Mercurial > almixer_isolated

changeset 48:00b770b0d2aa

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Workaround: There is a terrible OpenAL regression bug in iOS 5 dealing with streaming sources. alSourcei(source_id, AL_BUFFER, AL_NONE); fails to clear queued buffer queues on a streaming source. The workaround involves manually dequeuing the individual buffers before calling alSourcei(source_id, AL_BUFFER, AL_NONE);. But there is an additional race condition bug where the unqueue fails to take, so the included workaround keeps looping until the buffers finally report as cleared. The current check is compiled only for iOS and does a runtime version check against CoreFoundation version 674.0. When Apple finally ships a fix, this fix should be amended to not run on fixed versions. Also ironically, it was originally the Apple Mac OpenAL implementation that had a problem with buffer unqueuing which ultimately led to the use of alSourcei(source_id, AL_BUFFER, AL_NONE); This is another reason the workaround is only constrained to iOS. In some cases I've seen, the buffer unqueue also triggers OpenAL errors, however, the current workaround seems to usually avoid those OpenAL errors (even though the buffers fail to unqueue some times). The 20ms sleep seems to avoid the race condition entirely, but when it doesn't, the sleep seems to do something that magically avoids tripping OpenAL errors.
author Eric Wing <ewing@anscamobile.com>
date Fri, 30 Sep 2011 16:44:08 -0700
parents 9b772c81b550
children 4b0268d86298
files ALmixer.c
diffstat 1 files changed, 156 insertions(+), 132 deletions(-) [+]
line wrap: on
line diff
--- a/ALmixer.c	Thu Sep 29 11:33:34 2011 -0700
+++ b/ALmixer.c	Fri Sep 30 16:44:08 2011 -0700
@@ -1692,6 +1692,147 @@
 }
 
