• Open Menu Close Menu
  • Apple
  • Shopping Bag
  • Apple
  • Mac
  • iPad
  • iPhone
  • Watch
  • TV
  • Music
  • Support
  • Search apple.com
  • Shopping Bag

Lists

Open Menu Close Menu
  • Terms and Conditions
  • Lists hosted on this site
  • Email the Postmaster
  • Tips for posting to public mailing lists
Anyone had this kind of Audio Echo problem???
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Anyone had this kind of Audio Echo problem???


  • Subject: Anyone had this kind of Audio Echo problem???
  • From: Marc Van Olmen <email@hidden>
  • Date: Fri, 28 Jan 2005 21:46:38 -0500

Hi,

I have a problem with my application, and I'm not sure it is my fault, the driver, coreAudio or the hardware.

My software plays back audio/video I'm doing all these things by my self, coreAudio and video I use QuickTime vOut and I send the frames by myself one by one to the video card.

I'm using DeckLink Extreme card and 2.5 Ghz G5 latest MacOSX.

I'm playing 3 clips: one clip is about 30 seconds, 2nd clip is 1.5 second other one is .5 second. I'm looping these 3 clips endlessly.

On certain configurations (1.8 ghz G5) there is no problem but on my I have the following problem:

The problem manifest themselves in 2 ways:

1. The Audio suddenly jumps (I haven't heard/seen the jump) but after looking at the clips being played the audio has jumped for 1 second (backwards) (almost it is a little bit less). The gap doesn't increase it stays the same.
I have discussed this issue before this week. But now I noticed a second kind of error.


2. The audio is being echoed. I hear the audio twice with second one in one second delay.

So i recorded some audio of the result that comes out the Decklink Video Card:

So I uploaded a good sound which is about 58 seconds that I recorded:

http://www.sky4studios.com/goodaudio.mov

and I uploaded one with the Echo.

http://www.sky4studios.com/badaudio.mov


Question 1:
===========
Is it possible that coreAudio causes this kind of problem or would this be more a driver/hardware issue?
I currently tried this with the "Built In Audio" output but never had this issue,... but that's not really a proof the problem can take some hours before it happens...


Question 2:
===========
Has any one suggestions on how I can trace this issue to figure out what's going on. Currently the only idea I have is to copy the samples that I'm sending to the coreAudio "AudioBufferList" and store them to disk. But anyone else suggestions.



Regards and thanks for any feedback,

Marc Van Olmen

ps:


More Technical details about coreAudio:


I upgraded my coreAudio calls to V2 API after Williams Stewart suggestions of last week.



desc.componentType = kAudioUnitType_Output;
desc.componentSubType = kAudioUnitSubType_HALOutput;// kAudioUnitSubType_DefaultOutput; kAudioUnitSubType_HALOutput
desc.componentManufacturer = kAudioUnitManufacturer_Apple;
desc.componentFlags = 0;
desc.componentFlagsMask = 0;
comp = FindNextComponent(NULL, &desc);
BAIL_NULL(comp);
BAIL_OSERROR(OpenAComponent(comp, &fOutputAudioUnit));

if (aDeviceID != kAudioDeviceUnknown) {
//Set the Current Device to the Default Output Unit.
BAIL_OSERROR(AudioUnitSetProperty(fOutputAudioUnit,
kAudioOutputUnitProperty_CurrentDevice,
kAudioUnitScope_Global,
0,
&aDeviceID,
sizeof(aDeviceID)));
}


		BAIL_OSERROR(AudioUnitInitialize(fOutputAudioUnit));

		// Get the format that the AudioUnit expects us to give it
		input.inputProc = cNode_AudioOutput::DoAudioOutputCallback;
		input.inputProcRefCon = this;
		BAIL_OSERROR(AudioUnitSetProperty(	fOutputAudioUnit,
											kAudioUnitProperty_SetRenderCallback,
											kAudioUnitScope_Global,
											0,
											&input,
											sizeof(input)));
	

_______________________________________________
Do not post admin requests to the list. They will be ignored.
Coreaudio-api mailing list      (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden


  • Follow-Ups:
    • Re: Anyone had this kind of Audio Echo problem???
      • From: Marc Van Olmen <email@hidden>
  • Prev by Date: Re: Regarding 'VU meter' object
  • Next by Date: The Missing 'Secret Sauce' Headers
  • Previous by thread: Re: Music Device and channel handshake
  • Next by thread: Re: Anyone had this kind of Audio Echo problem???
  • Index(es):
    • Date
    • Thread