL_NAME(pa_stream_unref))(pa_stream *s);
    1.73  
    1.74  static struct {
    1.75  	const char *name;
    1.76 @@ -96,12 +122,48 @@
    1.77  		(void **)&SDL_NAME(pa_simple_new)		},
    1.78  	{ "pa_simple_free",
    1.79  		(void **)&SDL_NAME(pa_simple_free)		},
    1.80 -	{ "pa_simple_drain",
    1.81 -		(void **)&SDL_NAME(pa_simple_drain)		},
    1.82 -	{ "pa_simple_write",
    1.83 -		(void **)&SDL_NAME(pa_simple_write)		},
    1.84  	{ "pa_channel_map_init_auto",
    1.85  		(void **)&SDL_NAME(pa_channel_map_init_auto)	},
    1.86 +	{ "pa_mainloop_new",
    1.87 +		(void **)&SDL_NAME(pa_mainloop_new)		},
    1.88 +	{ "pa_mainloop_get_api",
    1.89 +		(void **)&SDL_NAME(pa_mainloop_get_api)		},
    1.90 +	{ "pa_mainloop_iterate",
    1.91 +		(void **)&SDL_NAME(pa_mainloop_iterate)		},
    1.92 +	{ "pa_mainloop_free",
    1.93 +		(void **)&SDL_NAME(pa_mainloop_free)		},
    1.94 +	{ "pa_operation_get_state",
    1.95 +		(void **)&SDL_NAME(pa_operation_get_state)	},
    1.96 +	{ "pa_operation_cancel",
    1.97 +		(void **)&SDL_NAME(pa_operation_cancel)		},
    1.98 +	{ "pa_operation_unref",
    1.99 +		(void **)&SDL_NAME(pa_operation_unref)		},
   1.100 +	{ "pa_context_new",
   1.101 +		(void **)&SDL_NAME(pa_context_new)		},
   1.102 +	{ "pa_context_connect",
   1.103 +		(void **)&SDL_NAME(pa_context_connect)		},
   1.104 +	{ "pa_context_get_state",
   1.105 +		(void **)&SDL_NAME(pa_context_get_state)	},
   1.106 +	{ "pa_context_disconnect",
   1.107 +		(void **)&SDL_NAME(pa_context_disconnect)	},
   1.108 +	{ "pa_context_unref",
   1.109 +		(void **)&SDL_NAME(pa_context_unref)		},
   1.110 +	{ "pa_stream_new",
   1.111 +		(void **)&SDL_NAME(pa_stream_new)		},
   1.112 +	{ "pa_stream_connect_playback",
   1.113 +		(void **)&SDL_NAME(pa_stream_connect_playback)	},
   1.114 +	{ "pa_stream_get_state",
   1.115 +		(void **)&SDL_NAME(pa_stream_get_state)		},
   1.116 +	{ "pa_stream_writable_size",
   1.117 +		(void **)&SDL_NAME(pa_stream_writable_size)	},
   1.118 +	{ "pa_stream_write",
   1.119 +		(void **)&SDL_NAME(pa_stream_write)		},
   1.120 +	{ "pa_stream_drain",
   1.121 +		(void **)&SDL_NAME(pa_stream_drain)		},
   1.122 +	{ "pa_stream_disconnect",
   1.123 +		(void **)&SDL_NAME(pa_stream_disconnect)	},
   1.124 +	{ "pa_stream_unref",
   1.125 +		(void **)&SDL_NAME(pa_stream_unref)		},
   1.126  };
   1.127  
   1.128  static void UnloadPulseLibrary()
   1.129 @@ -218,6 +280,7 @@
   1.130  	this->PlayAudio = PULSE_PlayAudio;
   1.131  	this->GetAudioBuf = PULSE_GetAudioBuf;
   1.132  	this->CloseAudio = PULSE_CloseAudio;
   1.133 +	this->WaitDone = PULSE_WaitDone;
   1.134  
   1.135  	this->free = Audio_DeleteDevice;
   1.136  
   1.137 @@ -232,26 +295,25 @@
   1.138  /* This function waits until it is possible to write a full sound buffer */
   1.139  static void PULSE_WaitAudio(_THIS)
   1.140  {
   1.141 -	/* Check to see if the thread-parent process is still alive */
   1.142 -	{ static int cnt = 0;
   1.143 -		/* Note that this only works with thread implementations
   1.144 -		   that use a different process id for each thread.
