3 ms·

I Dunno. "The main aim of the PREEMPT_RT patch is to minimize the amount of kernel code that is non-preemptible", that's nice and all, but there are still no gu

I Dunno. "The main aim of the PREEMPT_RT patch is to minimize the amount of kernel code that is non-preemptible", that's nice and all, but there are still no guarantees, which (in some interpretation of "real time") a RTOS is all about. For some applications the effort might suffice, but others will insist on those guarantees. For music recordings, I (perhaps naively) would expect a decent audio card with its own processor and (RT) firmware would yield better results.

cwillu 2y ago
I can easily manage several instruments at 1.3ms latency while still using my machine for gaming and such on this patchset without more than the occasional xrun, where the same machine can barely manage 10ms latency if I don't have _anything_ running but the audio applications. Something doesn't have to be perfect to enable a usage.
jpc0 2y ago
> For music recordings, I (perhaps naively) would expect a decent audio card with its own processor and (RT) firmware would yield better results. And is commonly used in high end professional settings for audio... I'm not speaking against the above comment. Audio is hard, but purely because of the timelines required with extremely low buffer sizes. It's pretty common to be running at buffer sizes at 256 samples or lower... However on a modern processor thats very low latency... At 48000 samples per second a buffer of 256 samples would generally give you a latency of 5ms give or take... But that also gives you 5ms to do all processing of that buffer which can be significant as was mentioned above. Honestly though in my experience, FPGAs are the way to go for super low latency audio, most modern implementations are measured in micro seconds for processing stages. The problem is you have to do all the processing on the FPGA since any round trip to the CPU would take eons compared. Avid HDX is the pricy but industry standard for studio and post production work. There are other options but because most people don't need them so they aren't popular, most people are fine with restricting processing during recording which is when the latency is important and then when producing and mixing latency could be several hundred ms and you don't care... Source: me, professional audio "engineer" with over a decade in the industry who has recorded multiple commercially successful albums, ad spots, generic corporate videos, radio spots and entire radio shows etc...
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cwillu 2y ago

I can easily manage several instruments at 1.3ms latency while still using my machine for gaming and such on this patchset without more than the occasional xrun, where the same machine can barely manage 10ms latency if I don't have _anything_ running but the audio applications. Something doesn't have to be perfect to enable a usage.

jpc0 2y ago

> For music recordings, I (perhaps naively) would expect a decent audio card with its own processor and (RT) firmware would yield better results. And is commonly used in high end professional settings for audio... I'm not speaking against the above comment. Audio is hard, but purely because of the timelines required with extremely low buffer sizes. It's pretty common to be running at buffer sizes at 256 samples or lower... However on a modern processor thats very low latency... At 48000 samples per second a buffer of 256 samples would generally give you a latency of 5ms give or take... But that also gives you 5ms to do all processing of that buffer which can be significant as was mentioned above. Honestly though in my experience, FPGAs are the way to go for super low latency audio, most modern implementations are measured in micro seconds for processing stages. The problem is you have to do all the processing on the FPGA since any round trip to the CPU would take eons compared. Avid HDX is the pricy but industry standard for studio and post production work. There are other options but because most people don't need them so they aren't popular, most people are fine with restricting processing during recording which is when the latency is important and then when producing and mixing latency could be several hundred ms and you don't care... Source: me, professional audio "engineer" with over a decade in the industry who has recorded multiple commercially successful albums, ad spots, generic corporate videos, radio spots and entire radio shows etc...

deleted 2y ago
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