Re: Coreaudio-api Digest, Vol 11, Issue 143
Re: Coreaudio-api Digest, Vol 11, Issue 143
- Subject: Re: Coreaudio-api Digest, Vol 11, Issue 143
- From: Robert Carroll <email@hidden>
- Date: Fri, 29 Aug 2014 18:53:49 -0400
| If you want sample accurate timing, I think you will have to get inside the callback and track the sample time.
Once you have that, its relatively straight forward to trigger the first part of a sampled sound, or a synthesized sound. The audioGraph sample code (extended from MixerHost) on GitHub would be a good place to start.
rob
Robert Carroll RSM Records Toronto
Message: 3
Date: Wed, 27 Aug 2014 17:21:00 -0400
From: "Mazzaroth M." <email@hidden>
To: coreaudio-api <email@hidden>
Subject: schedule silence of n length
Message-ID:
<CALYQoYBiYXqNmyQ0D4LsgY11pD55Au+Z=email@hidden>
Content-Type: text/plain; charset="utf-8"
Hi, I have a simple AUGraph with a AUFilePlayer and DefaultOutput node. I
schedule playback of a short sample from a file. I'd like schedule a brief
gap of silence after that, then schedule the sample again. I'm basically
making a simple metronome and the length of the gap of silence should be
configurable. I'm not sure how to do this. Here is a snippet of how I
schedule the original file:
UInt64 nPackets;
UInt32 propsize = sizeof(nPackets);
CheckError(AudioFileGetProperty
(player_->inputFile, kAudioFilePropertyAudioDataPacketCount,
&propsize, &nPackets),
"AudioFileGetProperty[kAudioFilePropertyAudioDataPacketCount] failed");
// set the start frame to the new position. position_ is always 0.
player_->startFrame = _audioFileInfo.frames * position_;
ScheduledAudioFileRegion rgn;
memset (&rgn.mTimeStamp, 0, sizeof(rgn.mTimeStamp));
rgn.mTimeStamp.mFlags = kAudioTimeStampSampleTimeValid;
rgn.mTimeStamp.mSampleTime = 0;
rgn.mCompletionProc = NULL;
rgn.mCompletionProcUserData = NULL;
rgn.mAudioFile = player_->inputFile;
rgn.mLoopCount = -1;
rgn.mStartFrame = player_->startFrame;
rgn.mFramesToPlay = _audioFileInfo.frames - player_->startFrame;
NSLog(@" %ld mFramesToPlay | @ rgn.mStartFrame %qd |
player_->totalFrames: %llu | player_->startFrame: %f", (long
int)rgn.mFramesToPlay, rgn.mStartFrame, _audioFileInfo.frames,
player_->startFrame);
regards,
Michael |
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