   1.145 -		*/
   1.146 -		if (parent && (((++cnt)%10) == 0)) { /* Check every 10 loops */
   1.147 -			if ( kill(parent, 0) < 0 ) {
   1.148 -				this->enabled = 0;
   1.149 -			}
   1.150 +	int size;
   1.151 +	while(1) {
   1.152 +		if (SDL_NAME(pa_context_get_state)(context) != PA_CONTEXT_READY ||
   1.153 +		    SDL_NAME(pa_stream_get_state)(stream) != PA_STREAM_READY ||
   1.154 +		    SDL_NAME(pa_mainloop_iterate)(mainloop, 1, NULL) < 0) {
   1.155 +			this->enabled = 0;
   1.156 +			return;
   1.157  		}
   1.158 +		size = SDL_NAME(pa_stream_writable_size)(stream);
   1.159 +		if (size >= mixlen)
   1.160 +			return;
   1.161  	}
   1.162  }
   1.163  
   1.164  static void PULSE_PlayAudio(_THIS)
   1.165  {
   1.166  	/* Write the audio data */
   1.167 -	if ( SDL_NAME(pa_simple_write)(stream, mixbuf, mixlen, NULL) != 0 )
   1.168 -	{
   1.169 +	if (SDL_NAME(pa_stream_write)(stream, mixbuf, mixlen, NULL, 0LL, PA_SEEK_RELATIVE) < 0)
   1.170  		this->enabled = 0;
   1.171 -	}
   1.172  }
   1.173  
   1.174  static Uint8 *PULSE_GetAudioBuf(_THIS)
   1.175 @@ -266,10 +328,19 @@
   1.176  		mixbuf = NULL;
   1.177  	}
   1.178  	if ( stream != NULL ) {
   1.179 -		SDL_NAME(pa_simple_drain)(stream, NULL);
   1.180 -		SDL_NAME(pa_simple_free)(stream);
   1.181 +		SDL_NAME(pa_stream_disconnect)(stream);
   1.182 +		SDL_NAME(pa_stream_unref)(stream);
   1.183  		stream = NULL;
   1.184  	}
   1.185 +	if (context != NULL) {
   1.186 +		SDL_NAME(pa_context_disconnect)(context);
   1.187 +		SDL_NAME(pa_context_unref)(context);
   1.188 +		context = NULL;
   1.189 +	}
   1.190 +	if (mainloop != NULL) {
   1.191 +		SDL_NAME(pa_mainloop_free)(mainloop);
   1.192 +		mainloop = NULL;
   1.193 +	}
   1.194  }
   1.195  
   1.196  /* Try to get the name of the program */
   1.197 @@ -297,12 +368,36 @@
   1.198  	return(progname);
   1.199  }
   1.200  
   1.201 +static void stream_drain_complete(pa_stream *s, int success, void *userdata) {
   1.202 +}
   1.203 +
   1.204 +static void PULSE_WaitDone(_THIS)
   1.205 +{
   1.206 +	pa_operation *o;
   1.207 +
   1.208 +	o = SDL_NAME(pa_stream_drain)(stream, stream_drain_complete, NULL);
   1.209 +	if (!o)
   1.210 +		return;
   1.211 +
   1.212 +	while (SDL_NAME(pa_operation_get_state)(o) != PA_OPERATION_DONE) {
   1.213 +		if (SDL_NAME(pa_context_get_state)(context) != PA_CONTEXT_READY ||
   1.214 +		    SDL_NAME(pa_stream_get_state)(stream) != PA_STREAM_READY ||
   1.215 +		    SDL_NAME(pa_mainloop_iterate)(mainloop, 1, NULL) < 0) {
   1.216 +			SDL_NAME(pa_operation_cancel)(o);
   1.217 +			break;
   1.218 +		}
   1.219 +	}
   1.220 +	SDL_NAME(pa_operation_unref)(o);
   1.221 +}
   1.222 +
   1.223  static int PULSE_OpenAudio(_THIS, SDL_AudioSpec *spec)
   1.224  {
   1.225 +	int             state;
   1.226  	Uint16          test_format;
   1.227  	pa_sample_spec  paspec;
   1.228  	pa_buffer_attr  paattr;
   1.229  	pa_channel_map  pacmap;
   1.230 +	pa_stream_flags_t flags = 0;
   1.231  
   1.232  	paspec.format = PA_SAMPLE_INVALID;
   1.233  	for ( test_format = SDL_FirstAudioFormat(spec->format); test_format; ) {
   1.234 @@ -330,6 +425,9 @@
   1.235  	paspec.rate = spec->freq;
   1.236  