 
+static ALboolean Internal_DetachBuffersFromSource(ALuint source_id, ALboolean is_predecoded)
+{
+	ALboolean retval = AL_TRUE;
+	ALint buffers_processed;
+	ALenum error;
+	/* Here's the situation. My old method of using
+	 * alSourceUnqueueBuffers() seemed to be invalid in light
+	 * of all the problems I suffered through with getting 
+	 * the CoreData backend to work with this code.
+	 * As such, I'm changing all the code to set the buffer to
+	 * AL_NONE. Furthermore, the queued vs. non-queued issue
+	 * doesn't need to apply here. For non-queued, Loki,
+	 * Creative Windows, and CoreAudio seem to leave the 
+	 * buffer queued (Old Mac didn't.) For queued, we need to 
+	 * remove the processed buffers and force remove the
+	 * still-queued buffers.
+	 * Update: This code is was changed agian due to a serious regression bug in iOS 5.0
+	 * Since the 1.1 spec, I think I can make some simplifying assumptions sans the iOS 5.0 bug.
+	 * Before I looked at buffers_still_queued and buffers_processed.
+	 * According to the spec, all buffers get marked processed when alSourceStop is called.
+	 * Also, in addition, alSourcei(source, AL_BUFFER, AL_NONE) is supposed
+	 * to detach buffers for both streamed and non-streamed so all the code
+	 * should just go through that.
+	 * Unfortunately, the iOS 5.0 bug doesn't detach/clear buffers with AL_NONE.
+	 * So I need a special handler for iOS 5.0 which manually unqueues the buffers.
+	 * Ironically, I think the original Mac version did not work reliably
+	 * with unqueuing buffers which is why I moved the code to the AL_NONE
+	 * solution in the first place. This means for safety, I need to
+	 * conditionalize the workaround as not to risk breaking Mac or other * platforms.
+	 */
+#ifdef __APPLE__  /* iOS 5.0 workaround */
+	#if (TARGET_OS_IPHONE == 1) || (TARGET_IPHONE_SIMULATOR == 1)
+	/*
+		fprintf(stderr, "kCFCoreFoundationVersionNumber: %lf\n", kCFCoreFoundationVersionNumber);
+	 */
+		/* I needed a C way to get the iOS version at runtime. This is returning 674.0 iOS 5.0 Beta 7. Apple hasn't updated the headers
+		 * for these constants since iOS 4.2, so I don't know if the value is also catching 4.3.
+		 * TODO: Once I learn which version Apple fixes the bug in, I need to update the range so this check is not run on fixed versions.
+		 */
+		if(kCFCoreFoundationVersionNumber >= 674.0)
+		{
+			if(AL_FALSE == is_predecoded)
+			{
+				ALint buffers_processed;
+				/* Wow this is the bug that just keeps on sucking. There is even a race condition bug where the unqueue may not actually work. 
+				 * So I have to keep doing it until it does.
+				 */
+				do
+				{
+					ALint temp_count;
+					
+					/* Wow this is the bug that just keeps on sucking. There is even a race condition bug where the unqueue may not actually work. 
+					 * So I have to keep doing it until it does.
+					 * Sleeping for 20ms seems to help. 10ms was not long enough. (iPad 2)
+					 */
+					ALmixer_Delay(20);
+
+					alGetSourcei(
+						source_id,
+						AL_BUFFERS_PROCESSED, &buffers_processed
+					);
+					if((error = alGetError()) != AL_NO_ERROR)
+					{
+						fprintf(stderr, "17aTesting Error with buffers_processed on Halt. (You may be seeing this because of a bad Apple OpenAL iOS 5.0 regression bug): %s",
+							alGetString(error));
+						ALmixer_SetError("Failed detecting still processed buffers: %s",
+							alGetString(error) );
+						/* This whole iOS 5.0 bug is so messed up that returning an error value probably isn't helpful.
+						retval = AL_FALSE;
+						*/
+					}
+					/*
+					fprintf(stderr, "Going to unqueue %d buffers\n", buffers_processed);
+					 */
+					for(temp_count=0; temp_count<buffers_processed; temp_count++)
+					{
+						ALuint unqueued_buffer_id;
+
+						alSourceUnqueueBuffers(
+							source_id,
+							1, &unqueued_buffer_id
+						);
+						if((error = alGetError()) != AL_NO_ERROR)
+						{
+							fprintf(stderr, "17bTesting error with unqueuing buffers on Halt (You may be seeing this because of a bad Apple OpenAL iOS 5.0 regression bug): %s\n",
+								alGetString(error));				
+							/* This whole iOS 5.0 bug is so messed up that returning an error value probably isn't helpful.
+							 retval = AL_FALSE;
+							 */
+						}
+					}
+					
+					alGetSourcei(
+								 source_id,
+								 AL_BUFFERS_PROCESSED, &buffers_processed
+								 );
+					if((error = alGetError()) != AL_NO_ERROR)
+					{
+						fprintf(stderr, "17cTesting Error with buffers_processed on Halt. (You may be seeing this because of a bad Apple OpenAL iOS 5.0 regression bug): %s",
+								alGetString(error));
+						ALmixer_SetError("Failed detecting still processed buffers: %s",
+										 alGetString(error) );
+						/* This whole iOS 5.0 bug is so messed up that returning an error value probably isn't helpful.
+						 retval = AL_FALSE;
+						 */
+					}
+					/*
+					fprintf(stderr, "unqueued buffers should be 0. Actual value is %d\n", buffers_processed);
+					*/
+					/* Wow this is the bug that just keeps on sucking. There is an additional race condition bug where the unqueue may not actually work. 
+					 * So I have to keep doing it until it does.
+					 * I hope this doesn't infinite loop.
+					 */
+					if(0 != buffers_processed)
+					{
+						fprintf(stderr, "Evil Apple OpenAL iOS 5.0 race condition. Buffers didn't actually unqueue. Repeating unqueue loop.\n");
+					}
+				} while(0 != buffers_processed);
+
+			}
+		}		
+	
+
+	#endif
+#endif /* iOS 5.0 workaround */
+
+		/* According to the spec, this is the best way to clear a source. 
+		 * This is supposed to work for both streamed and non-streamed sources. 
+		 */
+		alSourcei(source_id, AL_BUFFER, AL_NONE);
+		if((error = alGetError()) != AL_NO_ERROR)
+		{
+			fprintf(stderr, "17dTesting Error with clearing buffer from source: %s",
+				alGetString(error));
+			ALmixer_SetError("Failed to clear buffer from source: %s",
+				alGetString(error) );
+			retval = AL_FALSE;
+		}
+
+		return retval;
+}
 
