ASIO was not created at MS. It was actually created by the many high end audio editing software companies. It came about as there was a desparate need for a low latency, non-buffered, synchronous, sound API for Windows.
When you edit sound, unlike video, you only have a time cue to work with. There is no accurate visual indicator, like video, to tell if you are in sync or not with the other tracks.
The best side effect of ASIO was it was the first API which allowed 96Khz sampled music to play accurately on a reasonably fast system. It also allowed low overhead for the decoding of Dolby tracks in movies and for that audio to be played very precisely with the video content.
What happens without ASIO, is those packages revert to lower sample rates/slower streams in order to make up for the longer delays in audio playback.
Compromises in the video and audio will be done in order to keep it synchronized. As all versions of Windows sound API's treat audio as asynchronous events, another method to provide a synchronous event was/is needed. These are the original reasons ASIO came to exist. To solve those problems.
So, MS could never add DRM, and so they figured out how to prevent ASIO from being added to Vista. What they did not know, was that most sound card companies had been using ASIO to play all the audio in Windows for some time now. It simply worked better than the sound system in Windows. With lower overhead, and faster throughputs, audio suddenly became smoother, with less audio being dropped in games, for example.
So back to your original question. DRM, for audio, would only come into play for recording. And it would only effect recording through the digital inputs of the audio card. And in that specific instance, DRM can be by-passed for audio using ASIO.
Now, piracy of audio never made use of ASIO in the past. And that is because you can simply copy the data from a CD, without having to resort to playing and recording it on your computer.
But, with the advent of HD content. You will no longer be able to copy that data from the media to your hard drive. And as it is encrypted, you simply cannot extract the audio trackes from the media like you can from a normal DVD. So, if you want to copy the audio, you have to play it back and record it. ASIO would have allowed that to happen.
This is what I have been stressing about DRM. It only effects HD content, directly. Indirectly, everything in your computer has to pass through that additional layer of software. Which, of course, slows down everything to some degree.