   1.237  	/* Calculate the final parameters for this audio specification */
   1.238 +#ifdef PA_STREAM_ADJUST_LATENCY
   1.239 +	spec->samples /= 2; /* Mix in smaller chunck to avoid underruns */
   1.240 +#endif
   1.241  	SDL_CalculateAudioSpec(spec);
   1.242  
   1.243  	/* Allocate mixing buffer */
   1.244 @@ -341,36 +439,92 @@
   1.245  	SDL_memset(mixbuf, spec->silence, spec->size);
   1.246  
   1.247  	/* Reduced prebuffering compared to the defaults. */
   1.248 +#ifdef PA_STREAM_ADJUST_LATENCY
   1.249 +	paattr.tlength = mixlen * 4; /* 2x original requested bufsize */
   1.250 +	paattr.prebuf = -1;
   1.251 +	paattr.maxlength = -1;
   1.252 +	paattr.minreq = mixlen; /* -1 can lead to pa_stream_writable_size()
   1.253 +				   >= mixlen never becoming true */
   1.254 +	flags = PA_STREAM_ADJUST_LATENCY;
   1.255 +#else
   1.256  	paattr.tlength = mixlen*2;
   1.257 -	paattr.minreq = mixlen;
   1.258  	paattr.prebuf = mixlen*2;
   1.259  	paattr.maxlength = mixlen*2;
   1.260 +	paattr.minreq = mixlen;
   1.261 +#endif
   1.262  
   1.263  	/* The SDL ALSA output hints us that we use Windows' channel mapping */
   1.264  	/* http://bugzilla.libsdl.org/show_bug.cgi?id=110 */
   1.265  	SDL_NAME(pa_channel_map_init_auto)(
   1.266  		&pacmap, spec->channels, PA_CHANNEL_MAP_WAVEEX);
   1.267  
   1.268 +	/* Set up a new main loop */
   1.269 +	if (!(mainloop = SDL_NAME(pa_mainloop_new)())) {
   1.270 +		PULSE_CloseAudio(this);
   1.271 +		SDL_SetError("pa_mainloop_new() failed");
   1.272 +		return(-1);
   1.273 +	}
   1.274 +
   1.275 +	mainloop_api = SDL_NAME(pa_mainloop_get_api)(mainloop);
   1.276 +	if (!(context = SDL_NAME(pa_context_new)(mainloop_api, get_progname()))) {
   1.277 +		PULSE_CloseAudio(this);
   1.278 +		SDL_SetError("pa_context_new() failed");
   1.279 +		return(-1);
   1.280 +	}
   1.281 +
   1.282  	/* Connect to the PulseAudio server */
   1.283 -	stream = SDL_NAME(pa_simple_new)(
   1.284 -		NULL,                        /* server */
   1.285 -		get_progname(),              /* application name */
   1.286 -		PA_STREAM_PLAYBACK,          /* playback mode */
   1.287 -		NULL,                        /* device on the server */
   1.288 +	if (SDL_NAME(pa_context_connect)(context, NULL, 0, NULL) < 0) {
   1.289 +		PULSE_CloseAudio(this);
   1.290 +	        SDL_SetError("Could not setup connection to PulseAudio");
   1.291 +		return(-1);
   1.292 +	}
   1.293 +
   1.294 +	do {
   1.295 +		if (SDL_NAME(pa_mainloop_iterate)(mainloop, 1, NULL) < 0) {
   1.296 +			PULSE_CloseAudio(this);
   1.297 +			SDL_SetError("pa_mainloop_iterate() failed");
   1.298 +			return(-1);
   1.299 +		}
   1.300 +		state = SDL_NAME(pa_context_get_state)(context);
   1.301 +		if (!PA_CONTEXT_IS_GOOD(state)) {
   1.302 +			PULSE_CloseAudio(this);
   1.303 +			SDL_SetError("Could not connect to PulseAudio");
   1.304 +			return(-1);
   1.305 +		}
   1.306 +	} while (state != PA_CONTEXT_READY);
   1.307 +
   1.308 +	stream = SDL_NAME(pa_stream_new)(
   1.309 +		context,
   1.310  		"Simple DirectMedia Layer",  /* stream description */
   1.311  		&paspec,                     /* sample format spec */
   1.312 -		&pacmap,                     /* channel map */