 /* Will return the number of channels halted
  * or 0 for error
@@ -1701,8 +1842,7 @@
 	ALint retval = 0;
 	ALint counter = 0;
 	ALenum error;
-	ALint buffers_still_queued;
-	ALint buffers_processed;
+	ALboolean clear_succeeded;
 
 	if(channel >= Number_of_Channels_global)
 	{
@@ -1721,59 +1861,13 @@
 				fprintf(stderr, "14Testing error: %s\n",
 					alGetString(error));				
 			}
-			/* Here's the situation. My old method of using
-			 * alSourceUnqueueBuffers() seemed to be invalid in light
-			 * of all the problems I suffered through with getting 
-			 * the CoreData backend to work with this code.
-			 * As such, I'm changing all the code to set the buffer to
-			 * AL_NONE. Furthermore, the queued vs. non-queued issue
-			 * doesn't need to apply here. For non-queued, Loki,
-			 * Creative Windows, and CoreAudio seem to leave the 
-			 * buffer queued (Old Mac didn't.) For queued, we need to 
-			 * remove the processed buffers and force remove the
-			 * still-queued buffers.
-			 */
-			alGetSourcei(
-				ALmixer_Channel_List[channel].alsource,
-				AL_BUFFERS_QUEUED, &buffers_still_queued
-			);
-			if((error = alGetError()) != AL_NO_ERROR)
+
+			clear_succeeded = Internal_DetachBuffersFromSource(ALmixer_Channel_List[channel].alsource, ALmixer_Channel_List[channel].almixer_data->decoded_all);
+			if(AL_FALSE == clear_succeeded)
 			{
-				fprintf(stderr, "17Testing Error with buffers_still_queued: %s",
-					alGetString(error));
-				ALmixer_SetError("Failed detecting still queued buffers: %s",
-					alGetString(error) );
 				retval = -1;
 			}
-			alGetSourcei(
-				ALmixer_Channel_List[channel].alsource,
-				AL_BUFFERS_PROCESSED, &buffers_processed
-			);
-			if((error = alGetError()) != AL_NO_ERROR)
-			{
-				fprintf(stderr, "17Testing Error with buffers_processed: %s",
-					alGetString(error));
-				ALmixer_SetError("Failed detecting still processed buffers: %s",
-					alGetString(error) );
-				retval = -1;
-			}
-			/* If either of these is greater than 0, it means we need
-			 * to clear the source
-			 */
-			if((buffers_still_queued > 0) || (buffers_processed > 0))
-			{
-				alSourcei(ALmixer_Channel_List[channel].alsource,
-					AL_BUFFER,
-					AL_NONE);
-				if((error = alGetError()) != AL_NO_ERROR)
-				{
-					fprintf(stderr, "17Testing Error with clearing buffer from source: %s",
-						alGetString(error));
-					ALmixer_SetError("Failed to clear buffer from source: %s",
-						alGetString(error) );
-					retval = -1;
-				}
-			}
+			
 
 			ALmixer_Channel_List[channel].almixer_data->num_buffers_in_use  = 0;
 
