ASIO Sound Access

[FrankH]

Hi All!

 

Since LabVIEW uses only Windows MME driver for sound in and out, I'm looking for an other way to get sound data into LabVIEW with much less latency.

 

Has someone use ASIO4ALL for audio input?

 

For sound out I use Midi via MME and the Windows own synthesizer. Its latency is really not high. But the input data comes with some hundred milliseconds lateness.

 

With MME: I tested on 2 systems. About 350ms latency and not really depending of the system load. I tried also with small sample packages of 600 and 1200 byte/chn and a sound card acquisition rate of 96kS/s. In order to collect this data amount the time what the PC needs should be theoretical 6,25/12,5ms plus data transfer time and some reaction times of the system modules. But the response time of MME seems in-depending on it. It needs always around 320...380ms. And the processor load was very low.

 

Maybe someone can help me to use a faster software interface (ASIO?).

 

Best greetings,

Frank

[Rolf Kalbermatter]

Hi All!

 

Since LabVIEW uses only Windows MME driver for sound in and out, I'm looking for an other way to get sound data into LabVIEW with much less latency.

 

Has someone use ASIO4ALL for audio input?

 

For sound out I use Midi via MME and the Windows own synthesizer. Its latency is really not high. But the input data comes with some hundred milliseconds lateness.

 

With MME: I tested on 2 systems. About 350ms latency and not really depending of the system load. I tried also with small sample packages of 600 and 1200 byte/chn and a sound card acquisition rate of 96kS/s. In order to collect this data amount the time what the PC needs should be theoretical 6,25/12,5ms plus data transfer time and some reaction times of the system modules. But the response time of MME seems in-depending on it. It needs always around 320...380ms. And the processor load was very low.

 

Maybe someone can help me to use a faster software interface (ASIO?).

 

Best greetings,

Frank

 

It's a long time that I looked at ASIO. It appeared to to be a somewhat old fashioned API that wasn't interfacable to LabVIEW without a good intermediate shared library layer. If it would support low latencies is beyond my knowledge and also if it would be naturally achievable or if the intermediate layer would have to jump through several hoops and loops to support that. MME or more correctly DirectX as is used at least by the second versioun of the Sound APIs can be used for much less than 300 ms latency too, but you have to do some serious effort for that, something the NI developers didn't feel like doing, which is understandable as NI is in the business of selling high quality data acquisition hardware for that purpose.

 

Anyhow that project did finally not go anywhere as the effort for the ASIO interface was considered to expensive in relation to the rest of the project and buying NI hardware was simply cheaper than the combined costs of a high performance ASIO based audio interface hardware and the development cost of the LabVIEW ASIO interface.

 

Also you need to understand that ASIO is some sort of pseudo standard, proposed by one party in the field, with several others adopting it more or less accurately, with the less being in vast majority.

[Reds]

Hi FrankH - can you provide an update?  Were you able to use ASIO drivers with LabVIEW?  I am also working on an application that requires low latency sound output.  Thanks.

[viSci]

You might look into this library...

 

http://www.zeitnitz.de/Christian/waveio?mid=9