Alexander Carôt wrote: >> If I understand your question correctly, it is because they use two >> different buffers. If you aren't trying to play the capture buffer, it >> would wreak havoc to try to use it for playback while capture is going >> on. So there is a buffer for capture and a buffer for playback. And >> each has a latency. Someone who understands the system better might be >> able to give a better explanation, or even suggest a workaround. >> > > Sure - there is one input double buffer and one output double buffer. However, I wonder if there is a way to (somehow) get rid of the latter. > > The idea is the following : > > 1.) Of course there has to be an input double buffer which generates the desired block of samples. > 2.) Once this is generated it takes 2,6 ms to generate the next one. > 3.) Rather than using a double buffer for the playout wouldn't it be possible to choose only one physical playout buffer and parse the captured data in right at the interrupt. > > Or would this approach lead to timing and synchronisation problems ? I can see that either a parsing slightly too fast or too slow would result in wrong data but anyway - just an idea. What do you think ? > I think you would have to customize the driver to do this. In the special case that you are playing back the recorded input, you write the input buffer directly to the output buffer every time the input buffer interrupts because it is time to empty it. Adds an extra branch in the driver logic, and it has to know things outside of kernel space that it doesn't know now. Or if you are only going to use the card this way, you always do it. No need for extra branch or state knowledge. Hey, if you are going to customize drivers, why not make them really specific? :-) The idea that Florian suggested, shrinking the latency by shrinking the callback interval and increasing the frame rate is easier from user space. ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://sourceforge.net/services/buy/index.php _______________________________________________ Alsa-user mailing list Alsa-user@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-user
