Thanks David for your comments and suggestions. >Even if using push mode, wouldn't the timer interrupt be running >for each streaming device? Doesn't the timer interrupt act just >like a hardware interrupt with regard to the CPU state? From my understanding, the system timer is a single piece of hardware shared by all the audio engine instances, so in push mode there's only one actual hardware interrupt per polling interval regardless of how many instances there are. >Having written drivers for radio station automation systems in >the past, having any glitches in the audio would be a problem for >station running 24/7. Pull mode does give a more 'hardwired' >connection between the hardware position and the software >streaming engine. It just makes me 'feel better' to know that >the hardware is controlling the position instead of the >software guessing. Our cards are radio receivers, principally used for broadcast logging, not as on-air program source. In any case, though, in push mode it's still the hardware determining the stream position through its position registers, the only difference is that the registers are polled asynchronously to the audio stream. The benefit of pull mode is that it allows smaller buffers to be used, giving lower latency, but that isn't a requirement here. Provided the buffers are big enough in push mode to allow for the asynchronous timing, there shouldn't be glitches, and we haven't had any glitch problems in systems running on Vista (push mode only). >Is ASIO an option? That would give a single hardware interrupt >at the bufferSwitch point for all the channels and bypasses >everything Microsoft so you don't have to worry about a system >sound from an error dialog box interrupting the on-air audio. >No worrying about something in the streaming engine resampling >the audio or having to worry about the two extra limiters >that are put into the audio stream whether you want them or not. >Exclusive mode fixes most of that... :-) OK, I admit that I am >an ASIO evangelist. With one exception, we only provide the hardware, with our customers choosing whatever recording software they want to use, so unless all that software was ASIO compatible, it wouldn't be a solution. Also, in the case of the DAB+ card, the number of stations can vary dynamically as services are added or removed, and I'm not sure if ASIO would handle that. Jeff ****************** WDMAUDIODEV addresses: Post message: mailto:wdmaudiodev@xxxxxxxxxxxxx Subscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=subscribe Unsubscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=unsubscribe Moderator: mailto:wdmaudiodev-moderators@xxxxxxxxxxxxx URL to WDMAUDIODEV page: http://www.wdmaudiodev.com/