Re: [Alsa-user] Route input to output with minimal latency
On Thu, 20 Jul 2017 18:14:07 +, Robert Bielik wrote: >No, software input to output, i.e. capture data and send to playback >directly with minimal latency. > >But I realize that mmapping is not possible since capture and playback >device will have separate buffers, so I still have to copy from >capture to playback buffers. I don't know to what "zero-copy" in the description refers to, but even if there should be the need to copy, I doubt that latency caused by such copies would be an issue, at least not for a negligible amount of IOs. I guess if latency isn't caused by audio hardware, than usually by the signal processing of applications, but unlikely by the routing. However, I never programmed using ALSA and my audio recording experiences are from decades ago. I was just surprised about the < 1 ms, since I would expect software side this shouldn't be an issue. I might be mistaken. -- Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot ___ Alsa-user mailing list Alsa-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/alsa-user
Re: [Alsa-user] Route input to output with minimal latency
On Thu, 20 Jul 2017 17:47:17 +, Robert Bielik wrote: >I want to route input to output with minimal possible latency, this >will run on a Raspberry Pi, and the latency should be < 1 ms. > >I was thinking... if the ALSA capture and playback device is mmapped >to the same buffer area, this should be dealt with automatically. Is >this possible ? http://www.alsa-project.org/alsa-doc/alsa-lib/pcm.html I wonder if you are mistaking apples for oranges. Do you want to connect the audio device's hardware outputs with the audio device's hardware inputs with cables or do you want to connect software outputs with software inputs? -- Vote for apulse! echo $(w3m https://aur.archlinux.org/packages/apulse |grep 'Votes:') Votes: 86 Updated: Thu Jul 20 20:07:37 CEST 2017 -- Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot ___ Alsa-user mailing list Alsa-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/alsa-user
[Alsa-user] Route input to output with minimal latency
Hi all, I want to route input to output with minimal possible latency, this will run on a Raspberry Pi, and the latency should be < 1 ms. I was thinking... if the ALSA capture and playback device is mmapped to the same buffer area, this should be dealt with automatically. Is this possible ? Regards /Robert -- Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot ___ Alsa-user mailing list Alsa-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/alsa-user
