Hi all,
I develop an Audio Unit of the ‘aufx’ type that requires to read some data
ahead, e.g. to output N frames I need 2 * N frames.
I have a class derived from AUBase with the overloaded AUBase::Render
> OSStatus DeclipUnit::Render(AudioUnitRenderActionFlags &ioActionFlags,
> const AudioTimeStamp &inTimeStamp,
> UInt32 nFrames)
and have the following snippet of code in it. I simplified the code, actually I
need to buffer several packets before applying an effect. Here I just
demonstrate the problem:
> newTimeStamp.mSampleTime += nFrames;
> result = m_pMainInput->PullInput(ioActionFlags, newTimeStamp, 0, nFrames);
> if (result != noErr)
> return result;
where m_pMainInput == GetInput(0);
so I pull from the upstream object the same amount of frames but at another
timestamp. Then I initialize the output buffers like this:
> m_pMainOutput->PrepareBuffer(nFrames);
and fill them with data, for simplicity like this:
> for (UInt32 channel = 0; channel <
> GetOutput(0)->GetStreamFormat().mChannelsPerFrame; ++channel)
> {
> const AudioBuffer *srcBuffer =
> &m_pMainInput->GetBufferList().mBuffers[channel];
> const AudioBuffer *dstBuffer =
> &m_pMainOutput->GetBufferList().mBuffers[channel];
>
> memcpy(dstBuffer->mData, srcBuffer->mData, srcBuffer->mDataByteSize);
> }
This works pretty well in the AULab application but auval tool fails with the
following error:
> Input Format: AudioStreamBasicDescription: 2 ch, 44100 Hz, 'lpcm'
> (0x00000029) 32-bit little-endian float, deinterleaved
> Output Format: AudioStreamBasicDescription: 2 ch, 44100 Hz, 'lpcm'
> (0x00000029) 32-bit little-endian float, deinterleaved
> Render Test at 512 frames
> ERROR: AU is not passing time stamp correctly. Was given: 0, but input
> received: 512
>
> * * FAIL
> --------------------------------------------------
> AU VALIDATION FAILED: CORRECT THE ERRORS ABOVE.
> --------------------------------------------------
If I remove the line that changes the timestamp and call just
> result = m_pMainInput->PullInput(ioActionFlags, newTimeStamp, 0, nFrames);
> if (result != noErr)
> return result;
then auvall validates my plugin successfully. So I’m pretty sure that auval
concerns that my Audio Unit pulls data from a different timestamp. I found a
property that looks like to what I need to make auval sure that all is fine
with the timestamps: kAudioUnitProperty_InputSamplesInOutput
but auval never sets this property for my audio unit, so it looks useless.
Does anybody know if reading data at appropriate timestamps is possible for
‘aufx’ audio units? I tried to look at ‘auol’ (offline) units, but they seem to
be of no use, at least neither AULab, nor Final Cut Pro uses this type of audio
units.
--
Please help!
Roman _______________________________________________
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