   1.313 -		&paattr,                     /* buffering attributes */
   1.314 -		NULL                         /* error code */
   1.315 +		&pacmap                      /* channel map */
   1.316  	);
   1.317  	if ( stream == NULL ) {
   1.318  		PULSE_CloseAudio(this);
   1.319 -		SDL_SetError("Could not connect to PulseAudio");
   1.320 +		SDL_SetError("Could not setup PulseAudio stream");
   1.321  		return(-1);
   1.322  	}
   1.323  
   1.324 -	/* Get the parent process id (we're the parent of the audio thread) */
   1.325 -	parent = getpid();
   1.326 +	if (SDL_NAME(pa_stream_connect_playback)(stream, NULL, &paattr, flags,
   1.327 +			NULL, NULL) < 0) {
   1.328 +		PULSE_CloseAudio(this);
   1.329 +		SDL_SetError("Could not connect PulseAudio stream");
   1.330 +		return(-1);
   1.331 +	}
   1.332 +
   1.333 +	do {
   1.334 +		if (SDL_NAME(pa_mainloop_iterate)(mainloop, 1, NULL) < 0) {
   1.335 +			PULSE_CloseAudio(this);
   1.336 +			SDL_SetError("pa_mainloop_iterate() failed");
   1.337 +			return(-1);
   1.338 +		}
   1.339 +		state = SDL_NAME(pa_stream_get_state)(stream);
   1.340 +		if (!PA_STREAM_IS_GOOD(state)) {
   1.341 +			PULSE_CloseAudio(this);
   1.342 +			SDL_SetError("Could not create to PulseAudio stream");
   1.343 +			return(-1);
   1.344 +		}
   1.345 +	} while (state != PA_STREAM_READY);
   1.346  
   1.347  	return(0);
   1.348  }
     2.1 --- a/src/audio/pulse/SDL_pulseaudio.h	Mon Sep 21 09:18:42 2009 +0000
     2.2 +++ b/src/audio/pulse/SDL_pulseaudio.h	Mon Sep 21 09:27:08 2009 +0000
     2.3 @@ -32,20 +32,38 @@
     2.4  #define _THIS	SDL_AudioDevice *this
     2.5  
     2.6  struct SDL_PrivateAudioData {
     2.7 -	/* The audio stream handle */
     2.8 -	pa_simple * stream;
     2.9 -
    2.10 -	/* The parent process id, to detect when application quits */
    2.11 -	pid_t parent;
    2.12 +	pa_mainloop *mainloop;
    2.13 +	pa_mainloop_api *mainloop_api;
    2.14 +	pa_context *context;
    2.15 +	pa_stream *stream;
    2.16  
    2.17  	/* Raw mixing buffer */
    2.18  	Uint8 *mixbuf;
    2.19  	int    mixlen;
    2.20  };
    2.21  
    2.22 +#if (PA_API_VERSION < 12)
    2.23 +/** Return non-zero if the passed state is one of the connected states */
    2.24 +static inline int PA_CONTEXT_IS_GOOD(pa_context_state_t x) {
    2.25 +    return
    2.26 +        x == PA_CONTEXT_CONNECTING ||
    2.27 +        x == PA_CONTEXT_AUTHORIZING ||
    2.28 +        x == PA_CONTEXT_SETTING_NAME ||
    2.29 +        x == PA_CONTEXT_READY;
    2.30 +}
    2.31 +/** Return non-zero if the passed state is one of the connected states */
    2.32 +static inline int PA_STREAM_IS_GOOD(pa_stream_state_t x) {
    2.33 +    return
    2.34 +        x == PA_STREAM_CREATING ||
    2.35 +        x == PA_STREAM_READY;
    2.36 +}
    2.37 +#endif	/* pulseaudio <= 0.9.10 */
    2.38 +
    2.39  /* Old variable names */
    2.40 +#define mainloop		(this->hidden->mainloop)
    2.41 +#define mainloop_api		(this->hidden->mainloop_api)
    2.42 +#define context			(this->hidden->context)
    2.43  #define stream			(this->hidden->stream)
    2.44 -#define parent			(this->hidden->parent)
    2.45  #define mixbuf			(this->hidden->mixbuf)
    2.46  #define mixlen			(this->hidden->mixlen)
    2.47