ASIO4ALL - Universal ASIO Driver For WDM Audio |
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UFAQ (Ultra Frequently Asked Question): Why does the latency display in some applications (e.g. Cubase) appear to be incorrect with ASIO4ALL 2.0? A: Because it is supposed to be more correct than with 1.x. Really! The values displayed there are the values ASIO4ALL reports for the purpose of latency compensation. This means that recorded audio can be aligned perfectly with the rest and if that does not work out of the box, you can use the "Latency Compensation" sliders in the advanced section of the control panel to make it perfect! Assuming this is set up correctly, the sum of the input and output latencies indicate the actual physical time audio takes to travel from the input jacks of your sound device to the output (also called "round trip latency".) This includes any hardware inherent delay as well as delays in the Windows kernel or elsewhere. Earlier versions did not provide this facility. You may have noticed that in some instances the displayed output latency does not increase with buffer size as expected. This is normal and reflects what truely happens. Assume a buffer one second worth of samples, for instance, that is being sent to the driver for playback. If output latency would linearly increase with the buffer size, this buffer would be played back only one second after it has been sent. But this is not what happens - playback starts almost instantaneously after the buffer is sent. Therefore, the _perceived_ latency when e.g. playing a VSTi, which linearly increases with the ASIO buffer size is not the same as the latency that the ASIO driver needs to report to the host application for compensation purposes. The _perceived_ latency for any given buffer size has _not_ changed since ASIO4ALL 1.8! You can verify this and even apply neccesary corrections by connecting the outputs of your audio card with the inputs and bouncing a single pulse - or a percussive sound - through it. Then inspect the alignment of the recorded wave form relative to the original wave form. If there is any difference, this can be compensated with the "Latency Compensation" sliders mentioned above. Since it is hard to tell whether the difference is in the input or the output path, it would be prudent to adjust both sliders by half of the difference each. This information will be included into the ASIO4ALL documentation in future versions. |
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ASIO is a trademark of Steinberg Media Technologies GmbH. Everything else on this page, including the numbers 16, 48 and 100 is or may become a trademark of Microsoft, Corp., except for trademarks of their respective owners that are used for product identification purposes only. The rest, as well as the stuff mentioned above that has not yet become a trademark of Microsoft, Corp. is Copyright(c)2003-2004, Michael Tippach. |