Re: Can't have AudioServer properly get the list of available formats
Re: Can't have AudioServer properly get the list of available formats
- Subject: Re: Can't have AudioServer properly get the list of available formats
- From: Jeff Moore <email@hidden>
- Date: Tue, 12 Mar 2013 12:39:58 -0700
The only rules for the physical format list are that the formats all be legal and that the physical format list be the same as the virtual format list. The HAL doesn't really care what the actual details of the formats are.
FWIW, I was able to add a third format to the format lists that SA_Device implements without much trouble. Note that there are some details you might have missed when you tried it. For example, in the implementation of GetPropertyData for kAudioStreamPropertyAvailablePhysicalFormats, you need to make sure that the variable theNumberItemsToFetch is clamped at 3 and not 2. Also, you need to update the implementation of kAudioDevicePropertyAvailableNominalSampleRates to also supply 3 values (44.1k, 48k, 88.2k) rather than just 2 values.
At any rate, one thing you haven't mentioned yet is exactly how things are going wrong for apps. For example, what physical formats does HALLab show for the streams on your device compared to what they should be showing?
--
Jeff Moore
Core Audio
Apple
On Mar 12, 2013, at 12:05 PM, Eric Gorouben <email@hidden> wrote:
> Of course, I've hit "send" too quickly for this mail... sorry about that.
> However, my question would be: are there specific rules for the stream formats, compared to a HAL plugin?
> I can't get my formats to get displayed and I don't find the reason.
>
> Thanks
> Eric
> Le 12 mars 2013 à 19:44, Eric Gorouben <email@hidden> a écrit :
>
>> Hi,
>>
>> I'm implementing the kAudioStreamPropertyAvailablePhysicalFormats and kAudioStreamPropertyAvailableVirtualFormats properties. For some reason, this doesn't seem to work.
>> As an experiment, I modified my source to use the SA_Plugin values (the 2 44.1 & 48k formats). No problem.
>> I then modified it to have 3 formats (i.e. change the data size, and add a third format with a 88200 Hz sample rate
>> if(theNumberItemsToFetch > 2)
>> {
>> ((AudioStreamRangedDescription*)outData)[1].mFormat.mSampleRate = 88200.0;
>> ((AudioStreamRangedDescription*)outData)[1].mFormat.mFormatID = kAudioFormatLinearPCM;
>> ((AudioStreamRangedDescription*)outData)[1].mFormat.mFormatFlags = kAudioFormatFlagIsSignedInteger | kAudioFormatFlagsNativeEndian | kAudioFormatFlagIsPacked;
>> ((AudioStreamRangedDescription*)outData)[1].mFormat.mBytesPerPacket = 4;
>> ((AudioStreamRangedDescription*)outData)[1].mFormat.mFramesPerPacket = 1;
>> ((AudioStreamRangedDescription*)outData)[1].mFormat.mBytesPerFrame = 4;
>> ((AudioStreamRangedDescription*)outData)[1].mFormat.mChannelsPerFrame = 2;
>> ((AudioStreamRangedDescription*)outData)[1].mFormat.mBitsPerChannel = 16;
>> ((AudioStreamRangedDescription*)outData)[1].mSampleRateRange.mMinimum = 88200.0;
>> ((AudioStreamRangedDescription*)outData)[1].mSampleRateRange.mMaximum = 88200.0;
>> }
>>
>> ).
>> I get completely wrong results and AudioServer seems lost and gives the applications inconsistent values.
>> I'm stuck on this problem. What did I miss?
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