@@ -1801,60 +1895,12 @@
 						alGetString(error));				
 				}
 
-				/* Here's the situation. My old method of using
-				 * alSourceUnqueueBuffers() seemed to be invalid in light
-				 * of all the problems I suffered through with getting 
-				 * the CoreData backend to work with this code.
-				 * As such, I'm changing all the code to set the buffer to
-				 * AL_NONE. Furthermore, the queued vs. non-queued issue
-				 * doesn't need to apply here. For non-queued, Loki,
-				 * Creative Windows, and CoreAudio seem to leave the 
-				 * buffer queued (Old Mac didn't.) For queued, we need to 
-				 * remove the processed buffers and force remove the
-				 * still-queued buffers.
-				 */
-				alGetSourcei(
-					ALmixer_Channel_List[i].alsource,
-					AL_BUFFERS_QUEUED, &buffers_still_queued
-				);
-				if((error = alGetError()) != AL_NO_ERROR)
+				clear_succeeded = Internal_DetachBuffersFromSource(ALmixer_Channel_List[i].alsource, ALmixer_Channel_List[i].almixer_data->decoded_all);
+				if(AL_FALSE == clear_succeeded)
 				{
-					fprintf(stderr, "17Testing Error with buffers_still_queued: %s",
-						alGetString(error));
-					ALmixer_SetError("Failed detecting still queued buffers: %s",
-						alGetString(error) );
 					retval = -1;
 				}
-				alGetSourcei(
-					ALmixer_Channel_List[i].alsource,
-					AL_BUFFERS_PROCESSED, &buffers_processed
-				);
-				if((error = alGetError()) != AL_NO_ERROR)
-				{
-					fprintf(stderr, "17Testing Error with buffers_processed: %s",
-						alGetString(error));
-					ALmixer_SetError("Failed detecting still processed buffers: %s",
-						alGetString(error) );
-					retval = -1;
-				}
-				/* If either of these is greater than 0, it means we need
-				 * to clear the source
-				 */
-				if((buffers_still_queued > 0) || (buffers_processed > 0))
-				{
-					alSourcei(ALmixer_Channel_List[i].alsource,
-						AL_BUFFER,
-						AL_NONE);
-					if((error = alGetError()) != AL_NO_ERROR)
-					{
-						fprintf(stderr, "17Testing Error with clearing buffer from source: %s",
-							alGetString(error));
-						ALmixer_SetError("Failed to clear buffer from source: %s",
-							alGetString(error) );
-						retval = -1;
-					}
-				}
-				
+			
 				ALmixer_Channel_List[i].almixer_data->num_buffers_in_use  = 0;
 
 				/* Launch callback for consistency? */
@@ -5173,36 +5219,11 @@
 						}
 						if(buffers_still_queued > 0)
 						{
-
-#if 0 /* This triggers an error in OS X Core Audio. */
-							alSourceUnqueueBuffers(
-								ALmixer_Channel_List[i].alsource,
-								1, 
-								ALmixer_Channel_List[i].almixer_data->buffer
-							);
-#else
-/*							fprintf(stderr, "In the Bob Aron section...about to clear source\n");
-							PrintQueueStatus(ALmixer_Channel_List[i].alsource);
-*/							
-							/* Rather than force unqueuing the buffer, let's see if
-							 * setting the buffer to none works (the OpenAL 1.0 
-							 * Reference Annotation suggests this should work).							 
-							 */
-							alSourcei(ALmixer_Channel_List[i].alsource,
-										AL_BUFFER, AL_NONE); 
-							/*
-							PrintQueueStatus(ALmixer_Channel_List[i].alsource);
-							*/	
-#endif								
-							if((error = alGetError()) != AL_NO_ERROR)
+							ALboolean clear_succeeded = Internal_DetachBuffersFromSource(ALmixer_Channel_List[i].alsource, ALmixer_Channel_List[i].almixer_data->decoded_all);
+							if(AL_FALSE == clear_succeeded)
 							{
-		fprintf(stderr, "Error with unqueue, after alSourceUnqueueBuffers, buffers_still_queued=%d, error is: %s", buffers_still_queued,
-								alGetString(error));
-								ALmixer_SetError("Predecoded Unqueue buffer failed: %s",
-									alGetString(error) );
 								error_flag--;
 							}
-
 						}
 						
 						/* Launch callback */
@@ -6238,8 +6259,11 @@
 								* setting the buffer to none works (the OpenAL 1.0 
 								* Reference Annotation suggests this should work).								 
 								*/
-								alSourcei(ALmixer_Channel_List[i].alsource,
-										  AL_BUFFER, AL_NONE); 
+								ALboolean clear_succeeded = Internal_DetachBuffersFromSource(ALmixer_Channel_List[i].alsource, ALmixer_Channel_List[i].almixer_data->decoded_all);
+								if(AL_FALSE == clear_succeeded)
+								{
+									error_flag--;
+								}
 	/*							
 								PrintQueueStatus(ALmixer_Channel_List[i].alsource);
 	*/